[Wtrott]

So, we had the boy's SLK 230 running good, or so we thought.
He was on the freeway, running fine, then a lot of smoke. He pulled over immediately, and shut it off (not sure if it was still running or not). I went to pick him up (200 mile trip), when I got there to put it on the tow dolly, there was a big pool of oil under the car.
We towed it home, put it in the garage and let it sit until I could look at it. We put it up on stands, looked underneath for an obvious oil leak, no luck.
Pulled all plugs and 0 compression in all 4 cylinders. They are all cycling like they should, cam is rolling like it should.
Any ideas?

 

[Idiot101]

Perhaps the timing chain has jumped time. Just cause cam is turning doesn't mean it is in timing to fire.

 

[Wtrott]

Thought of that, but would you expect to have all 4 cylinders to have 0 compression?

 

[jbanks15]

what about the puddle of oil?

 

[56brd]

I personally have never had an engine jump time at highway speed. I have however seen the aftermath and it can be very serious. I have seen V8 engines that had no compression on any cyl. If the piston reaches top dead center at the same time a valve is open to it's maximum the two can make contact. I certainly hope this is not the case in you engine.

I am not familiar with Mercedes engines, however I do believe they are not so different than other internal combustion engines. I have had more than one that ran perfectly when turned off, then fail to start the next time someone tried to restart the engine, either the next day or just minutes later. Usually there is no damage done when one jumps time. I recently put new timing belt on my Granddaughter's Chrysler. Her little car quit at highway speed, and no damage done to any internal parts. I would assume it all depends on how far out of time the valves manage to be.

As Jeff says, I kind of wonder about the goodly amount of oil that I believe you said you found under the car at the time you managed to get it loaded on the car dolly.

 

[efair]

You sure your gauge is working?

 

[DSSG]

Smoke & oil and zero compression? Probably time to say RIP.

Did you bother to look at the temperature gauge? Over heating is the death knell for most engines.

I believe the Mercedes 4 & 6-cylinders are interference engine. Since it has a chain, I doubt it failed. Only thing you can do with all of these problems is pull it and tear it down. Probably too expensive to repair, but you could source one from a Mercedes junk yard specialist.>

 

[Wtrott]

He said it got hot on the way down, but he shut it down before it hit 120c. It was low on water but that is common, there is a small crack in the reservoir I haven't been able to get 100% sealed up. He put water in and it ran perfect the rest of the trip.
The compression gauge works fine, I even hooked it up to my Harley to verify.

we added a gallon of oil last night, didn't get any leaking out as before, he then added water, (I am thinking something with the HG), I just drained the oil and there was a bunch of water in it, hadn't been there long enough to turn milky but it was def. water coming out the drain hole at first.
I pulled the top of the motor off exposing the cams, lots of burnt residue up there, possibly bad enough to plug some of the oil valleys. Timing chain and gears look better than anything else I see in the top of the motor.

A visual of the piston tops (through the spark plugs, show no catastrophic failure.
Was thinking about pulling the oil pan to take a quick look from the bottom but it looks like a pretty good job to get it off, any ideas or tricks?

My question is if it is a head gasket, I have never seen all cylinders lose compression, anybody care to weigh in on that?

I appreciate all the assistance.

 

[DSSG]

Engine failed due to overheating. It also cracked the head, block, or blew out head gasket explaining the water and probably zero compression. I tell people over and over again with old cars, to replace the hoses and radiator with a rebuilt or new unit.

The zero compression can be explained by stuck valves too. Also when you blow out a head gasket or crack head or block, the cylinders can't hold compression due to the air escaping out through the gasket or cracks in head or block. BTW, you did a real number on it.

Forget about a rebuild, this engine is junk. You'll be able to pick up a salvaged unit for not much coin. This time put in a new radiator and hoses.>

 

[Idiot101]

Should be able to find an engine in Atlanta or Greensboro. I have seen some for sell in both places.