Alternator fixed, still somewhat overheating..need help

[Carado1984]

Had the alternator replaced and that fixed the charging issue, its now at 12v and about 13.5 when driving. However, eventually the engine will heat up to 3/4 or more and the AC will start blowing hot. Even if I turn the AC off and put the heat on the car will still hover around 3/4 randomly going above and dropping below. I drove it about 40 miles today on the highway and stop and go traffic and it does this regardless of the conditions. Oddly enough, it has never actually overheated.

I am so frustrated having only owned the car for 3 weeks. No shop around here will touch it and the closest Audi dealership around is Tom Williams Audi in Irwindale, AL just south of Birmingham. They quoted me 2300$ to replace the timing belt, pulleys, water pump, thermostat etc. I do get a 10% military discount...wooooohooo. I have read the threads about the thermostats going bad but I find it odd that it will not fully overheat. Again, no light has come on indicating it was about to. I'm at a loss.

Again, any input would be appreciated. I would hate to have that done and still be having issues but its looking like my only option. Also, the electric fan appears to be working properly and is still running normal, even after engine shut down.

[4everRS]

If you scan it, I will bet a nickel that your cooling system is going into emergency mode. It is sensing that something is not right.

It could be the t-stat, but it could be the coolant temp sensor just behind the drivers side cylinder head. It's green in color and plugged into a hose/fitting.

[Carado1984]

Is the coolant temp sensor something that could easily be replaced?

[Carado1984]

After looking at a few other threads, my fans do run for a min or maybe even longer after the car is off. I'm going to drive it now to the auto hobby shop on my base and scan the codes, see what we find. Ill post back as soon as I figure it out.

[Carado1984]

Advance auto will have one here tomorrow morning at 730 am for $20. When this sensor goes bad, could it be giving a false readout to the gauge in the cluster also?

[Carado1984]

Temp warning light came on so im currently sitting along side the road listening to the fans

[lswing]

Your best bet is getting the RossTech scanner, shows much more detail, and you can log data. Priceless tool...

Don't get too frustrated, remember this is a ten year old car with a lot happening in that engine bay. I fixed things here and there, eventually you'll get it sorted.

[Carado1984]

Thanks. I know im just having a huge string of bad luck. I love the car so I'm trying to stay positive hoping I can look back at this in a few years and laugh. I will be ordering a rosstech scanner, im just on somewhat of a time crunch right now. I was suppose to leave for the beach tomorrow and meet my family halfway at the airport then drivr the rest so you can imagine the stress I'm under.

[LIRS6]

Leave the car for the w/end and rent something - I wouldn't play around with the overheating issue that you are experiencing. You'll get past this, as Iswing suggested.

[Carado1984]

Oh Im def not driving it anymore. Ill replace the sensor tomorrow but if that doesn't solve it, its getting towed to the dealer. If it does solve it, its being driven there for the timing belt service.

[LIRS6]

From another post you mentioned that the car has 73k on it and "half" of the 75k service done. If the "other" half includes timing belt, then I would say that by all means you should get it done as the timing belt likely will have been changed only once in 10 years, (assuming it was done at 35k). Search the forum for other suggested maintenance items while the belt is changed - it's a timely opportunity to replace O2 sensors, etc., in addition to the water pump and thermostat.

[DHall1]

2300 for the timing belt at the dealer is a good price as far as dealers go.

At 75k you should have the water pump done for safe measure.

Make sure the 2300 includes the belt, upper rollers, damper, thermostat. If it also includes the lower idler and roller then the 2300 is a super deal.

[bmlee007]

2300 for the timing belt at the dealer is a good price as far as dealers go.

At 75k you should have the water pump done for safe measure.

Make sure the 2300 includes the belt, upper rollers, damper, thermostat. If it also includes the lower idler and roller then the 2300 is a super deal.

+1 for that price, my dealer quoted me $3k. I bought the parts and the tools for about $700, did it myself and set the remainder aside for other fun stuff.

Also, join ACNA if you're not already a member. Most dealerships offer 10% discounts on parts and labor, and I've seen a few up to 20%.

[Carado1984]

Theyre giving me 10% off for military and yes that is the other half that needs done. I planned on having it done but I would prefer to drive it there if possible so im hoping the sensor switch allows me to do that. And the 35k service was done at 39k according to the records I have. The price quoted includes water pump, thermostat, timing, serpentine, and all pulleys. I talked to the technician who will be working on in and he has two rs6 customers that run their cars at Barber Motorsports Park that go to the dealership several times per year. They're probably hiding out on this forum somewhere.

Thanks for all of the input guys. Ill let you know tomorrow how the sensor replacement goes and if anyone knows of a thread or how to on it please link. I've been out all day typing on my phone so searching is somewhat of a pain in the ass until I get home in a few hours.

[Carado1984]

As a bonus they're going to flush my tranny fluid for 179 using my filter and gasket since its oem audi that I bought for 60$. Now if I could talk them into using the 9 quarts of redline tranny fluid I just bought.... I will be towing it there sunday if the coolant temp sensor doesn't fix anything.

[P1054]

I'm sorry to hear about your bad luck. For what it's worth, I replaced my coolant temp sensor a couple of months ago after my gauge started randomly not working while driving. Sometimes it would read correctly (exactly at 12 o'clock), then it would randomly drop to zero. Occasionally it would start working again while driving, but usually it would only start working after the car sat for a while turned off. After I read some threads on here, it seemed like the most likely culprit was the sensor, so I ordered a new one from Pelican Parts. If I remember right it came to about $15 shipped.

To find the sensor, look at the engine from the front of the car, the sensor will be behind the airbox a little to the right of center. It green (at least mine was) and plugged into a coolant line, with a wire plugged into the top of it. It is held in place by a plastic c-clip, to remove it just unplug the wire, pull out the c-clip, and pull the sensor out of the hole. It has an o-ring and fits snuggly in the hole, so it may take some wiggling to get it out.

Most people suggest removing the airbox to access the sensor. I was able to replace mine without removing the airbox, but I think it would be worth removing it to give yourself the extra room to work. Also, I would suggest tying a piece of fishing line or thread or something similar to the clip before trying to push it back in, I managed to drop mine and had to fish it out from way down behind the engine.

Hopefully the sensor solves your problem, good luck!


Theyre giving me 10% off for military and yes that is the other half that needs done. I planned on having it done but I would prefer to drive it there if possible so im hoping the sensor switch allows me to do that. And the 35k service was done at 39k according to the records I have. The price quoted includes water pump, thermostat, timing, serpentine, and all pulleys. I talked to the technician who will be working on in and he has two rs6 customers that run their cars at Barber Motorsports Park that go to the dealership several times per year. They're probably hiding out on this forum somewhere.

Thanks for all of the input guys. Ill let you know tomorrow how the sensor replacement goes and if anyone knows of a thread or how to on it please link. I've been out all day typing on my phone so searching is somewhat of a pain in the ass until I get home in a few hours.

[lswing]

As a bonus they're going to flush my tranny fluid for 179 using my filter and gasket since its oem audi that I bought for 60$. Now if I could talk them into using the 9 quarts of redline tranny fluid I just bought.... I will be towing it there sunday if the coolant temp sensor doesn't fix anything.

That's a super low price...I think we used about 13-14 quarts to flush and fill mine, a few quarts just for flush. That's the cost of fluid alone, seems odd, cause it takes a few hours. You could also trim just a 1/4 inch or so off your filter pickup, little tube that sticks down, some say 3/8 I believe. Search on here and you'll find the threads. We also cut some little notches around the edge of mine, just in case the pan got pushed up, there's a bit more room for flow.

[Carado1984]

Thanks P1054! I will definitely take your advice. I have a feeling this is the thermostat and the car is actually getting close to overheating. It seems most coolant sensor issues are more with the sensor not reading the temp then over reading or stating its too hot. Either way, I will be happy if the thermostat/water pump replacement fixes it and its not the radiator. I haven't looked up any issues with the radiator and I don't even want to know what that costs should it be clogged or something etc. Anyway, I will keep everyone posted and I appreciate the help from everyone given how new I am to this forum. Previous to this, I have always been an GM LS guy and those parts are cheap, and interchangeable with almost any other GM LS series engine, and somewhat of a breeze to work on. Then again, this engine wouldnt be too bad if it wasnt for how packed in it is.

Anyhow, thanks again!

[Carado1984]

lswing........ I have seen the threads about trimming the pickup tube but I dont think Audi would like that so maybe I'll do the tranny myself after the rest is sorted out. I am wondering why Audi doesnt include tranny flush/refill in any of their service intervals. The tech told me this today also and I was surprised.

http://www.rs6.com/showthread.php/20286-RS6-service-schedule-with-part-numbers

[Carado1984]

Also lswing.. Do you know anything about the cost of the replacing the fuel filter? I'm looking at my maintenance records to see when it was done and I'm assuming the 35k service done at 39k. thanks.

[lswing]

lswing........ I have seen the threads about trimming the pickup tube but I dont think Audi would like that so maybe I'll do the tranny myself after the rest is sorted out. I am wondering why Audi doesnt include tranny flush/refill in any of their service intervals. The tech told me this today also and I was surprised.

http://www.rs6.com/showthread.php/20286-RS6-service-schedule-with-part-numbers

Sounds good, the trim is just a precaution. I believe that fluids are listed as lifetime, yea right! Pretty sure diff fluids are "no change" also...

[Carado1984]

I have never let an automatic go more than 50k without a tranny flush. I truly hate automatics for the simple fact that they are ticking time bombs. Since this car was serviced at an Audi dealer its entire life I would bet it hasnt had a tranny flush so you think i'll be ok doing it with 75k? I'm referring to the fact that many people are afraid to change the fluid if it hasnt already been done because the difference in new tranny fluid could cause it to slip.

[905084]

Resolution?

[Carado1984]

Geico towed it 2 hours to the dealer for free. Timing belt service, trans and diff flushes, and a fuel fuel filter. It was not the coolant temp sensor so I suspect the thermostat. I think theyre working on it right now so I hope to hear back soon. Should I have the crank and cam position sensors replaced while theyre in there?

[DHall1]

Sounds like your on the right path here. No need to change cam/crank sensors.

Just make darn sure they change the oring on the transmission filter screen. The new screen does not come with a oring. Dont ask me how I know.


Geico towed it 2 hours to the dealer for free. Timing belt service, trans and diff flushes, and a fuel fuel filter. It was not the coolant temp sensor so I suspect the thermostat. I think theyre working on it right now so I hope to hear back soon. Should I have the crank and cam position sensors replaced while theyre in there?

[lswing]

Sounds like your on the right path here. No need to change cam/crank sensors.

Just make darn sure they change the oring on the transmission filter screen. The new screen does not come with a oring. Dont ask me how I know.

Yep, I remember we had the o-ring separate...

Hope the dealer is good with all fluids. I have trans fluid paranoia due to the damage not enough can cause. Drove easy for a few weeks then went back to get it topped off!