2003 A4 1.8T coolant leak and turbo malfunction
 

Hi, I just bought my first Audi from a private seller and i am having a problem with a slow coolant leak. It pools on the ground below my car so i know i am not burning it. I have had the car for a little over a week now and ive had to top off the coolant every couple days. So far i have used about a half gallon. Also, sometimes when i start the car the turbo makes a loud noise, a mechanic told me that it was the waste gate releasing pressure and that it definitely shouldnt be doing that but thats all he could tell me. Once the car is warmed up it wont make the noise any more. I have a couple questions regarding this whole thing...

1. Could the coolant leak and the turbo problem be related?
2. Is the problem with the turbo serious enough to blow my motor (or other serious consequences) if i dont have it fixed ASAP?

In still in the process of finding a good and honest audi mechanic locally before i take it to the dealership which is my last resort.

Hmm.. I've got an 02 that just started the coolant leak thing too. I can't see where it's coming from. Usually its either the thermostat housing under the intake, or even more likely the flange on the back of the head (both plastic). Not sure on the turbo, but shouldn't be noisy on startup. Probably not related to the coolant issue as there's no direct connection inside the turbo where the coolant could leak (oil could though)

Thanks for your input. I am trying to decide which is more of a priority to fix right now. I was just at the dealership yesterday getting the ignition coils replaced and they didn't say anything about either (neither did I)

Neither the coolant flange nor the thermostat are really all that difficult to DIY. The thermostat seems like it would be a pain to do but there's a good write up here or on the net by Matt Devo. I used it and it was fine - but take care not to pinch the new "o" ring (I had to do it again because I did that),

Also, find a good independent shop for this sort of stuff - also look at the audizine forums they're pretty active too.

Leaking coolant isn't the worst thing to have to worry about on our cars. You should get on the regional forums though and at least get someone who knows to see if they can identify what the issue with the turbo might be, I can't say I've come across it - also search here and the other forums on the net to see if anyone can shed any light.

Best of luck.

1) Where does the coolant leak? Front of engine slightly driver's side would be the thermostat or j plug. Back of engine basically in line withthe front wheels would be coolant flange or heater hose.
2) Are you sure you have a turbo problem? The SAI (Secondary Air Injector) pump is just below the turbo and when failing makes a whistling sound. If you had an issue with your turbo, you wouldn't have it just on start up, but all the time,

Thanks for your input. It is in the front, slightly drivers side. I am taking it to a local garage tomorrow to have the coolant leak diagnosed and hopefully repaired. I will let you know what they say. As far as the turbo goes, it doesnt make a whistling sound, its just loud. I am going to wait on having that diagnosed for now

the turbo does no real work at idle sure it spins but at a very low speed. At idle the engine pulls negative vacuum the acceptable stock range is -18 to -23 psi meaning the turbo is doing zero because the engine in pulling vacuum. The noise you are probably hearing the the secondary air injection pump doing what it is supposed to be doing. At idle the secondary air injection pump introduces air into the engine to help with cold start idle emissions. It sounds like a jetplane sometimes, almost like an auxiliary fan. The turbo usually STARTS doing work at approx 1800 RPM under load and if the vehicle is stock will boost 7.5 psi MAX or if you have the 170hp motor 11.5psi MAX IIRC, please note I said start doing work at 1800 RPM, that means you will not get MAX boost at 1800 RPM it just starts boosting at 1800RPM and builds boost and HP in a nice linear fashion

Had it in the garage today, they said the secondary air intake hose was completely disconnected. They have reconnected it and im hoping that will fix the problem. So far, so good, but the real test is starting it up tomorrow morning when its cold. Thanks for the info, i truly appreciate everyones advice and input. I have to take it back for the coolant leak on monday.