Coolant Leak - Thermostat Housing - Help!!!

[Brian Willcox]

I started noticing the smell of burning coolant and found that I have some kind of leak. I looked everywhere and could see fluid in spots, but couldn't find a bad hose or anything. I have been having to add coolant/water in the resovoir for a few weeks now, so I know it is substaintial. I finally took it to a local repair shop and they said that the actual thermostat housing has a pinhole leak. Supposedly the housing is plastic and after a while (i just turned 100,000) from the heat this can happen, they have seen it before. They also mentioned that the new replacement part from Ford is a different design, possibly improved.



Has anyone had this problem? They are wanting to charge $425 for parts & labor. Is this something I could do? I have some mechanical experience (just changed those damn spark plugs and wires with success), and my dad has good mechanical experience.



Also, while they are doing this, would it be a good idea to replace the actual thermostat, it is the original one.



2001 ST with just over 100,000 purchased October 01.



Sorry for the long post, thanks in advance!!!

 

[Kevin Palmer]

Too much money...



Many members have replaced their own T-Stat.



If your local dealer has a replacement housing in stock get it and do it your self.

If not, check with the local auto parts store. It will probably be heavier duty then the OEM one for that matter....



Get a t-stat that is equal to the OEM stat. You do not want to screw with raising or lowering the temperature unless you have an ECM that has been flashed or re-coded to run the temp change. It will cost you fuel if you drop the temp for example...

 

[Brian Willcox]

I looked at a picture of the termostat housing, I can't imagine it being very hard to change. Has anyone change the actual housing?



Here is the picture of the housing: http://www.rockauto.com/ref/Airtex/Detail.html?AO4385.jpg



RockAuto has it for $26.89. It even says in the description that OEM part was plastic.

 

[Allen Brandt]

It's a 10 minute job. Just remove the plastic engine cover (the black one on top with the 4.0L engraved in it), and the thermostat housing is right under it. Held in with 3 screws, if I remember correctly.

 

[Fudged Undies]

Rewind.... Is it the T-stat housing or the upper part that you remove to replace the t-stat. They are two seperate parts. I know, I got to swap mine out about two month ago. The housing itself is not stocked by the dealers here in miami, so I went the Rusty route (<a href="http:\\www.fordpartsfast.com"target=top>fordpartsfast</a>) ran about fitty bucks and had it within a couple of days.



It's not too difficult to remove but it is a bit of a pain. From the best that I can tell, you're probably supposed to remove the intake manifold to more easily replace it, but it's not necessary. That would explain why the dealer wants so much to replace. It can be done by the weekend mechanic but it's tight and can be delicate. Both temp sensors are on the t-stat housing which makes for very little room to get the housing in and out. You may want to check the manuals but I couldn't find anything specific on the t-stat housing. May be under rebuilding the 4.0 with out specific cross reference.

 

[Brandon W]

Hi all.



Replaced the thermostat about a month ago, as the old one was bad and engine was getting too hot. We are running nice and cool now, but I have a small leak out of the housing now. I presumed this was from using the old O-ring (Had to bc couldn't get the old one in-stock anywhere). Finally got the O-ring in and replaced it a few days back. However, I still have a leak.



It's not a fast leak at all. after about 100 miles of driving over the weekend the coolant in the reservoir droped about a half inch. BUT, it's getting to be a pain having to pop to hood every week and re-fill.



It appears that the leak is coming through between either the lower housing joints (where the lower housing parts come together), or else the main joint where the upper housing meets the lower housing (where the t-stat and o-ring sit in).



Anybody have any thoughts or creative ideas, or does it sound like replacing the entire housing is the best action?



Thanks as always.



Brandon

 

[Fudged Undies]

Brandon, Refer back to my thread. The T-statu housing seams to be two (three if you include the t-stat cover) pieces that are "glued" together. In my case, the seam facing the intake manifold began to seperate. You really couldn't see a leak at idle but as you revved the coolant would spurt. Removing/replacing this part is a nussance and that is why I suspect SupaB was gonna get hit so hard in the wallet. It is doable without removing the intake manifold, but it is a very, very tight fit.



If you are leaking, Do everything you can to isolate/locate the leak first. If you cannot, I would suggest ordering an o-ring online first and make sure this isn't the cluprit. You will be able to use the o-ring again if you have to replace the housing. Check the lip of the t-stat cover and make sure there aren't any chips or grooves in the lip that may be permitting the leak, since you will remove it to replace the o-ring. If the above fails, then the housing may be the next logical step. Removing the alternator will give you some added room, though physically removing the housing without removing the manifold will be difficult and be careful with the sensors so you don't mangle a wire. There are two.