dmccart812

I have a 2004 Audi S4, 6 speed with 35k. On a recent visit to my mechanic, he said he spotted minor anti freeze dripping from the bottom of the car. He readjusted a hose and clamp, pressure checked it, and everything seemed to be fine. Several weeks after, I had been driving the car for about 10 minutes when I suddenly noticed the temp guage moving over towards how and immediately following a warning flashed across the dash. I immediately shut the car off and had it taken back to my mechanic. The coolant fill reservoir was still full, however the system seemed to have lost most of the coolant. My mechanic is a Porsche/Audi trained tech, however he rarely sees the 04 and newer S4’s and has not been able to pin point the problem. He told me yesterday that the engine may need to come out of the car to find out where the leak is. I’ve seen numerous postings on several Audi forums about the 2000-02 having coolant leak issues, but can’t find anyone that have had problems with the 04 and newer S4’s. If anyone has any helpful comments, I’d really appreciate it.

hellbringer

This sounds quite bizarre. .
- where was the originial coolant leak coming from?
- there's an issue with the aux radiators. .and there's a valve to open them when the engine gets hot (my understanding). so I'm not sure if a pressure test will find the issue
- did the mechanic check the coolant temp sensor? Since you indicated the temp moving "how". .which I assume you meant "low".. .and you said the coolant level is full I'd check the coolant sensor. search the forum for coolant sensors. someone recently had a similiar issue with the engine temp dropping
- how do you know you lost coolant? "however the system seemed to have lost most of the coolant"

Something sounds fishy. . esp since he's saying the engine needs to come out.

dmccart812

Thanks for the info, I will have him check the aux radiators and coolant temp sensor. The original leak seemed to be coming somewhere off the back of the motor closest to the firewall. To clarify what happened, after driving the S4 approximately 10 minutes, it heated up, the temp needle went into the red zone quickly and the temp warning flashed on the dashboard. At the same time, I looked up and saw white smoke in my rear view mirror. I turned the car off immediately and pulled over at which time there was a huge puddle of coolant on the ground. I sure hope my mechanic can figure this out and avoid taking the engine out.

joeycuccaro

If there was a puddle of coolant we can pretty much rule out the possibility of it being the temperature sensor. Thankfully you shut off the car quickly at the temperature rose, otherwise you are looking at a blown head gasket and possibly warped the heads.

There is a major coolant line that runs in the location that you explained above. I hope your motor does not have to come out for this.

If you can get the car on a lift, take the belly pan off and try to locate and old and crusted coolant. This will give you a good indication of where the leak is coming from.

dmccart812

I just received a partial update from my mechanic. He tried resealing the water pump and unfortunately this did not improve the problem. He said he has narrow'd down the leak somewhat - it is coming down drivers side of the engine and dripping off the pan. He said he is having a terrible time seeing up into that area and is going to try and rent a scope that will allow him to see up into that area better.

Anyone have ideas on what might be on the left side of the engine that could be leaking? Hopefully it is not a cracked block.

s4master1

your mechanic seems to be confused on this issue specially when he wants to jump and pull the motor out
get a pressure test at the radiator cap, it has a relief valve and it leaks at the driver,s side of the motor however for this to happen usually means the system is having excessive pressure(overheating)
is the coolant circulating to the radiators? this is very easy to check, is the thermostat opening?
what happens if you set the heater to the highest with the econ button depress?
get all these info and will make it easier to diagnose your problem, but pulling the engine is the last thing in the picture
remember audis are famous for plastic impeller in the water pump failing suddently
how you seal a water pump???

dmccart812

Thanks for your comments and advice guys. I have forwarded these to my mechanic and hopefully this will help him further trouble shoot the problem.

Thanks, Dave

oasis

I realize this is an old thread, but it described my situation exactly.