Facelift Coolant leak around bottle

kpm278

kpm278

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Hi

I have a 2014 tdi 2.0 that intermittently empties its coolant bottle. I can see coolant around the bottle/engine mount area and on the bottom engine cover/splash shield. I removed the pipes and bottle and looked for splits but all good. I filled it back up and monitored and it stayed level for a couple of days until tonight when it emptied again.

I’ve read caps can go naff and is a straightforward replacement obviously. Is there anything else common I should look at?

Thanks
 
Most likely the system is over pressurised and it's emptying the coolant out that way. Go for a drive and see how much pressure is in the system, the coolant pipes should have a good amount of pressure but if they are rock hard then somehow excess pressure is getting into the system. This could be down to waterpump, stat or even head gasket.
 
Thanks for the info. Did 175 miles without really losing any, but then noticed a bit around the bottle after another 30 miles. Coolant pipes were still squishy after 175 miles. Next step I’ll wrap some tissue around the ends of the pipes and under the bottle and see what gets wet first.

Water pump was changed a couple of months back. I noticed they didn’t fasten one of the pipe clips back on but made no difference when I fixed that.
 
Had been fine for 500 miles but got back in the car 12hrs after a 40 mile run up the motorway and coolant bottle was empty. It’s definitely coming out the hole under the tank which does indicate pressure increase as suggested. It’s also not dropping over time but suddenly. Would a garage able to pressure test something that apparently happens randomly and at great intervals?
 
You will probably find it’s not random.
Most likely when the car is under hard boost that’s when it’s likely to start leaking.
I remember from an old tunes Subaru that the radiator cap was rated to 1.1 bar and as soon as it was boosting it was coming out the cap at a rapid rate. Changed the cap to a 1.3 bar and all was good. Not sure if this applies to the a3.
 
update. been driving the car a bit harder recently but no leak. car is in the garage now, they pressure tested and all is fine. they said one of the hoses has noticeably more crystallisation around it, indicating concentration of coolant and suggest i replace it at £156. that sounds like a bit of a stab in the dark considering the coolant is emptying out the hole at the bottom and not the hose. i'm inclined to not replace the hose at this point, any thoughts?
 
been looking around and come across a couple of threads indicating coolant leak when a certain set of parameters are met:

dpf regerenation
+
coolant at operating temperature
+
certain speed

https://www.briskoda.net/forums/topic/446946-coolant-lost-during-dpf-active-regeneration/
http://forums.tdiclub.com/showpost.php?p=5379013&postcount=9

is there any way to tell when regeneration is taking place? i've never noticed a light on my dash or unusual sound.
i have vcds now so perhaps i can test the theory with a forced regen
 
Maybe try a replacement cap. Cheap fix if that's what it is. My coolant leaked out of the top but that is because Audi overfilled it when they serviced the car. It didn't empty the bottle though. You've checked hoses for splits but what about the security of any clips? It passed a static pressure test but that isn't at operating temperature. If Audi is saying a hose has crystallisation around it are they saying it is blocked? You could take it off and clean it out. I believe draining the cooling system is problematic though as it is supposed to be filled back up under vacuum so that there isn't air trapped in the system (at least on my engine)
 
Last edited:
Managed to get the warranty company/ dealer (not audi) to cover the cost of the hose so i'll let it be replaced. no residue around the cap when it leaks (it all comes out the bottom) so i'm thinking the cap is sound, but for the sake of £10 (or whatever it costs) that will be my next fix if it happens again, alongside vcds regen. i'll also ask the garage if they pressure tested it with a warm engine. thanks for input all
 
Car has been running sound for the past 5-6 weeks, no sudden loss of coolant. Checked today while under the bay and coolant level is sitting on the lower marker level now and I can feel slimy coolant under the tank. So it's lost a cupful. An improvement I suppose.....
 
Having suffered loss of heating - intermittent at first and had same issue with coolant loss discovered heater matrix was blocked - coolant seemed to be lost after driving and car stood - as I understand it an electric coolant pump is started when car is parked up to help cool engine and i'm wondering if with a blocked matrix this is what pressurises the system and kicks the coolant out. Water pump/cam belt has just been changed along with coolant tank cap - leakage doesn't seem as bad since new heater matrix fitted.....(A3 8V audi)
 
The VW/Audi coolant reservoir is designed with a safety pressure relief at the side which vents excess pressure. I suspect you have a faulty reservoir if you are losing coolant intermittently, with signs of coolant at the sides and bottom. Looks like time for a new reservoir.
 
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kpm278 said:
Hi

I have a 2014 tdi 2.0 that intermittently empties its coolant bottle. I can see coolant around the bottle/engine mount area and on the bottom engine cover/splash shield. I removed the pipes and bottle and looked for splits but all good. I filled it back up and monitored and it stayed level for a couple of days until tonight when it emptied again.

I’ve read caps can go naff and is a straightforward replacement obviously. Is there anything else common I should look at?

Thanks
Click to expand...

Hi, did you ever fix the issue? I currently have the same problem with my 184 TDI A3.

Thanks
 
Have a look at the joint that goes around the centreline (above the max fill mark). where the top and bottom hemispheres meet.

Mine has a hairline crack along this joint and is slowly leaking coolant.

The replacements come without the silica bag which is a good thing as they are known to leak and block the cabin air heater matrix. The replacements don’t come with a cap either so worth ordering one of those at the same time.
 
Also got same car with same problem!
Have replaced bottle + cap but still the same?
 
Luckylucas said:
Also got same car with same problem!
Have replaced bottle + cap but still the same?
Click to expand...
How long have you been living with the problem? The garage couldn’t find any leaks using a pressure test yesterday, the guy said he’s pretty sure it’s the bottle, although can’t be 100% so he has replaced that. My car is still with him at the moment as he wanted to check it over night…. Mine would be completely fine driving 200miles…get home check it and it still be full, then the next morning completely empty
 
Samjski101 said:
How long have you been living with the problem? The garage couldn’t find any leaks using a pressure test yesterday, the guy said he’s pretty sure it’s the bottle, although can’t be 100% so he has replaced that. My car is still with him at the moment as he wanted to check it over night…. Mine would be completely fine driving 200miles…get home check it and it still be full, then the next morning completely empty
Click to expand...
Prob 6 months on & off!
Tryed the cheapest things first but still ongoing?
Had some advise on possible causes i. e thermostat, water pump etc but for now I've changed spring clip with hose clamp on the top hose from expansion bottle just to rule that out too! No leak yet.
 
audi upgrades
I had a similar problem recently. during DPF regen water escaping from the expansion tank lid.

I replaced the reservoir and lid. still occured. This happened for a couple of months, 2 garages pressurised system and found nothing wrong.

Eventally took it back to Audi to give them a shot. They first suggested the lid and were swiftly informed it has already been replaced but nice try.

I told them about a whining noise coming from the back of the engine/dashboard area when the engine is turned off. This then led to them thinking the waterpump was over pressurising.

Since the water pump being replaced the car no longer gargles and whines or has coolant escaping! A bit annoying as just over 2 years ago i had it replaced and long with the belt! Fingers crossed this has solved the issue for good!
 
Could be waterpump then, have no strange noises from dash or under the bonnet but it's looking most likely at the mo!
 
Is your EGR valve ok?
Mine failed on my 8P 184 2.0 TDI Quattro sport at about 55k miles symptoms started with it using water and having to be topped up weekly then noticed heavy steaming from exhaust when cold, this was an absolute pig of a job to do as the EGR is mounted on the back of the block under the turbo, loads of kit had to come off just to be able to see the EGR valve, rack, column, subframe, transfer box, oil feed pipis etc. etc. etc. took me a week!!!!
I have done one before on an 8P 1.6 petrol when it started sticking open again at 55k miles and that was not as bad you could just get at it without removing everything.
 
Only needs topping up after a good run out 50+miles & nothing unusual coming out exhaust.
The last week or so to & from work all ok at mo!
 
After a trip to Cornwall, having had the waterpump replaced, my heating is now playing up.
All the way down the motorway no heating at all.
At slower speeds around towns I could either have HOT or COLD air with no real inbetween.
Any ideas?
 
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