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Engine Raising / Dropping / rebuilding for 1994 c280

1K views 5 replies 6 participants last post by  panzerbenzer 
#1 · (Edited)
Hello all,
So, I just bought a used 1994 c280 with the classic 2.8 liter/in-line 6 cylinder engine. On a good day, the car drives great. It runs smoothly; the chassis is sturdy(it handles speed, corners, and bumps better than any other car I've driven :thumbsup: ); but the engine is complete garbage :crybaby2: . It has every standard bug and issue associated with this model. It stalls at a standstill, it smokes like a chimney, I only get 10-13 highway miles per gallon (!with premium gas!), changing the oil doesn't help because it turns dark again after about 70-80 miles, and most recently I've been having trouble starting it. Given the amount of issues the engine has and the amount of mileage on it (175k), I've decided to attempt an engine overhaul/rebuild, rather than taking it to a mechanic for bare-minimum repairs. I'm a newbie at working on a benz, so I wanted to know if the engine can be removed from the car without moving the transmission, or must the transmission be removed with the engine as one unit :confused: ? If anyone has some suggestions, I'd appreciate it.
 
#2 ·
Hmm, I'm not sure what on earth could have happened to cause some of that. But big parts of it can be explained by the known issues: head gasket, wiring harness.

I have read horror stories of what happens to an m104 when the previous owner ran nothing but 87/89 in it, thinking that mercedes went through all the trouble of putting multiple "PREMIUM ONLY" labels all over the car in various languages for nothing.

Sounds like you know what you're doing, though. I'd pull the oil pan and look for metal shavings first, before I bothered with a rebuild :)
 
#3 ·
You could be very well wasting your money trying a full teardown. I'd do a leakdown check and pull codes to see if the 02 sensor and MAF are OK. Really I think you may need just a good tune and a few pieces / gaskets.

Is it burning oil and smoking?

rjp
 
#5 ·
I don't know the answer to your question about removing the engine with transmission attached or not, but wanted to offer another piece of advice. You may be better off getting a used engine and dropping it in instead of rebuilding the existing one. There are all kinds of M104s out there. You could pick up a used one from a wrecker/recycler and probably get a warranty on it and save a ton of money over a complete teardown/rebuild.
 
#6 ·
before anything I would do a compression check on the cylinders. on 2.8 models according to mitchell normal compression should be 196-225 psi. minimum would be 174 psi.maximum difference between cylinders is 21 psi.
Thats first do a wet and dry compreession and compare the results. As far as the engine yes it has to be seperated from the transmission.
First find where your oil is coming from is it under the hood out the exhaust? be more specific. what color is it white blue black?? could be you have a head gasket issue which is common or a warped head (chances are warped head)
Without properly telling the issues and say my car is running good then like crap has no bearing upon what you have done to previously check into the matter besides saying i need a new engine
 
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