Thermostat housing still leaking after multiple repairs

[tekgarage]

Hello all,

I purchased an 02 ford explorer limited 6-7 years back and when I purchased the car,it has a tiny leak in the coolant overflow resevoir. No problem I though. I just kept adding a bit of coolant every so many months. Finally, I decided to wise up and change the resevoir. After a little time passed, my radiator cracked, and was replaced. Next my thermostat housing began to leak. It leaked out of the bolt holes as well as the seams of the plastic housing itself. To date, Ive replaced the housing 3 times because of the same issue. It happened again today and im wondering what can be creating so much pressure in the housing that it keeps cracking? Any ideas people?

Bout to pull out my hair!!!

 

[swshawaii]

Possibly over tightened? Torque spec for the three lower thermostat housing bolts is only 89 inch/lbs. (7-8 ft/lbs) Upgrade?

http://www.explorerforum.com/forums/showthread.php?t=362922

 

[tekgarage]

Thanks swshawaii,

I'm gonna look into properly torquing. Metal housing is hard to find to purchase, no more on ebay. Before I replace with the metal either way, I would like to know if there is any scenario where coolant pressure can go "through the roof" to cause problems like this. Im afraid to replace the housing only to have something else punctured through because of the pressure, maybe the radiator will leak again.

If anyone has any other ideas,please let me know, gonna throw the car apart tomorrow and see if I can get a final fix.

 

[swshawaii]

Radiator caps DO fail, and 16 PSI isn't much. Pressure test or replace it. Could be the best $6.37 fix EVER.

http://www.rockauto.com/catalog/x,carcode,1377660,parttype,2068

 

[tekgarage]

Already changed that as well :/.

Last time there was a hairline crack through the plastic and now it looks as if it is coming through the seams.

Does running the AC put more pressure on the engine cooling system, aside from the fact that obviously the engine is working harder. Does it actually increase the PSI within the system?

 

[Exproblems]

Radiator caps DO fail, and 16 PSI isn't much.

Just to give the OP an idea of the engine cooling system pressures, a household garden hose has approx. 20 psi of water pressure running thru it at full flow, so the vehicles engine cooling system runs at an even less pressure than that.

 

[Bobmbx]

Already changed that as well :/.

Last time there was a hairline crack through the plastic and now it looks as if it is coming through the seams.

Does running the AC put more pressure on the engine cooling system, aside from the fact that obviously the engine is working harder. Does it actually increase the PSI within the system?

The AC does not interact with the cooling system other than controlling the fan speed (to draw more air across the AC condensor). The compressor doesn't add that much of a load to the engine. The pressure of the cooling system is controlled by the radiator cap, which vents off air/expanded fluid when the coolant temperature increases. As others have said, most caps open into the recovery tank at 16psi, although you can buy caps with different ratings.

As a note, the pressure in the cooling system is not required. I ran my 2006 with a leak in the very top of the rad for years with no cooling issues, other than I never had any coolant in the recovery tank. Once the rad level was below the hole, I stopped losing fluid.

NOTE: If you run pure water or a low coolant/water ratio, you'll end up boiling over. The pressure, in this case, keeps the water from boiling. It works just like a pressure cooker. The coolant (glycol) has a much higher boiling point than water.

 

[tekgarage]

Thanks for all the input guys,

I understand the whole pressure thing now. The reason why I had that logic was just because of the continuous leaks throughout the cooling system at different component. First starting at the reservoir, then radiator, then thermostat housing. It just seemed like every time I remedied one situation, the pressure would break/crack something else. I guess it was just a coincidence that all that happened?

The only other thing I can think of, but highly doubt, is a faulty water pump, would this cause any issues?

Other than that, I guess the Ford thermostat housing design is just a huge POS! Don't want to get rid of the car, but I'm just sick and tired of dealing with the same issue over and over and over again.

 

[Bobmbx]

Thanks for all the input guys,

I understand the whole pressure thing now. The reason why I had that logic was just because of the continuous leaks throughout the cooling system at different component. First starting at the reservoir, then radiator, then thermostat housing. It just seemed like every time I remedied one situation, the pressure would break/crack something else. I guess it was just a coincidence that all that happened?

The only other thing I can think of, but highly doubt, is a faulty water pump, would this cause any issues?

Other than that, I guess the Ford thermostat housing design is just a huge POS! Don't want to get rid of the car, but I'm just sick and tired of dealing with the same issue over and over and over again.

The radiators for earlier Explorers suck. No other way to describe it.

The T-stat housing is a remarkably poor design. Constant failures with them, most commonly along the joints (seams). Over-torquing causes the majority of failures. But, then again, almost every T-stat housing ever made, for any car, has had issues. Anyone here who has never snapped off a T-stat bolt flange raise your hand.

The recovery tank issue is a rare one, although I could probably fix that with some Permatex.

I don't see any cause/effect relationship with your failures, except for poor design of the whole cooling system. You'd think they just invented it or something.

 

[tekgarage]

I don't see any cause/effect relationship with your failures, except for poor design of the whole cooling system. You'd think they just invented it or something.

Haha I hear you!

Since I can't seem to find the metal housing anywhere, is there any specific part you recommend as far as OEM(motorcraft) to aftermarket goes (like a dorman).

Also, is there any type of sealant or extra steps I can take when installing to have a better result?

Thanks!!

 

[Bobmbx]

Haha I hear you!

Since I can't seem to find the metal housing anywhere, is there any specific part you recommend as far as OEM(motorcraft) to aftermarket goes (like a dorman).

Also, is there any type of sealant or extra steps I can take when installing to have a better result?

Thanks!!

I put one from Advance Auto in mine (pretty sure it wasn't Motorcraft). No sealant required.

I would advise you to clean the sealing surface on the block first by scraping it with a razor and then using some fine sand paper on it. Use your fingertip to feel for any irregularities on the sealing surface. Shiny and smooth works best for this type of seal.

Then, make sure you put the housing on STRAIGHT DOWN. Don't angle it on and then "flatten" it out by torquing the bolts. The seal is a lip seal, not a gasket or o-ring and can easily get folded over and you'll never see it. The 3 plastic tabs can also get in the way.

Finally, torque. Don't monkeyfist the bolts. Take your time, snug them by hand, then start running them down like you would do for lug nuts, a little on #1 , a little on #2 , a little on #3 , then back to #1 , etc.......

If it feels like you've got'em nice and tight, you've over-tightened them.

 

[swshawaii]

Have you tried contacting the seller direct? BTW, Amazon also sells them.

http://www.explorerforum.com/forums/showpost.php?p=3176031&postcount=2

 

[Exproblems]

Other than that, I guess the Ford thermostat housing design is just a huge POS! Don't want to get rid of the car, but I'm just sick and tired of dealing with the same issue over and over and over again.

Have you tried installing a "Dorman" brand t-stat housing yet? They sell them at Advance Auto Parts stores or online at their web site. Dorman claims to have corrected the cracking problems that the Ford t-stat housing comes with. I installed one last year in May 2013 in my Ex and had no issues at all with it for the first 3 months, but my timing chain crapped out in late August 2013 and my engine was replaced by a new remanufactured engine that came with a new factory Ford t-stat housing already installed on it. If you decide to try the Dorman product and want to order it from Advance Auto parts, go to www.couponcabin.com first and get the appropriate valued online coupon from them to use at the Advance web site and use during the ordering process. I think the new t-stat housing cost roughly $80-$90 and comes with both seals (housing to manifold and t-stat o-ring), a new t-stat, extra accessory plug/clip etc. Make your order total $100 and you can get a $40 off coupon from couponcabin.com