83 240D low Oil Pressure. Rebuild it? - PeachParts Mercedes-Benz Forum

jt.hunter · #1 05-14-2006, 01:03 PM

I have a 83 240D with 200K miles that has low, meaning zero bars of oil pressure at idle. As the RPM's come up the oil pressure will slowly steadily build, as the the rpm's drop the oil pressure slowly drops back to zero. There is a screeching coming from the engine that sounds like a rusty water pump. The car had been sitting for 2 years when I got it, but I just charged the battery and it fired right up. I'm afraid the screech is actually the main bearings. There is a significant oil leak at the front of the engine that appears to be the front seal.
I did change the oil and all the filters (Air, Fuel, Oil), replaced the rubber inector lines, and belts. After searching this forum I went ahead and replaced the small o-rings on the oil filter cover shaft also, but very little if any difference in oil pressure after that.
I am going to start taking the engine down and out at this point unless someone has any suggestions.
I am wondering if it is practical at the point to try to just check crank and rods for tolerances, and if good just replace rod and main bearings and put it back in the car? I intend to keep and drive the car for a long time. Sorry for the long post, and thanks in advance for any suggestions or advice.

t walgamuth · #2 05-14-2006, 01:55 PM

if you are squirting oil out the front main seal you must have oil pressure and very worn bearings.

you could drop the little oil pan in front and look at one rod and maybe two main bearings, and plasitguage maybe.

but then if bad, and it sounds like that will be the case, you need to pull the motor down. it also prob needs head work too. now you could perhaps skip that but if you do you will be back at it in a while.

and the crank will prob need turning, and perhaps the oil pump will need rebuilding too.

if you are on a tight budget you might be able to find a good used motor. the 616 motor is extrememly long lived if cared for. but if the oil and air filters arent changed it will wear out the same as a chevette.

but they are very time consuming to tear down, and it doesnt make much sense to scrimp on parts once you make the committment to tear one down.

imho

tom w

hawthorne90250 · #3 05-14-2006, 05:36 PM

Are you using the dash oil pressure guage for readings?, If so try a second source to verify that the car has actually low pressure and not a bad gauge.

JimSmith · #4 05-15-2006, 12:01 AM

Also, go through the trouble to clean the front of the engine. The AC compressor bracket, or the PS pump bracket (I don't remember which now) can have a bolt hole in the block that penetrates an oil passage and when the bolt falls out you get big leakage. That happened on my 1982. Good luck, Jim

Samuel M. Ross · #5 05-15-2006, 03:07 AM

(1) Clean up the areas the oil is leaking from so you can see more clearly where it is actually leaking... and get the guys here,

(2) See if you can pin down the source of the noise, [I'm betting it's the water pump or a belt]... and

(3) Double check the accuracy of your oil gauge.

Regards,
Sam

ConnClark · #6 05-15-2006, 10:40 AM

If you have oil pressure this low and want to save the engine its time for a rebuild NOW.

If you want to go until it blows then look into a quick fix

TonyFromWestOz · #7 05-15-2006, 10:52 AM

Remove the fan belt ,A/C belt and PS belt to isolate the source of the noise.

t walgamuth · #8 05-15-2006, 01:18 PM

the intervening posts are all good if you are not sure where the oil is spurting out from.

and given the investment involved in tearing things apart prob a good idea to be sure.

tom w

jt.hunter · #9 05-15-2006, 09:05 PM

I am relying on the dash gauge and will try an alternate, but I figured since it does cover the range from zero to pegged, I could rely on it somewhat. I have cleaned the engine and it does appear that the oil is coming out around the front seal. I will pull the belts as a part of the disassembly, and start it without them to see if I still have the noise. At that point if it is making noise I guess I'll have to open it up. Would a 79 240D engine fit?

t walgamuth · #10 05-16-2006, 05:49 AM

it will prob fit but the earlier engines had significant differences in external accessoriy mountings most notable the ac mounting. i am not sure exactly what the differences in the blocks are if any.

i would look for an 82 or 83 block, but the other one may work with some fiddling. someone here will tell you the exact differences i believe.

tom w

winmutt · #11 05-16-2006, 08:09 AM

Wouldnt a 617a fit in there nicely to?

t walgamuth · #12 05-16-2006, 08:42 AM

617 s turbo or non will bolt in.

tom w