terrymargate

I have a 2013 ML350, bought from Copart, previously flood damaged (I bought it knowing it may well need a new engine)
Initially it would not turn over, just clicked on starter
I removed all plugs and used a breaker bar on crank to free it. Once it started to turn, tons of water came out of a couple of cylinders, nice clean water, looked good enough to drink, so am not too worried about corrosion in cylinder etc

Now heres the bad news… as I was turning it over on the crank with bar, it suddenly hit something (sounded like metal) and stuck. A few more turns back and forward and it was OK again, then it hit something again and this time will not turn past whatever its hitting (but turns back fine and then forward to this point again)

Could anyone give me some pointers as to what this could be and how to locate for sure to find out if its terminal? I read that it could me connecting rod, push rod, valves etc. Obviously would be great if it was something that was fixable without full rebuild (although I’m not normally that lucky)

It seems to me that car was driven into the water and then stopped. Most everything else on the car is fine, almost all electronics which is unusual for flooded vehicles.

Any advice appreciated

Terry

terrymargate

UPDATE.

OK I rocked the crack back and forth about 20 times, still would not move past the original point, was hitting something hard.

Then I rotated 1 full rotation anticlockwise, then clockwise again.

Not only did it sail past its original sticking point, but I've rotated it 10 more full rotations without it hitting anything.

I'm still too nervous to try cracking it with starter, would rather investigate further first to save any more serious damage

Any thoughts on what could be the culprit? am gonna change the oil tomorrow, am thinking may be some water in there judging by the amount that came out of cylinders.

terrymargate

Yep, check out hydrolock and figure something is likely bent

took out oil today, not water in it at all which was surprising, also sifted it and no metal whatsoever which may be a good sign

still need to find out what its hitting though and if fixable

Once I get the cylinder head covers removed, can anyone point me in the right direction to check anything please? Am hoping its rockers or camshaft damaged as that's a whole lot easier to replace than the engine

another_geek

You will probably get a much better response by moving this thread to the regular W166 section. This section is specifically for the ML63 W166s only.

terrymargate

Good plan, how do I move it? tried editing it but no joy

N_Jay

Fresh oil, spray the cylinders with some type of top end lube.


Do a compression test. a bent rod will probably show low compression.


Other option is get a borscope (cheap on ebay for the USB computer kind)
Scope each cylinder at TDC and BDC and see if there are any oddities.


If both those check out, new plugs and give it a whirl.


https://www.youtube.com/watch?featur...VVtqmbZE#t=136

terrymargate

OK it seems it was the con rod. I put a his res borescope into the cylinders and rotated crank 5 cylinders performed perfectly the other piston did not move. So I'm guessing it it a broken rod. Also I dropped the oil pan and found a couple of bits of metal in there that look suspiciously like parts of a con rod.

Next step is to get the engine changed.

As for this one, is it worth trying to have the conrod replaced, or its it a total rebuild needed? I hear stories about the crankshaft possibly bending if the conrod breaks due to hydrolocking.

Not sure if I should try to sell this engine as a project for someone (it only has 8000 miles on it) or try to get it fixed then sell

all advice appreciated as usual

N_Jay

I have broken a con rod and not bent the crank on an old AMC V8, so it is possible.


What cylinder is it? If all else is good, I would probably throw in a new rod and piston (the one head will have to come off) and see if it runs smooth.


These stupid MB engines are just a bit pricy even in the scrap yard.

terrymargate

Its a 6 cylinder.

MMMmmmm may be worth a fix then ;-)

Is it possible to get fixed in situ or is that pushing my luck??

If I get the engine lifted 2 inches I can get the oil pan off, easy to take the head off, have already removed intake manifold)

Would it be worth at least getting this inspected first before removing the engine, and if just rod and piston, have piston pushed out the top, then new piston and rod fitted.

If this is bonkers, please tell me, this is outside my usual area, I normally just fix the electronics

N_Jay

That is how we did the V8.
If the cylinder wall looks good, just put in a new piston.
If it was only one rod hopefully the crank is not twisted.