Rod Bearing Replacement, $ or $$$, DIY? - PeachParts Mercedes-Benz Forum

imagesinthewind · #1 06-02-2006, 07:29 PM

Sorry to start a second thread but no one seems to be looking at the first one.
I am going to look at a 73 220D with a 240D engine.
It's making what the seller calls a knocking noise and thinks
it may be rod bearings. The car runs and drives (not over 20mph at this time, could be fuel related) and has been sitting for 2 years.

If the problem IS Rod bearings, what will it sound like and is the fix a driveway weekend fix or is it a pay-a-mechanic-$75-per-hour to fix
I'm leaving in 30 minutes so any help before then would be great.
Thx,

blueranger · #2 06-02-2006, 07:41 PM

a rod bearing should mean engine rebuild.... and that can cost a lot...
The price could vary from 4000 to 500 just depending on your skills...

If the pistons were ok, and the oil pump is ok, and you replaced the timing
chain, bearings and rings you could get your parts here, and DIY probably
600 bucks....

I have never done this, and its probably not advisable, but theoratically you could remove the oil pan, and with the piston on the full down stroke, you could loosen push it up a little and manuver in another top and bottom bearing. You could probably even go to the u pull junk yard and get the bearing for a buck...

t walgamuth · #3 06-02-2006, 07:47 PM

give us the detailed symptoms of the problem.

then we could maybe tell you something.

no information will result in no input. sorry.

tom w

Matt L · #4 06-02-2006, 08:45 PM

Quote:

Originally Posted by blueranger

You could probably even go to the u pull junk yard and get the bearing for a buck...

What a horrible thought. Tearing the pan off of a car in a junkyard for a rod bearing! They can't be all that expensive new.

Zeitgeist · #5 06-02-2006, 08:47 PM

If it is a rod bearing, it should knock louder upon deceleration than acceleration. Wind it up, then sharply let off on the throttle, and listen for the rat-a-tat-tat sound.* Incomplete combustion in an indirect injection diesel will also make loud knocking sounds, which have been incorrectly associated with rod bearings.

*caveat: This generally holds true for gassers, but I've never personally heard a rod bearing go bad on a diesel, which has much higher compression, so YMMV

blueranger · #6 06-02-2006, 08:52 PM

i said i would not do it, and i would not recommend it but you could probably do it.... thats what i said,

the rod bearing set cost $30 and the main bearing set cost $80 so that would be 110 if you were just going to wing it and not rebuild the engine then you would go and pull a bearing.... if i bought both bearing sets i would rebuild the engine...

basically, when you have a lower end knock it time to rebuild the engine...
and you should rebuild quickly... before it gets worse....your object is to save the piston and the block...

blueranger · #7 06-02-2006, 08:54 PM

i had a wagon just like yours, gasser, i had to have the engine rebuilt twice.
for a lower end engine knock...

imagesinthewind · #8 06-02-2006, 10:02 PM

Okay, went and looked.
Several holes in the body near the wheels. Straight, but rusty spiders on the back right door. Interior looks like it's from 1973, some rust in the trunk.
All that is easy.

A severe knocking sound, nothing like the sound a diesel makes.
When it was started the seller reved the engine and I stepped backward expecting a rod to come shooting out of the block.

When you put your hand in the exhaust stream you feel a rather noticable miss. Big time blowby, too.

Blower motor doesnt' blow, but the AC blower blows.

It's a cute car but I'm not sure I've got the time to put into a project car.

What do ya'll think?

rs899 · #9 06-02-2006, 10:06 PM

You will not realistically be able the replace rod bearings in an OM 615 engine without removing the engine from the car.

I have replaced both rod and main bearings on a TR-7 with the engine in the car. It was very difficult. Impossible in 220D with the crossmember AND the upper oil pan(well maybe you can do #1 cylinder)

rs899 · #10 06-02-2006, 10:08 PM

Based on your description of the car, RUN AWAY.

blueranger · #11 06-02-2006, 10:25 PM

well, its a 100 dollar car that you will spend all winter working on...

total engine rebuild, rust and body work,

imagesinthewind · #12 06-02-2006, 10:38 PM

Well, if anyone in Denver wants to see it or wahtever, it's on craigslist, denver.

#13 06-02-2006, 11:16 PM

From your description, $100 is on the high end of it's value.

Link

Run, run fast, and don't even take it for free. It's not worth it.

t walgamuth · #14 06-03-2006, 05:05 AM

yep.

unless all you want is an education and you are willing to pay for it, there is no way to come out on that one even if it were given to you.

its always sad to see a benz in such sad condition.

i once went to look at an 83 300dt. it wasnt that bad overall but showed signs of neglect. but when he started it i heard something in the motor. i had him shut it off and checked the oil. i couldnt touch any on the dipstick. so i just walked away without even driving it. i didnt want to be driving it when a rod took leave of the crank!

what are people thinking?

once i test drove a four wheel drive pickup and when i drove around a curve the inside rear wheel simply walked all the way out of the axle tube and that side of the truck dropped right down on the ground! I walked back and handed them the keys and told them where to find it. they didnt act surprised. ?????????? are they thinking someone will come along and buy it without driving it?

then there was the time i drove all the way to indy to look at a 51 caddy coupe with a "very good body". it was sitting in his garage. i walked up to the side of it and stuck my head inside to look around and right down through the floor at the front of my shoes. boy was i pissed off! i hate liars.

left without saying much.

tom w