Driving with a coolant leak from the timing cover

[98FordLove]

Hi all,

Joined this forum because it's specific to my Ford, so I would like to hear from other Ford owners. 98 Ford Explorer XLT 4.0L.

I just discovered that I've been driving all along with a coolant leak coming from the timing cover for 2 years now. It seems minor for now as it seemed to have gone about 8 months before it lost 4L of coolant in the radiator. I just refilled the rad and put in 6L of coolant in including top ups. I've had this truck for 2 years now and it runs perfectly fine otherwise. It does have a minor oil leak coming from the valve cover gasket too but I've left this since it was very minor. It has 195k km on the truck and new tires are due within the next 3-4 months.

The question I have is, both short and long term, what would be the problems that could result if i continued to drive the truck with a coolant leak from the timing cover? I'm not talking for years and years but say 1 year? I have a car as well as this Ford truck, so it won't be seeing all the miles but would still be driven daily with maybe some long distance trips in the summer. I am reading about on here that it's the t-housing that is leaking and that often leaks on these 4.0L Ford Explorers? I'm guessing the t-housing is the timing cover?

If I check my coolant say once a week and make it a habit of keeping the coolant topped up and burp out any air pockets from the cooling system whenever I feel a drop in the cabin heat. Do you think this would be okay and buy me time? Can anything super bad result from this (like cause other problems)?

TIA.

 

[XLTrunner]

If you have the SOHC engine, chances are good that the leak is indeed the thermostat housing. And, no...the housing is not mounted to the timing cover (it sits near the top of the engine above the timing cover). Could very well be running down the front of the block appearing to be the timing cover leaking. May not be noticeable above that point as the hot engine could be burning it off. This is a well known problem with this engine and is well documented on how to replace it on this forum. I put up with mine doing this for over a year before I knew about this issue. It eventually got significantly worse and forced me to address it. Would add coolant as needed while keeping a close eye on the coolant level. No harm...no foul. But, that's living dangerously and could easily escalate on you with little notice. Look for leakage around the base of the t-stat housing (difficult to get a good look at it) and around the middle mold seam and the base of the sensors. Also, it may also be pooling on top of the engine in the engine valley; although it sounds like yours is still slow enough of a leak that whatever might run into the valley would get burned off.

 

[C420sailor]

Basically no risk if you stay on top of it...but you aren’t staying on top of it. Letting it drop 4-6L is way, way too much. Check it more frequently. Personally, I wouldn’t let it go more than a liter low. Carry premixed coolant in the truck.

 

[98FordLove]

If you have the SOHC engine, chances are good that the leak is indeed the thermostat housing. And, no...the housing is not mounted to the timing cover (it sits near the top of the engine above the timing cover). Could very well be running down the front of the block appearing to be the timing cover leaking. May not be noticeable above that point as the hot engine could be burning it off. This is a well known problem with this engine and is well documented on how to replace it on this forum. I put up with mine doing this for over a year before I knew about this issue. It eventually got significantly worse and forced me to address it. Would add coolant as needed while keeping a close eye on the coolant level. No harm...no foul. But, that's living dangerously and could easily escalate on you with little notice. Look for leakage around the base of the t-stat housing (difficult to get a good look at it) and around the middle mold seam and the base of the sensors. Also, it may also be pooling on top of the engine in the engine valley; although it sounds like yours is still slow enough of a leak that whatever might run into the valley would get burned off.

Thanks. My mechanic who checked it out today said the leak is at the front of the engine and is going straight down to the ground. I believe he said it was on the drivers side, can't remember. But he said the coolant is basically just leaking right down and not getting into like the alternator. He said it's in the early stages too and is slow right now. I will check the coolant from the rad once a week and make sure it's topped up. Just not worth me sinking money into this car so just buying time until I replace it with some other truck.

Yes I believe mine is the SOHC engine.
I believe mine is the thermostat housing as well. How long did it take for yours to get signficantly worse like you said?

 

[98FordLove]

Basically no risk if you stay on top of it...but you aren’t staying on top of it. Letting it drop 4-6L is way, way too much. Check it more frequently. Personally, I wouldn’t let it go more than a liter low. Carry premixed coolant in the truck.

Thanks. Well I wasn't staying on top of it because I didn't expect a leak in the system until I ran out of coolant twice now in about 9 months. When I had big air pockets last year and got them all out, the mechanic at the time said that there was no leak in the system so I just carried on and didn't check the rad levels. But for now on I will be checking the coolant once a week. I keep 3 full 4L jugs of coolant in the truck at all times now. Never know when I may need it.

 

[XLTrunner]

Impossible to say when it might get worse. If you are truly intent on replacing it, I'd just monitor the coolant level religiously and nurse it along. For most of us on this forum, replacing a t-stat housing is hardly reason to dump their vehicle; especially, if it runs fine otherwise. But, if it's rusted out and/or an eyesore and you're just plain tired of it, then by all means. Just a reminder if you do decide to keep it and replace the tires...you'll want to replace all four with a matched set.

 

[98FordLove]

Impossible to say when it might get worse. If you are truly intent on replacing it, I'd just monitor the coolant level religiously and nurse it along. For most of us on this forum, replacing a t-stat housing is hardly reason to dump their vehicle; especially, if it runs fine otherwise. But, if it's rusted out and/or an eyesore and you're just plain tired of it, then by all means. Just a reminder if you do decide to keep it and replace the tires...you'll want to replace all four with a matched set.

Well I would normally just replace the T-stat too but there is also a small oil leak from the valve cover too and not sure if the engine has a warped cylinder head. If it has a warped head then I wouldn't sink a penny into the car because it's just not worth it. Would hate to pay to replace the t-stat and have a blown head gasket soon down the road.

I know what you mean though. The truck still runs perfect and who knows, worse comes to worst if I can't find a suitable affordable replacement for this truck then I just get the t-stat done. The valve cover is another story, that's a big job and repair to fix that oil leak. Also, if one replaces the t-stat they would likely replace both timing chains too while at it since they are there. But then the costs go up and exceeds the value of the car.

Thanks for the reminder on the tires. Yes I always replace all 4 at once.

 

[98FordLove]

@98FordLove
The JunkPlastic ThermoStat Housing on 1997~2011 Ford V6~4.0L~SOHC engines, either FordOEM or AfterMarket brands,
are notorious leakers. The HotGlued Seam\Flange between the LowerBody & UpperBody on these plastic housings is the
weak spot that eventually cracks+leaks. The only real dependable fix is to install an Aluminum ThermoStat Housing.
There's a choice of several Aluminum makers\vendors, but typically they are not available at your local parts counter;
so a little ambition to find the specific Aluminum Housing online & patience to wait for it to be delivered are needed;
if you have niether, then your remaining choice is the local Ford PartsCounter for the OEM Plastic Housing
or your nearest PartsStore for an AfterMarket brand.
Cost of Aluminum Housings have come down to be comparable to AfterMarket Plastic Housings,
& certainly are cheaper than the OEM part from the dealership.

Your leak may have been there for several years now, slowly loosing coolant; it may not get worse for several more years;
then again it could fail catastrophicly tomorrow & cause severe+expensive overheating damage to your engine.
I would not trust the vehicle until this is fixed.

On a 23yr old vehicle, if the coolant system has not been maintained or serviced recently, it's time is now:
~ New Coolant Hoses\HeaterControlValve\Pump\ThermoStat
~ New Fan\FanClutch\SerpentineBelt
~ New Radiator+Cap

More info at

Engine Coolant ThermoStat

In early 2019 & 19+ years, the FactoryOE ThermoStat Housing on my 2001 Ford ExplorerSportTrac started to leak per the pics below; at first just an irritation, this leak steadily grew much worse. Under the Throttle on the V6~4.0L~SOHC engines TopFront in several 1997~2012 models, the FactoryOE...

2001fordexplorersporttrac.fandom.com

Engine Coolant HeaterValve

It seems that the engineered DesignLifeTime for this vehicle, assembled in 2000, was\is around 18 years; starting in 2019, during every Coolant system maintenance task (ThermoStat Valve, Hoses, Flush+Fill,...), yet more OEM plastic parts (TStatHousing, HoseTeeFitting, RadiatorTank...)...

2001fordexplorersporttrac.fandom.com

Engine Coolant Fan+Clutch+Pump

Coolant Pump \ Penetrant Soak + SiliconLub Bearing BothSides Ford# 6L2z-8501-a \ f77z-8501-ad \ pw458 Coolant Pump FiberGasket With HiTemp RTVSealant LiteCoat BothSides Ford# fotz-8507-a \ FelPro# 35474 HiTemp RTVSealant 750f PermaTex# 27038.OptimumRed \ 700f PermaTex# 81878.UltraCopper Coolant...

2001fordexplorersporttrac.fandom.com

Engine Coolant Radiator+Cap

In 2020Jun, while replacing TimingTensioners, the ThermoStatHousing had to be removed for access to left Tensioner; while draining Coolant, discovered a 6" split & leak in the old 2RowPlasticTankedRadiators right tank & drain. Described here is the new 4RowAllAlumRadiator which I installed...

2001fordexplorersporttrac.fandom.com

Thanks.

I did learn about the aluminum thermo housing. How bad is the plastic one? How long before they start to leak? I saw that the metal one is like 5 times the cost. I'm almost in Canada.

The mechanic says it's the timing cover leaking but I am guessing it's the thermo housing. Either way, both are right next to each other so I would replace both anyways. I would also replace the valve cover gasket too to fix my oil leak.

Good timing you posted this. I actually just got off the phone with a friends friend getting a quote for him. He can do the repairs much cheaper than at my mech today because he has no overhead. Like I said in my OP, I really don't want to get rid of the truck. I love it and if I can get a good quote on the repairs then this is the route I would prefer to take. Then I don't have to constantly check levels and keep oil and coolant in my truck all the time. Isn't this a safety hazard since they are flammable?

I did do a coolant system service last year but I didn't replace the coolant hoses and heater control valve or fan. How important are replacing these even if they still show to be good? Usually hoses people only replace if they are cracked or leaking. Also new radiators are not cheap.

 

[98FordLove]

Okay I just checked and my engine is the OHV push rod, not the SOHC. So looks like I have no plastic thermostat housing? If so, great news. Looks like it's the timing cover gasket then that is causing the leak like the mech said today.

 

[CDW6212R]

The timing cover gasket isn't a fun job to do, plan for a day and try to be ready for more. Sometime the cover may break in removing it, that's more likely with the 5.0 engine.

Buy Prestone from Walmart, the $11ish gallon version. That's the cheapest, quality antifreeze you can get right now. I have a timing cover gasket leak in my latest 98 302 truck. I'm using Liquid Copper to try to get me through Winter, because the job is rough to do outside.

Be sure the leak is the timing cover, and not the T'stat housing, which can leak on any version if the gasket wasn't set in right. That's an easy job versus the timing cover.

Don't mix stop leak products, flush out any old brands before adding a new kind.

 

[fast_dave]

@98FordLove

This is the OHV factory timing cover.

The gasket that is leaking is made of thin paper and is teflon impregnated.

The Germans that designed this engine made a "weep channel" on each water passage to notify you when it's time to change the gasket...

Hope that helps -

 

[98FordLove]

The timing cover gasket isn't a fun job to do, plan for a day and try to be ready for more. Sometime the cover may break in removing it, that's more likely with the 5.0 engine.

Buy Prestone from Walmart, the $11ish gallon version. That's the cheapest, quality antifreeze you can get right now. I have a timing cover gasket leak in my latest 98 302 truck. I'm using Liquid Copper to try to get me through Winter, because the job is rough to do outside.

Be sure the leak is the timing cover, and not the T'stat housing, which can leak on any version if the gasket wasn't set in right. That's an easy job versus the timing cover.

Don't mix stop leak products, flush out any old brands before adding a new kind.

Thanks. I won't be doing it but a backyard mech if I get a reasonable price.

Yup the Prestone coolant (yellow bottle) is the one I am using right now. What does liquid copper do? Do you put it in your rad?

100% know the leak is from my timing cover. I have the OHV engine so from what I read there is no thermo housing on this.

Is there any stop leak products that work for coolant leaks?

 

[98FordLove]

@98FordLove

This is the OHV factory timing cover.

The gasket that is leaking is made of thin paper and is teflon impregnated.

The Germans that designed this engine made a "weep channel" on each water passage to notify you when it's time to change the gasket...

Hope that helps -

View attachment 327073

View attachment 327074

View attachment 327075

Thanks. I wonder how long it would take to take it down to do the repair.

 

[fast_dave]

Thanks. I wonder how long it would take to take it down to do the repair.

Link 1: Removing timing cover on 4.0 OHV

Link 2: 4.0 OHV Timing Cover & Gasket Issues

Here is where your thermostat is.

1st pic is for perspective - top/front of engine, on the aluminum intake manifold (look towards CAUTION FAN sticker).

(3) bolts hold the thermostat cover on - (1) is on the bottom of the thermostat housing - not visible in 2nd Photo.

 

[donalds]

Is there any stop leak products that work for coolant leaks?

you can TRY! k-seal

 

[98FordLove]

you can TRY! k-seal

Thanks, looking into it now. Wonder if it will work and for how long. Looks pricey but cheaper than a repair Job.

 

[CDW6212R]

They all have a thermostat housing, the OHV has the gasket vertical while the SOHC is horizontal. The gasket falling out of place while installing is the only worry on your type, or the 302 V8 for example.

If you are sure it's the timing gasket, I'd find the Liquid Copper for it. There are tons of stop leak products. I have tried many, the old Alumiseal was my favorite(small and easy to carry, dry powder material). I used K-seal several times when my last truck had a radiator leak, it worked okay too.

For my recent timing cover leak, the K-seal didn't stop it fully, and it leaked a bunch one day. I added Alumiseal that I found handy, and that slowed it to a virtual stop. I tried Liquid Silver that I had known of for decades, and it's similar to the Alumiseal. That also kept the leak unseen most of the time, but it got worse again after a few days.

I then called Barr's, the brand who makes the most kinds. They recommended their Liquid Copper, as a step above their Liquid Silver, and to flush the old stop leak products out. I did that, and the leak stopped completely for about a week. I have smelled coolant for ages, since last Winter when I bought the truck. This week then was the first time I haven't smelled it at all. It slowly leaked again though the following week, just a little. I added a little more Liquid Copper, and it went another two weeks. But last week it opened up again and lost a half gallon while I was working. I keep distilled water with me in a gallon apple sauce jug(thick plastic). When I got home I drained another gallon from the petcock, and added another full bottle of Liquid Copper. It has stopped the leak again, but probably not permanently. My gasket leak is surely a blown section, and nothing short of getting to it to apply something, or take it all out, is going to solve mine.

Your leak sounds minor so far. Put in the stop leak and try to stop it from getting worse. If it is very minor now, you may catch it in time, and not have to replace the gasket really soon. I'm trying to get mine to Spring, and after I retire to be able to work on it leisurely. Good luck,

 

[98FordLove]

They all have a thermostat housing, the OHV has the gasket vertical while the SOHC is horizontal. The gasket falling out of place while installing is the only worry on your type, or the 302 V8 for example.

If you are sure it's the timing gasket, I'd find the Liquid Copper for it. There are tons of stop leak products. I have tried many, the old Alumiseal was my favorite(small and easy to carry, dry powder material). I used K-seal several times when my last truck had a radiator leak, it worked okay too.

For my recent timing cover leak, the K-seal didn't stop it fully, and it leaked a bunch one day. I added Alumiseal that I found handy, and that slowed it to a virtual stop. I tried Liquid Silver that I had known of for decades, and it's similar to the Alumiseal. That also kept the leak unseen most of the time, but it got worse again after a few days.

I then called Barr's, the brand who makes the most kinds. They recommended their Liquid Copper, as a step above their Liquid Silver, and to flush the old stop leak products out. I did that, and the leak stopped completely for about a week. I have smelled coolant for ages, since last Winter when I bought the truck. This week then was the first time I haven't smelled it at all. It slowly leaked again though the following week, just a little. I added a little more Liquid Copper, and it went another two weeks. But last week it opened up again and lost a half gallon while I was working. I keep distilled water with me in a gallon apple sauce jug(thick plastic). When I got home I drained another gallon from the petcock, and added another full bottle of Liquid Copper. It has stopped the leak again, but probably not permanently. My gasket leak is surely a blown section, and nothing short of getting to it to apply something, or take it all out, is going to solve mine.

Your leak sounds minor so far. Put in the stop leak and try to stop it from getting worse. If it is very minor now, you may catch it in time, and not have to replace the gasket really soon. I'm trying to get mine to Spring, and after I retire to be able to work on it leisurely. Good luck,

Thanks for the info and mentioning about the OHV still having thermo housings. I told my mechanic to look for it tomorrow and may just replace it even if it's still good because they are so prone to leaking. Does the OHV engine use the same cheap plastic as the SOHC thermo housing?

I did look into and really consider just using a stop leak but it's such a hit or miss and no promise it even works. It could be a miracle in a bottle and buy me time or it could be a waste of money and time to try out and experiment. Plus I would rather not spend the time experimenting on stuff, would rather just get it fixed right and get it over and done with. I know that leaks only get worse over time and the only way to truly stop them is by replacing the gaskets.

I just got back from dropping my truck off at another mechanic (who is very good, likely better than my main mech who was too lazy to find out what was causing the loss of coolant [not the mechanic yesterday but my main one]). He checked and yes it's the timing cover gasket that is leaking and both valve cover gaskets are leaking oil too and from the looks of it a lot worse than I expected. It's just the matter of time before it only gets worse and there is no timeline on when that could be. But the engine oil leaks were worse than I thought, and I thought it was only one but it's two. I was holding off on this the past 2 years and just topping up with oil every couple of weeks or so (went about 1.5-2quarts of oil in between oil changes). It got really tedious constantly having to check your oil and top up though especially when I did longer trips. I would check the oil the day before I leave and then when I get back. Now that I will be getting the repair done right, no more of this constant checking.

He's not cheap but he's also not a backyard mechanic because I want this done right. I've had crappy mechanics do bad gasket jobs on my previous cars and then I had to pay another mech to do it properly. So pay more for someone to do it right the first time. I figured since I rely on this truck so much and it's been nothing but a rock for me in the 2 years I've had it and I do want to keep it for as long as I can, I would just pay up and get the gaskets done.

Since he is changing timing cover gasket, he will have a lot of it out anyways, may as well just change both valve cover gaskets too since I am paying a pretty penny for his labour. He will change the intake manifold gaskets too since he ordered the intake manifold kit and it's all in the same area. Then that way I drive away with a no leak truck in tip top shape and I will keep checking levels. But at least this way I don't have to constantly check my oil and coolant once a week or every few days and keep topping up. I will still keep a quart of oil and a jug of coolant in the truck just in case for safety.

I don't know if the rear main seal is leaking but from what I read, a 23 year old truck, it's probably likely. But the leaks on these are too big of a job and most just leave them anyways.

 

[fast_dave]

PM Sent

 

[98FordLove]

PM Sent

Me? Didn't get a PM, could you resend it? Thanks.