Coolant, difference between brands?

BTW I've covered almost 5000 miles since I got the car which was 28th July and I could not find any pages online that state if driving long distances in short spaces of time can evaporate certain fluids. Anyone confirm?
 
Coolant shouldn't drop significantly through normal driving unless it has leaked regardless of driving style. I did silly mileage in my old rover and the only time the coolant dropped in 2 years was because the head gasket failed.
 
mrk said:
BTW I've covered almost 5000 miles since I got the car which was 28th July and I could not find any pages online that state if driving long distances in short spaces of time can evaporate certain fluids. Anyone confirm?
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I do between 500 and 1000 miles per week in my S-class, to a total of 30k now since i bought it. Its never dropped even 1mm of coolant. Coolant is held in a closed system, it shouldnt be able to escape.
 
Hmm people have mentioned this a few times in the thread that coolant should not drop and this concerned me so had a quick phone chat with local snows bmw service who said it's normal for the coolant to drop and should be checked every month and topped up as required. I did mention the current level of coolant remaining and he said it’s normal and I’d need around half a litre of 50/50 mixture water/coolant.

I mentioned since it’s a closed system it should not be going anywhere and he replied that it will still evaporate through microscopic holes in a similar way to how tyre pressures become low over time.
I'm no super expert on how engines work but does this sound fair? I know the same might not apply to all engines but in general for this type of engine especially as some people have said their levels have not dropped at all?

Can anyone call up their local dealer to see if they say the same as well ? would be interesting to see if you are told something different!
 
He is wrong. The 530d has not required a single top up in the 50k miles we have done in it so far. Its more likely whomever changed it last did not quite fill it perhaps?
 
[TW]Fox;12482487 said:
He is wrong. The 530d has not required a single top up in the 50k miles we have done in it so far. Its more likely whomever changed it last did not quite fill it perhaps?
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YES.

Coolant does not just disappear unless theres a leak. Its a closed system, and after a bleed and topup the level should remain the same for many miles.

Mines been the same for two years.
 
[TW]Fox;12482487 said:
He is wrong. The 530d has not required a single top up in the 50k miles we have done in it so far. Its more likely whomever changed it last did not quite fill it perhaps?
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Only one way to find out I suppose and that's fillup myself and monitor for a month!
 
[TW]Fox;12475817 said:
The inside of my kettle looks so awful that 99p for distilled water (Or infact free if you have a water dehumidifier in the house somewhere) seems a bargain.
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Do you have an estimate of how many litres of water has been through your kettle compared to the 7 litres in your car?
 
under what condition would the pressure get too high? when valvetronic/vanos is working or just generally driving in hot/cold weather?
 
Assuming the coolant level was correct when you collected the car, the only way that it could have dropped to the level it did in 6 weeks is if there was a fault with the car. There is no normal mechanism for dumping coolant like that in the E46 cooling system. As to what the fault could be, it could be anything from a tiny leak (My money is on this IF there is a fault) to a failing head gasket.

IMHO, there are two possible reasons why your level was noticeably down:

a) Whoever last did a coolant change in this car simply didn't top it up enough.
b) There is a fault.

My money is on a). Have a look in your service history and check when the coolant change was last done - its under 'Evidence of Time Based Maintenance' and should have been done 4 years after date of first registration.

You've topped it up now, the level is correct, check it once a week and forget about it if everything stays fine :)
 
Ok a quick update.

I know now why the collant had dropped.

It had evaporated! I know this because when I was in London on Thursday I checked the coolant level, it was the same level as when I topped it up earlier on in the thread (normal) but what I forgot to do was close the coolant filler cap up tightly so it was evaporating away!

This morning the coolant level light came on when starting up the car and I was dreading the thought of a leak over the last 200~ miles but when I went to re-top up found the filler cap was loose so I had indeed forgotten to tighten it shut hence why the coolant level dropped so much in the course of a few days!

Needless to say, I have topped up again and tightly closed the cap.

Looks like it does indeed evaporate away either slow or fast depending on how the cap is put back on. IIRC it is pressurised so if the cap is not on tightly it's not going to help much!
 
The coolant reservoir is pressurised, with the cap on hardly at all (only placed on top and marginally turned so it doesn't fall off) it's not going to pressurise the reservoir and the liquid can evaporate away in the hot engine bay which is what happened it seems.

I drove around London, Luton and St Albans during this time all long journeys at motorway speeds too so suppose it's to be expected.
 
Using the recomended coolant doesnt always work out, check us owners of cadillacs and our replacement coolant pipes and pumps. *Cough* thanks GM and the only recommended coolant Dexcool ;)

just shove some cheapo pre mixed coolant in, 1 litre is like 2 quid.
 
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