We've noticed over the last four months that we've had to add a quart of oil every 600 miles to our 300E.

Our mechanic did a leak down test and says that in cylinder 1 to 3 we have 10% leakage and in cylinder 4 to 6 we have 70 to 80% leakage.

He also told us that our spark plugs were full of oil.

Our questions are these:

1.What's a fair price for fixing this problem?

2.Can we still drive the car safely by changing the plugs occasionally and adding more oil until we can afford to have it fixed in a couple of months?

3.Would this problem be better fixed by a dealership than an independant shop?

P.S. This car has 105,000 miles on it and runs great. Other than having the oil problem, we have no complaints.

Russ,
I assumed this is a post 86 300e, based on the mileage, since you did not mention the year . The earlier 300e are well known for problems with guides and seals. How much do you drive? What did you mechanic recommend? Where are you? Are you planning to keep the car? etc, etc. It sounds like a valve job ($1500-2000 depending where you are). A GOOD MB independant can do it. Get a warranty.

__________________
J.H.
'86 300E

Either your rings are shot, or you are well on the way to a blow headgasket. Either way, you should get this dealt with ASAP before you put the engine at further risk. Valve seals, guides are a definite need to do item. Plugs tell the story. You need to get an assessment of how bad the rings might be if that's the problem. However, unles the car has been totally neglected, the rings are probably not the culprit. Has it ever been run hot?? If so, then it's the headgasket heading south along with the guides and seals. Don't sit on this one for too long. As to cost, maybe Donnie or Steve can give you a ballpark. You're probably looking at about $2,000 if it's the head, valves, gasket...That number is only a guess based on what I have seen posted here. Good Luck..

__________________
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.

Dear JH 86 300E

Addendum: This is a 92 300E and we live in Contra Costa County, Bay Area, California. Our mechanic recdommended a valve guide fix for around $1500-2000. He didn't say anything about a full valve job. He has to send out the head, so we may as well grind all the valves while we're at it. Correct?
Thanks for your imput.

300E Russ

Well to do the valve guides, the head has to come off, and with new guides the valves will have to be ground to properly seat with the new guides in place. I can't imagine not doing the valves and seats on a head that the guides are being replaced in...it's not much more work to get that done..

__________________
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.

Like Jeffsr said,
do the whole enchilada since you are already there. May I suggest changing the timing chain, tensioner, rails, etc. The extra cost should be just for parts. The price sounds about right. I live in Florida and that is the going price around here.

__________________
J.H.
'86 300E

Russ,

I own an '85 190E and had the same problems as you did. Power was lacking and the car burnt oil. It turned out to be the valves, which cost a good $2000. Also, try to have it fixed ASAP becuase if not, you'll have to put out another $250 for the catalytic converter, for it will be clogged with oil.

-Happy driving,
vu

Some else has already mentioned the valve stem seals. Leaky valves could explain the compression loss. Bad valve stem seals will definitely cause high oil comsumption. I changed out mine (88 300SEl) at 85,00mi and cut oil use in half. Your engine is pretty tuff. Unless some let it get low on oil or it severely overheated, I doubt your cylinders are damaged.

Is there a vacuum pump on this model? My 280 had a hole in the diaphragm and drew out 4-qts in a hundred miles. A cinch to fix.Steve

The vacuum pumps are only on the diesels, because the diesels make almost no vacuum.

It sounds like top end time to me.

Best of luck,

S'funny, I just changed the plugs and rotor--right after I replaced the vacuum pump diaphragm. No wonder this six-banger runs lousy. I've been running it on gasoline. LOL
Steve

GS Sparhawk,

I'm amazed. I'm trying to understand why a gas engine needs a vacuum pump. I thought they were only on the diesels. What model gas MB do you have?

Have a great day,

I have the 1975 280 sedan. It has a diapragm vacuum pump driven off the RH cam on the front of the engine. It is a boost for the brakes and the rest of the system. Funny, though, after replacement, I drove it hard and still puffs smoke on slowing. Could be some residual oil still in there somewhere. We'll see. I was hoping it wasn't valve guides.
No shame in not knowing every model, Larry. Too many versions-too many models. And, I thought I had a handle on the various quirks of automobile behavior. But, my connection in Salt Lake City keeps me amazed at the variations of problems and solutions. Best Wishes, Steve