Leaking thermostat after replacement

[jdd]

Two weekends ago, I replaced the thermostat on my B7 2.0t. Low coolant indicator came on after about a week. It was impossible to see what precisely was the culprit, but after removing the alternator again, I'm reasonably certain that it's not any of the coolant tube to t-stat connections, but rather the t-stat to engine block interface. I loosened it up, and reseated the t-stat and re-torqued the bolts. It's leaking again, but definitely less so. I've just ordered another gasket and hopefully will redo the job this weekend, provided it arrives on time.

My question is, are there any tips or tricks or special instructions for installing the thermostat correctly? I'm hoping I just pinched the seal somehow the first time and a more careful re-install will solve it. Anyone else experience this issue? I really want to make sure I get it right the second time and not have to attempt a third. Plus that coolant isn't cheap.

jdd

[Hugh@EuropaParts]

What brand of thermostat did you buy?

[SLYCAT]

I also have nicked the seal when redoing my thermostat the first try, causing a small leak. By adding a little silicone lubricant to the seal the second time helped it seat better and didn’t pinch while putting it back in. Hope that helps.

[philip_g]

What brand of thermostat did you buy?

probably a wahler like the one you sold me that leaked.

[jdd]

Bought it from JHM, unsure of the brand. SLYCAT, just to be clear, you're not talking about rtv, right?

[brandonpham]

By gasket we mean the rubber ring right?

I got mine OEM and did it last week. Bought it through the dealer for like $50?

[jdd]

Sorry, yes. Should have said o-ring.

[brandonpham]

Gotcha. Scared me. I was like, I don't remember a regular thermostat housing gasket......lol.

[blackcivic11]

the orientation of the bracket on the hardline is very important. Make sure you mind that it goes back on the way you took it off either behind or ontop of the bracket on the block. If you reverse the orientation the line will be crooked and could cause a leak

[konarider94]

I think the t-stat should also come with an o-ring for the hard line. I replaced mine and it leaked because I didn't think to get a new o-ring with it. You said you don't think that is your problem, but just a word of caution to be sure. They take a compression set over time which is why its always good to replace them.

[jdd]

I did replace the o-ring on the hard line and I reinstalled the bracket correctly. I removed the alternator to inspect all those connections to be sure, and saw no signs that they were the source of the leak. It's definitely leaking at the block.

[M0E7]

I pinched that seal during my first install as well, resulting in some visible damage to the seal and a small leak..

Just be more careful lining up the thermostat with a new seal and you should be fine.

[B72011]

I replaced mine proactively when I did the timing belt. I overtorqued it causing a pinch that would shrink just enough and when it got cold it had a leak. I replaced the whole Tstat with an OEM unit (even though mine only had 30k miles on it) and it came out fine--probably should have just used a new O ring. . But the hardline wouldnt go back in properly--I had to bang it in.---when I started it--it leaked. Pulled it all apart and added a small bit of rtv to the oring and let it set so it was on that hardline good. Then applied another thin film to the oring to aid in assembly, let it dry and it worked great--no leaks and the hardline went in easily. I saw a guy on youtube (a pro mechanic use some rtv so I figured no harm.)

[SLYCAT]

I used the grease a dealer acquaintance provided for the moon roof lubing.