[Dinky☘️]

Hey all! New to the community and world of Saab’s.

Thermostat replacement on 9-3 1.8t 2008
- smooth process right up until refilling the coolant.

Noticed the coolant was leaking pretty much straight back out almost directly under the thermostat housing

Now, when I put in the new thermostat I had to use the old O-ring, which was stretched and worn and obviously too wide.

I know (now) to patiently wait for my new O-ring to arrive but in the meantime I’m (slightly) worried about the location of leak, there was a little bit of leaking around the housing (which is where I thought it would come from if anywhere) but the majority was from underneath the housing in a place I couldn’t quite pin point with my eyes - too far down and not a good angle to see.

Any coolant I put into the reservoir would quickly end up on the floor from this non-visible area. I tightened some things, had a look here and there which slowed it and then started the car to check, and this made the leak return to its original pace.

What’s down there under the thermostat housing that might be where the leak is coming from?

Or is this solely related to the thermostats O-ring not being a proper fit?
Or have I an actual leak?

Checked hose clamps etc and all seems in good shape. I’m aware that if the thermostat isn’t fitted right that coolant will pass it but why is it passing the Stat and then leaking from a point beyond that where there was no previous leak. I don’t think I caused damage to anything in the process and this certainly wasn’t happening before this until I opened the thermostat housing.

 

[steve12955]

On the 2.0 there’s a coolant tube that runs horizontally between the housing and the water pump on the backside of the motor. A large o-ring seals it at either end.

 

[Dinky☘️]

On the 2.0 there’s a coolant tube that runs horizontally between the housing and the water pump on the backside of the motor. A large o-ring seals it at either end.

Didn’t touch it in my process and no prior issues, but could I have messed with it when I opened the thermostat housing in some way do you think?

 

[steve12955]

Thermostat housing is plastic and I imagine gets more brittle with age and heat cycles. It’s possible that it’s cracked; I’d get under the car with a light and check it.

 

[Dinky☘️]

Thermostat housing is plastic and I imagine gets more brittle with age and heat cycles. It’s possible that it’s cracked; I’d get under the car with a light and check it.

thanks will have a second look though pretty sure housing is fine

 

[93inmo]

When I changed my thermostat housing a few months ago I placed the thermostat upside down. The unit leaked when I filled it. I tightened the housing more (thinking it was loose) and ended up cracking the cover while tightening it.

 

[Dinky☘️]

When I changed my thermostat housing a few months ago I placed the thermostat upside down. The unit leaked when I filled it. I tightened the housing more (thinking it was loose) and ended up cracking the cover while tightening it.

Yea I can see it would be pretty easy to do that, I think I’ve got the Stat in properly, spring down and bleeder hole at 12pm. Will take out all involved parts today and inspect while waiting for my O-ring. Thanks for your comment!

 

[Bob12312357]

I had a leak after replacing my t-stat. I used a new o-ring but I either torqued down unevenly initially or didn't seat the gasket properly. One careful disassembly/reassembly fixed all issues....I would definitely start there.

 

[Dinky☘️]

I had a leak after replacing my t-stat. I used a new o-ring but I either torqued down unevenly initially or didn't seat the gasket properly. One careful disassembly/reassembly fixed all issues....I would definitely start there.

I think that’s my plan of attack Bob, was your leak like mine and also in around the housing but not exactly from the housing itself? If I could describe the leak from what I see I would say it’s under my housing anyway. Appreciate the reply

 

[Bob12312357]

I could only see my leak by filming a vid on my phone with the flashlight on. As far as appearance it seemed to be coming from behind everything because I only saw it dripping off the housing, which is why I suspect the gasket wasn't seated properly either due to shifting or uneven torque when finishing up. I know its only a few lbs of torque but if I pinched one side of the 3 bolts too much it would cause a slight widening on the opposite side. Either way, I definitely did reassembly almost blind & by hand the first time because of how hard it is to fully visualize back there so I was far more careful the 2nd time to make sure the gasket stayed seated when the housing was placed over it.

IME when you touch something, then have a problem it is unequivocally related to what was just manipulated....Occam's razor

 

[Dinky☘️]

I could only see my leak by filming a vid on my phone with the flashlight on. As far as appearance it seemed to be coming from behind everything because I only saw it dripping off the housing, which is why I suspect the gasket wasn't seated properly either due to shifting or uneven torque when finishing up. I know its only a few lbs of torque but if I pinched one side of the 3 bolts too much it would cause a slight widening on the opposite side. Either way, I definitely did reassembly almost blind & by hand the first time because of how hard it is to fully visualize back there so I was far more careful the 2nd time to make sure the gasket stayed seated when the housing was placed over it.

IME when you touch something, then have a problem it is unequivocally related to what was just manipulated....Occam's razor

Nice one man top notch reply, new ring hopefully delivered in two days will post the update