Not sure where the coolant went???

lmorris · October 16, 2013

2009 F450, 170495 KM. Original complaint: Overheating and oil in coolant. Visual inspection, degas bottle empty, inner walls are black, no signs of oil in coolant though. Drained rad, got about 3L of that red "Heavy duty coolant" Checked oil level, black, thick and over full. Pulled the oil filter and the oil is so thick it would not drain back to pan, filter looks like its been in there for awhile. Drained the oil, all 30L of it, let it drain over night. When I dumped out the buckets I found about 3L of coolant in them. Pulled of the upper rad hose, no sign of oil in there either. New oil and filter. Filled with 13L of water. Ran engine. Lots of blow-by. Pressure tested cooling system, seems to have a coolant leak, but can't see one. If it's getting into the crankcase, why am I down 12L? The oil condition does not suggest that it has 12L of cooant mixed in. It looks like tar. This one has me a little confused. Going to do a compression test and try to get a long block.

Matt Saunoras · October 17, 2013

All the 6.4s I saw with front cover cavitation never had a whole lot of loose coolant in the oil but the oil was very thick and sludgy like you describe. Also I would be looking at the horizontal cooler for any clean spots on the inside, that seems like a pretty good tell for one that's starting to fail. I've had a few mystery coolant loss, no smoke complaints that wound up being the horizontal cooler.

Bruce Amacker · October 17, 2013

Oil analysis, Napa/Wix PN 4077 or 24077, $14.

:grin:

lmorris · October 17, 2013

Compression test is good. Although after some cleaning, I discovered the upper rad hose has been changed. Going with Matt's advice on the timing cover inspection and will have a good look at the EGR coolers whilst in there. Thanks Matt for the info, never would have thought a slow leak would do that to the oil.