2000 V70 AWD Thermostat Housing Will not seal

sawtooth4x4 · Post by **sawtooth4x4** » 09 Dec 2013, 20:40

I have just installed my second gasket on the thermostat housing. This is my only leak after doing a complete head rebuild.

I do not know why it will not seal. I used gasket glue and even put some thread sealant on my bolts for the thermostat housing. the gasket matched up perfectly to the housing.

The thermostat seams to seal fine. its just between the head and the housing.

Edited 1 time- please abide by forum rules- no use of Help in titles

Post by **Ozark Lee** » 09 Dec 2013, 20:46

Are you sure the housing itself isn't cracked? The lower housing is a very weak link in an otherwise over-engineered engine. We have had many members break the housing just trying to get the thermostat cover off to change the thermostat and ECT sensor.

...Lee

sawtooth4x4 · Post by **sawtooth4x4** » 09 Dec 2013, 21:12

It could be. I guess I'll order a new one.

Post by **northernlights** » 09 Dec 2013, 22:35

Here's a TSB from 1997. Volvo recommends using two gaskets to avoid leaks on 850's. I would not be be surprised if a 2000 V70 is similar unless there were significant changes made.

SECTION 2
Group 26
NO.
804
DATE
Apr.-97
Thermostat housing leakage, double gaskets 850 1992-
REFERENCE: TP 2102201, SECTION SECTION 2(21) RECONDITIONING ENGINES B5202, B5204, B5234, B5252, B5254; 850 1992-
Double gaskets for thermostat housing
Background:
To ensure that no leakage occurs between the thermostat housing and the cylinder head always use two gaskets. This method should be used as a service measure to correct coolant leakage from thermostat housing or when reconditioning.
Please change the text in the following Service Manual, page 66, section L3, from one gasket to two gaskets.
TP 2102201 Section 2 (21)
Reconditioning Engines B5202, B5204, B5234, B5252, B5254 850 1992-
Materials: Gasket for B5204, B5234, B5254 2 x 1397574-3
Gasket for B5202, B5252 2 x 1397437-3

sawtooth4x4 · Post by **sawtooth4x4** » 10 Dec 2013, 06:11

Interesting. I was wondering why my gasket kit came with two thermostat housing gaskets.

Thanks.

When I put it together last time, i did not see anything wrong with either gasket surface on either the head or the thermostat housing face. That is definitely something i'll try.

Thanks! This is a much better forum then the other one I've been using!

sawtooth4x4 · Post by **sawtooth4x4** » 10 Dec 2013, 08:02

found a couple of thermostat housing gaskets at carquest. so i can try to fix it again tonight. should i use some silicone between the two gaskets or just use gasket glue.

Post by **northernlights** » 10 Dec 2013, 08:30

If you use anything, I would use it very sparingly. Volvo does not recommend additional sealant (like blue RTV) on these gaskets in my references and is usually very specific about having completely clean surfaces. But, when needed, a few dots of something to hold things in place during installation is better than having misaligned gaskets.

sawtooth4x4 · Post by **sawtooth4x4** » 11 Dec 2013, 06:10

Found the problem last night, and it was probably the reason the car had a blown headgasket when i bought it. the housing is cracked. not sure how it happened. I'm sure i couldn't have done it, i didn't tighten it that hard.

Off to the junkyard i head today, then I think I can finally start it up tonight.