Diagnosing a head gasket

[95BMWIC]

I know I could post in the broader M20 forum - but I thought I would try here.

I am trying to confirm I have a head gasket leak.

I have a 1990 325ix with 170,000 miles.The car blew the throttle body to engine block hose and lost a lot of coolant. My son was driving it at the time.

Unfortunately for me he is not much of a car guy and although the coolant light came on - he drove for a period of time (maybe 30 miles) and didn't pay attention to the temp gauge.. So I have no idea if the car ran hot or not. He just noticed the coolant light on the overhead check panel and let me know about it.

I went and checked out the car and noticed the coolant resevoir was empty. I checked the oil cap and saw that there was some white froth and there was some evidence of white froth on the dipstick - albeit very slight.

I trailered the car and fixed the hose last night. As I replaced the throttle body hoses I also replaced the crankcase vent tube and noticed the milky froth caked inside the tube.

SO - I pulled each of the plugs and they were somewhat wet looking - all were the same condition.

I ran a compression check on all 6 cylinders - all at 150-152 -
Vacuum at idle was fairly steady - with a minor blip?.. 18in

Car runs fine - no misfire. Added a 1 gallon of coolant. Put in new plugs.
It's a bit too cold to check out exhaust smoke - as all my cars are putting out some exhaust clouds in 4 degree weather. No major plumes of sweet smelling exhaust..

Temp in my garage a splendid 40+ degrees (depending on if I am working in there - last night it was 60+ as I changed the hoses.

After driving the car for 20 minutes - I had a frothy white film build up on the oil cap. I know I might have condensation - because in a 24 hour period the car went from 60 degrees to 4 degrees.

Im thinking about driving it and watching for more signs.. either that or have local mechanic try the ultraviolet dye test..

Thoughts? How long does it take to "burn off" condensation?


Recommendations? What should I look for?

[95BMWIC]

Also - I may post this in the M20 forum also if nobody objects..

[spdracrm3]

drive it and monitor coolant level ,oil condition and temp gauge like a hawk

condensation under oil cap and some on dipstick is normal at those temps especially if driven only short trips (not long enough or up to temp long enough to burn off condensate in oil, 2-3hr trips are needed). just dont want oil that looks like milkshake

Napa carries the dye test kits

[The Dark Side of Will]

I ran a compression check on all 6 cylinders - all at 150-152 -

This is definitive as far as fire rings go... you don't have a head gasket leak.

That does not rule out a leak from either the pressurized oil passage to the cooling jacket or the drainbacks to the cooling jacket, however.

Just drive it, watch the coolant level and check the oil frequently. Oil in the coolant will start to show up in the reservoir.

[95BMWIC]

Ok - Walked through all the issues with my son.. His drive to work is 30 miles. So not sure if he can get much longer trips done (hes on a gas budget)..


Told him to watch the temp gauge and check the coolant level (I marked a line in orange) regularly.

I ordered all the parts I need for the head gasket change so I have them if needed. I just don't want to do it in the winter if I dont have to..

Thanks!