4.0 OHV Timing Cover & Gasket Issues | Ford Explorer Forums - Serious Explorations

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4.0 OHV Timing Cover & Gasket Issues


Explorer Addict
June 6, 2005
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City, State
East Bay - Nor Cal / PRK
Year, Model & Trim Level
'98 Spt 4.0 OHV 5 spd 4x4
My 98 Ex Sport 4.0 OHV has reached 203,000 Miles.

7 years / 40,000 Miles ago, due to an Anti-Freeze Leak on the Driver's Side, I replaced the Timing Cover Gasket on my 4.0 OHV, and wrote an extensive write up on it.

LINK: Removing timing cover on 4.0 OHV

History: The entire time I've owned my Ex, it has never leaked oil. To clarify, it's weeped oil, but never leaked oil to the point where it left small puddles on the garage floor.

Specific Problem: Recently, my Ex has suffered a pretty major oil leak from the Timing Cover.It drips down from the Timing Cover, and leaves small puddles of oil on the garage floor.

In short, I think the OEM FORD Green Teflon Coated Timing Cover Gasket slipped down, and allowed oil to leak.

If you look carefully at the two pictures BELOW, the chopstick is pointing to where the the oil leak is starting from. Note that the Timing Cover Gasket is not exposed past the Timing Cover. In effect, it has "sucked below" below the timing cover between the 2nd and 3rd bolt from the top Timing Cover Bolt, on the Passenger Side.



The picture BELOW shows where the Timing Cover Gasket has "bowed" outwards, within the valley that is to release Anti Freeze when your timing Cover Gasket has reached the end of it's service life. It's my feeling that that the Timing Cover Gasket gasket is bowing outwards indicates that the Timing Chain Cover and Gasket are shifting down towards the ground.

Seven years ago when I replaced the Timing Cover Gasket, there was next to no info on the internet about this procedure on a 4.0 OHV. To this day, there is still next to nothing. So I fell back on my shade tree mechanic skills/experience; First I cleaned all of the gasket mating surfaces on the block and timing cover. Since the gasket is Teflon coated, there was very little to clean on BOTH the block and the Timing Cover.

Then, I cleaned out all of the timing cover bolt holes with spray parts cleaner, chased them with a tap, and then blew out the holes with compressed air. I followed this up with cleaning all of the bolt threads with a wire brush, cleaned the threads with parts cleaner, and then wiped them down with a high-nap cotton towel.

On the five oil pan holes/bolts that mate to the bottom of the Timing Cover, all that was required was to spray clean out the five oil pan bolt holes with parts cleaner, and stick a clean Q-Tip in each hole to clean/dry it out. The five oil pan bolts were cleaned with parts cleaner, and dried off with a high-nap cotton towel.

REASSEMBLY: The reassembly was as follows. First, I installed the timing cover and timing cover gasket. I torqued them in a "star" type order like you would a wheel, so as to evenly distribute the load - i.e. bottom left, top right, top left, bottom right. I torqued all bolts in three stages, first to seven pounds, then to eleven pounds, and finally at 15 lb ft. ALL bolts were dry = no oil & no threadlock/loctite. Also, The Block sealing surface and Timing Cover sealing surface were left DRY (NO OIL) This is how the Original Engine left the factory and lasted 13 years / 165,000 Miles before the gasket failed, and anti-freeze leaked from the Timing Cover Leak Channels. Remember, the OEM Gasket is Teflon Coated, and that's what I used when I repaired my Ex the First Time.

Second, I installed the five bottom oil pan bolts, and torqued them down in two stages, 1st 3lb ft then 7lb ft.
All five bolts were dry (No oil & no threadlock).

Observation & Ultimate Question
* To date I haven't found a write-up on replacing the 4.0 OHV Timing Cover Gasket as extensive as what I originally wrote. Hence my wanting to get all this info out there as I feel that this is easily a 400,000 Mile motor (if properly maintained).

* Since having this Timing Cover oil leak, I've found online articles on other engines (i.e small block Ford 302 and Cummings Diesel) that have timing cover oil leaks, with timing cover construction similar to the Ford/Cologne 4.0 OHV (a Timing Cover with a Water Pump mounted on the front = high weight load, high heat cycles, and lots of vibration).

* With the ABOVE point in mind, I've read well-written articles talking about two significant differences with regards to how I made my original repair.

A) 1st = Torque the Oil Pan Bolts FIRST (pulling the Timing Cover DOWN), and then torque the Timing Cover 2nd.

This method/order of operation takes care of the "gravity factor" first,
and then connects the Timing Cover to the engine block.

B) Using Thread Lock - Loctite BLUE - on BOTH the Oil Pan Bolts and the Timing Cover Bolts to deal with the weight of the Water Pump hanging off of the timing cover, the heat cycles of the Water Pump, and the vibration of the Water Pump.

So - what say you?

  • Have you ever done this repair and experienced what I have experienced = gasket slipping DOWN?!
  • What do you think about torquing down the Oil Pan 1st, and the Timing Cover 2nd?
  • Have you used thread locker / Loctite Blue on the Timing Cover & Oil Pan Bolts with success?
  • Any and all comments are welcome!

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Thank's! Nice write up with pic's,I'm going to save this Post for future references.Hopefully others will chime in with some tips.

Thank's! Nice write up with pic's,I'm going to save this Post for future references.Hopefully others will chime in with some tips.

A little late, but here's the write up.

So I took out the radiator, alternator, idler assembly, fan, water pump, and here we are at the final stage.

I have an old section of molded heater hose that used to go from the water pump to the heater vacuum operated heater valve. The Outer Diameter of this hose is a perfect "snug" fit to stick through the water passage holes and into the block. It's duct taped to the hose of my Harbor Freight wet/dry vacuum. Turn on the vacuum, and suck out all of the remaining anti-freeze in the block, so it doesn't contaminate the motor oil in the pan when the Timing Cover is removed. Works like a charm ;-)



I took the Timing Cover off, and this is what I found.
A cracked & torn Timing Cover Gasket at exactly the point where I had the oil leak.

REMEMBER: The Timing Cover is shown FACE DOWN.



I cleaned and prepped the block bolt holes and bolts (see 1st post in this thread as well as the original write up), and for this reinstall, based on my internet research, I chose to do three things differently this time around from my first write up.

1st) I used Loctite Blue on ALL of the bolts. In my first write up - all bolts were installed "dry".

2nd) I torqued down the (5) Oil Pan Bolts FIRST. This was done in two sequences.

3rd) I torqued down the Timing Cover Bolts SECOND. This was done in three sequences. I used a black "sharpie" and made a "hash mark" next to each bolt so that I didn't lose track. I used a quasi "X" pattern when tightening the bolts (bottom left/top right) (top left/bottom right) and so on so that the torque was evenly distributed across the Timing Chain Cover.

When done, I chose to let the mounted Timing Chain Cover sit overnight so that the Loctite on the bolts could could cure, and the following morning I installed the water pump and all the sub assemblies.

I hope that this write up saves someone the headache I experienced!

Nice write up, hopefully I never have to change this gasket but if I do I'll look back at this post ...

Very good writeup.

I'm not a fan of those thin teflon coated gaskets. Upon reassembly I coated the gaskets (front and back) with Permatex aviation gasket sealer. Same with the water pump gasket. Used black Permates sealant at the cover/oil pan interface.

Absolutely no sign of leaks or seepage after about 3 years and 20K miles.

Good tip on torqueing the pan bolts first. I don't remember if I did it that way, but it makes sense considering the weight/forces/vibration on the timing cover.

Just joined this forum yesterday. Great info thanks! I'm in the middle of this exact job and appreciate the advice.

While I'm in there I figured I'd change out all the timing chain stuff. After reading a bunch of posts on this forum and others online I'm glad I have the OHV and not the SOHC when it comes to the timing chain. Taking the engine out of the car was not going to be an option.
I have a couple questions however. I'm not sure when I may get an answer but I'll try and see...
Engine: 1995 4.0 OHV 6cyl, 4WD, Automatic, 192k mi
The timing cover gasket that was on there was the green original.
It blew out but on a 25mph residential street where I could stop immediately so things didn't massively overheat.
1. There is some minor (but noticeable) pitting on both the timing cover gasket face and the engine gasket face near the coolant ports on either side. Not right up to the lip...but within 1/8 of an inch. They are definitely not mirror finish. I'm hoping some RTV and the gasket may negate that?
2. I've seen some youtube videos of people re-using that Harmonic Balancer bolt but then I read that it's a "torque to yield" bolt and shouldn't be re-used. Not sure how much they are...but is that absolutely necessary to get a new one?
3. The radiator was gunked up. looked like someone put brown playdoh in there. (got a new one) But....I was wondering if there would be back pressure from trying to push through all that crap and may have helped to blow out the weak part of the gasket?
ok. I'll see wait and see if anyone responds.
Thanks again. I'm hoping by joining this forum I can get 300,000 out of this engine like I hear some people get. The car was my Dad's so I don't want to get rid of it.


Welcome FlipPhoneHoldOut.
I too changed out the timing chain and gears. It quietened the engine considerably. My chain had worn into the plastic guide and did have a bit of slack in it, enough to cause a slight rattle sometimes. I noticed the new chain guide had a weaker spring, probably to alleviate that wear problem. I believe I used Sealed Power parts, and Fel-Pro gaskets.

Adding RTV to pitted gasket surfaces is an acceptable solution. I installed the cover gasket with Aviation sealant on both surfaces just as a precaution, but I don't remember if they were pitted or not.....probably not bad or I would remember.
Many folks reuse the harmonic balancer bolt, but I used a new one. Don't remember where I got it, but it's a Ford item which I couldn't find in the aftermarket. Your local Ford dealer will have them, and $6-$8 comes to mind for the pricing. I used blue thread locker on this bolt, and probably did on the others too. Can't hurt.

The balancer is a tight fit on the crankshaft, and you don't want to use a hammer. I placed my new balancer in direct sunlight for a few hours before installation, and it slid on easily,. (You'd be surprised how warm this gets it.)

Good luck, and let us know how it goes...

@ FlipPhoneHoldOut

No Problem - glad my write-up is helping you enter into this repair.
My responses to your questions are written below, in larger font.

1. There is some minor (but noticeable) pitting on both the timing cover gasket face and the engine gasket face near the coolant ports on either side. Not right up to the lip...but within 1/8 of an inch. They are definitely not mirror finish. I'm hoping some RTV and the gasket may negate that?

Your situation is totally different than mine (in my write ups). Specifically, you have pitting on BOTH the block gasket surface & timing cover gasket surface. SO the following info is offered with the thought of saving/reusing your original timing cover.

OK - the OEM/FORD/German gasket is thin and teflon coated, and won't work properly with your pitted parts. It's made to work with finely machined FLAT surfaces. The gasket isn't thick enough to swell and fill in pitted surfaces. It'll break before that occurs (as was your experience - backpressure in your cooling system had nothing to do with it).

With that in mind, if I were you, I'd buy an AFTERMARKET thick paper gasket (i.e. Mahle JV1139 for $9.31 from Rock Auto). Mahle was the OEM manufacturer of the FORD Green Teflon Gasket, and it will be a perfect fit - therefore I don't recommend the Fel-Pro offering.

Clean the timing cover gasket surfaces with Scotchbrite Red Pad wrapped around a piece of cut 2 X 4 that's essentially a "block". That way you don't round the gasket surfaces OR make high and low spots.

Don't be tempted to use a a steel brush on the Timing Cover - it's too aggressive on the aluminum...

BUT - You can use a
FINE steel brush from Harbor Freight on the cast iron block gasket surface.

Clean ALL of the gasket surfaces with Lacquer Thinner and a high-nap clean rag. If you can't get it, Brake/Parts cleaner will work - but in YOUR CASE, the LT is preferred - you NEED to really clean out those pits so that the Ultra Copper RTV has a clean surface to "glue" to.

When cleaned, use Permatex Copper Coat RTV on both sides of the paper gasket. Essentially, since you're re-using pitted parts, you need to do two things; fill in all the pits & glue everything together.

NOTE: Permatex Ultra Copper is TOP DOG on the RTV chart - don't save a buck or two and buy any of the lower grades of RTV. It'll fill in the pits and hold fast - provided you do your prep work properly. You're entering into a job where 80% of your outcome will depend on you taking your time, and doing the proper & necessary prep work.

Rock Auto Link: 1995 FORD EXPLORER 4.0L V6 Timing Cover Gasket / Set | RockAuto

2. I've seen some youtube videos of people re-using that Harmonic Balancer bolt but then I read that it's a "torque to yield" bolt and shouldn't be re-used. Not sure how much they are...but is that absolutely necessary to get a new one?

This is the LEAST of your problems ;) Seriously - Don't worry about re-using the TTY Harmonic Balancer Bolt. It's very large diameter and not going to break in your lifetime. I've re-used mine based on the many successful reports of others, and have taken it off & reused it twice now - no signs of stress/cracks/imminent failure.

3. The radiator was gunked up. looked like someone put brown playdoh in there. (got a new one) But....I was wondering if there would be back pressure from trying to push through all that crap and may have helped to blow out the weak part of the gasket?
ok. I'll see wait and see if anyone responds.

Waaaayyyy back in the day, my HS Auto Shop teacher used to preach: Coolant (and lubricants) are the lifeblood of your engine and they're cheap - change them often. You're now seeing what occurs when that isn't followed.

With that said, again - if I were you and putting the time into this, I'd add to your new radiator a NEW water pump, fan clutch, thermostat, radiator cap and Upper & Lower hoses.Change out your Coolant a few times over a year period until it looks good. TIP: Buy Coolant CONCENTRATE at Walmart. Cut it to 50/50 with Deionized water (do not use tap water). In the end, you'll get 2 Gallons of 50/50 coolant for the price they sell 1 gallon of 50/50 pre-mixed. Now you see how you can afford to change your coolant a few times over a year to get rid of the crud :thumbsup:

OH - with regards to the crud in your cooling system. If anyone suggests back-flushing your cooling system (and adding flushing chemicals such as with a PRESTONE kit that cuts "t" into your heater line) I don't recommend it. Back-flushing (and chemicals) MIGHT damage your 24 year old heater core - and then you'll be in a world of pain, pulling your dashboard & pad, dealing with dried out vacuum lines, fragile plastic vacuum tees, and miles of wiring...

Thanks again. I'm hoping by joining this forum I can get 300,000 out of this engine like I hear some people get. The car was my Dad's so I don't want to get rid of it.

Thanks for the well-written post and report back - we'll get you through it. Hope we can get you to 400,000 :chug:

PS - Make sure you follow the order of operations laid out in my 2nd posting regarding torqueing the oil pan bolts that go into the bottom of the timing cover FIRST, before torquing the timing cover "face" bolts.

Mahle JV1139

Permatex Ultra Copper RTV

Amazon Link for Ultra Copper @ $4.35 a tube



Here's a 5% off discount code from Rock Auto

5% Discount Code: 7218F8D293D908
Expires: October 23, 2019


+1 on the ultra copper and reusing the harmonic balancer bolt ....I did twice....
If anyone hasn't said this change your oil afterwards obviously but I would just put like 2 quarts in the pan then empty it out just to get anything that's left in there out my two cents
Good luck

ok wow...excellent advice here thank you!
There's going to be a slight delay in the project because turns out they gave me the wrong lower sprocket in the timing set and the other place that I was getting the radiator from "lost my order" and now it will be getting here after the weekend.
oh boy.
Luckily I have a 2000 chevy blazer (also close to 200k mi) a friend loaned me indefinitely (had to fix that one first...just a bad rear caliper and chewed up rotor, but it'll have major issues soon no doubt) Plan for the next year is to go back and forth...fix one...drive the other...that one breaks....fire up the other....repeat until one has a catastrophically expensive failure Money is a little tight at the moment. I'm going to learn alot about these cars. Which I guess....is not a bad thing. For the amount of swearing I do while working on the cars you'd think I hate doing it...but I actually like it.
One day I'll do it because I WANT to not because I HAVE to though...hopefully.

First...again everyone..thank you very much..lots of great info here. Much appreciated!
I will try putting the balancer in the sun prior to install.....it WAS a tight fit coming off. If that helps getting it back on...so much the better.
Yes, I didn't think to cover the opening to the oil pan and all kinds of little bits of stuff fell in there. (Plus the crank key - which had to be fished out with a magnet.) I actually thought of getting some cheap oil and doing exactly what you suggest. pour it in...and then...drain it right out just to clean out the crap. Then do a full oil change when this is done.

Radiator- Along with the radiator, I did go in for the upper and lower hoses and the thermostat and cap. (there is alot of "as long as I'm in there" on this project) and that seemed like a good idea.
I changed out the water pump just 3 years ago and looking close at it now (I left it on the cover)...it doesn't seem to have leaks so that part should be ok I'm hoping.
I did not think about the fan clutch though...that's also probably a good idea.
Gaskets - I got the felpro gasket. But I will be getting the Mahle- sounds like I'll be glad I did.
Thanks for the link! Man that's a good price on that set!
RTV - I do have a tube of the Ultra Copper from the water pump job so....that's good.
I was worried about those pits and so....too much cleaning is not enough cleaning on the gasket faces it sound like. I'll do the red scotchbrite with a block method and the LT.....I'm seeing that cleaning the gasket surfaces takes LONGER than getting the cover off of there! At least it wasn't a ton of RTV (like I'm about to do! ha hopefully for the last time) that teflon gasket came off pretty easy. Still stuff to clean up, but not the nightmare the water pump gasket was a few years ago. It had become part of the metal it seemed.
Bolt - I'll be reusing the original. That is good news.
Torque Sequence - Will be following that advice for sure. That reminds me though, I've been looking for the torque specs for the timing kit, and actually...for the whole deal....timing cover, timing kit etc. I'm sure that's on this forum somewhere but I didn't find it yet. There is probably a link that has all that info no doubt.

Another Question:
In relation to torquing....holding stuff stationary while I torque things like the top cam sprocket bolt and the balancer.
I made a tool (basically a stout piece of wood with 2 stubby bolts sticking through it at the same space as the holes in the cam sprocket) and WAS going to put that in there when I tightened that thing down and the balancer. I know that at that point there is just that metal "nub" sticking into the keyway on the back of that thing taking the force. But I figured the engine would crank it harder than that. is there a "normal" way to do that?
Off to the parts store to get them to order the right sprocket.
meanwhile....Oh yea...I have to work.
Once again.....THANKS FOR ALL THE INFO!!!
one of these days maybe I'll be able to contribute some useful answers!
I'll post my progress.


Don't know if you realize it, but there is an ORIGINAL post that answers many of the questions that you have.

The post that you've started this thread with is the UPDATE to the ORIGINAL.

Here's the link to the ORIGINAL: Removing timing cover on 4.0 OHV

Good Luck!

aha! no I did not see that thread thanks for the link!
I'll be reading all that.
One thing...I found out that even though my explorer is a 95, looks like the timing chain set is for a 93. There is NO keyway on the lower sprocket so they gave me the correct set for a 95, but....for whatever reason, I've got a 93 set up in there?
everything fits perfect except there is no locking "nub" on the back of the 95 lower sprocket.
I see why they updated that, it made no sense to have to take the key out when it could slide over it and lock on the key at the same time.
However...the 93 set is 30 dollars more. I believe I will use the old lower sprocket. It looks pretty good. Frankly..it all looks good...I just figured I'd change it "as long as I was in there". I don't know for sure of course...but I doubt that sprocket will fail.
thanks again.


I had a feeling that you didn't see that link posted in the 3rd sentence of the update posting ;)

TIP: Anywhere you see BLUE LETTERING in these forum posts, those are LINKS you can "left click on once" for further information. Hope that helps.

NOTE: I can't tell you about a '95 because I have a '98.

BUT - what I can tell you from the years on this forum is that '95's are a "one year" for many parts - i.e. the Camshaft Position Sensor Assembly that is at the rear of the engine, where the Distributor Assembly used to be. It's a one year only part, and every few months (as they die) it's brought up in forum discussions under "how do I source this"?!?!

With that in mind - you might want to peruse the Rock Auto Catalog, specifically the pictures for the '95 Timing Parts you are thinking of replacing.

Rock Auto has an excellent catalog of the actual part you are buying from them; they are very good at showing the pictures of the parts AND when you look at the "picture box" that the picture is in, if you see red arrows to the left and right hand side of the box, click on the arrows to get different views of that particular part. I hope that makes sense.

I didn't need to replace my timing chain assembly so the issues you're having - I haven't experienced first hand.

Hopefully between Rock Auto's Catalog, and the knowledge base here on the forum, your questions can be answered.

BTW - I can supply you with torque numbers for your parts - but they'll be from a 98 Explorer Shop Book. I imagine though that they shouldn't be too different from a '95 - but I dunno' :dunno: I'll give 'em to you tonite/this weekend as I read that you're not involve in the repair yet.

Ok..back at it.
Got my gaskets from Rock Auto today.
But as I'm really cleaning things it's looking not so good. I didn't think the pitting was so bad at first but now I'm not sure. Couple of questions before I keep going.

Question 1.
This is either side coolant port of the cover gasket facing.
Is there enough RTV in the world to make this thing hold water if the cover face looks like this?
Would I be wasting my time putting this back on? The engine facing is a little better than this. But as I'm getting everything completely off of there...it doesn't look fantastic either. That part I don't think I have any choice with but this part I do.
Screen Shot 2019-09-17 at 3.46.03 PM.png
Screen Shot 2019-09-17 at 3.46.16 PM.png

Question 2.
I have a crank seal from another gasket set and the one from Rock auto. They look very different.
The Rock Auto seal has a metal outer part (the blue) but the FelPro is all rubber (gray).
either one of these better than the other?
Screen Shot 2019-09-17 at 3.54.31 PM.png

Question 3.
This also came with the Felpro set. What is it and where does this go?
Screen Shot 2019-09-17 at 3.57.36 PM.png

time to look around the web and see how much timing covers are just in case.
thanks again for any advice!

I have never owed an 4.0L OHV (and it's likely I never will) so I have not spent a lot of time reading this entire thread. However, perhaps I can offer a little insight I learned during many years while working on BMW air-cooled motorcycle engines in the 70's and 80's.

Different metals expand/contract at different rates. BWM motor cycle engines had aluminum engine blocks with iron cylinders and aluminum heads. They used a flat steel gasket at the base of the cylinder where it was bolted to the block sealed with a special BMW propitiatory sealant. I found that the cylinder's would always start seeping/leaking oil after around 7,000 miles. This was because the cylinders would "walk around" on the engine block as the two metals heated up and expanded at different rates. I used to be as OCD about my motorcycles as I am about my vehicles and hated always seeing oil leaked at the base of the cylinders. I tried different sealants, but the result was always the same.

I read where the OP used a Teflon coated gasket on the timing cover. No doubt this gasket was coated in Teflon to allow the aluminum timing cover to move around on the cast iron block without leaking. I guess eventually the Teflon wears out and the gasket sticks to one side, or the other, pushing out or sucking in the gasket. Anyway, that's mt 2 cents.

For whoever asked about the below part,,, It's called a quick sleeve. You glue it over the end of the crankshaft (with the tube if red stuff) when your crankshaft has a wear groove worn into it. This gives the new seal something smooth to seal against.

Thanks. That makes sense about the Teflon gasket. I wonder though if the facing surface on his was in better shape than mine.
Thinking more about it, I may not have much choice but to clean this pig up as much as possible, put RTV on the gasket and hope for the best. Although, short of Ebay, a NEW cover is 90 bucks from Home Depot of all places??? Can't seem to find one on Rock Auto yet.

The pitting around the coolant ports on the cover is not that bad, I have seen and used parts a lot worse with no problems. You can use a thin film of RTV on the gasket if you like, just make sure is is a thin film on the gasket, too much will just squeeze out and break off inside the engine and cause problems. I have always used "COPPER COAT" on all my gaskets (except where noted otherwise by gasket manufacturer), in either the spray can, or the can with furry ball applicator and have always had one hundred percent success, never had any leaks.

That's good to hear. I have seen people put an awful lot of RTV on a gasket and had that same thought - that it would squeeze off into the engine when it got tightened down. I'll take it easy on the RTV.
I was planning on filling those round grooves around the ports with the RTV though.
Does that groove serve some purpose and needs to stay clear?

Koda200 - also thanks for letting me know what that metal part from FelPro is.

FlipPhone, torque spec for the cam sprocket bolt is 44 to 50 ft lbs., and the timing
chain guide and tensioner bolts torque at 84-108 INCH-lbs and 84-96 INCH-lbs respectively.
Timing chain cover bolts are 13-15 ft-lbs.
Crank pulley bolt is 30-37 ft-lbs and then an additional 90 degrees. Since you're re-using the
old bolt, you might want to check with someone that's done that. I recommend blue
thread locker on all the bolts.

I don't know why the grooves are in the cover, but I wouldn't fill them. There's another option
for filling the pits. You can use JB Weld as filler, then file or block-sand the surface flat.
However, just using a good sealant with the gasket should work fine...

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* The groove in the timing cover is a "visual safety" - it allows coolant to weep out when the timing cover gasket has reached the end of it's service life - akin to the hole on the bottom of a water pump.

* The pitting shown in the pics is minor. Ultra Copper RTV & Thick Gasket will handle it, provided you prepped the mounting surface with Scotch Brite & then cleaned the surface w/ Lacquer Thinner.

* As @Runnin'OnEmpty suggested, if you're still bothered with the minor pitting, you can fill it in w/ JB Weld and fine draw file/block sand in flat.

* The (5) oil pan bolts that screw into the bottom of the Timing Cover are torqued to 15 lb/ft on a '98. TORQUE THESE (5) BOLTS FIRST BEFORE TORQUING TIMING COVER TO ENGINE BLOCK BOLTS!

* Re-using crank pulley bolt is covered in the original write-up. Link: Removing timing cover on 4.0 OHV

* Both crankshaft seals you showed in your pics are fine, choose the one that feels tighter/more snug in the hole. Also covered in the original write-up, before pressing in the Crankshaft seal, smear some Ultra Copper 360 degrees in the Timing Cover hole that holds the Front Crank Seal. This is done so as to assure no oil leaks around the exterior of the seal. It can and does happen. Old school trick, leave nothing to chance.
Link: Removing timing cover on 4.0 OHV

HTH & Good Luck