Phenomenon01

Hi guys,
I started parking my A4 in the garage and I noticed a burning coolant smell coming from the front of the car.
I had my coolant pump / thermostat housing replaced under warranty a few years ago. Ever since the replacement, my coolant level has never fallen below the minimum, they filled it up the max line and is always stayed at the max line.
Curious if this is normal, or should I get the dealer to check the coolant lines. I'm assuming if there was a leak, the amount in the reservoir would have went down by now.
Thanks.

A4Audi4Fun

Coolant smell in a garage is always an indicator of a coolant leak though it could be very very small. In the confines of a garage, the nose is quite sensitive to the smell of hot coolant - the most likely cause is a pinhole in the radiator or slight weeping at a coolant clamp if you are not seeing any coolant level drop. Larger leaks are when the coolant level drop would become more noticeable.

After you've parked the car in the garage, while things are still at operating temperature, open the bonnet and see if there are any signs of steam within the engine bay and surrounding hoses.

ptmdsharp

I've been smelling it off and on for practically the entire ownership of my A4. I point it out to the dealer every time it's in for service. Everytime, they tell me there's no evidence of a leak, water pump problem, etc. My coolant level never changes. Weird, weird, I tell you.

Phenomenon01

I exactly in the same boat as you, 100%. I can bring it up next time I go in for service, but if they are going to charge me to take a look then what's the point.

ptmdsharp

If you figure it out, then let us know. Frankly I'm not sure how hard the dealership looked at mine before it was out of warranty. My concern was always the water pump given the high failure rate but mine has avoided replacement thus far. The A4 now 6 years old and going strong despite the random/occasional coolant smell.

Airfan

I had my coolant pump / thermostat housing replaced a few years back and since then the coolant dropped from Max to Min. I have constant smell of coolant in the garage after I park the car but I wouldn't bother addressing the issue, since it takes 2+ years to get from Max to Min and there are sensors that will inform you when it drops below Min. Just fill it up and don't think about it. It is cheaper to top it up instead of replacing it again for a small leak.
A few months back before the warranty of the repair was to expire I went to the dealer to do a check for coolant leaks and they said that there are no leaks or the machine can't sense them so I won't bother with that. There are more important things in my life than that.

142 guy

If the cold engine temperature coolant level in the expansion tank is not changing I would not be concerned. Following a service, Audi specifies that the coolant level should be filled to the Max level with a cold engine. If you start out at Max with a cold engine and are gradually dropping towards Min then you may have an issue. The normal way to check for leaks is to apply air pressure to the cooling system and then let it sit while you monitor the system for pressure loss. Slow leaks may take a while to register a pressure loss so if your service tech is paid by the hour they may be inclined to pump it up, leave it for a minute and if the pressure does not drop then assume it is good. One of the problems with the pressure test is that they normally use an adapter to replace the pressure cap on the expansion tank for the test. If the pressure cap is leaking or if it is below spec the test will miss that. If the pressure cap has gone out of spec then it may be burping coolant from the cap when it shouldn't.

If you had a coolant service and the coolant tank was slightly overfilled then the pressure cap may burp the excess coolant through the pressure cap when the engine is hot. Once it has burped enough coolant to return the cold coolant level to the Max level then the burping should stop.

sandune

I, too, have had the same issue since day one of my purchase. It was a year old at the time. I brought it up every time it went in for service and every time they said they found nothing and the level was always OK. No matter, if I smell it, there must be a leak somewhere no matter how small. Fast forward to when I just recently fell out of warranty and guess what? They tell me I have a leaking thermostat/ pump housing. I believe unless the "leak" is beyond a minimum threshold, it is not considered an issue and not covered by VAG so it's not considered a problem yet. I have now had it replaced and a few weeks have passed since the repair. Unsurprisingly, after four years of chasing this issue, I seldom notice a coolant smell anymore. Luckily they covered quite a bit for me as a goodwill gesture when I complained about it but now that Canada also has a class action settlement I will happily ask for the portion I ended up having to pay myself.

I recommend you keep an eye on it. It's just a matter of time.

Cheers,

LightningTruck

My Audi dealer always gives a FREE estimate w/part numbers during Audicare oil change visits.
.

Kaiser2015

I have owned my 2017 Allroad since new and this smell is common but not normal. After fighting with Audi saying everything was normal they gave me Audi Care up to 100k to shut me up. About a year ago there was a class action
lawsuit sent to me regarding this problem. From what I understand Audi will replace the water pump or reimburse you for water pump up to 80k miles at a pro rated amount. The coolant smell appears to be from the plastic water pump. Coolant is leaking but
burning up at the same time so you don't see a leak and only smell coolant. I don't think replacing the same water pump will make a difference however. I just learned to live with it and have them top off my coolant at every Audi Care visit.
And yes, when I got the class action suit I forwarded it to my service director who thought I was a nut and said.. I told you so.... I never got a reply ..