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oil leaking from top of dipstick......please help

15K views 14 replies 3 participants last post by  benzover 
#1 ·
I determined that oil is leaking from my dip stick. I have done a few searches online and one possible cause might be the crank case ventilation. I removed the PCV and it doesn't appear to be clogged or stuck. I don't know what else could be wrong. My car died on me a few days ago going to work. i've posted this thread on other forums but no help. please i need some advice.

1997 C230
140K
 

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#2 ·
Hi. This post would have been better placed in the W202 forum where the other C230 guys hang out...:)

Just a suggestion. Your oil pressure from the pump is controlled by the 'oil pressure relief valve'. If that has failed, you could be getting excess oil pressure that is causing your overflow from the dipstick tube.

This relief valve is accessed by removing the engine pan - not a job to be taken lightly, as it entails lifting the engine.
 
#3 ·
hey keyhole. thanks for the info. its the best answer ive gotten so far. yes i know i couldve posted this thread in the w202 forum but i figure since the M111 engine is used on several chassis i figure i would get more response if posted in the "general" section.

anyways is this something that i can do myself? ive consider removing the oil pan before this and i know that the front sway bar and steering dampener are blocking it if i remember correctly. there can still be a few more things that im missing. is lifting the engine the only way of removing the oil pan? or can i just remove these components?
 
#4 ·
**update**

finally got around to removing the spark plug cover and valve cover and it wasnt a pretty sight. oil had filled all 4 spark plug holes. i thought the rings were busted but it cant be all 4 simultaneously. the pressure have to had pusehed the oil up into the spark plug cover. if im wrong please tell me.

also i wondered if any of my exhaust valves were stuck open causing the excessive pressure if thats even possible. i took a feeler gauge and measured in between the cams and the "striker plate" if thats what you call it and got .036 in. i dont know what the specs are but thats what i got +/- .002 in. on both the intake vavle and exhaust valve.
 

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#8 ·
also i wondered if any of my exhaust valves were stuck open causing the excessive pressure if thats even possible. i took a feeler gauge and measured in between the cams and the "striker plate" if thats what you call it and got .036 in. i dont know what the specs are but thats what i got +/- .002 in. on both the intake vavle and exhaust valve.
I took a look through my WIS for inlet/exhaust valve gaps for your M111 engine, and there is no information.

There is reference to a device referred to as ' hydraulic valve clearance compensation element' that would seem to fit between the valve stem and the camshaft. Does that make any sense?
 
#5 ·
Have you done a compression test? I still believe it's blow-by, if ext valve open it'll backfire. I think the oil in spark plug area is because of bad seals on valve cover and not same problem. I may be the one who's wrong but I believe Keyhole is mistaken, engine running creates a vac in crankcase, you have positive pressure in crank case, cause by ext gases bypassing rings and pushing oil out dipstick, to test Keyhole's idea hook up a pressure gauge to spot in block for oil pressure sending unit. To test my idea pull all spark plugs and do compression test, all four should be around 150psi ( I think). One other thought, you over filled crankcase by 4/5 qts. I actually hope Keyhole is right, it's a lot cheaper fix. good luck
 
#7 ·
That would certainly be a good starting place... I thought that the dipstick had a seal at the top - so it must be quite a positive pressure to force oil up there.

seattle_202:

I've supplied the WIS drawings for a) removing the pan, b) removing the PRV.

Not every task listed is applicable to your W202, but you will see that the 'engine lift' is hardly DIY work, unless you have access to workshop equipment.
 

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#9 ·
There is no lash( valve gap) the lobe of the cam replaces the push rod/rocker arm and opens/closes valves That system is old school, in fact the last car to win the indy 500 with a push rod engine was actually( if my memory serves me) was a MB, at what degree of cam rotation are you measuring the .036in. There is a point when the cam does not open or close the valve( depending on TDC of piston for that cyl). Another test , if your not sensitive enough to feel the positive pressure, is to put a pressure gage over dipstick tube, if you don't have one use a small baloon, if it inflates you got a problem, if not it's not blowby, run engine 10/15 minutes with baloon attached and see what happens.
Let us know what you find out, I'm sure we're all interested to learn what the problem is/was.
 
#10 ·
thanks benzover. sorry for the delay reply. stressing about whether to dump the car and sell it for parts or put more money into it and hope that nothing else goes wrong. as of right now its a none running car. i found a very small thin piece of metal on my dip stick as i was taking it out a few days ago. im afraid to know what it is.

no, i havent done the compression test yet. can that be done on a disabled vehicle? or does it need to fire up?

for the degree of cam that i measured was roughly at the base. not where the cam would open the valves open at the wider end. (sorry i dont mean to insult your intelligence, im just trying to describe it as how i understand it)
 
#14 ·
Insult away, it's no big deal , all of us learn from these forums, there are no stupid questions. Keyhole is right compression test should be done on warmed engine, but in your case, as it would confirm bad rings or worn bore( I'm leaning towards rings), I might say just pull plugs squirt a little oil in cyl crank over a few seconds and see what the numbers tell you , example, if one is at 135 and all the rest are at 90, it's worn out, it's not exact measurement just a ball park idea, so you can gage your next move, if you want to keep car. You said it's not running, does it turn over, it's possible you've spun a bearing on crank/rod if you pumped all the oil in the engine out, if that's the case, engine is pretty much toast.
 
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