2006 Ford F350 6.0 Diesel

I have a problem with this engine. It seems that diesel fuel is leaking into the coolant causing an overfull condition of the coolant. The fuel overflows out of the filler cap on the coolant system expansion tank and dribbles all over the engine compartment , the inside of the left front fender and down the left side of the vehicle to the left rear fender. I was wondering if any other owners of this truck have had the same problem and what might be the cause and the solution to this problem. I have taken it once to the Ford dealer where I bought it and the service manager there said he had never heard of this problem.

Congratulations, you own the absolute worst diesel engine Ford and Navistar have ever built and put in anything. For what It’s worth, I had a 2004 and put up with that miserable pos for 2 years before seeing the light and being told by Ford they didn’t want me driving their trucks any more. I said I hadn’t been in the last 6 months, I’d been riding in a Chevrolet wrecker with it on the back. I now have a Dodge 5.9 Cummins and couldn’t be happier.

I could go into what is likely wrong with your engine, but it would be a very long and complex post to do so. Trust me, I have a very good idea what’s wrong with it, and you are looking at major expense to fix it. It will not be the last problem you will have with that pile of junk once it begins to have problems. There are a very few places that fuel could actually get into the coolant and it involves the heads. A head job requires removing the truck’s entire cab to get to the engine to be able to work on it. Are you sure it isn’t oil? Oil in a diesel smells like fuel. Most oil in the coolant problems have the same source in the heads.

Ford has lost hundreds of millions of dollars performing warranty work on these engines. They sued Navistar over the warranty problems. Federal courts became involved, shipments of engines to Ford only continued under court order after Ford tried to extract payment for warranty claims from money owed Navistar for engines. Ford has taken the attitude that they will not do any more to these engines other than keep them running and hope they can drag things out till the warranty is gone and it’s your problem.

Here’s what I would do, and this is coming from someone who lost thousands on one of these piles of garbage.

So long as it would still run, I would drive it to the Dodge/Chevy Dealer and trade it if they will actually trade for it. These things are well known problems and some dealers won’t consider trading for them at all. You’ll be dollars ahead for it to become someone else’s problem and not yours.


Fuel getting into the coolant?? Is that even possible??

I’ll admit that I don’t know as much about diesels as I should, but wow. I remember reading your novella about your Ford truck, Skipper, and after that could only shake my head. I’ve never liked Ford trucks, and these kinds of weird problems don’t help.

Yes it’s possible.

The Ford diesels use a HUII type injector instead of a Bosch type. They are electronically and high pressure oil driven. There’s a high pressure oil pump on the back of the engine that provided the hydraulic power to drive the injector and an electric solenoid on top of each injector that releases it. Inside each head are 2 sets of cavities. One for oil and one for fuel. The electric fuel pumps put the fuel into the heads and pressurize it and both fuel and oil go into their respective cavities in the injectors. When the solenoid fires, it releases the injector and the oil pressure forces fuel into the cylinder.

Of course the heads are on top of the block with a head gasket between them and the water jacket of the engine with the coolant in it.

The 7.3L Powerstrokes were relatively bullet proof save the electrical gizmo called a cam shaft position sensor that nearly every owner carries a spare around with them. With the 6 liter, for reduced the engine size by nearly 100 cubic inches and increased the horsepower by about 75 horses. The 6.0 is a modified VT365 Navistar which is not really a bad engine however, in the Navistar form it’s about 230 horse power. In the Ford form it’s 350 or so horse power. To do this, Ford used a lot larger turbo charger than they had previously. The boost on an old 7.3 engine is about 11 or 12 pounds. It’s over 30 on the 6.0 liter. That little engine can’t take that kind of pressure.

One of the root causes of the problems with this piece of crap is the EGR system which they never did figure out until they put a particulate filter on it for the new 6.4 engine. The EGR feeds exhaust back to be reburned. The sooty diesel exhaust drops soot in the intake which eventually collects on another stupid Ford idea, the Variable Vaned Turbo. The turbo on the 6.0 liter has vanes that open and close like an airplane propeller to adjust the amount of boost. Otherwise at higher RPM’s you’d end up sticking 50 psi of boost into the engine and blowing thing up. The problem is, that soot gets into the pivots of the vanes and eventually they get stuck. If they stick in the closed highway position, you can’t get the truck to pull out from a dead stop. It’ll have 0 low end power. If it sticks in the high boost position, it will blow things apart on the engine like the boost tubes if you are lucky. If you are unlucky, it may be the manifold cooler, or worst case, lift the heads off the engine causing the coolant to puke oil or fuel into itself and worse, coolant into the oil.

If he’s got one with oil/fuel in the coolant, his cause problem is most certainly in the heads, however, the root cause of that problem is a much more difficult animal. It can’t be fixed. Without completely reengineering the intake and egr system to put that crap into the exhaust only instead of the intake it will reoccur from now on. That’s why Ford went to a new engine after a 3 year experiment with this piece of garbage. The normal cycle on a Ford diesel is 8 to 10 years.

BTW: Both Chevy’s Isuzu and Dodge’s Cummins went through re-designs as of Jan 1, 2007. Both of then now have a lot of the garbage on them that got Ford into trouble with that 6.0 engine. My best advice would be to find an old 5.9 L Cummins in a Dodge for a replacement. In 07, there were some Dodges made with 5.9’s (ones built prior to Jan 1st 07 and a Coal Field Special that is supposedly only sold to mining companies for off road use) I would look for one of these, there are still a very few around new on lots left over, or even used would be better than what you are getting into with what you have.