Thermostat housing

[griston64]

Fitted a new stat and seal when I did my coolant flush the other week and I think I have a slight weep on the stat housing. Worried in case I have over tightened.

[Laird Scooby]

Did you fit a new seal and/or gasket Mark? I'm having a mental block at the moment and can't think of the red-block 'stat but something is telling me it's the "grooved 'O' ring" that wraps round the outside of the 'stat. If so, did you scrap away any oxidisation on the 'stat housings and smear it with Vaseline or silicone grease?

Also worth cleaning the bolt threads and also the bolt hole threads and putting a smear of copper grease on them to help prevent intermetal corrosion.

Finally, clean the mating faces of the 'stat housing and where it bolts onto the head - ay dirt here can cause a weep. Likewise with the oxidisation in the recesses in the head and 'stat housing where the seal sits.

[griston64]

Hi Dave

It comes with a new seal and I thoroughly cleaned and scraped both mating surfaces. It was a Volvo genuine stat and seal so just wondered if by tightening too much it could possibly distort the seal ?

I've cleaned up around the housing and will keep an eye on it. Not sure if there are torque settings for those bolts

Cheers, Mark

[classicswede]

If they shear off then its too tight.

Corrosion can cause issues with sealing. You can often need to give them a clean up with sand paper

[griston64]

Originally Posted by griston64

Hi Dave

It comes with a new seal and I thoroughly cleaned and scraped both mating surfaces. It was a Volvo genuine stat and seal so just wondered if by tightening too much it could possibly distort the seal ?

I've cleaned up around the housing and will keep an eye on it. Not sure if there are torque settings for those bolts

Cheers, Mark

All cleaned

[Forrest]

In my experience the nuts don’t need to be very tight at all but it helps to tighten them evenly. I use a small 1/4” torque wrench. If you over tighten them it will be difficult to dismantle again in the future. These nuts are very easy to round off.

[griston64]

I found 11-15 lb ft on web. Around 17 nm


One of mine was starting to round off slightly so I used a 6 sided socket.

I only did them up hand tight and just kind of nipped them half a turn after that

Spose it depends how strong you are though

[jpliddy]

Hi i fitted genuine stat and had a weep i took stat off and cleaned it with fine emery paper to mateing surfaces and then i use a silocone based stat sealant and no leaks now

[Forrest]

Originally Posted by griston64

I found 11-15 lb ft on web. Around 17 nm

I’d be wary of the torque settings on the web. They are quite high for the size of the bolts. They are 10mm head but only 6mm thread. I’ve used a maximum of 6-7 ft lbs in the past. The same applies to the water pump. There’s a report here warning about those.

http://www.calgaryvolvoclub.com/foru...php?f=1&t=3029

[jpliddy]

hi the gasket sealant i was advised to get was HYLOMAR instant gasket i have never heard of it its done the job for me and easy to get hold of . only my thoughts! make sure surfaces are clean i sed a 600 grit emery paper