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View Full Version : Oil in coolant. oil/fuel cooler ??



Bazzle21
15th October 2025, 09:46 AM
I was looking at a Disco 3 which has oil in the coolant, diagnosed as the heat exchanger. No other issues i know off. I was advised that all coolant pipes would require replacing. Reading through some posts, it seems some people just flush the system. Any issues just flushing, or is replacing hoses the go. I have not purchased vehicle at this time. Investigating cost of repair. Baz

RANDLOVER
15th October 2025, 08:17 PM
The hoses are replaced due to the mineral oil degrading the rubber hoses, as eventually they'll get soft. You can probably get away with it for a while depending on how bad and how long the leak was.

PerthDisco
16th October 2025, 09:56 AM
Should be ok if just the oil cooler and you have a bit of oily residue. You will need to flush a few times to exit it all and drive around a few days on demin water. Then replace coolant bottle and fill it fresh.

If it’s got choc milk oil it could be a head gasket then you have more issues than hoses.

A hose kit and new radiator ex uk is not too expensive and highly worth it after [emoji637][emoji6[emoji640][emoji637]] years of age as plastic bits get brittle.

Globetrotter
20th October 2025, 08:11 PM
You can order a radiator through Supercheap here in Australia.

DazzaTD5
21st October 2025, 11:35 AM
cooling system parts as in hoses, expansion tank etc will degrade with hydrocarbon contamination.

BUT as its a complicated cooling system i always recommend once clean, you drive it for a bit and ensure there is no more oil in the cooling system, flush again if needed. Once it is squeaky clean start to replace components. if you prematurely replace parts before its clean in the short to long term they will fail. Its dependent on how long oil has been in the cooling system.

I see plenty of vehicles that have had the cooler replaced along with obvious hoses and expansion tank only to see black residue in a new expansion tank.