Still losing coolant somehow, what else could it be?

**Dixit** · 09-16-2008 08:40 AM

So Ive been trying to nail this problem down for awhile on an 04 A4 1.8T CVT (55k miles on it) that I used to own and gave as a gift to my sister in law. She loses about the entire coolant overflow tank in say about 2-3weeks of driving. There is no visible smoke while driving.

The rear flange is not leaking what so ever. So I thought it was the oil cooler, I replaced that, same thing still happening.

So Im down to two things, either leaky headgasket or turbo seals. Now Im really not thinking its headgasket as the performance of the car feels great, if there truly was a leaky headgasket id definetely have some rough idling and I feel definetely see some white smoke (coolant burning) from the tail pipe under hard acceleration or normal driving. So I feel its not that.

So now Im leaning towards it being a turbo bearing seal issue. I know the turbo is cooled via coolant so the coolant is passing through it, so that could be a culprit. Im thinking the leak is so slow that its not visible enough to see the white smoke from the exhaust. I was thinking of capping off the coolant lines going into the turbo to see if that stops it as I test to see if that it, but at the same time dont want to burn up the turbo. But that may not be an issue as my sister in law is driving, aint like she dragging it.

I just want to nail this sucker down. Im fairly close to buying a turbo and replacing it, but again dont want to drop the cash for that and find out that aint it either.

Anyone else have any ideas or experience on what it could be?
Thanks
Dixit

**CO AVANT** · 09-16-2008 08:56 AM

Is there any white residue on the turbo, hoses to and from turbo, or on the belly pan? Take a sample of coolant out of the reservoir. Go pour it on the asphalt. If it is rainbow color on the black asphalt then combustion gasses are leaking into the coolant reservoir and over-pressurizing it cauing the coolant to escape from the over-flow port through the cap. This is a head gasket issue. I had this problem with brand new head bolts on a freshly rebuilt engine. I put in new oem head bolts (now running arp) in by replacing one at a time in the correct torque sequence and correct torque force+. This eliminated all my problems losing coolant. This was one of those wierd head gasket issues since there was no coolant being burned, no oil/coolant mixing, no internal leaks causing piston tops to be "steam cleaned".

Have you looked down the spark plug holes (with spark plugs removed) with a flashlight to see what the top of the pistons look like? Look for white residue anywhere under the oil pan area or entire under area for that matter...

**AudiA4Turbo22** · 09-16-2008 08:57 AM

have the exact same problem but for me a small rock hit my radiator and it leaks from there.

**Dixit** · 09-16-2008 09:06 AM

Thanks for the info. I will have to check on the coolant having signs of fuel gas. I dont see any signs of that on the belly pan mainly cause there is none anymore, pieces of it were broken so bad that I just removed it entirely for now.

As far as white residue on the turbo, or lines, wouldnt that only happen if it was leaking out of there, sorry if i sound confused but if the system is sealed and its not phyiscally leaking out anywhere then its internally burning and wouldnt really see that unless it was leaking out of the hose somewhere and the heat is causing it to turn white on the outside where it leaks.

Other option i need to do is do a leakdown test and pressure check on the cylinders to see if there is a possible head gasket leak. But good idea on checking the plugs and piston to see if its whitish residue anywhere.

Dixit

**A4Avant02** · 09-16-2008 11:16 AM

I had a similar issue on my tip trans. The O rings on the trans fluid lines that run to the radiator leaked ever so slighthly and their location was hard to see, so the leak was not real easy to find. I changed the trans fluid and pulled the lines to the radiator and replaced the O rings and have no issue with coolant levels now.

**Dixit** · 09-16-2008 01:04 PM

So Im trying to figure out how the Orings caused the leak for coolant. Lines going to the radiator from the tranny are for the tranny cooler and that should only be tranny oil, so not sure where the coolant is coming into the mix. The tranny section in the radiator shouldnt be mixing the coolant unless its internally leaking.

Dixit

**aaronz** · 09-16-2008 01:18 PM

Any luck? I know this might be a shot in the dark but my bleeder screw had melted and that is where my leak came from. The screw, when melted, warped and thus allowed coolant to slowly leak out. Doesn't sound like your problem but just in case you over looked it.

Good luck!

**CO AVANT** · 09-16-2008 02:12 PM

Originally Posted by Dixit

Thanks for the info. I will have to check on the coolant having signs of fuel gas. I dont see any signs of that on the belly pan mainly cause there is none anymore, pieces of it were broken so bad that I just removed it entirely for now.

As far as white residue on the turbo, or lines, wouldnt that only happen if it was leaking out of there, sorry if i sound confused but if the system is sealed and its not phyiscally leaking out anywhere then its internally burning and wouldnt really see that unless it was leaking out of the hose somewhere and the heat is causing it to turn white on the outside where it leaks.

Other option i need to do is do a leakdown test and pressure check on the cylinders to see if there is a possible head gasket leak. But good idea on checking the plugs and piston to see if its whitish residue anywhere.

Dixit

If the headgasket is leaking coolant into the cylinders, your pistons tops will be clean as hell. What it does is pretty much "steam clean" them... Just a regular dry compression test is a good tool as well. Just make sure you take the 4 engine management fuses out if you do so...

**dougyfresh** · 09-16-2008 03:14 PM

Originally Posted by CO AVANT

If the headgasket is leaking coolant into the cylinders, your pistons tops will be clean as hell. What it does is pretty much "steam clean" them... Just a regular dry compression test is a good tool as well. Just make sure you take the 4 engine management fuses out if you do so...

Or unplug the fuel injectors from the engine harness and clear that code when you are done.

**A4TL** · 09-16-2008 04:12 PM

my radiator cracked and leaks but it takes a while to go down like 6 months. costs too much to replace so i just park it :)

**Pothole** · 09-16-2008 05:47 PM

Id check the bleeder screw too, mine was striped out and lost about the same amount of coolant, its right under the plastic engine cover on the coolant line that runs down the head

**slow&low** · 09-16-2008 07:26 PM

Take it to a audi shop and have them pressurized your coolant system. I was loosing fluid and couldn't find the leak either. Never had a drip in my driveway but I would lose all my fluid. turned out to be the coolant flange. A pressure check test only cost me $30. Better than replacing the turbo!!!!!!