Engine/Transmission (1994 - 1998) coolant leak again

[JRS]

Well, it's happened for the third time. I'm getting coolant leak around the thermostat housing. (I've verified it's not the head gasket) I have changed the thermostat gaskets each time, making sure the sealing surfaces are hospital clean. I can drive around for 5,000 miles with no leaks, but 100 miles after I start towing my car trailer (6K lbs. ) I get leakage. I'm using Cummins parts, and have even gone as far as using brand new Cummins bolts. (I always use a torque wrench) I think the only thing left is to replacing the thermostat housing, but I can't see any reason for this. Any other ideas?

 

[CRobbins]

I had the same problem. Use a small amount of ultra black silicone on all the gaskets. Fill the cracks between the gasket and engine lift bracket. After I fixed that, I found the head gasket leaking. :{



cr

 

[JRS]

thanks, but I did that last time. I used the high-temp orange silicone, which is what I use on everything on my race car. I even jacked up the front end of the truck so that the excess coolant rolled to the back of the engine and away from the opening for the thermostat. That way I could ensure the silicone had a dry surface to adhere to. Everything is fine until I start towing something.

 

[Sled Puller]

Check all surfaces for a warp... ?

 

[JRS]

good idea. I have a small steel machinist's rule. will try it this weekend.

 

[endoqwest]

Hi JRS, I've just encountered a similar problem. Unfortunately, I have determined that my head gasket is the problem. I removed my thermostat housing to replace the seals and thermostat. All were in good condition. Upon closer inspection, now that the housing was off, the leaking gasket was obvious. I will try some stop leak but don't have much faith in that stuff. I'll probably have to pull the head. Bummer. I've got photos but can't figure out how to get them on the post. P. M. me if you want to see them.

What did you end up doing?

 

[DBogo]

i had the same problem on the powerstroke and a little bit of the blue silicone cured it

 

[WDixon27]

today i just squashed a leak that i thought was a HG leak, theres a seal between the alternator/ac compresser bracket and the block and mine was rock hard and seaping worse and worse, the lower radiator hose connects to the center of the bracket, it's fun to change too took 3-4 hours and i turn wrenches for a living

 

[hsmith]

Just fixed mine with a new head and marine gasket. Had already replaced tstar gaskets twice.

 

[hsmith]

Correction, make that tstat gasket.

 

[Desperado]

today i just squashed a leak that i thought was a HG leak, theres a seal between the alternator/ac compresser bracket and the block and mine was rock hard and seaping worse and worse, the lower radiator hose connects to the center of the bracket, it's fun to change too took 3-4 hours and i turn wrenches for a living

My 1995 just started leaking by the a/c compersser also, would you happen to have the part # for that seal, I would reather spend 3 or 4 hours to fix it myself then give good money to someone that thinks it's juist another job. TIA

 

[WDixon27]

unfortunatly i don't have the number, after about 5 minutes at the dealer looking at different screens we guessed and it was a good guess, only a couple bucks black rubber and about 1. 5 inches round

 

[Desperado]

Thanks I go to the dealer on Monday and take a look.

 

[Desperado]

Well I went to the dealer and found the part I think (item #26 Part #4429 697 Seal ring) it looks like a square edge o-ring, will find out Wednesday afternoon.