I may need an engine for my 81 300D!! Car only has 138 kmi and looks great, but PO did not care for engine properly; car has been using (not leaking) oil excessively (qt/300 mi); pressure has been good 'til today; now, pressure hangs near 0 at idle, creeps up to 3 when revved.

Wher can I find a perfect, "low-milage" engine for reasonable price? Thanks.

I have seen used engines priced at 5K! If it does turn out to be the engine i suggest a rebuild at a good shop instead.

I'm not driving it. I was three blocks from home when I noticed low pressure. Pressure goes up with engine speed; 'drove it home, put qt. of oil in up to top mark on stick, 'haven't driven it since. Thanks.

OBTW, independent tech gave rebuild estimate of $5.5k.

engine
 

Try metric motors in Calif.

I believe they have a website by the same name or look up the name under the search function.
For used stuff try silver star recycling in Sacramento, CA.
Try the search for details, I'm out of town right now.
Good Luck

Try this site for an idea! Was posted in a reply to Larry Bible and when I checked it there was much to see. It is in Oregon and you would have to ship, but prices where reasonable.
http://www.mercedesusedparts.com

Sounds like oil pump to me also!

Engine
 

There is a Metric Motors in Edmond, OK.

http://www.metricmotors.com

Haven't found the one in Calif. yet.

Good luck!
Rich

Don't think it's the engine
 

Greetings,

Why don't we try something, although most think it's unheard of. Let's measure the oil pressure using another reliable gauge connected to the gauge port at the oil filter housing. If you get the same results after running the engine for a very short interval, look to the oil pump as not meeting it's pressure requirements. Can't say anyone here on this site has heard of oil pressure just dropping out of sight overnight and it's the engine gone bad, unless you've run it dry on oil for a day. If this isn't the case, it's the oil pump gone bad or the check valve in the system giving you a false reading on the gauge. Start the engine with the oil fill cap off and see if the cam gets fed with oil to the cam oiler under pressure. If so the engine is getting oil but either the filter bypass is full open and stuck there or the pump check valve has gone bad. Check it out before replacing a good engine with the same.

Charles

cando & others, I agree wholeheartedly that the sudden loss of pressure is not likely to engine suddenly gone bad, but likely a pump or check valve or screen problem. Notice, my original comment, "I MAY need and engine ----". This comment was based on continued excessive oil use PLUS this present pressure prob. MB tech picked up car today. We suspect pump, check valve or screen, etc. If I get the pump/pressure prob fixed, I'll still have an engine using excessive oil - that's why I said, "I MAY need and engine". So, I STILL may need an engine or keep feeding it oil - that's what I'll probably do for a while, anyway. Thanks for the good tips, etc.

Metric Motors in Canoga Park , Calif.

a recommended outfit by techs of this site.
they rebuild engines, long and short blocks available.
Viel Gluck!

Have the tech check your vacuum pump for leaks
 

Greetings Wilton,

When I first got my Benz, which by the way has the 300D engine, but non-turbo it used about the same quantity of oil, and I scratched my head over that one for quite a while, and went though various posts trying to figure out the problem. It was in front of me the whole time but appeared invisable. Although all vacuum operated systems worked perfectly, the slight tear in the vacuum pump rubber diaphragm was sucking oil from the engine on the outward stroke and sending it via a slight steam to my intake manifold where it was being burned. After replacing the diaphragm my consumption went from a quart every 250-300 miles to now about 3/4 of a quart in 1650 miles. I consider that liveable considering that I know where most of that oil is going now is out the rear oil pan seal that seems to constantly seep. If I had the time and the equipment to pull the engine up in the chassis I would replace the seal and most likely pick up the biggest part of my lost oil. Hey, if there's someone out there that knows an easy way to replace a rear oil seal let me know. I would assume that if you change the rear, you screw up the front so it will have to be replaced as well.

Good Luck Wilton, keep us informed on the outcome.

Charles

Charles,

Thanks for tip on vac pump. MB tech said yesterday that he put a new vac pump on the car several years ago. The oil consumptiom prob very well may be the vac pump as you suggested - I'll try to look into it. MB tech found stuck oil check valve yesterday; 'installing new oil pump Mon. The car runs great; has very good power; nice and quiet for the vintage - sounds like a well-oiled and well-maintained industrial sewing machine; all cyl have good compression. 'Hope I can drive it another couple of hundred thou. Thanks, again.

'Glad to get my 20+ year-old car back today!! MB tech installed new oil pump. Repair bill = $700!!! Pump = $250; labor = $345. Car picked up on a truck a week ago today; returned today. Bill for pick up and delivery = only $50; about 134 - 140 mi round trip.
'Did not like the Neon rental car at all- too low getting in and out; visibility to rear terrible, especially to right, rear. Oh, BTW, rental adds another $209 to the bill.

Charles,

Can/will you please list the details of changing that vac pump diaphragm? I think I need to really get serious about that. It looks like it's probably simple and straight forward, but I have a motor nerve prob that causes very shaky hands, especially when trying to work with small things like the screws in front plate of the vac pump. 'Had a "helluva" time getting the oil drain plug back in last week!! I may have to ask son or someone else for help with the vac pump; the more details I have about it, the easier I may be able to get some help. Thanks.

OUCH!!! that bill would have left a bruise
 

Greetings Wilton,

I learned after my first experience with a so called import MB mechanic, that the DIY'S items need to be either accomplished by youself or someone you trust. First off, if you suspect the vacuum pump as one that is failing, I'd follow the vacuum line coming off the pump to the intake manifold and disconnect it there and run the engine for a short period of time to see if it is actually pulling oil from the engine and feeding your intake. I did this simply by removing the plastic line from the air filter housing and rubber bandind a small white sock to the end of it and running the car to work, some 40 miles. Looking at the white sock after the trip told the whole story that I was losing quite a bit of oil through the pump, it was dripping wet when I got there. Do this first to determine whether you actually have a problem that needs fixing. If you do please post again and I will gladly go through the procedure to replace the diaphragm.

Charles