Vehicles that need their coolant topping up

  1. earthman Member

    Messages:
    857
    I'm talking about 'modern' vehicles here, ones that use a sealed cooling system, have you guys noticed that a particular make/model may require the expansion tank topping up from time to time where other makes/models, the level between the min/max never changes for months or years even.

    I first experienced this years ago when the wife and I owned a couple of Fiat Cinquecento's, they both needed topping up now and then, not by much by any means but I did wonder where this coolant were going,.....neither cars ever got that hot or overheated and there were no leaks or white smoke etc.

    I'm currently experiencing similar with a motorbike, again it's only a small amount over say a 3 or 4 month period, the level seems to want to migrate/stay close to the min mark rather than the middle/max.

    Could this just be down to the height/position of where an expansion bottle is actually placed on a vehicle??
     
    Brad93 likes this.
  2. armalites Member

    Messages:
    4,052
    Herefordshire
    I've had vehicles that liked to find their own level and even if that wasn't at the max if I left them they were fine. If I topped them up then I would be topping them up again. Obviously that should imply a leak somewhere but I never smelt or saw anything.
     
    earthman likes this.
  3. Ali

    Ali Member

    Messages:
    312
    Location:
    Cheshire
    Yes, I have this with my 07 Jetta.

    I’ve been over it myself repeatedly, and every time it’s been in for any work I’ve asked the garage to have a look for any leaks and none have ever been reported. One garage in particular I really trust have had a look a few times.

    The weird thing is it didn’t do it for the first 2/3 years of ownership, only over year 4/5 to present. It actually seems to be getting worse, it’s gone from perhaps 6 months to 3 months which leads me to think it actually is a leak somewhere. Never had to top up another car before really and I do a lot of miles.

    Interested what the mechanics have to say.
     
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  4. brightspark

    brightspark Member

    Messages:
    26,846
    Location:
    yarm
    had a Vauxhall combo van and only ever slightly topped it up once in 9 yrs .120 thousand miles
     
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  5. Muppet Member

    Messages:
    94
    Location:
    Lancashire
    Weird girl friends TT has thrown coolant low level dash light up twice in a week , thought it was the car sits on a slight slope on the drive ,
    Levels correct hope it's the sensor
     
  6. zx9

    zx9 Member

    Messages:
    3,421
    Location:
    South East London
    The electrical connector on my A4's coolant tank has been known to need pushing back into its recess under the sender. The loose connector will throw a dash warning, why it works loose I don't know, possibly something to do with the non genuine tank not gripping the connector.
     
  7. m_c Member

    Messages:
    31
    Location:
    East Lothian
    If it only needs topped up every few months, I wouldn't worry about it.

    Very few cooling systems are perfectly sealed. Water pump seals weep (some manufacturers actually moved the drain hole from allowing coolant to drain downwards, to pointing upwards, so minor weeps could evaporate off and leave no indication of the weep), and often hoses will weep slightly.
     
  8. earthman Member

    Messages:
    857
    Thanks, I'm not really worried about it because I'm 99.9% sure that there isn't a leak, just thinking out loud and about all the other vehicles the wife and I have owned.
    The height/placement of the bottle were the only aspect I could think of.
     
  9. hotponyshoes Member

    Messages:
    1,262
    Location:
    Somerset. Uk
    Some modern cars have all sorts of fancy stuff fitted to the cooling system for auxiliary heating and water cooling for turbos and alternators and so on.
    My work truck is a vw amarok, from new I topped up the coolant every couple of months or so (probably less than a cup full each time)
    When I turned the car off I could hear a gurgling from behind the dash along with one of the electric water pumps running for anything up to a couple of minutes depending how hot the weather was.
    I changed the timing belt and water pump nearly a year ago and I used a vacuum filler when I put new coolant in.
    Since then the coolant level has remained rock steady and the gurgling noise has gone.
    I think it must have had various air locks from the factory and maybe an air space in something hot like an egr cooler allowed coolant to boil off causing the slight drop I had before. I dont know how it could have escaped the system from that unless the steam was pushing out somewhere but since the proper bleed it's not used anything.

    Edit: the water pump was the only component I replaced (and that's only because I was in there for the belt) and I removed and refitted a couple of hoses for access so I suppose it might have been one of those things that had a slight leak but I didn't see any signs of it.
     
  10. Climber

    Climber Member

    Messages:
    500
    Location:
    Hampshire UK
    Only car I've ever had that mysteriously lost coolant was losing it from the connection into the heater matrix. I found all the missing coolant under the footwell carpet.
     
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  11. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    8,634
    Location:
    Bedfordshire England
    Interesting.
    I got a lot of gurgling on killing the engine.
    Haven't noticed it since I got it back Friday. Egrvalve and cooler were replaced.
     
  12. chris pruteanu Member

    Messages:
    719
    Location:
    ROMANIA
    Most likely a porous head or a punctured EGR cooler...coolant slowly gets into the combustion chamber and gets burnt- if severe can hydrolock the engine...
     
  13. Brad93

    Brad93 M J B Engineering

    Messages:
    5,957
    Location:
    Essex
    I’ve got loads of moisture in the car lately and I’m loosing coolant. Could be the same issue.
     
  14. Wallace

    Wallace Member

    Messages:
    6,467
    Location:
    Staines, Middlesex, England.
    I would mark the level when near the low level then monitor any further loss. How long have you had the bike?
     
  15. 500e

    500e Always buy fire insurance a flood is hard to start

    Messages:
    3,931
    Location:
    Somerset UK
    All the Fiat Doblo vans we have had lost water about a cup full every few months gave up looking, carpet dry no leaks visible new water pumps on belt change made no difference
     
    Last edited: Nov 10, 2019
  16. earthman Member

    Messages:
    857
    Getting on for 4 years now, other owners have said the same thing, level always seems to want to sit near the min mark.
     
  17. Wallace

    Wallace Member

    Messages:
    6,467
    Location:
    Staines, Middlesex, England.
    If the cap is on the expansion tank I wouldn't worry about it and just give it a cursory glance each time you ride the bike if the leval is easily visible.
     
  18. hotponyshoes Member

    Messages:
    1,262
    Location:
    Somerset. Uk
    On some cars the Min mark is the cold level and the Max is the hot level.
    If you top it over the min when cold it will blow out the excess when hot and take itself back to the normal level.
     
  19. What's so weird about your g/f muppet ?:p
    I've got a tt 2002 model had a very small water leak I found a hairline crack in a coolant flange on eh side of engine , plastic fitting it was :rolleyes: Only a fiver for a quality pattern part tho :)
     
  20. zx9

    zx9 Member

    Messages:
    3,421
    Location:
    South East London
    Easy to change on a transverse engine, not so easy to change on the A4 / Passat with the inline engine, that flange on the cylinder head is very close to the fire wall.
     
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