Author Topic: Coolant/Oil Mixing (Read 6473 times)

asmir · « **on:** February 27, 2012, 04:58:23 PM »

I bought my e30 with a blown headgasket and have replaced it successfully or so I thought. I am now mixing coolant and oil and can't figure out why. I have 195 compression all the way through. I think it's mixing at the rubber gasket by the timing chain, is that possible? If I was to remove the head and check everything over can I reuse the new headgasket or do I have to use another new one? Any suggestions are welcome, thanks.

d.hitchcock · « **Reply #1 on:** February 27, 2012, 05:24:30 PM »

The first thing that springs to mind is a warped cylinder head caused by blown head gasket and overheating.

Did you have the head serviced when you took the engine apart, or just pull and reinstall as is?

d.hitchcock

danlolasdad · « **Reply #2 on:** February 27, 2012, 05:46:56 PM »

What he said and to answer if gasket is reusable its not

asmir · « **Reply #3 on:** February 27, 2012, 05:50:33 PM »

Hm i checked and was nice and straight no cracks,cleaned and installed . But compression is 195 +- in each of four cylinders ?

rob_e30 · « **Reply #4 on:** February 27, 2012, 05:57:14 PM »

do not reuse the gasket. it's a cheap part given all the other labor. Could also be a crack in the cylinder head (common) or block (rare). It MIGHT be that you contaminated the oil with water when you removed the head and didn't allow it to drain properly.

Drain the oil, change the filter, and pray. You can do those in whatever order you like.

Most likely is warped head, cracked head, bad profile gasket or install, and cracked block in (roughly) that order.

asmir · « **Reply #5 on:** February 27, 2012, 06:40:04 PM »

Interesting is the engine run nice.I start engine with no problems,temperature just right but oil disappeared.Run 10min or more and fresh oil come thru top of radiator and the ugly milky staff ?

asmir · « **Reply #6 on:** February 27, 2012, 06:51:56 PM »

After i replaced hg i flushed radiator and engine.Before and 2 times after new hg.One time only with water.Engine start nice smooth.Temperature just below center line.But oil disappeared and come thru top of radiator?

Geoff · « **Reply #7 on:** February 28, 2012, 05:57:23 AM »

small and hard to see crack in the cylinder head. I had one and could not see it until it was pointed out to me by the machine shop. car ran fine with no compression issues also.
Geoff

DesktopDave · « **Reply #8 on:** February 28, 2012, 07:15:30 AM »

The head gasket can't be reused. It'll fail in a few months. Other gaskets can be re-used but it's better to replace them all while you're in there.

Did you re-use the head bolts? If so, that might be your problem right there. They're intentionally damaged when they're installed (torque-to-fail), they can't be re-used.

Unfortunately, a lot of M42 heads crack, yours might have gone between the oil check valve and the coolant jacket instead of the usual cracks between the combustion chamber and cooling jacket. BMW went too light on the casting.

BadCab · « **Reply #9 on:** February 28, 2012, 07:50:14 AM »

I'm betting cracked head too. When i rebuild my friends E36 m42 I took 4 heads off of different running engines before i found one with no cracks. They seem to crack easily if they overheat. If you have a new gasket and new head bolts then my money is on the head.

asmir · « **Reply #10 on:** February 28, 2012, 07:45:52 PM »

The head is in garage again.the to chain cover gasket look like is missing one piece of 2-3". I take head to shop tomorrow .Haw much the usual charge for head?

deansweet · « **Reply #11 on:** February 28, 2012, 08:10:10 PM »

It really depends on all what needs done but if it isn't cracked it's around $200 here and if you have replacement valve guide seals they'll put those in as well.

asmir · « **Reply #12 on:** February 28, 2012, 08:23:35 PM »

Tank you dean, anyway i was thinking to send valve and replace seals.

16v of E30 · « **Reply #13 on:** March 07, 2012, 12:40:24 AM »

my brain hurts reading from reading your posts. did you graduate elementary school?

keflaman · « **Reply #14 on:** March 07, 2012, 07:40:56 AM »

Quote from: 16v of E30;110834

my brain hurts reading from reading your posts. did you graduate elementary school?

That's not how we typically treat others on this forum.