Help...CRD melted pistons!

[ryanh1006]

So I run a adventure jeep rental business in Kyrgyzstan (I know, asking for trouble and I deal with a lot of breakdowns). Got a new one. One of my Jeeps started ticking just a little, like an old-school lifter with too much gap, then about 50 km later blew a bunch of oil out of the coolant overflow. A client was driving, so I'm getting all this from him. He says it didn't overheat that he saw.
Unable to deal with it enroute, we put it on a truck back to Bishkek (the capital city here). I haven't been able to find someone who could pressure test the coolant system, so I just changed the heat exchanger and flushed out the system. It ran but very, very poorly. We limped it around a little and discovered that it overheated rapidly. Shut it down and back into the shop. Finally decided we couldn't do anything more until we could open it up (shop couldn't do a compression test either). Pulled the motor and discovered that piston number 4 is badly burnt/melted and piston number 3 has got a little of the same. In both cases not only is the outside bad, but the edge of the dip in the middle is badly deformed. The other cylinders at least look ok. Any ideas?

The head looks ok. I'm going to take the injectors to a shop that can test them as well. Our other CRD once got a tank full of gasoline/petrol because a fuel station couldn't get diesel, so they filled their diesel pump with gasoline and didn't say anything. In that case the computer shut off the motor before there was damage. If this was a smaller percentage, could it do it? But then wouldn't the head be damaged? And why just two pistons and not all of them?

I'm stuck between rebuilding this block and hunting down a used motor (really expensive right now). If I rebuild, I want to locate the cause of the meltdown so that I don't just melt another set of pistons!

Here's a couple pics:

[bodgie]

My understanding is this can be caused by a faulty injector, I can't remember the exact cause but if you have a look on the Sprinter Source forum:

http://sprinter-source.com/forum/

Specifically in the T1N forum you'll be able to find some more info.

Jason

[layback40]

Originally Posted by bodgie

My understanding is this can be caused by a faulty injector, I can't remember the exact cause but if you have a look on the Sprinter Source forum:

http://sprinter-source.com/forum/

Specifically in the T1N forum you'll be able to find some more info.

Jason

X2
It does look like a fueling problem more than a straight overheat issue.
Dont understand how you ended up with oil in the coolant though.
Was the jeep pulling a load through hills?
Is the head gasket burned at all?
How does the bore look?

[fester]

Strange. The 2 pistons only do seem to indicate a fueling issue but I'm not sure how that could contribute to the oil in the coolant unless the head or gasket went.

The oil in the coolant though is very typical of the oil cooler crapping itself. This leads to the oil pumping into the cooling system and displacing the coolant. I can see how this could lead the engine to have low and poor cooling and the temp sensor not reading this correctly if there is no coolant for it to read. This all in turn could lead to an overheated engine that could melt pistons but I would expect more damage than just your 2 pistons.

when my oil cooler went I had oil right down into the overflow bottle under the headlight and oil blown out through this all over the suspension and wheel arch. Luckily caught early enough but no temp warnings, no low water or low oil warnings. Just noticed because we pulled up for morning tea before heading home otherwise I suspect we would have cooked the engine.

[bodgie]

Which pistons are the problem?

If it is 4 or 5 how blocked does the inlet ports on the head and the manifold look?

Are they badly restricted?

[Michael71]

How many miles has this engine done?