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2002 A3, Overheating, Tried everything - PLEASE HELP!

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2002 A3, Overheating, Tried everything - PLEASE HELP!

  #1  
Old 10-11-2009, 10:04 AM
AZA
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Default 2002 A3, Overheating, Tried everything - PLEASE HELP!

After having the waterpump in my car replaced, along with the radiator temp sensor, thermostate with housing and "both temp sensors" and the fan relay control unit, my car is STILL overheating.

Is there anything else left to replace? When the dashboard water gauge is on just over 110, code 51 on the climate control shows 66 degrees. When I then set code 49 on the climate control, it says 82 degrees. This corroborates what the garage said, that there's a difference of 30 degrees roughly.

The fans don't come on, and when I do get them on using AC blasting out, the temperature didn't seem to stop rising on the dash when I rev the car a little.

Here's a pic of what looks like it's been replaced, I've heard the temperature sender is a relatively common fault, but it looks like it's been replaced? Do you think from the pic the sender has been replaced?

Could anyone please give me any advice as I don't want to take it to Audi for about 500 if I can do it myself. This is driving me mad. I'd really really appreciate any advice that can help me get to the bottom of this.



 
  #2  
Old 10-13-2009, 10:20 AM
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I have the exact same problem on mine, after having the Radiator, Water Pump (which was broken) and thermostat replaced.

The difference on mine is that the 49c reading on the CC unit matches my dash gauge, so it sounds like your temp sensor could be out. Try taking it out and cleaning it - literally a 30 second job. If no joy, you may as well buy one from your local parts dealer - they don't cost that much.

To add, have you noticed if your radiator is hot after a drive? Although my temps get up to 105c, I can still touch the Rad - it's not cold, but it certainly isn't warm.

I'm thinking it could be that my Thermostat was replaced with faulty one - that it's stuck shut and not allowing coolant to the rad. That would explain (to me) why the bottom pipe is not pressurised and the rad is only luke warm to the touch. I'm not too sure if i'm correct though.
 
  #3  
Old 10-18-2009, 10:13 PM
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Just to be sure, do you know for sure that the cooling system was fully and properly burped after your parts were changed? It's possible that you still have air bubbles in the system. It's easy enough to do this.

Jack up the car in such a way that the thermostat is pointed upward. With the cap on the reservoir, start the car. Let it warm up to and beyond the normal temperature mark. If you have to, fire up the air conditioning and give it some revs to get the temp up there. When you get about 3/4 of the way to overheating, shut it down and let it cool a few minutes. Wrap a thick towel over the reservoir cap and unscrew it slowly to purge pressure. Be very careful and keep that towel there to catch any coolant that erupts.

If you have any air bubbles, they'll be jammed behind the t-stat and with the system sealed, they keep it from opening which causes the engine to overheat. Once you pop the cap and release pressure, it opens and the bubbles push up to the reservoir and "burp" out. If this is the case, the coolant level will likely drop after the burp. Let the engine cool and then top off the coolant with water. Then fire it back up, see if it overheats again and if not, go for a drive around the block a few times to see if it overheats again. If not, you've probably fixed it.
 
  #4  
Old 10-19-2009, 05:56 PM
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sounds like if everything has been replaced it prob needs a bleed. ive found the best way to bleed the system is run the car up to temperature with the res cap of and the bleed screws open. normally one on the rad and one on one of the coolant hoses.

squeeze all coolant hoses plenty of times whilst its running with a rag around your hand because it will get hot, as you squeeze the houses bubbles will come out the expansion bottle and bubbles will appear through the bleed valves which means your bleeding the system. keep your eye on the bleed screws and as soon as the water comes through warm and no signs of much bubbles shut them of.

your fan should kick in. it may take a few times to bleed through but it works for me.
 
  #5  
Old 10-20-2009, 05:30 AM
AZA
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Thanks for the replies, guys.

The thing about bleeding it is that I've been told that because the tank is the highest point in the system, it doesn't ever need to be bled in the A3. I've tried to run it with the cap off and give the pipes about 10 squeezes, but it never does anything.

Where can I find a bleeding screw? Are there any on the A3?
Thanks
 
  #6  
Old 10-20-2009, 08:51 AM
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You've been told wrong. It doesn't matter that the tank is highest. When you drain the system and then refill it you get air bubbles in the system down below. You have to get them out. Try what I told you above. If there are bubbles, it will get them out.
 
  #7  
Old 10-22-2009, 09:42 AM
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2nd that you've been told wrong. like said them bubbles need to come out and the only way is up and out. on my a3 there is a bleed screw at the bottom of the radiator hose. also have a look at the other hoses there maybe one on there. on previous cars there normally on the matrix hose going through the bulkhead. hope that helps a bit
 
  #8  
Old 03-24-2010, 09:11 PM
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Hi ,I have an 2002 Audi A3 1.8T,recently I have noticed a gurgling sound like a boiling kettle at the top of the engine when it is switched off.After driving for about 20km at 100k then stopping and switching off the engine,the noise occurs,top of the engine is hot(temp gauge never goes above 90 c)the lower radiator hose remains cold.Any suggestions ( thermostat was replaced about 6 months ago) jammed shut may be?
 

Last edited by scan1; 03-24-2010 at 09:17 PM.
  #9  
Old 03-24-2010, 09:34 PM
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I don't know about the 1.8T but the 2.7T (S4 engine) has an after-run coolant pump in that area if I recall correctly. Your engine may as well. If so that is probably normal.
 
  #10  
Old 03-25-2010, 02:29 AM
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Thank you ,yes it does have an after run motor to cool the turbo I have heard it running in the past, but this loud sound is like pouring cold water on to a red hot plate.
The bottom hose to the radiator is cold and not pressurized.
 
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