thermostat leaking

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Jul 11, 2009 | 07:28 PM

smoky_diesel

Thread Starter

Cargo Master

Joined: Sep 2007

Posts: 2,470

Likes: 535

From: Chandler, AZ

thermostat leaking

had coolant leaking off the bottom of the engine so I replaced the water pump with a unit from Napa.

the thermostat is leaking. the pump cam with 2 o-rings. one is slightly smaller, and bigger one has squared/bevel profile. I put the regular o-ring on the t-stat as the larger one is too big.

do I need to force the oversized square/bevel job in the t-stat and strech the too small regular o-ring on the lower pipe? help.... thanks

Jul 11, 2009 | 07:54 PM

DieselCamper01

Fleet Owner

Joined: Mar 2007

Posts: 28,306

Likes: 6

From: BLT, MN

I have not done this so I am unsure but here is a bump

Jul 11, 2009 | 08:08 PM

miller_feed

Hook it, I'll pull it.

Joined: May 2007

Posts: 15,037

Likes: 4

From: Grand Lake, La.

If the t-stat housing is leaking. I had the same thing, I had to tighten the 3 bolts at the same time, half a tur on each. I did this 3 times before I got it to stop leaking. The gasket goes on top of the stat.

Jul 11, 2009 | 08:15 PM

smoky_diesel

Thread Starter

Cargo Master

Joined: Sep 2007

Posts: 2,470

Likes: 535

From: Chandler, AZ

It appears to get this thing to seal the o-ring needs to be forced up against the parameter of the seal. otherwise a 2 o-ring sandwich is needed.

i tried the old seal and it leaks too. I hope to only try one more time.

5 hours in 112+ degree heat is enough for today. going to watch the UFC fight and hopefully GSP will get a his a$$ beat.

thanks FTE'ers

Jul 11, 2009 | 08:21 PM

miller_feed

Hook it, I'll pull it.

Joined: May 2007

Posts: 15,037

Likes: 4

From: Grand Lake, La.

I also used a little of RTV High heat on the housing twice. It took tighting the bolts even to get the thing to seat and not leak. I don't have a leak now. Good luck.

Jul 11, 2009 | 08:49 PM

countrycar

Posting Guru

Joined: Mar 2007

Posts: 1,425

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It seems that when ever you take the T-stat housing apart, it's gonna leak when you put it back together. I've read hear and on other forums that this is a bad design as well. When I did my water pump about 7 months ago my T-stat leaked also. I tried to tighten it more but I couldn't get it to seal. I bought a new aluminum housing from Bob at Diesel site to replace the old one with. It's never leaked agian. They rust out at the base, and begin to leak there too.

Jul 12, 2009 | 05:48 PM

Supercab

Lead Driver

Joined: Feb 2000

Posts: 5,374

Likes: 46

From: Palm Bay, Florida

I have to agree that you really need to get the billet tstat housing from Bob at Dieselsite, double clean the contact area on the pump, and use a new "O" ring-I believe the thicker one goes in that area though I used the thick one on the lower radiator hose connector at the advice of many here when the thin one leaked from brand new.
Also might want to take the time to get the 203* tstat from Bob as well and 3 new bolts to install the housing with and apply some anti-sieze to the threads......Be careful in the heat!! Good Luck