[boiler123]

Hi all,

I had oil in coolant expansion tank and had the dealer do coolant flush (x3 times according to dealer to get all the oil residue out), get a new OFHG(oil filter housing gasket), water pump, T-Stat.

I still have oil/coolant mix in my coolant tank. The chocolate color residue on my coolant tank cap and have a very small traces of oil floating around. Dealer said the oil was 'caked' in to the tank so small trace is due to that in spite of multiple flushes.

Dealer now recommends coolant tank replacement when I asked them to re-flush the coolant.. I don't think i have cracked head gasket as i dont have white smoket etc and engine temp is 240F.

1)If the oil is caked into the tank is getting the new tank only option or should i push them to flush the coolant.
2) Is it really that bad to have small traces of oil in the coolant?

[braus427]

What are they using to flush it? Keep in mind the electric water pump that needs actuation to bleed, not like a belt driven that runs all the time. I'd try water mixed with simple green. This effectively breaks down oil residue and acts as a degreaser without foaming like even a low sudsing dish soap does.

[unrulyteach]

Wondering why they didn't replace the tank the first or second time