compression check on M%$ X% 3.0I
 

I had a post last night and thanks to the folks who helped. I went in to do a compression check just as a check to ensure that the motor / head gasket where still tight. I have a 2003 x5 with the M54 3.0I motor. I was performing a compression check (my first BMW) and took all 6 plugs out as thats easier on the starter. When I cranked the motor I go oil out of some of the open sprak plug holes and there seemed to allot of compression still with plugs removed.

Has anyone done a compression check and experienced the high compression with plugs out? Second is the oil coming out of the cyclinders reminscent of the oil seperator being bad?

Appreciate the help

You could have oil in the cylinders from the oil separator failing, but it isn't likely. If the oil separator freezes closed, it pressurizes the crankcase and the pressure blows out the weakest point, usually the valve cover gasket. That is consistent with you revving the engine and getting oil leaks afterwards. If the oil separator freezes open, it is possible for the engine to ingest oil, putting oil directly into the cylinders. That doesn't result in oil leaks, it results in clouds of smoke out the exhaust (not under the hood), the possibility of a hydraulic lock, and no reason for new oil leaks like you experienced.

What is more likely is that it froze closed, pressurized the crankcase, blew out the gaskets, and the residual oil that was sitting around the plugs ran down into the cylinders when you removed the plugs. A good reason not to take the plugs out.

Recommend you drop the whole compression test idea, and go back to the oil separator and valve cover gasket as previously recommended.

Thanks JCL. My plugs were soaking wet with oil, and to one of your points my issue is that I have a ton of oil in the piston's and had a very tiny leak out of I think the valve cover gasket. When i tried to do the compression test I got probably 5 to 6 ounces of oil (its a guess) out of the open 5 cylinders, the 6th had the compression tester. So if I understand your description if the oil seperator freezes open than oil can get sucked into the intake thru the oil seperator. How is that much oil sucked in? Is it thru the line from the oil seperator going to the dipstick?

Again thanks for your response.



aprreciate the help.

Well from reading on other posts its clear to me that the oil seperator frooze open and suck oil into the cylinders. The engine cranks and tons of oil come out (not realy but alot). I can see new plugs and new oil seperator.

Does anyone know if there is a new design oil seperator and where one can get the new design?

Suggest you do a search, there are a lot of articles and posts here on the subject, with pictures. It is variously called an oil separator, a crankcase ventilation valve, or a CCV valve. All refer to the same part. You get the parts from the dealer.

While you can change to the updated separator, it doesn't actually fix the problem in my opinion. The problem is that if you don't get the engine hot enough in daily driving, moisture accumulates over time. If you do get it hot enough the moisture (from condensation inside the engine) simply boils off. The condensate ends up trapped in the separator, and since it is largely water it can freeze. The modified separator is insulated, and it will reduce the likelihood of freezing, but the root cause remains the fact that short trips and insufficient warm-up causes a buildup of condensate.

You can simply clean it out, replace any soft or split hoses, and check it again in a few years as a PM step. It likely took many years for the condensate to build up to the point where you had a problem.

I still think it is more likely that it froze closed, and the oil ran down into the cylinders when you removed the plugs. If the engine ingested oil, you would be a candidate for a hydraulic lock, with a bent rod.

Look down around the spark plug holes, and see if there is any trace of oil on the outside of the plug holes. If so, that is what ran into the cylinders.

Jeff