Is my timing cover leaking coolant?

[84FLH]

After a slow coolant leak (fill overflow tank once a month) turned into a weekly filling and then smelling coolant in the cabin, I found these areas under hood soaked with coolant:

- top of passenger side shock tower
- top of passenger side motor mount
- transmission lines running across passenger side motor mount, parallel to frame rail
- passenger side of block, near front of motor and under exhaust manifold.
- entire front of engine under water pump, down to/including cross memgber

Local shop said water pump bad, replaced same @ 375, didn't fix leak. Same shop then said heater control valve bad, replaced same @ 133, didn't fix leak. Same shop now says lower T-stat housing leaking. I pulled air intake duct and throttle body, then raced motor by hand. Didn't see any coolant leaking from top or lower T- stat housing but flat area behind lower housing had wet area about 1/2" W x 2" L. Wet area is so small it doesn't seem possible it's source of coolant that's covering the above listed areas.

Had noisy timing cassette replaced 8 years ago (2012) by Ford mechanic. I put about 100,000 miles on since then. The guy was a top mechanic (friend of a friend). I'm thinking he used the correct green Teflon gasket on timing cover, and the job shouldn't be leaking after only 100,000 miles.

Can't figure out how to download smartphone pics to my pc so I can't at this time post pics. Appreciate any advice, suggestions, input from those who've gone down this road before me.

 

[donalds]

V6?
Most likely a t stat housing replace it with a metal one

And find a new shop

If you want to be 100% sure pressure test the cooling system

 

[410Fortune]

If he has timing cassette then its a SOHC V6 on 2000 Mercury

Thermostat housing is most likely
BUT
There are some coolant hoses, the front timing cover, lower intake can also leak coolant

@donalds has you covered = Pressure test the cooling system will usually show the leak

if it s really hard to spot then you can use the dye and light kit also
Usually I can find the source with just a powerful flashlight
With coolant its always the highest point that you can find wetness

 

[84FLH]

V6?
Most likely a t stat housing replace it with a metal one
And find a new shop.
If you want to be 100% sure pressure test the cooling system

Hey donalds;

Thanks. Yeah, 4.0 sohc. 345,675 on the clock. Motor runs good.

There's no trail of coolant from lower/upper T-stat housing to the places soaked in coolant (top of shock tower, top of motor mount, top of trans lines). I've read how the lower T-stats do indeed leak and need replacing. It's just that there's no coolant trail from the housing to the soaked areas (top of shock tower, top of motor mount, top of trans lines, etc). Can't imagine by what means a leaking T-stat housing would soak those areas without leaving a heavy trail of coolant from housing.

What brand metal housing? One or two piece lower?

Thanks again.

 

[84FLH]

Hey donalds;

Local shop p-tested the system and said no leak down. But by now I don't trust them. Especially when they said they couldn't buy a lower T-stat housing but had to buy the entire assembly. At a bargain price to me of $275.

The next day I bought a lower T-stat housing and gasket from my local Ford dealer. $33.12 out the door. Haven't had time to do the install. Might look into that metal housing you talked about.

 

[84FLH]

Thermostat housing is most likely

Would that throw coolant on top of front pass side motor mount? On top of pass side shock tower?

I don't see any trail of coolant from those areas to T-stat housing. I'm thinking underside of intake manifold would be wet if that was happening but underside intake manifold dry.

Pessimist in me thinks timing cover leaking.

 

[XLTrunner]

I've been thru the leaking t-stat housing several times and the dead give-away was the pooling of the coolant on top of the block. It's hard to see underneath the upper intake...but, with a flashlight at night, I could see back under there easier. I really couldn't see any visible signs of leakage around the housing, either. The coolant would burn off as the engine would heat up...but, eventually the leak became so bad that it would pool and then drip onto the ground if I parked at an incline. Initially, shop I took it to told me it was a head gasket. Wasn't buying it and, after learning of the chronic problem with these t-stat housings, fixed it myself. Took a couple of tries because of the horse-s**t design of the plastic housings...so, finally learned my lesson and will be using a metal housing if I have to do this job again.

 

[donalds]

4.0 SOHC Metal Thermostat Housing Comparison

 

[koda2000]

If the leak is coming from the t-stat housing, which is a well-known issue on the SOHC V6's, return the plastic Ford housing (or any other brand plastic housing) and get an aluminum t-stat housing. I prefer the Simmons aluminum housing ($135) some here like the Austec housing (which I believe is a little less expensive, but IMO not as good). Search the forum for "metal thermostat housing comparison" but first make sure this is your issue.

Also, find a new mechanic. Not only are they needlessly throwing parts at your problem w/out verifying the actual problem, they're also overcharging you for the parts and repairs. If they really did a cooling system pressure test (which should have been the first thing they did) it would have indicated exactly where the leak was going from.

375K on a Ford 4.0L SOHC V6 is almost unheard of without a major engine rebuild. Mine didn't make 200K before having cracked heads and needing timing chains.

A Ford OE Motorcraft water pump costs $62.79 on RockAuto and a OE Motorcraft heater control valve costs $18.45. Labor for installation time of both parts is minimal, maybe an hour for the W/P and 15 mins for the heater control valve. Shops buy their parts locally and typically don't buy OE parts. Then they typically add 20%-40% to the cost of the part. Even if they charge $100 an hour for labor replacing these parts should not have taken them more than 1.5 hours. This is why i do my own repairs. I realize not everyone can do their own repairs, but spending what you have and still not having the problem repaired is ridiculous.

Considering how much work is would be to replace the timing cover gasket (if that's where the leak is coming from) I think your shop's bill would exceed the value of your truck.

 

[84FLH]

Koda! Was hoping to hear from you.

If the leak is coming from the t-stat housing

> How can I tell if this is the case?

Considering how much work is would be to replace the timing cover gasket (if that's where the leak is coming from) I think your shop's bill would exceed the value of your truck.

> How can I tell if timing cover is leaking coolant? Use the dye and light recommended above?

> Agree with all you said on this shop. They replaced a fuel pump for me last year at $225 with a free tow (about 1 mile), so I thought they'd be good again. There's nothing near where I work and expedience dictated using this shop again. But experience shows me to find a new shop.

> I'll probably take it to a dealer. Trans works good. Motor runs good although I hear a clacking sound like a lifter that's not pumping up. The sound is intermittent. Not there when I start the motor. Might show up when I park at work after a 25 mile ride in. Then again, might still be quiet when I get to work. 4WD works. Auto 4WD works. Don't want to rush into buying something. Spending $1500 for timing cover gasket replacement is worth it to me.

 

[84FLH]

375K on a Ford 4.0L SOHC V6 is almost unheard of without a major engine rebuild. Mine didn't make 200K before having cracked heads and needing timing chains.

345,675. Bought it with about 245,000 on it from orig owner with many receipts. Orig motor. Tranny housing is Ford, may be orig, may be rebuilt, but shifts up/down very good.

 

[84FLH]

With coolant its always the highest point that you can find wetness

> Great to know. Highest point seems to be just below water pump. Meaning timing cover may be leaking.

 

[C420sailor]

The stock t-stat housing sucks and should be replaced anyway, because it WILL fail.

Some people go metal. I’ve heard great things. I went with a plastic from a later model that uses the SOHC. Much better design than original. I’ve got the Motorcraft part number in my maintenance book. I’ve had it in my truck for 120,000 or without so much as a drop.

 

[koda2000]

A pressure test (with or w/out florescent dye) should show where the leak is coming from. A SOHC t-stat housing leak can be hard to see (because it typically leaks from the back), but this is a very common failure point on the SOHC. Dry up any leaked coolant, surround suspected leak area's with paper towels, pressurize the radiator to around 15 PSI and see what get's wet first. You can borrow a cooling system pressure tester from most auto parts stores for free with a deposit.

In my experience, unlike on the V8's, the timing cover gasket on the V6 SOHC is not particularity prone to coolant leaks, but anything is possible. Radiator, hoses, W/P bypass hose and t-stat housings are all common coolant leak points.

 

[410Fortune]

the fan will blow the coolant rearward, so yes it can leak all over the passenger side, it flows down the hoses......

we are seeing more and more sohc engines with over 350K on them stock, usually they are 2002 and newer SOHC engines that reach these miles
regular oil changes with synthetic is the KEY

 

[84FLH]

the fan will blow the coolant rearward, so yes it can leak all over the passenger side, it flows down the hoses.....

>Upper rad, bypass, lower T- stat housing, and three other hoses (behind T-stat) all dry. Coolant puddled on top of pass side motor mount. Top of shock tower very wet. Will take another look at T-stat housing with motor running this weekend. Work 5/12 hr days and 1/2 day Sat. Darn tired on Sunday.

.we are seeing more and more sohc engines with over 350K on them stock, usually they are 2002 and newer SOHC engines that reach these miles
regular oil changes with synthetic is the KEY

>Mobil 1 since day 1, per prev owner. I kept up tradition. Every 6,000 miles 5w/30w with Mobile 1 M301 filter. What's the loud, rhythmic clacking sound I hear at bottom of motor, near front cross-member?

 

[410Fortune]

balance chain slapping around most likely
with timing cover off you can update your main chain tensioner and delete the balance chain

These trucks keep me on my feet 7 days a week, we dont get no stinkin time off! Shop time working on trucks is time off LOL

 

[koda2000]

>Upper rad, bypass, lower T- stat housing, and three other hoses (behind T-stat) all dry. Coolant puddled on top of pass side motor mount. Top of shock tower very wet. Will take another look at T-stat housing with motor running this weekend. Work 5/12 hr days and 1/2 day Sat. Darn tired on Sunday.


>Mobil 1 since day 1, per prev owner. I kept up tradition. Every 6,000 miles 5w/30w with Mobile 1 M301 filter. What's the loud, rhythmic clacking sound I hear at bottom of motor, near front cross-member?

The noise could be due to a broken front jack shaft chain tensioner, or (if 4WD) it could also be the balance chain tensioner. Neither are as critical as the plastic timing chain cassettes/guides breaking, but there are a lot chains whirling around under the timing chain cover. Removing the timing chain cover is quite a bit of work to check and with an engine with as many miles on it as yours not worth the expense IMO. On my SOHC I had chain rattle at startup and later it developed an intermittent clicking sound from the front of the engine. I drove it this way (locally only) for almost 20K before it blew a head gasket. During the autopsy of my engine I discovered I had a grenaded rear timing chain cassette guide, a broken balance shaft tensioner, a broken front jack shaft tensioner and cracks between the valves on both heads. I'm amazed it ran as well as it did (noises not withstanding) before it started loosing coolant, with no external leaks, and it began overheating. I'm now in the process of rebuilding my Job 2 SOHC engine, but I had to think hard about attempting these repairs. The cost of parts alone will be around $2,000-$2,200 even with me doing all the labor. Oh well, I'm retired, enjoy working on vehicles and have nothing better to do with my time. Once repaired IDK what I'm going to do with the Sport Trac, as I don't need 3 vehicles. If I can get a good price for it I may just get rid of it. I was going to give it to my daughter, but I bought her a really nice used car last October and she already has it and her old 2000 Mountaineer 5.0L.

 

[donalds]

 

[84FLH]

Simmons says my factor OEM temp sensors (2000 Mountaineer 4WD) are screw in type, and his T-stat housing uses clip in type sensors. He includes the clips but I'd have to buy the sensors.
1997-2001 Explorer , ranger, Metal Thermostat Housing (SA3) w/ clips and bolts

Thought my sensors were clip in, but couldn't really see when I had the throttle body off. What sensors and where to buy?