So long story short i have done alot to my 1996 E300D cus it was running bad. Some of the things I did where, replaced all fuel lines, all fuel o rings and seals, Engine wiring harness due to broken insulation, and Injector sleeve O rings (was leaking fuel into engine oil).

Now after i got it all back together it still runs ruff. After alot of research and 120$ on good compression tester i find cylinder 3 with a big 0.

My 1 question is can i remove the oil pan and see the rods and some of the bottom side of piston???

I have removed intake and exhaust and i can look at the valuves and see 95% of them and they look good. I was going to pull the head but think it wortht he time to pull the pan first and see if i should even bother.

Any help would be awsome. Thanks in advance.

Stuck Rings?

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Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

I don't know if the applies to diesels but my 2001 DTS I would put it in 2nd gear and run it upto 6,000rpm and let it engine brake to 4,000rpm, I would do this 3 times in a row. This run up takes the carbon off the pistons and the engine braking rattles the rings removing carbon from them.

I know you don't want to go to 6,000rpm on a diesel but close to redline and let it come down a couple of thousand rpms and repeat.

If it is stuck rings this might be a cheap solution.

Good Luck

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Moss Gate Bed & Breakfast
1985 300 TD GG done in by a red light runner
1984 300 CD Sold
2008 Titian
2000 Cadillac SLS
1966 FLH Sold
2003 Harley Ultra

You might want to see if you can find a repair shop that has a borescope or a tool rental outlet that has them for rent. It is a fiber optic device that can be inserted into the glow plug hole, or injector hole and gives you a birds eye view of the cylinder walls. You will be able to see if there is any scuffing, or groves caused by bad rings. With 0 compression, my first thought would have been a bad valve. Good luck

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96 E300d

Hi
0 compression is quite unusual. Stuck or even broken piston rings are more likely to show some compression - say 100 lbs. or so.

Sounds to me like a possible hole in the piston - or intake valve failing to open or exhaust valve failing to close.

With the valve cover off you could observe if the valves on that cylinder appear to be moving well - possibility of bad cam.

With the oil fill cap off - do you see puffing when the engine is turning with the starter?

You could try pressureizing the bad cylinder with compressed air and check where the air seems to be going.

You could also try putting 1/2 cup of oil into the cylinder and see if it drains down into the engine - or blows out the injector (or glow plug ) hole when the engine is spun with the starter.

Let us know what you find.

Good Luck,
Joseph

Seconding this. I'd lay my money on a stuck valve. Get the valve cover off and take a peek. Has the car had a timing chain failure at any time in its past? Could explain a slightly-bent valve.