Brown gunk under radiator cap

[bignev]

Hi all

I have noticed I have a lot of brown gunk under the radiator cap. The last coolant flush was about 6K ago last November. The car did get very hot while driving on Frazer (~120 degrees). I am wondering if this is rust, burnt coolant, or head gasket on it way out (no milky stuff under the oil cap/dipstick)radiator.jpg

[mudnut]

If it didn't use any water it is probably just gunk that got loosened by the heat.

[MB]

Guilty too, radiator caps, vehicle specific, psi/kpa, we should all carry spares


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[pollenface]

I had the same in mine .... I used 2 rounds of 2x bottles of nulon radiator cleaner ... kept dumping the radiator and filling with water a couple of times a day until it ran clear, then added 1.5 bottles of penrite concerntrate. It did seem to run a few degs cooler after doing the flush. I had the radiator out and all fins were clean.

If I did it again I'd use distilled or filtered water instead of tap water