Hi, I've noticed recently my coolant level drops towards minimum after a few days but when I open the cap on the tank the coolant bubbles and goes back to the max line. Is this the early stages of HG failure?

Yup shouldnt be pressurised after a few hours

New head gasget required! Fit arl headbolts too with new gasket as they are stronger

I'm no expert, but I don't think so.

Do you have any signs of coolant loss (i.e. when you vent the coolant system it bubbles and is below the maximum mark)?

Do you have mayo in the coolant cap? Or the oil cap after long journies?

The coolant system is pressurised and it is not unkown to see a drop in level over a few days after venting the system. By venting it, you are releasing the pressure and allowing the coolant and air to decompress back to original volumes.

As there is not a lot of volume between max and min lines in the header tank, it looks worse than it is.

Obviously I'm no mechanic and have not seen you car, so take my thoughts as ramblings based upon owning a Mk1 Fabia that did have a head gasket problem.

Well it varies sometimes I check it every 3 or 4 days and it hasn't moved much at all and other times it's on the min mark. I was going to top it up and opened the cap and it bubbled back up to max so I haven't actually lost any coolant? No mayo on oil cap etc.

The times when it will be loosing coolant is probably after a good blast! Possible 'head lift' not so uncommon

You could try torquing down the head bolts to see if it helps but it may not

My money is on a blown radiator. How old is the car??

If it was losing coolant then would it rise back up to maximum when the cap is removed? 06 reg 92k on the clock.

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If it was losing coolant then would it rise back up to maximum when the cap is removed?

Exactly what I was thinking...

Our Fabia (with new gaskets & cylinder head) still does this. No sign of any actual loss of coolant, no mayo and no issues driving it.

Answer - sniff test .

Could it be that you have air pockets in the system? Once engine gets warm and pressure build up to system air compresses in those pockets and is filled with coolant. Once you relieve pressure it looks normal level again. I'd try to bleed the system and anyway wouldn't worry about that because you're not actually loosing coolant.

I've had 4 cars fitted with the PD 130 engine, two ibiza's and two fabia's and this is the first time I've experienced it. So the coolant drops but rises back to the max level once the cap is opened to release pressure so it's never needed topped up from actually losing coolant.

Seen a few threads on this section referring to coolant loss and HG failure and these guys are having to top up the coolant and also have warning lights on the dash. Any other signs I should be looking at to determine if it is the HG failing? As mentioned above maybe a sniff test would be the next move.

Thanks for the replies.

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Coolant level is actually above maximum today, is that ok?