Hello

My 2009 roomster with 16v 1.4 petrol had the overheating dash light up today (a very hot day). Restarting the car removed the light. It has never done this before.

When cooled down, I examined the coolant it appeared a like it had lost a little. But more worryingly the coolant header cap had a little fresh motor oil on it - car had an oil change last week. Also on the cap was a little white chalk-like grit on the threads.

Any idea what could it be?

Oil on top of cap could have been some spilt during oil change. Was there any signs of oil actually in coolant or inside expansion vessel? The white crystals are probably antifreeze thats dried out. I would top up to max and monitor it regularly. If there was oil inside vessel it may be due to oil cooler failing.

Alasdair

No oil inside. It was kind of on the threads. Could have spilled on top of vessel and seeped down? Agree top up and monitor coolant. Whereabout can I find the oil cooler on this engine?

Edited Wednesday at 15:454 days by GrimReaper

Not sure. Have a look near oil filter housing maybe under intake manifold. They normally tend to leak internally. This is one I think for the BXW engine copied from autodoc.

Alasdair

If there was no oil in vessel chances are its down to extreme hot weather or perhaps coolant pump or temp sender is getting tired. As said keep an eye on it

Alasdair

Edited Wednesday at 16:004 days by Alasdair1

1 hour ago, GrimReaper said:

Whereabout can I find the oil cooler on this engine?

I don't think there is one.

There is a heat exchanger on the back of the engine block that sometimes leaks on the BXW, I seem to remember.

A search on keywords like BXW and coolant leak may find threads.

1 hour ago, Breezy_Pete said:

I don't think there is one.

There is a heat exchanger on the back of the engine block that sometimes leaks on the BXW, I seem to remember.

A search on keywords like BXW and coolant leak may find threads.

Re. The heat exchanger on the back of the engine, yes I know all about that I changed it 30,000 miles ago. Sigh. Stupid design (plastic moulded part that carries how water in a part of the engine bay that gets hottest - what could possibly go wrong?)

More green eco nonsense, over engineered stuff that fails early, often causing the car to be scrapped. Rant over.