Thermostat housing question

[Anvil]

I spent the past few days replacing all of the cooling system components (1997 Fzj80) along with the front crankshaft seal and oil pump cover gasket. I cannot get the thermostat housing to seal. I've tried 6 times using OEM thermostat gaskets... finally resorted to using RV sealant along with new gasket, and allowed it to dry for 24 hours. It still leaks!

I'm beginning to think it is the housings. Has anyone else had this problem? Does anyone have the part number for the flange the thermostat housing bolts to?

Thanks!

 

[Cass007]

Did you use a OEM thermostat? I had an issue with the aftermarket one I got at Advance Auto. Also, did you orient the thermo correctly with the relief valve pointed up? Lastly, did you put the gasket (new one) around the thermo? It sits in a groove in the gasket, not in front or behind it.

I don't have the part number, but I know the flange is available. I just got one the other week.

 

[TomOsborne]

 

[TomOsborne]

Have the O ring like above pic? I didn't get mine like I assumed when I bought the stat. Put me behind a week

 

[Cass007]

^^^ That does not look like a '97 housing

 

[Cass007]

6

• Cass007
• Feb 24, 2018

My 97 housing. I think this is the piece he is asking about

 

[Cass007]

9

• Cass007
• Feb 24, 2018

R22

• Cass007
• Sep 11, 2017

R21

• Cass007
• Sep 11, 2017

You can see where the rubber ring goes around the thermo here and the small relief valve as well. PO had some sort of stop-leak crap in the system, so I had to basically swap out all of the components.

 

[TomOsborne]

Oh Im sorry. I have a 3FE. Is there a ring on the 97? If there is maybe its still the problem. Again apologies.

 

[Anvil]

Did you use a OEM thermostat? I had an issue with the aftermarket one I got at Advance Auto. Also, did you orient the thermo correctly with the relief valve pointed up? Lastly, did you put the gasket (new one) around the thermo? It sits in a groove in the gasket, not in front or behind it.

I don't have the part number, but I know the flange is available. I just got one the other week.

Yes sir, I used OEM thermostat and OEM gasket... 6 times now...

Yes, the thermostat is positioned correctly. The gasket is installed around the thermostat correctly. Still leaks.

I also wire wheeled the housing flange to make sure it was clean. Still leaks.

 

[Anvil]

6

• Cass007
• Feb 24, 2018

My 97 housing. I think this is the piece he is asking about

Yes sir, I need the part number for the piece the housing bolts to. I've been unable to find it. Thanks!

 

[inkpot]

are you sure that it is the thermostat housing that is leaking? It can be real challenging to get the vertical bypass tube to seal up where it fits onto the top of the thermostat housing.

 

[Anvil]

I want to thank you all for the input! I finally found the problem...

The bottom of the thermostat housing had a 1/4" hair line crack, near the bottom bolt. I finally used a mirror and flashlight and could see it slowly dripping. I have no idea how or why this happened, it had never leaked before. Fortunately, Lostinafog had a spare! No more leaking!!! Thanks again!

 

[Adsing]

Resurrecting given I had a similar problem with my housing.

Brand new from the Toyota. If you look closely you’ll see the hairline crack on the bottom stud. Super disappointed. Bummed that I now have to resort to the old (gunked up one) in the meantime while I track down a new one and give the dealership a piece of my mind.
Lesson learned. Look at your new part before leaving the dealership.