Brown mayo in rad

UK forum for general and technical discussion about the Z3 roadster
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Brown mayo in rad

Post by BonBon »

Anyone care to guess the cause?
4 teaspoons of brown "yogurty guuk' removed from just inside the radiator cap (under the guuk was some black gravel stuck to the rad wall)
Minimal loss of oil.
No loss of coolant or any foaming on oil cap.
Did head gasket 2 years ago (30,000km ago)
Here's a pic
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Last edited by BonBon on Sat 10 Mar, 2018 19:41, edited 3 times in total.
Howard Adams
Joined: Mon 10 Oct, 2016 15:39
Posts: 57

  Z3 roadster 3.0i

Re: Brown guuk in rad

Post by Howard Adams »

Looks very likely you have a head/head gasket problem. Doesn’t take very much oil getting into the coolant system to cause that...
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: Brown guuk in rad

Post by BonBon »

I agree - hoping it’s just the gasket :oops:
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: Brown guuk in rad

Post by BonBon »

The car in a M44 auto - if the transmission oil is cooled by water it could be the failure of the heat exchanger.
I see in realoem the transmission oil has an air cooled radiator. Will need to go to my Indy - perhaps somehow there is also a water interface??
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BonBon
Joined: Tue 08 Jan, 2008 21:10
Posts: 1227

  Z3 roadster 1.9

Re: Brown guuk in rad

Post by BonBon »

Indeed the transmission oil is air cooled - so that obviously was not the cause of the oil leak into the coolant reservoir.
As there is no water in the oil the diagnosis of my INDY was that there is corrosion in the rear timing plate. (pic below). He says he's seen it once before on a E46.
It seems the fix is either replacing the plate which is a big job......or as my engine is 365k km (~225kmile) - with similar amount of labor, to go for a reconditioned engine. (whole job would be 1000quid or 2000quid respectively - these parts and cars are dear here :head: )
Until that happens, is there a sealant solution that can stop the ingress of oil into the coolant? I have been recommended to try liquid copper (pic below)- but form what I read, that seems to stop coolant leaks (into the oil).
Any insights from the knowledgeable would be real welcome. I want to keep it forever!
(I'm 60 this week :?)
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