BrickBoard Archives
The files contained in this listing have been automatically archived from the active forums. Because the vast majority of posts are now in one place, this archive is considered legacy. You should use the SEARCH feature OR choose your topic and select date tabs within the forum you choose.
Oil leaks & Crankcase Ventilation - B230FT[700/1989] posted by Martin Kestle on
Tuesday, 15 September 1998, at 12:21 p.m.
Background:
I recently purchased a 1989 760 Turbo wagon (120,000 km) which had had a new Mitsubishi turbocharger installed to cure a severe oil burning problem (this did in fact solve the problem). Since then, the engine has sprung a couple of oil leaks. The first one was due to a bent flange on the turbo oil return pipe (this has been fixed). The second appears to be leaking from the area of the rear camshaft seal between the distributor and the head. I'm a little concerned now that the crankcase ventilation system may be allowing positive pressure to build in the case.
Questions:
1. How does the crankcase ventilation system work on the B230FT?
2. How can I diagnose whether the system is working or not? - do I simply remove and check the contents of the plastic box attached to the engine block under the intake manifold for fouling?
3. Can anyone recommend a good shop manual for this car? This is the first car I've owned which does not have a readily available factory repair manual.
Any assistance would be greatly appreciated.
Re: Oil leaks & Crankcase Ventilation - B230FT[700/1989] posted by Steve Seekins on
Tuesday, 15 September 1998, at 2:49 p.m.
First, check the condition of the oil filler cap gasket - if hard, replace it. Then, with engine idling, loosen but do not remove the oil filler cap. If it 'dances' you have excess pressure in the crankcase. If it remains sucked tight against the valve cover, then the crankcase vent system is working fine.
If it dances - do maintenance on PCV system - all hoses, orifices, and nipples - make sure they are clean and clear. It may be necessary to replace the hoses - they often build up a hard coating inside that restricts flow. On the turbo, the PCV system is essentially an oil/vopor separator (black plastic box on left side of block below intake manifold), and a couple of hoses that connect to the air intake duct betwen the AMM and the turbocharger. Note that the turbos shoul NOT have a flame trap installed in the plastic fitting above the oil separator box.
If the PCV sytem looks good, do a compression test. If you have some bad rings or a damaged piston, you can get excessibe blowby into the crankcase - only solved by overhaul UNLESS the condition is the result of stuck rings on the pistions. In this case, a heavy duty crankcase cleaner followed by use of synthetic oil may help, though probably not immediately.
--Steve Seekins