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Discussion Starter · #1 ·
Hi All!

Not sure if I have a problem or not (yet!!!), but I've had my A4 for just over a year now and everything seems to have been fine!!! I do a lot of miles, on an average week I can do around 500-800 miles, and so have got to know the car and it's behaviour quite well.

Up to last week, the temp gauge used to increase as the engine got warmer up to 90 degrees and stayed there no matter what. I could vary the speed, the outside temp could go higher or lower, and the precise engineering of German quality just dealt with it.

However..........

Last week, I noticed the the temp gauge isn't going above 70 degrees, and what's more, it's fluctuating on a journey (just like today where I've done 120 this morning) between 50 and 70 degrees, not rapidly, but nonetheless it's fluctuating whereas for the last 12 months it's been pretty much stationary during a journey at 90 degrees!

What's concerning is that something may be on it's way out (thermostat perhaps?? or something more or less worrying) and I'm thinking one of the engine experts on here might be able to point me in the right direction!

Not sure if it's related, but a couple of months ago the heater stopped producing hot air, after investigating that, most people are saying the heater matrix needs flushing, and to stick a hose pipe on the outlet and blast water through to push out any crap. I'm hoping to look at this at the weekend, but thought it might be worth mentioning as I wondered if this could be related???

Hopefully hear some ideas and/or solutions soon!

Cheers,

J
 

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Sounds like a sticking thermostat causing over cooling, or an airlock which would also cause loss of hot air in the cabin.

Has it had any work done that has involved draining the coolant recently?
 

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Discussion Starter · #4 ·
Sounds like a sticking thermostat causing over cooling, or an airlock which would also cause loss of hot air in the cabin.
Has it had any work done that has involved draining the coolant recently?
Hi,

Thanks for the suggestion!!!

No, not had any work done other than the regular servicing where I'd guess they'll have checked coolant levels.

On the basis it could be a faulty thermostat, and that you think that could also be the reason for the heater not working, would you suggest I'm best NOT to flush out the heater matrix just yet and get the thermostat swapped out?

Is that a big job?? Feasible for someone a bit handy (but not a mechanic) to do? Or am I best getting it booked in? Any clues as to what I should expect to pay?

Thanks!!!

J
 

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I am not sure where abouts they are on an a4 and how easy they are to get to, ,I would start with the thermostat, it was an easy job on a ford Granada that was the last one I changed , I am sure Jim will know how easy they are to change out on an A4
 

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When I did mine (1.9tdi not 2.0tdi) every how to said to remove the alternator. I managed without removing it, just put some tin foil over it to stop all the fluid going into it. It's not a hard job at all, but it can be a bit fiddly in parts so just take your time.

I would just flush the heater matrix out after you've changed the stat before you fill it back up. Just remove both pipes and fire the hose pipe through it for a minute.
 

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Hi I had exact same fault , replaced stat £25 inc vat for stat and new seal , approx 1 litre coolant required as when pipe removed , only 2 bolts hold it to block , tech at work did mine in less than half hour , now gets to and sits at90c and mpg better too, just remember to bleed coolant system with rad cap off till all air out and check level next day when all settled ,
 
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