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Overheating and coolant loss issues

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by donsajid, Jan 11, 2011.

  1. donsajid
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    donsajid Member

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    Hi,

    After just under 6 months of trouble free motoring that all changed a few days ago. Driving down the M6 after being stuck in stationary traffic, I got a coolant level warning with the coolant level on max, I was doing above average motorway speeds at the time.
    I was gonna pull over, but noticed that as I was slowing down, the temp came back down to the middle so i carried on at a cautious 40-50 miles an hour. When I got to my destination, I checked the water and it took about half a jug. Thought thats what it was, so set off again to my new location. Got there no probs, but on the way home, the coolant level flashed again and the temp went to max. I was again doing normal motorway speed at the time. As I slowed right down, temp went back to middle.
    Checked water level, and this time it took a full jug, and that was after around 70 miles of driving since I last topped it up.
    Since then, the coolant level is on max, but I have only done local driving, taking it very easy, and even when the temp goes up to the middle, the heaters set on Hi are still only blowing lukewarm air, which I assume is part of the problem. I have checked for obvious water leaks from rad etc, but cannot see anything obvious.
    The fan also appears to be kicking in.

    I am hoping someone here can steer me in the right direction of what the possible culprits are before I take it down to the garage, because the last thing I need right now is a major car repair bill.

    Any and help will be very gratefully received.

    I should also add that the car is a B6 2.5 tdi audi a4 avant on a 02 plate and its not the AKE engine (Sorry I don't know the code)
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  2. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep

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    id say you have a small leak somewhere
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  3. adamss24
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    adamss24 Well-Known Member

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    The impeller on the water pump is loose on the shaft, you're looking at a 500 quid job as its wise to replaced the belts while at it. Where abouts are you ? I do them belts for a good price (most of the cost is the parts), drop me a pm if interested, I am in N. London. Regards, Chris- 077 899 12128.
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  4. donsajid
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    donsajid Member

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    'The impeller on the water pump is loose on the shaft'

    Surely this can't be the only possible culprit? If it were this, does is explain the coolant loss?

    I am hoping its something simple like a leak.

    Also, I have heard of a temperature switch or something like that? anybody ever had problems with that?

    JUst reading about, I did notice that this can happen if there is a sludge buildup in the cooling system due to mixing of blue and red anti freeze. I am pretty sure I had red anti-freeze in there and when I topped it up the firt time, I did add blue freeze, so I am guessing that this could be a possible issue. I will have the coolant all flushed and replaced tomorrow and see how we go from there.
    Last edited: Jan 11, 2011
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  5. Mike B
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    Mike B Member

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    You might like to check the back of the coolant res .We hadthis on our2.5TDI and only found by chance when removing the res to look beneath for the leak there was a slight crack which was weeping thus the leak and loss of pressure.New tank was £12 and no more probs.Faulty pump would be serious but would not explain leak
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  6. donsajid
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    donsajid Member

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    Well, finally managed to get my mate to have a look at this, and whilst driving to him, stuck in traffic, and doing slow speeds the whole way, the temp did not misbehave at all. Not a drop of coolant loss was noticed. Got it there, he had a good look, and what we have found is that on the feed pipe into the coolant reservoir, when we detatched this and started the car, no water came out of it, even if revved very hard, so it looks like the water pump is indeed knackered and there is no coolant flow in the system. fans are kicking in, and then when we over revved the car kept it at 4000, the temp started to creep above 90 and then shot up.

    Has anybody tried stafford audi for a cambelt and tensioner change on their v6?

    I dont fancy takin the car like this to london, but if i dont get any joy locally, I hope you don't mind me giving you a a ring and i'll get the car to you.
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  7. adamss24
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    adamss24 Well-Known Member

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    I've done Swarcup's a4 v6 tdi a few months ago (fellow forum member), he came from Yorkshire just for that- thermostat stuck open...There is no way the Stafford audi will replace all for the same price like me...Thermostat, water pump, full cambelt kit, aux. belts and computerised setting of the injector pump... Parts are 350 quid trade...add a genuine thermostat and seal + 5 L of antifreeze and it all adds up !
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  8. donsajid
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    donsajid Member

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    audi stafford just quoted me £501 for cambelt kit including idler pulley and tensioners, thermostat and waterpump. On this occasion, seeing as they are not too far, I may just give them a go. If the car wasnt so poorly, I would have made the trip to london, but this is the easy option for me.
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  9. donsajid
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    donsajid Member

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    Just an update on this. Took it down to stafford audi with the fan on full blast and kept it at just under 50mph all the way down the motorway. Car didnt overheat. When they checked it, it was definitely the plastic water pump that was the problem. They also found my cam belt cover had been rubbing against the pulley because of a non-replaced spacer the last time the cam belt was done. That could have been pontentially catastrophic and doesnt really bear thinking about.
    They also diagnosed my air bag light to a broken wire in my osf wheel. Apparently, there is an airbag sensor going to each of the wheels, so that if any of the wheels were to stop suddenly, the airbags will deploy.
    So, if like me, you have an airbag light which hasnt gone off after a reset on VAGCOM this could well be your issue.
    They also replaced a few screws etc missing from around the engine, and finally came back with a good prognosis for the general health of the engine. Mercifully, the mechanic said that he believes the head has got away without any damage so that was my main concern which hopefully he is right about(!).

    Washed and vaccumed it too, and a general all round good service. Simon in the service department is a top bloke and I would heartily recommend the audi cambelt replacement from stafford audi. £500 all in for v6 cambelt + tensioners/pulleys + Water pump + thermostat. You will struggle to find that price at any garage anywhere.
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