Coolant leak (yay!)

[Craig]

Just what I needed.

Unfortunately I didn't notice the puddle until about 2 hours after I parked so any traces of the liquid on in the engine compartment are long since dried up. I am off work tomorrow, so will be checking it out. The drip spot appeared to be fairly far back, so I'm hoping it's not the headgasket leaking (which would be the third in as many 535is, dammit).

Any tips on how to find this are appreciated, I'd rather not have to get the car hot and then crawl under it. There are so many coolant hoses around that back of the motor I'm hoping it's one of those.

[andyman32]

My coolant went way down just recently, within the past 3 weeks... when the weather got HOT. Weird. Both in the BMW and the Volvo - kaput. Both are almost bone-dry after just a few weeks once the weather gets hot. I topped off the E39 with BMW coolant and it hasn't gone down at all since. I dont' know, I'm going to hesitate replacing things until I find a steady flow.

[Mr Project]

You could get it hot and then start squeezing hoses in the back of the EC while it's running... that should reveal if one of the hoses is leaking. I've seen pinhole leaks become nice visible squirts when squeezed. You'll want decent gloves for this job, obviously.

[Jeff N.]

Check the expansion tank for cracks, Craig. Look for coolant trails on the back of the firewall, on the support post for the tank. When they get old they split along the seam - hard to find.

Other suspects would be that rats nest of heater hoses in the back by the aux pump and firewall passthru. Hose clamp symphony for sure. Hard to inspect as well.

One more place to check is the "T" connection in the major radiator line on the top of the motor. Had slight leaks there as well. The T was going just enough to leak but not enought to blow.

...sure you thought of all these, but just in case...

Jeff

[Craig]

Thanks, I'm about to crawl under it now. Hadn't even though about the coolant tank, will give that a good look too. My first suspicion was the head gasket due to how far back the leak was, I hope I'm wrong.

[Craig]

Welp, looks like a potential head gasket. There appears to be some seepage at the very back of the head/block interfact, right above the very rear-most exhaust stud. I cleaned it up and will check it out tomorrow after a drive to and from work and see if the seepage tracks return. I'm hoping I'm wrong, but I can't find any other signs of leakage.

So, now I get to learn how to do a head gasket.

[Jeff N.]

Be sure to let him hook up yer timing chain..

[ryan roopnarine]

don't you m30 folks have the non torque to yield headbolts....IE, can't you make a go at retorquing it before you have to pull the head off?

[Martin in Bellevue]

I knew at the time that we were setting up a machined (shaved) head with a bigger cam.

Erick was happy with my help in setting up his timing. We all know his car is stronger than somebody's car.

Be sure to let him hook up yer timing chain..

[Craig]

don't you m30 folks have the non torque to yield headbolts....IE, can't you make a go at retorquing it before you have to pull the head off?

That would be nice, but I'm planning on doing a turbo and want to make sure I have everything working right.