Long story short... I bought an 02 Excursion 7.3 4x4 with 217k and knew that it had fuel/oil in the reservoir at some point. I drained the coolant and had a bunch of black sludge drop out of the radiator/reservoir.

So, I did a oil cooler o-ring rebuild and flushed the coolant system using Gooch's method (T-tap into heater core hose and cascade flush followed by distilled water rinses and full strength ELC-1 coolant.

Now I don’t know if this is just a BIG coincidence or whether the previous owner didn’t use the appropriate sealant when he had the injectors and injector cups done about 40k miles ago…but it ran fine during its 1100 mile drip from Montana back down to Oregon, and is only now showing fuel in coolant AFTER the coolant flush and ELC coolant swap.

It's been running fine for the last 500 miles or so, but I have noticed the coolant level dropping in the reservoir even after topping it off a few times... I took if for a longer drive yesterday and checked the reservoir afterwards and now have fuel in my coolant reservoir with chunks of black rubber... I don’t know whether it’s residual from when the PO replaced injectors and cups (wishful thinking) or whether the sealant has failed and now I need injector cups…

Questions... What needs replaced now that the coolant has been contaminated with diesel fuel?

Upper radiator hose (mandatory)
Lower radiator hose (mandatory)
Reservoir cap (mandatory)
Reservoir inlet hose (???)
Reservoir outlet hose (???)
Water pump (???)
Heater core inlet hose (???)
Heater core outlet hose (???)

Do I need to do oil cooler o-rings again now that the coolant/fuel mixture has hit those o-rings?

Also, will it harm the system more leaving the truck parked until I can get to draining the coolant and doing the repairs?

Thanks in advance.

 

@Sous will you move this to the diesel threads?

 

Sir, I am no longer a moderator here after leaving the position a while ago. I have tagged @Toreador_Diesel in an effort to see if the thread should be moved.

 

First update to the thread.

I wasn’t sure if I had a cracked injector cup or failed sealant. I was able to wick up a small amount of the fuel with 2 blue shop paper towels. Then ran the truck a few times and got less coming back into the degas bottle.

I thought I may have gotten lucky and it was residual from when the PO replaced injectors and cups 2 years ago. But I took it for a longer drive yesterday and ended up with a thin layer again. Probably 1/8” floating on top. It's Brown with gold/copper flecks?

At this point I think I am going to buy a radiator pressure test kit and pull the injectors to see if any cups are leaking. That’s the only way I’ll know for sure.

Stay tuned.