Draining Coolant Tank B8 S4

[blackjak]

Hey guys, recently I have noticed my coolant tank continues to drain at a consonant rate of 2-3 days after I fill it up. It's a 2011 B8 S4 with the upgraded water pump. I had the thermostat replaced with the all metal housing replacement after the plastic one gave out on me. I can not identify a leak of any sorts via looking for frosted/dried coolant in the engine bay. Luckily it's winter and the car can run just fine without overheating however I want to get it fixed asap. I was wondering if anyone has run into this same issue of a draining coolant tank? I'm assuming it's a loose hose somewhere in the system, but I cannot find it. I was planning on taking it in for a check up at my local Audi dealership, but they are going to charge me at least 150 for the check up just to diagnosis. Before I take her in I wanted to check here with everyone and see if they have any advice about were to look or any tips or tricks on isolating the issue.

Any recommendations are greatly appreciated. Thank you in avance.

[creativecody]

I've heard of more than a few people that this happened to. Cause was a rock that got kicked up and punctured the tank. Audi knows of this problem and the one guy I talked to said that Audi installed some sort of shield to protect the tank.

[amz]

Any strange exhaust smoke/smell? Also, check your engine oil to make sure coolant isn't finding it's way there. Basically, if a fluid that goes through your engine is disappearing, and not disappearing to the outside of the engine...it's probably disappearing inside the engine.

[jacaobsdenmark]

There is no other way expect spending on your engine and I feel Audi dealers may take better care of this issue if it is major one. They will simply install the tank protecting shield.

[S4'ed]

Do you have water gurgling noises from behind the dashboard, when the engine is cold, and goes away after the engine is warmed-up?

[blackjak]

I do not have any gurgling noises behind the dash prior to warm up. No odd signs what so ever. Car is running perfectly minus the leaking coolant issue. I am going to refill it again today and see if I can track the issue down. I have been driving on empty coolant however I am somewhat afraid to refill again if it is in fact an internal leak... Il follow up after refill. I don't recall any bad smells.

[jygesq]

The coolant is going somewhere . Have audi or an Indy do a pressure check. This is nothing something to let go without finding what is the cause. If you are just over warranty expiration AOA may do something for you if major engine issue. If you have a good relationship with your dealer go there now.

[blackjak]

The coolant is going somewhere . Have audi or an Indy do a pressure check. This is nothing something to let go without finding what is the cause. If you are just over warranty expiration AOA may do something for you if major engine issue. If you have a good relationship with your dealer go there now.

Yeah - you are right. I've been driving in it just fine, but it need to be taken care of. Scheduled an appointment for Friday. Il follow up and let everyone know.

[amz]

you can also get UV dye-packs that you can add to your coolant, drive until you need to tank up again, and then poke around with a UV light. That should give you a pretty clear indication of where the coolant is going.

[blackjak]

Do you have water gurgling noises from behind the dashboard, when the engine is cold, and goes away after the engine is warmed-up?

I have noticed this noise now that you said something, it sounds like water is slushing around behind the dashboard. Any ideas?

[S4'ed]

I have noticed this noise now that you said something, it sounds like water is slushing around behind the dashboard. Any ideas?

If you don't have a leaking intercooler radiator, my scary theory (that nobody wants to hear.....) is that you have a head gasket issue. I think there is a design issue with the head-gaskets on the 3.0T.....but that is only my opinion.....

[ATX_S4]

Check this thread - especially the last post http://www.audizine.com/forum/showth...1#post10718493

[cspcrx]

If it is a head gasket you will see it in one of a couple ways.

Smoke in the exhaust.
Bubbles in the coolant with some oil
Coolant in the oil

[schirm]

I have noticed this noise now that you said something, it sounds like water is slushing around behind the dashboard. Any ideas?

My scary theory (that nobody wants to hear.....) is that you have a head gasket issue. I think there is a design issue with the head-gaskets on the 3.0T.....but that is only my opinion.....

I have had this noise for 100,000 miles now when the engine is cold(many others have too). I would say its nothing to worry about.

[ENV²]

My scary theory (that nobody wants to hear.....) is that you have a head gasket issue. I think there is a design issue with the head-gaskets on the 3.0T.....but that is only my opinion.....

I would on occasion here that in my old B8. Never had any issues at all. It stopped happening after it crossed 35k miles.

[B8_Jim]

Hey guys, recently I have noticed my coolant tank continues to drain at a consonant rate of 2-3 days after I fill it up. It's a 2011 B8 S4 with the upgraded water pump. I had the thermostat replaced with the all metal housing replacement after the plastic one gave out on me. I can not identify a leak of any sorts via looking for frosted/dried coolant in the engine bay.

My thermostat was leaking under the blower, so it wasn't visible in any way until 3yr 3 mo in - even though I had to refill the tank with coolant every ~4k miles and I brought this to the attention of the dealer twice - the first time they told me it was "normal H2O evaporation from the system"...

At any rate - the leak got bad enough (lost about 1/2 of the Max-to-Min mark every 3-4 days) that there was liquid coolant on the under-tray, and the dealer went to bat and finally tracked it down after pulling the blower. Apparently the lower leak rates were allowing it to dry before running out, but it got bad enough it finally ran out and down the front of the engine.

Seems like your leak is even higher rate than I had, so seems you should be able to see coolant... ???

[-leman-]

Could be also a leak in one of the heat exchangers which are located in the compressor housing. I heard of such issues with 3.0tfsi engine, in such a case you will not see any coolant leaks under hood for obvious reasons. If its bad enough it should be visible as white exhaust and uneven engine sound / vibrations. If its a light leak only it would be either invisible or visible as occasional cylinder misfires via VCDS and such.