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I was doing some "while you're in there" projects when replacing a clutch on my 2004 MCS and found some serious build up in my cooling system. My Oil Cooler was leaking internally. Oil mixed with coolant and caused sludge. Sludge built up in the oil cooler and surrounding hoses. (I didn't find any water in the oil.) This did NOT cause the engine to overheat because there was still circulation from the radiator. I changed the oil cooler, coolant, and blocked hoses. Flushed everything with a water hose thoroughly and made sure none of the other hoses were clogged. Now seems to be just fine.
Front End Service Mode
Engine And Transaxle Removed
Hose 3 on Diagram. The Beginning of Sludge.
Hose 6 on Diagram. Full on Sludge. Hard Texture, almost like cork. No water was ever going to go through there.
Oil Cooler. Packed full.
Coolant Hose Diagram. Hoses 1, 3, 6 were clogged.
Last edited by MINICooperS_R53_2020; Jan 31, 2020 at 06:04 PM.
Exactly, that looks to be oil mixed with coolant, most likely from failing seals on the oil cooler itself, which actually happens quite often.
Myself and many others have mixed and or swapped coolant on our cars with no adverse effects.
Any good quality coolant should be fine to use, EXCEPT DEXCOOL this is the only thing you NEVER want to use or mix it in a Mini cooling system, it will coagulate and plug the system.
I will agree with the others, from my 40+ years as an auto technician, that is not a sample of mixed coolants, it's engine oil and coolant mixed......you need to find the problem and fix it. Otherwise it will come back and you will have a milkshake all over again
I just took off my oil filter housing and found the exact same problem. I am going to replace lines 3 and 6 on mine anyway, but how did you flush the system? Did you take off line 1, or did you connect a hose up somewhere else and run it until everything was clean? Was there any other issue after this (blown head gasket) that appeared later? Thanks for the help!
With the engine already out, might as well consider a head gasket. I'm in the middle of a similar project. No sludge like that, but a lot of little things that needed attention. Re-doing all the seals and gaskets too.
