Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke

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Sat 6 Jul 2024 20:55
Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke - Splatt4000

I've just bought a 2009 995cc Matiz. Driving home the coolant light came on. I topped up the coolant (it was low) and ran the engine for a few minutes with the cap off and foam appeared in the expansion tank.

The expansion tank or foam doesn't look oily and I checked the oil cap and dipstick before buying and saw no mayonnaise. There's no white smoke from the exhaust. These are my usual checks for possible head gasket issues.

Anyone have any ideas what might be causing this? Is it most likely a head gasket failure, or could it be something else?

Sam

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Sat 6 Jul 2024 21:43
Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke - elekie&a/c doctor
Foam in the coolant tank is possibly due to it being topped up with water that’s had some detergent in it , or perhaps it’s had some leak sealer added . ? Perhaps drain it all out and start again with fresh water and antifreeze.
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Sat 6 Jul 2024 21:59
Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke - Splatt4000

Thanks. Hopefully that's the explanation. I'll flush and refill and see what happens.

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Sun 7 Jul 2024 00:34
Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke - edlithgow

Could be you've got air in the system, which on some cars can be difficult to clear. This can do a pretty good impersonation of an HG failure, though of course without mixing.

On the Skywing (like a 3-cyl Daihatsu Charade) I cleared it by jamming a medium, and then a large large funnel, stacked, in the radiator, disabling the cooling fan, and running the engine until the coolant boiled into the funnel, taking the air with it.

This was a bit alarming but I felt it was safer than running with air in the system.

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Sun 7 Jul 2024 22:49
Chevrolet Matiz 1.0 SE Plus - Foam in coolant expansion tank, but no white smoke - Splatt4000

Thanks. I've drained and flushed the system, taken out the rad and tank and flushed them separately. Nothing messy or oily came out, tested thermostat. I'll refill, bleed and see what happens.

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