How to: 4.0 OHV Refresh

[donalds]

Do you think I'm okay to keep running these, or should I pick up a couple new plugs

Get new ones imo

 

[donalds]

Get all new ones
Because that some of the porcelain is different on other plugs too it's sticking out more than others it seems like the core of the plugs are being pushed out might have some faulty plugs here

Compare those plugs really well to your new ones the color looks good though

 

[97Sandbox]

Get all new ones
Because that some of the porcelain is different on other plugs too it's sticking out more than others it seems like the core of the plugs are being pushed out might have some faulty plugs here

Any recommendations that are better than these Motocraft plugs? I usually trust FoMoCo for stuff like this, but it seems their plugs may not be up to snuff.

 

[Fix4Dirt]

Any recommendations that are better than these Motocraft plugs? I usually trust FoMoCo for stuff like this, but it seems their plugs may not be up to snuff.

have had good luck with ngk

 

[donalds]

Any recommendations that are better than these Motocraft plugs? I usually trust FoMoCo for stuff like this, but it seems their plugs may not be up to snuff.

From doing lots of reading on this forum I can tell you motorcraft plugs only this is just a weird situation with your plugs People find when they run other plugs they get misfires at idle stuff like that

If I had to pick an after market I would say autolite

 

[97Sandbox]

After taking another look at the plugs in-person, the porcelain protrusion looks pretty consistent across all six plugs -- I think it's just something goofy with the angle of the picture that made them look different.

And for those eagerly awaiting, leakdown results are in!
Cyl#1: 64%, audible hissing from oil filler neck and dip stick tube, no bubbles from radiator
Cyl#4: 90%, audible hissing from oil filler neck, no bubbles from radiator
Cyl#2: 76%, audible hissing from oil filler neck and intake (with throttle open), no bubbles from radiator
Cyl#5: 83%, audible hissing from oil filler neck and dip stick tube, no bubbles from radiator
Cyl#3: 94%, audible hissing from oil filler neck and dip stick tube, no bubbles from radiator
Cyl#6: 55%, audible hissing from oil filler neck, dip stick tube, and intake, no bubbles from radiator

I was surprised not to see any radiator bubbles -- could that be because I didn't remove the thermostat?

Regardless, I've got unhealthy cylinders in both banks.



EDIT: I should add, the percentages above are the static pressure, not the percent leakage.

 

[97Sandbox]

After doing some reading, I'm thinking the biggest piece of information the leakdown test told me is that this engine likely has some really worn rings (not entirely surprising for an engine with 260k that may or may not have always been well taken care of). Another observation consistent with ring wear was a gasoline smell as the air blew out of the oil filler neck -- I'm assuming there's quite a bit of blow-by in at least a couple of cylinders.

Overall, I'm still thinking the dirty coolant bubbles are the result of a minimally blown head gasket or slightly cracked head that only allows combustion gas into the cooling system when the engine is running hot and everything expands. While reman heads and new gaskets may solve the combustion in the cooling system issue and even the leaky intake valve, they won't do anything to stop blow-by. That being the case, I'm not sure it's worth it to put a new top end on a worn out rotating assembly and/or block.

Any thoughts from you Explorer experts before I dump a bottle of head gasket repair in and run the old 4.0 till it blows?

 

[Clutch5sp]

Hi...if there is a crack in the head(s), there very well could be air passing thru to be heard sorta like a valve seat being bad. This tricked me while doing the tests. With 260k on the counter, there could be all sorts of probs not just one.....rings, valves, cracks, leaking gaskets. Decide if you will want to save this engine core before something serious goes bad like spun bearings, rods thru block etc...

 

[97Sandbox]

With 260k on the counter, there could be all sorts of probs not just one.....rings, valves, cracks, leaking gaskets. Decide if you will want to save this engine core before something serious goes bad like spun bearings, rods thru block etc...

Unfortunately, I just don't have the space to rebuild this engine where I live currently. I hope to move somewhere with a bigger garage or even a shop by the summer, so I'd realistically just like to limp this engine along until then (hence the reason I'd actually consider a temporary fix kind of product).

When I do eventually pull the 4.0 out, I'd really rather replace it with something that has a couple more cylinders, so the 4.0 core doesn't mean all that much to me. I wanted to get to know the OHV and give my engine a second lease on life when I bought my Sport, but it doesn't seem like this one is worth saving.

If anyone knows someone in the Midwest who's dumping a healthy OHV for cheap in order to swap in a V8, I'd still be willing to try a like-for-like swap to buy me time until my own V8 sawp. I just can't justify $3k for a reman long block that doesn't get me any closer to my end goals.

 

[Clutch5sp]

Now I understand. You did mention an upgrade in cylinder qty in the beginning of your thread.

 

[97Sandbox]

Now I understand. You did mention an upgrade in cylinder qty in the beginning of your thread.

No problem! Your prior reply actually did prompt me do some more thinking. It looks like I could buy a supposedly healthy 100-150k mile OHV for about $550. Some of the refresh components from my current engine could be swapped over (timing set, ignition system, cooling system), but a lot would still need to be re-purchased and reinstalled on the "new" engine (gaskets and hardware mostly). By my estimates, I could swap in and lightly refresh a good used engine for about $1000 including needing to purchase an engine hoist. To do the same to a engine with bad heads (factoring for more gaskets and reman heads) would be more like $1500, so there's no money saved going that route. Either way, these options are both well below the roughly $3500 it'd cost to get a reman 4.0 and install it, unless of course the used engine turns out to have bad rings like my current one.

This leaves me with a couple questions:

• Is it even reasonable to think I could pick up a well-maintained 100-150k OHV that won't leave me in a similar situation down the road?
• Short of running a compression test, lookdown test, or driving the truck I pull an engine from (all of which I expect I won't be able to do prior to purchase), what are some tips for evaluating the health of a used OHV?

If $1000 and a weekend of hard work gets me one of those "bulletproof" OHVs that folks on here rave about, I'm interested. But if it's more likely I'll just be throwing time and money at another clunker, I'd rather save up for a V8.

 

[Clutch5sp]

Just an FYI.... searched a car-parts thingie in & around Dallas and there is a crap-ton of 5.0L 99-01 explorers sitting in salvage yards. There is some legal ordeal they can't sell the entire truck butt you can get all the parts ya want off em.

There seems to be a lot involved in swapping V6 to V8. Not as simple as engine trans ecu cluster. There is PATS fuel lines exhaust cooling etc...you probably know. Wouldn't it be easier to start with one that had the V8 originally and go from there? Saw one on CL for $1,500 with probs butt it ran (they said).

Once a Saturday morning TV show POWER NATION redid a Ranger to have a 4.6 L. Of course they have unlimited budget & tools galore, it was still neato to see it all come together.

Truthfully, I'd rather have an Expedition. Never liked the Explorer driving long distance. Wife loves it....not too big or small.

 

[Fix4Dirt]

From doing lots of reading on this forum I can tell you motorcraft plugs only this is just a weird situation with your plugs People find when they run other plugs they get misfires at idle stuff like that

If I had to pick an after market I would say autolite

interesting! never knew that always ysed aftermarker like ngk bosch etc snd bever had any misses, good to keep in mind! thiught it was a v8 only thing interesting

 

[97Sandbox]

Just an FYI.... searched a car-parts thingie in & around Dallas and there is a crap-ton of 5.0L 99-01 explorers sitting in salvage yards. There is some legal ordeal they can't sell the entire truck butt you can get all the parts ya want off em.

There seems to be a lot involved in swapping V6 to V8. Not as simple as engine trans ecu cluster. There is PATS fuel lines exhaust cooling etc...you probably know. Wouldn't it be easier to start with one that had the V8 originally and go from there? Saw one on CL for $1,500 with probs butt it ran (they said).

I noticed the same thing here in SE Wisconsin.

There is a lot involved (I'll start a new thread shortly to begin discussing that), but since Ford never made a 5.0, manual trans, two-door Explorer you have to build them yourself!

 

[97Sandbox]

I've continued driving my Sport periodically these last several months and it's held up fine so far (I never added stop leak either). I normally avoid driving it on hot days for fear of further warping/cracking whichever head is leaking at high temperature, but I took a chance and drove it to a car meet I hosted on Saturday.

On the way home, I thought the old 4.0 finally met its end when it started stumbling under load. It felt a lot like when I almost ran out of gas once -- it idled okay but did not want to accelerate, especially pulling away from a stop. I thought it was maybe misfiring due to coolant getting into the combustion chamber, but there was no white smoke out the tailpipe and no CEL for a miss. I limped it home and parked it. A few hours later, I started poking around and was surprised to see my coolant reservoir level still right where it should be. Thinking that meant my cylinders likely were not full of coolant, I decided to fire it up. It ran like normal as if nothing happened.

Based on all of this, I'm suspecting the issue is actually a dying fuel pump that started running too hot (it was 103 deg F here on Saturday). Looking on RockAuto, it appears the same fuel pumps are specified for the 4.0 and 5.0, so whatever new pump I install can live on to see use in the eventual swap. Can anyone recommend a good fuel pump? I've had good luck with Bosch products when it comes to other motorized parts, but I know all the OEM bits are Denso on my Civic and they've held up well. Are any of the other brands good? For the hassle it'll be to drop the tank, I'd just assume put in a good pump that'll last for years even if it costs a bit more.

 

[fast_dave]

@97Sandbox

Just sayin' - Everybody has their favorite fuel pump on the website.

I bought a TYC from Rock Auto. TYC is a mainstream manufacturer to auto & truck manufacturers, research them on their website.

Link: https://www.genera.com/

The TYC was a much more powerful (PSI) aftermarket pump than my OEM Bosch Factory Pump ever was.

Your money, your choice, carry on and hope that helps -

TYC 152017A for $15.58 @ Rock Auto

Pump Pic: View attachment 435968

I upgraded the provided fuel strainer "sock" to an Extra Large Fuel Strainer (Denso 952-0033) = $9.34

Sock Filter Pic: View attachment 435967

 

[96AWD5.LOL]

I've recently purchased a 91-94 explorer Walbro fuel pump. Made in USA and under $100. Looks like there is one for 97-02 Explorers too:

Genuine Walbro/TI GSS342 255LPH Fuel Pump + QFS 766 Kit for Ford Explorer ALL 1997-2002

FREE 2-DAY SHIPPING, EASY INSTALL from the AUTHORITY on OEM replacement Fuel Pumps. SAVE up to 70% off on parts for your Ford Explorer 97-02 with WAL-GSS342G3-766

www.highflowfuel.com

 

[97Sandbox]

Thanks for the input guys!

 

[410Fortune]

Good ol truck! You made the right decision keeping the 260k engine
I would probably use some head gasket repair in a bottle and add a bottle yearly just keep on motoring!!!!

Bosch pumps are avail on rockauto they have been hit or miss the last couple of years, meaning they are in stock then not. (Amazon, summit, etc) all the same.
I have installed somw
Delphi pumps lately because carquest sells them $120 each and I get in town warranty. So far so good, although you guys know I like the Bosch

 

[97Sandbox]

I thought seriously about head gasket repair products, but decided against it. As long as I keep the temp down, combustion gas does not escape into the cooling system. I was worried that any stop leak product might clog my old radiator and then I'd really be in trouble, so my solution was a 180 deg F thermostat.

I'm running 10W-40 to help reduce the blowby and I check the coolant level often. Still no tailpipe steam, no milkshake in the crankcase, and I see very little sludge accumulating in the coolant reservoir. Seems like the old 4.0 will just keep limping along as long as it stays cool and gets enough fuel!