IDUA Posted March 9, 2018 Share Posted March 9, 2018 Hi all, I own a Audi A3 2.0tdi (150bhp) ive got a unusual problem, day to day it runs fine, now and again my wife will do a 50mile round trip with a couple of hours gap, when she returns home and parks up all is well, the next morning when she leaves for work the expansion tank will be empty of coolant? 2 garages have checked for leaks both have pressurised the system with no loss of pressure reported, all mechanics and technicians scratch there heads. Any suggestions?? Quote Link to comment Share on other sites More sharing options...
Magnet Posted March 11, 2018 Share Posted March 11, 2018 SHello Rob, I've delayed responding to this strange problem thinking that someone else will come up with some pointers. Maintaining an essential sense of humour with these things, if the problem only occurs when your wife is driving, then you must stop her using it - simple! Sorry Rob! Now down to progressing a solution via. asking for some more details:- Car new to you or not, and how long has the issue been there, and did it occur all of a sudden or has it just got worse? Has has there been any work carried out on any parts of the coolant system in recent times? This might include a cambelt change, where the water pump was also replaced? Does your wife's 25 mile out, 25 mile journey involve higher rpm/speed than your normal use? Have I read it correctly that the coolant tank is up to the max. mark (when hot) when her journey ends, but is empty when cold in the morning? I guess you then refill (to just above min?) and if she repeats this journey immediately, then same loss of coolant occurs? Have you tried placing some cardboard under the car on a dry night after your wife's journey to see if there is any external evidence of a coolant leak? Have you had a good inspection around the engine to look for tell-tale signs of pink residue? -take the coolant is pink. Any dampness in the front carpet? If any work has been carried out on the coolant system then it could be that there is an airlock - but I would have thought it would have been cleared by now with you topping up the tank. Incase not, as soon as your wife returns from her journey, dial the heater up to max. temp. and squeeze all the hoses, particularly the smaller bore (heater type) ones. Last question. When you have this loss from the tank, do you get any smoke from the exhaust on start up? As soon as your wife returns from her journey, get her to rev. the car to 2000rpm and hold it steady around that for at least a couple of minutes while you check for any smoke from the exhaust. Apologies Rob, but let us know how you get on, and some more detail. Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
IDUA Posted March 12, 2018 Author Share Posted March 12, 2018 I’ve decided to trade the car in today as the list of niggeling faults are getting longer and longer, I would like to thank Gareth for his reply, it’s forums like this that support other drivers with their car “troubles” and can make owning a car that little bit easier. Quote Link to comment Share on other sites More sharing options...
Gazcoedcae Posted August 9, 2020 Share Posted August 9, 2020 I'm suffering with the same problem, approx every month I'll get in the car and have an alarm warning me that the tank is empty. This has been going on now for about 6 months but the car drives fine with no low level alarms until the following day when the tank is empty. There's evidence that it's coming out from the cap, which has been replaced along with the tank. The heating has also become very poor (worse on the drivers side for some strange reason) so I removed the heater matrix expecting it to be blocked but that was free flowing with no leaks. Any ideas if the system can over pressurise itself and vent coolant through the expansion tank cap when the engine is switched off? Quote Link to comment Share on other sites More sharing options...
B.S Posted August 11, 2020 Share Posted August 11, 2020 Hi, I have the same issue. I drive 100 miles a day, every 3rd day or so the coolant will have released through the pressure release valve in the cap of the coolant reservoir. I have replaced this for a new one just in case the valve was weak. Still have the same issue. The heating also is poor. The coolant usually drops whilst driving, I have found this as I get the warning of low coolant level when coming too the end of my commute. I also check after I finish driving and sometimes the level is low at this point too but the warning hasn't popped up yet. Any Ideas of where to look next would be appreciated Quote Link to comment Share on other sites More sharing options...
CoventryAudi Posted October 8, 2020 Share Posted October 8, 2020 Silica bag has split Quote Link to comment Share on other sites More sharing options...
Andrej Posted May 3, 2021 Share Posted May 3, 2021 It was the same with mine. Loosing coolant through the expansion tank (there is a small hole on the bottom of it and it was wet), poor heating eventually no heating, engine temp normal, top pipe to the cabin/matrix hot, bottom one luke warm... Back flushed the matrix and flushed the whole system (quite a lot of debris orange in colour and looked like flakes), which unblocked the matrix but in a month time it happened again. Changed the matrix everything works fine-ish there is still sloshing sound coming from the dashboard but not to bad, I think there could be some air trapped I intend to flush the system again to see if there is still any debris in the system. Quote Link to comment Share on other sites More sharing options...
Audi_152 Posted January 21, 2022 Share Posted January 21, 2022 On 5/3/2021 at 6:12 PM, Andrej said: It was the same with mine. Loosing coolant through the expansion tank (there is a small hole on the bottom of it and it was wet), poor heating eventually no heating, engine temp normal, top pipe to the cabin/matrix hot, bottom one luke warm... Back flushed the matrix and flushed the whole system (quite a lot of debris orange in colour and looked like flakes), which unblocked the matrix but in a month time it happened again. Changed the matrix everything works fine-ish there is still sloshing sound coming from the dashboard but not to bad, I think there could be some air trapped I intend to flush the system again to see if there is still any debris in the system. How did it go? Is it all resolved? Quote Link to comment Share on other sites More sharing options...
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