Ford Focus - Foamy Dark Yellow Coolant - Pootle

Hi All,

Had a look under the bonnet of my other half's 2001/Y MK1 TDDi Focus to see that coolant had been spraying out from the pressure cap. The coolant is foamy and a dark yellow colour, and has stayed that way once cooled down. There's a layer of foam with coolant liquid underneath in the expansion tank. I had a quick Google and am worried it might be the head gasket. The oil cap isn't emulsified on the underside, the oil is jet black.

The car runs fine, the temperature gauge is dead centre, where it should be. About 2 months ago I topped up the coolant (all liquid at the time, no foam) with a different brand of coolant mixed with water.

Has this problem happened to anyone out there - and if it is the head gasket, is it even worth considering getting it repaired - I'm guessing this is big bucks?

I'm losing patience with the Focus, I've thrown quite a bit of cash at it; my own car is a 1999 Mazda 323, which seems to just keep on keeping on. Maybe I've been spoilt with the Mazda - expecting a Focus to have similar reliability? Am thinking of maybe getting rid of the Focus and getting a Mazda 3 instead!

Ford Focus - Foamy Dark Yellow Coolant - graham3232

Spraying out of the pressure cap? I guess you mean the foam was coming out? Sounds like you mixed incompatible coolants, hence the foaming, i would suspect this is the problem and not the gasket. The oil should be changed every 12k miles at least, when did you last chage it?

The focus should be fine if you change the oil, coolant and pressure cap. This is all quite cheap to do.

Ford Focus - Foamy Dark Yellow Coolant - Collos25
All coolant products will mix with each other if they didn't there would be cars breaking down all over the place.If your coolant level has dropped then the problem is most likely to be head gasget but other suspects could be the thermostat,water pump,radiator cap or blocked radiator or ceased radiator fan. From what you describe I would be looking at the head gasget first.I would disregard the previous reply as poppycock.

Edited by Andy Bairsto on 17/05/2010 at 11:16

Ford Focus - Foamy Dark Yellow Coolant - kithmo
A new pressure cap would be my first move, a weak seal on the cap will allow the coolant to boil, expand and overflow. Make sure you only top up to the MAX mark on the expansion tank or some coolant may overflow when it expands, even with a new cap.
Ford Focus - Foamy Dark Yellow Coolant - Roly93

Almost certainly head gasket.

You dont tend to get the mayo under the oil cap like with a petrol engine.

I'd say its worth getting it repaired as its mostly labour, Focii are usually very reliable actually. They should be just as good as the Mazda if treated the same.

Ford Focus - Foamy Dark Yellow Coolant - springyboy

I'm no expert but mixing antifreeze brands should not matter, but mixing different types of antifreeze may well matter. Car manufacturers seem pretty insistent about the type of antifreeze in their engines and this is because they know all about the different metals and plastics and rubbers used in their engines and rads and ahat types are compatible with them. It is best to stick with the recc'd type, e.g glycol based or organic acid based. Using the wrong type may result in long term corrosion or seal failure due to chemical reaction. What happens in the short term depends on exactly what gets mixed together. Some time ago I faced the dilemma of using the "wrong" type of antifreeze or waiting till I could get the right type, so I experimented by mixing samples in a glass jar. The result was a glutinous stringey deposit and I certainly did not want this inside my engine, blocking narrow water ways. If you have any unused samples an experiment may be enlightening. It is possible that the mixture in your engine is no longer a homogenous free-flowing mixture, If the foam is being generated deep down rather than just at the surface where it is in contact with air then it's coooling ability may be reduced. I would be inclined to flush the whole system and refill with the recc'd stuff.



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