Thermostat gasket leaking (1 Viewer)

[saleach]

Hey guys,

I replaced my water pump and timing belt a few weeks ago and I am having trouble getting a good gasket seal at the thermostat housing. (See pics).

I have done the gasket twice. The first time I followed the directions on the permatex gasket maker (red). I put the material all around the opening and bolt holes covering the whole mating surface. (I realized this was wrong after reading the diy by scottm).

Then, I tried it again using the scottm method, filing both sides, scraping out as much gasket as I could from the grooves (some still remained that i could not get fully out, but it was 99% gone, just residue). I also used the surface prep activator. However, it's still leaking! The leak appears to be coming from the bottom side of the housing.

So, I have the following questions:
1. How much gasket material am i supposed to use around the recessed lip of the thermostat housing?
2. How do I get the housing into the water pump to correctly seat the housing? (It seems like the o-ring portion above the gasketed part has to be wiggled into place; this may be what is ruining the gasket)
3. Any other advice? I would like to be finished with it after the 3rd time.

 

[jemsec]

Replace gasket and use a good sealant. Let it set long enough for the sealant to harden before starting the engine. Use factory torque setting.

 

[aging fleet]

I used Permatex water pump and thermostat housing gasket maker and followed the instructions from the FSM regarding how to apply the FIPG. I let it cure for 18+ hours before I added coolant.

 

[nissanh]

I ran the toyota sealent the way the manual (above) shows but didn't press in the O-ring arm into the engine block with hand. I used one hand to hold the thermostat housing few mm's from the engine block and install the two bolts. Then slowly turned the two bolts (about 2 full turns each) alternatively. Continue to do this and easily you'll get the O ring arm to slide into the engine compartment. Make sure to apply a small film of coolant into the inside of the housing where the O-ring slides/sits in. Do the same for the heater line O-ring. DON'T apply coolant/oil right on to the O-ring.

 

[saleach]

Thanks for the reply guys! I took everyone's advice and it appears to be ok now. 3rd time was the charm! For the sake of future searches what I did to get it to work was:

1. Use permatex water pump and thermostat specific gasket maker ($3 at orielly's)
2. Clean both sides of thermostat and water pump very well.
3. Spray permatex surface activator on both surfaces
4. Use a small bead of gasket maker on the thermostat as shown in the FSM, make sure it gets into the groove and is overfilled but doesn't extend much past the groove. (i had to do this twice since the first time i was a little to liberal with the gasket maker)
5. Use coolant to lube both the hole to the engine that the thermostat so it slides in easy

Thanks again!

 

[BillZ260]

Glad you got it! I'm just going to chime in because I did it this past weekend and maybe this will help.

I scraped out all old black gasket, then I hand filed the mating surfaces smooth, no real pressure, just graze the surface to clean up any burs. I used the black Toyota sealant recommended and made sure to fill the channel and have plenty on the face as well. Put a bit of soapy water on the new o-ring and pressed it in. I let the bolts pull the pieces together tightening them each a bit at a time until tight and let it set/dry overnight. Have had no issues.