Join Date: Jul 2013
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Strange heat problem
Having a hell of a time getting this figured out. Wondering if anyone else has had the same issue and can shed any light.
Bought truck in September with 112k miles on it. DPF/cat delete, intake, and H&S tuner. Had signs of puking out of the degas bottle and was low on coolant, but the price was right so I bought it. Didn't have any issues with the truck except that if coolant was filled in the bottle to the "Cold fill mark" lines, it would puke out. After a while of getting annoyed with that, I set out to fix it. The first thing I did was replace the coolant cap - that did nothing. The next thing I did was flush the coolant system and replace the thermostats. I flushed the system with Cummins Restore, tons of water, and refilled with EC-1 coolant. Didn't have any issues afterwards, but it still puked. The next thing I did was delete the EGR coolers.
After I deleted the EGR coolers, it was still puking, but my heat started acting weird. It would blow hot a few minutes after starting, then would stop, then would start again after a while - like air was trapped in the heater core. I tried putting a funnel on the degas bottle and just letting it run to get the air out, driving it for a few days to get the air out, and no change. Finally I took it to a friend's shop that had a vacuum filler. We drained the radiator, drew a vacuum on the system (Held 15 inches solid, no leaks), and filled it back up. Had to add another half gallon of distilled water to bring the coolant back up in the bottle so I thought we were good to go. That was this past Sunday. Since then, I tested the "new" cap I bought from Ford a while back and found that it doesn't hold pressure. I went to Advance Auto two days ago and bought a Stant cap - that has completely solved my puking issue. However, this morning, the heat acted up again. Was blowing hot at the end of my road, but then I got on the highway for a couple miles, and when I stopped at the gas station it was blowing cold. Shut it off, went inside, came back out, and it was blowing cold until I was another couple miles down the road.
It's acting like there is air in the system, but I have done everything to bleed it. My next step is going to be to drain, vacuum, and refill one more time if nobody here has any ideas.
I thought maybe a headgasket was popped and causing pressure/air to be put into the coolant system, but I tested the coolant for combustion and the test came back good. The truck runs great and returns great fuel mileage, I just can't seem to figure this heat issue out after the EGR was deleted.
2008 F350 6.4