Fuel in coolant?

I am looking at buying a 2005 Passat TDI with just over 200k miles. Current owner says there is fuel getting in the coolant? I asked to clarify, and he says actual fuel, not exhaust/combustion gases. Has anyone heard of this before? What could be the cause of this?

A crack in the cylinder head casting would be the ONLY way I could see that happening, and that would be really, really strange.

That's what I thought, and that's also what the current owner suggested. Are there good options out there new/reman heads, or am I just best off to find one from a salvage yard somewhere if that is the case?

50mpgtdi said:

That's what I thought, and that's also what the current owner suggested. Are there good options out there new/reman heads, or am I just best off to find one from a salvage yard somewhere if that is the case?

Click to expand...

First take the engine apart and properly diagnose the problem. Only then consider what the next steps can be. Most salvage yards sell the engines complete with the heads unless the engine is broken. In that case you might not want a head off an failed engine.

That makes sense, I'm just trying to get an idea of what the potential cost would be to determine if I want to make a purchase or not.

Cost is all over the place.

Your labor or someone else's?

New head?

Used head?

Used engine?

You can take the head off, strip it down, and have a machine shop do the magnetic flux trick on it, to see cracks, but I can tell you that given the locale of the fuel channel in the head in relation to the inner water jacket, you may not even be able to find a crack... and even if you did, may not be able to be repaired anyway.

Also, fuel in the cooling system will have done some damage... basically EVERY cooling hose, possibly the radiator, possibly the heater core, could be subject to failure. Rubber and plastics designed for coolant do NOT like diesel fuel.

If you got the car for free, and you had to spend $4k on the car, you could potentially have a decent car for a decent price all said and done. But if you are looking to spend $2k on the car, and fix it for $1k, you are likely going to be disappointed.

Silly question - how was the vehicle tested / verified that there is in fact fuel in the cooling system?

Good call oilhammer. All the potentially failed cooling system components is something I had not considered. If I do buy it, it won't be for more than $1000. It will be my own labor. I have not seen the car in person, so I have not verified myself what is going on. I will try to ask the guy how the problem was verified, because some people just simply don't know much about this stuff.