Thermostat Housing- leak that wont stop

JordaninTX

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A friend (who is a mechanic) and I have just finished putting new gaskets on my 2.8 motor. The thermostat housing is essentially a sandwich between two gaskets. You know what I'm talking about if you've ever taken one apart. The problem is, it will NOT stop leaking. He took it apart 3 separate times. The final time, we ditched the gasket and just used gasket maker. It went from a constant stream, to about a half-dollar size puddle after shutting it down. The surfaces have all been filed clean. The gasket maker was allowed to set up over night before fluid was introduced.

Does anyone make all the pieces aftermarket that's good quality? Or does anyone have a NOS set up? If it's taken apart again, I want it to be fixed with different parts. I would appreciate any help on this!
 
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JordaninTX

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Where would you recommend buying a quality housing? I'm new to this motor and I don't know who sells quality parts.
 

LILCBRA

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If you can pick one up from whomever you choose I'd think anyone would suffice. Chances are there are only a couple manufacturers at best who are reproducing these. I'm no authority on the 2.8 though, so I'm sure someone else can give you a better answer than that. I'll defer to @jozsefsz - I think he's our resident 2.8 expert! ;)
 

78mIIman

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Unfamiliar with 2.8L engine thermostat gasket/location. Does it sit vertically on the engine? If so..get some weatherstripping adhesive, smear it on the backside of the t-stat, and stick it in place before putting the housing on. Let it sit a good hour. Problem most people (myself included) would have, is t-stat will slide down out of its spot, and as you put the housing on, it will not sit flush with the intake, causing a big leak.
 

jozsefsz

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Hi @LILCBRA quite an honor to be considered a 2.8 expert. :) The link you posted is great, I actually wasn't aware Dorman started making the front lower and the upper housing too. Dorman is the only manufacturer still making these parts @JordaninTX , brighter side they're decent quality.

You're probably getting leaks because the bolts are weak, and the threads in the rear housing don't allow you to tighten enough because they're stripped out and corroded.

There are quite a number of parts all sandwiched together by those 3 skinny bolts. The order of parts is front housing, front gasket, thermostat, thermostat seal, water pump housing, water pump gasket, timing cover, rear housing gasket, rear housing. Lots of opportunities for leaks.

In addition to front or rear housing (rear is most important as that has the threads for the bolts in it), you'll want the various paper gaskets (I typically cut my own from material I get at the parts store) as RTV usually won't work too well in place of paper gaskets in the cooling system.

Replace the bolts too, if yours are corroded or weak (they are). They're M6x70 and M6x90 bolts, they won't be at the hardware store.
 
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JordaninTX

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Thank you for your
Hi @LILCBRA quite an honor to be considered a 2.8 expert. :) The link you posted is great, I actually wasn't aware Dorman started making the front lower and the upper housing too. Dorman is the only manufacturer still making these parts @JordaninTX , brighter side they're decent quality.

You're probably getting leaks because the bolts are weak, and the threads in the rear housing don't allow you to tighten enough because they're stripped out and corroded.

There are quite a number of parts all sandwiched together by those 3 skinny bolts. The order of parts is front housing, front gasket, thermostat, thermostat seal, water pump housing, water pump gasket, timing cover, rear housing gasket, rear housing. Lots of opportunities for leaks.

In addition to front or rear housing (rear is most important as that has the threads for the bolts in it), you'll want the various paper gaskets (I typically cut my own from material I get at the parts store) as RTV usually won't work too well in place of paper gaskets in the cooling system.

Replace the bolts too, if yours are corroded or weak (they are). They're M6x70 and M6x90 bolts, they won't be at the hardware store.
Thank you for your information. Is there a certain supplier you typically order these dorman parts from? I’m assuming they will also have the bolts.
 

jozsefsz

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You can google the Dorman part numbers and pick your favorite merchant - Summit Racing, eBay, Autozone carry or can order them.

I usually get nuts & bolts from Amazon.com believe it or not, just search M6x70 and M6x90. I don't think anyone makes or markets the originals for this engine, generic bolts will work.

Stainless isn't a bad idea considering the environment, also something with a decent bolt-head (a thin phillips-screwdriver bolt-head won't be able to be tightened enough) something like this: View: https://www.amazon.com/uxcell-Thread-Stainless-Socket-DIN912/dp/B01N1EN1KH/ref=sr_1_7?keywords=m6x90&qid=1571392205&s=home-garden&sr=1-7-catcorr
 
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JordaninTX

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You can google the Dorman part numbers and pick your favorite merchant - Summit Racing, eBay, Autozone carry or can order them.

I usually get nuts & bolts from Amazon.com believe it or not, just search M6x70 and M6x90. I don't think anyone makes or markets the originals for this engine, generic bolts will work.

Stainless isn't a bad idea considering the environment, also something with a decent bolt-head (a thin phillips-screwdriver bolt-head won't be able to be tightened enough) something like this: View: https://www.amazon.com/uxcell-Thread-Stainless-Socket-DIN912/dp/B01N1EN1KH/ref=sr_1_7?keywords=m6x90&qid=1571392205&s=home-garden&sr=1-7-catcorr
Thank you for your help! I will get on it & report back when I have it fixed.
 
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JordaninTX

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Does anyone have a picture of their lower thermostat housing? I am starting to think the front lower housing has been modified. I am trying to find a replacement but none of them in the pictures look like the one I have on my engine.
 

jozsefsz

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Hey there @JordaninTX unfortunately my II is in winter storage or I'd snap you a pic. To the best of my recollection mine looks exactly like the 902-1059 at the link above (https://www.partsgeek.com/mmparts/thermostat_housing/ford/mustang_ii.html)

It connects to the lower radiator hose, and also one of the heater hoses that takes the long route back up towards the firewall.

Feel free to post a pic of what they've done - the 2.8L was used in a lot of cars through the 1980's, very possible a previous owner engine-swapped or pulled some components off of a newer model.
 
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JordaninTX

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As you can see, on the front connection the pipe just comes straight out instead of doing a 90* turn like the other ones.
8207A1FD-997B-474B-A3F6-51302BC8BD6A.jpeg
 

jozsefsz

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That's all very non-stock and custom-fabricated I'm afraid. It looks as though they took a 2-bolt manifold-mounted thermostat housing and 'made it work.' There's at least one of the 3 ears cut off, and that button-head through-bolt in the water pump housing definitely doesn't belong. The rear housing is incorrect too, as is that radiator hose. Some extra googling shows me that even through the 80's Taurus's and Bronco's they 2.8L v6 always used a 3-bolt housing.

The 902-1059 is the correct part for the front.
The 902-1064 is the correct part for the rear.

You can verify these parts here: https://www.dormanproducts.com/

Hopefully they haven't hacked up the timing cover - it kind of looks like they might have but I can't see past that heat-shield sleeve. I'm afraid that's not a stock 2.8L v6 configuration from any year, it's someone's hack-job.
 

JordaninTX

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Jul 1, 2019
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That's all very non-stock and custom-fabricated I'm afraid. It looks as though they took a 2-bolt manifold-mounted thermostat housing and 'made it work.' There's at least one of the 3 ears cut off, and that button-head through-bolt in the water pump housing definitely doesn't belong. The rear housing is incorrect too, as is that radiator hose. Some extra googling shows me that even through the 80's Taurus's and Bronco's they 2.8L v6 always used a 3-bolt housing.

The 902-1059 is the correct part for the front.
The 902-1064 is the correct part for the rear.

You can verify these parts here: https://www.dormanproducts.com/

Hopefully they haven't hacked up the timing cover - it kind of looks like they might have but I can't see past that heat-shield sleeve. I'm afraid that's not a stock 2.8L v6 configuration from any year, it's someone's hack-job.

Well then... this is going to be an interesting fix. Thank you for your help. I may just order new bolts and cut some custom gaskets and see if that does the job. Not much I can do otherwise. I ordered the "correct" replacement parts. Might give those a whirl and see if there's anything that can be done there to make them work in this configuration.

Thank you. I will report back if anything develops.
 

JordaninTX

Member
Jul 1, 2019
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That's all very non-stock and custom-fabricated I'm afraid. It looks as though they took a 2-bolt manifold-mounted thermostat housing and 'made it work.' There's at least one of the 3 ears cut off, and that button-head through-bolt in the water pump housing definitely doesn't belong. The rear housing is incorrect too, as is that radiator hose. Some extra googling shows me that even through the 80's Taurus's and Bronco's they 2.8L v6 always used a 3-bolt housing.

The 902-1059 is the correct part for the front.
The 902-1064 is the correct part for the rear.

You can verify these parts here: https://www.dormanproducts.com/

Hopefully they haven't hacked up the timing cover - it kind of looks like they might have but I can't see past that heat-shield sleeve. I'm afraid that's not a stock 2.8L v6 configuration from any year, it's someone's hack-job.
Sorry, another question. You said it looks like the took a 2-bolt manifold-mounted thermostat housing and made it work. Can you elaborate on this a little bit? Is that the same as the "water inlet" at the top of the block? Is that what you mean?
 

jozsefsz

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Sorry, another question. You said it looks like the took a 2-bolt manifold-mounted thermostat housing and made it work. Can you elaborate on this a little bit? Is that the same as the "water inlet" at the top of the block? Is that what you mean?
No problem, that's what I'd meant yes, it looks like a water inlet you'd find on top of the block, perhaps not even from a 2.8L. Kind of hard to tell from the angle of the photo though, but it's obvious it's not the right part.