Correct coolant level

[SirDavidAlhambra]

Hello my friends. Apologies I have been away for a bit but I had the coronavirus and some heart attacks. But all ok now I am pleased to say.

Does anybody know what level the coolant should be at on my Alhamb when cold? It has two marks, max and min but always seems to settle at the min mark. I tipped it up to max last week but within a week it was back down to min again. It sort of reaches min and just stays there, it doesnââ,¬â,,¢t seem to go lower.

I looked inside the reservoir, which is like a sphere with a flat ââ,¬Å"shelfââ,¬Â in it and a hole which goes down into the bottom half of the reservoir. The bottom half of the reservoir always seems full up and the coolant level sits a few mm above the internal ââ,¬Å"shelfââ,¬Â.

Does that sound right or is something amiss please?

Thank you all and I hope you are all staying healthy and safe despite the corona virus and the riots in London. Also donââ,¬â,,¢t forget your mental health, too much time indoors isnââ,¬â,,¢t good and remember to avoid eye strain in the computer. Thank you

[Mirez]

Ahh good to see you back! 'Some' heart attacks? Wow that's not good - hopefully on the mend.

It should sit between the min and max when cold, min is ok but normally a sign the expansion cap is leaking steam when hot.

[SirDavidAlhambra]

Thank you very much, it feels like the time has flown by but so happy to be back here as it feels like a little family or community of friends to me. The corona virus wasnââ,¬â,,¢t too bad, Iââ,¬â,,¢ve had pneumonia in the past and you just have to sit it out and hock it all up really, but the heart attacks are painful even though theyââ,¬â,,¢re only very small ones Iââ,¬â,,¢m told. My wife now tells me I have to lose weight and ââ,¬Å"eat healthilyââ,¬Â.... arrrggghhh! He he

Thank you for the tip about the reservoir cap, I would never have guessed that. Will try and get a spare one from the e-bay and see if it makes a difference. I did notice by the way that in the middle of the little ââ,¬Å"shelfââ,¬Â inside the reservoir tank, there is a little bit of tubing poking up through the middle and the coolant seems I think to be level with that. Itââ,¬â,,¢s not really tubing so much as an inbuilt thing that looks like a few mm of pipe sticking up above the shelf, imagine a small well on a flat garden, sort of like that. I did wonder if that might be some sort of automatic self levelling thing perhaps. I have no idea what it does! Am hoping the coolant doesnââ,¬â,,¢t go down any further though, itââ,¬â,,¢s already back down to min again... if it goes further below that then I know I defo have a problem

[Mirez]

The tube contains a floating magnet, that's how the level sensor works to put a warning on the dash if the level drops too far.

[SirDavidAlhambra]

Wow, you literally know everything about these cars - thank you!

So I examined my tank in a little more detail and couldnââ,¬â,,¢t see any obvious white stains around the lid area but Iââ,¬â,,¢ll get a new cap just to be safe. Out of interest, should the screw on cap have a rubber ring or washer around it? Mine does not have one but I wondered if it should, to make a watertight seal. I did also wonder if the pressure release but in the cap might be letting steam out, is that sort of thing a common fault perhaps.

Whatââ,¬â,,¢s puzzling me most is why the coolant goes to the min level and then just seems to stay there rather than dropping further, very puzzling indeed

[johnnyroper]

Yes there should be a seal on the cap to allow pressure in the system to remain in there,well up to a point anyway. That might explain your issue as like Mirez says steam escaping causes level drop.

[brianh]

The other place I've known for a leak like that to develop is the thermostat housing, the seal goes hard and can leak very slowly under pressure. Usually detectable as it gets wet over time and stained with coolant marks if its doing it. Also if the fan switch is like the petrol models (in a solid plastic piece suspended in the middle of a rubber hose) then that can crack and leak under pressure.

Other places that can cause a slow leak is either the radiator or heater matrix, but either of them should be obvious as you will see coolant dripping from the radiator and smell it if the heater matrix is leaking.

[insanitybeard]

I also found the (primary mechanical) water pump O-ring to be slowly leaking coolant the last time I changed the timing belt, though the rate of loss was fairly low. Other places I've had coolant leaks on my diesel Galaxy in the time I've owned it have been the (primary) water pump core plug (which meant having to change the timing belt again 5000 miles after replacing it originally) and the secondary water circulation pump for the booster heater at the back of the engine bay.

[SirDavidAlhambra]

Hello my friends! Thank you for all your kind advice. So, I bought a new radiator cap and have fitted that, hereââ,¬â,,¢s hoping it works! He he. I have driven 250 miles so far and the coolant hasnââ,¬â,,¢t gone down yet. Interestingly, the old cap has a bit of a rattle in it but the new one does not. The new one is a generic brand so Iââ,¬â,,¢m not sure if the difference is just due to manufacturing technique or perhaps because the old one was broken maybe? I wonder if the original radiator caps always did rattle. Hmm.

Thank you again for all your help and I very much hope you all have a lovely evening. Iââ,¬â,,¢m told the weather will be good this weekend so I hope you all enjoy that too!

[SirDavidAlhambra]

Thank you for all your help my friends, I replaced the cap like my knowledgable friendly mirez said and now I have gone 700 miles and the coolant has stayed at the max level. So impressive how u guys know all this.