I am getting a small intermittent coolant leak after a total engine rebuild, about the size of your fist on the passenger side near the back of the front tire.

This leak just started but it only occurs right after engine start and there is no evidence of a leak on the block, around the water pump , radiator and no smell of burning coolant. Also the coolant tank and all lines are brand new and the radiator is less than 4 years old with no leaks that I know of.

Is it possible that the coolant tank would spill over through the overfill line momentarily if the system was too full as the the system get full pressure from the water pump right after a cold engine start?

Thanks!

 

I got something similar and upon further inspection I noticed a hairline crack on the Expansion Tank that was not consistently leaking and very hard to see. I used one of those very bright lamps to inspect it closely and found it. I replaced the Tank and the problem was solved. Hope your are as this simple.

 

The expansion tank is brand new from Roger and after I park the car, no leaks on the floor at all. It has to be pressure leak of some type but i notice no leaks if you crawl under the engine while the engine is running. I guess I will have to get it up on a lift. Thanks

 

check the heater valve, and check ALL the conniptions to the tank. thats the only thing back that far. also check the heater lines on the side of the fender.

 

what year/model of 928?

The later engines fuel regulator is held to the block using the bolts that also secure the coolant connection for the water valve. If the bolts are not tight or the gasket not intact will leak on engine start all the time as its on a main coolant passage.

 

Mine is a 82 5 speed.

 

I had a coolant leak...took me a while to find....

See it....? The breather hose running from the oil fill reservoir to the air cleaner has a water jacket in it....mine was broke....I did not see it with my eyes at first...the camera caught it......don't know if this is where yours is leaking, but ya never know....

 

That unusual and no longer available water heated oil breather hose is 78-79 models only....

 

I see....I just got one from Mark on the 1/2 off sale....I consider myself very fortunate to have gotten it.

Thanks James...

 

Found the leak! I needed to tighten up the new hose clamps on the new hoses coming out of the new expansion tank.

Thank God it was simple and not a gasket or radiator leaking from a new rebuild. Just a drip coming out the tank hose migrating down the passenger side and dripping off the frame rail behind the passenger front tire. It was puddle about half the size of a clenched fist on the floor every morning.

Now on to taking the sunroof out and cleaning 30 year old grease from the drive mechanism.

 

sun roof work..... UGH. Good luck!