2.7t overheating and almost no boost

[jenyus425]

hey everyone, i've done some searching on here for these two issues but havent found any conclusive answers. i just bought a 2001 audi allroad 2.7t with 61k miles. here are my questions 1. i drove it 600 miles home and it started overheating on me and now overheats all the time. i changed the temp sensor last night and it doesnt seem to have changed anything. id assume it is a thermostat and im going to change it this weekend 2. it seems to be lacking a little power. i can feel it take off until about 2500 rpms and the it seems to lose power. theres no drilling noise but there is a sound that sound like a really loud fan when i accelerate and i dont think its the clutch fan. the driver side intake from the intercooler to intake manifold popped off the other day since it wasnt tightened down all the way. what should i be checking to see whats going on with the turbos?

[eightyhorsepower]

1. There may be air trapped in the cooling system. Look for any cracked hoses ( look around the hoses and near the clamp areas).
Try bleeding the system( expelling air out of the coolant) & refilling with new coolant/water.

2. The engine may just need a tune-up: new spark plugs, oil, oil filter, fuel filter.
Can you narrow the loss of power down to Spark, Fuel, or Air? That can give you a starting point.

Good luck with the search

[jenyus425]

thanks for the reply! whats the best way to bleed the system? also, i noticed that this car has the green coolant instead of the special pink stuff, do you think thats important? i used my inspection camera and looked at the aux water pump and it looks like its been leaking so i ordered another one of those.

i ordered a new set of diverter valves, they were both shot, so i'm hoping that helps the boost issue. i took it to a shop for some other stuff and had them check all the lines for the turbos and they didn't find any. i'm doing new spark plugs and fuel filter right now.

[eightyhorsepower]

I'm not too familiar with this engine; however, bleeding the system on a different German car went something like this:

After emptying the coolant through the radiator and/or engine block drain plugs, refill the system with 50/50 coolant + water into the coolant resevoir tank.

**on this car there was a bleed screw on the top of the thermostat housing**

Have the car on a slight uphill gradient: this will allow air to escape upwards out of the engine.
Unscrew the bleedscrew, start the engine and turn on the heater to full blast. Rev engine a little bit.
Coming out of the bleedscrew will be coolant with bubbles (oxygen air bubbles). Wait until the bubbles disappear- this means all the air has been "bled" from the system. Put the bleedscrew back in immediately.

Turn off the heater and car. Fill the 50/50 coolant into the tank for what was lost during bleeding.

[nelsonjr20]

Originally Posted by jenyus425

hey everyone, i've done some searching on here for these two issues but havent found any conclusive answers. i just bought a 2001 audi allroad 2.7t with 61k miles.

here are my questions

1. i drove it 600 miles home and it started overheating on me and now overheats all the time. i changed the temp sensor last night and it doesnt seem to have changed anything. id assume it is a thermostat and im going to change it this weekend

2. it seems to be lacking a little power. i can feel it take off until about 2500 rpms and the it seems to lose power. theres no drilling noise but there is a sound that sound like a really loud fan when i accelerate and i dont think its the clutch fan. the driver side intake from the intercooler to intake manifold popped off the other day since it wasnt tightened down all the way. what should i be checking to see whats going on with the turbos?

Hello Bud: I'm having a similar problem with my 2.7T where it seems to be running hot and my fan clutch is constantly engaged because I always hear that wind rushing noise when I accelerate. Have you been able to find a solution to yours?? Please let me know becuse this sound is very annoying and yes the car does feel underpowered.

[Peter Badore]

Originally Posted by nelsonjr20

Hello Bud: I'm having a similar problem with my 2.7T where it seems to be running hot and my fan clutch is constantly engaged because I always hear that wind rushing noise when I accelerate. Have you been able to find a solution to yours?? Please let me know becuse this sound is very annoying and yes the car does feel underpowered.

I would expect that the thermostat is stuck closed or is only partially open. If the thermostat is OK then there could be a water pump failure with the original design plastic impeller. My low miles 2.7l 6 speed A6 failed its
thermostat open at 46,000 miles this winter but at 11 years old the original part must have suffered an aging related problem. The thermostat can be changed without removing the timing belt but I always take out the timing belt and change the thermostat, water pump and timing belt system components at the same time. I do all my own work so the labor cost of paying someone else is not a factor. Also if the coolant in your Audi is the incorrect type it is possible that sludge has formed clogging the radiator or other parts of the cooling system. Last are you sure the fan clutch isn't defective as the mechanical fan is a very important part of the cooling system on this generation of Audis?

[Peter Badore]

Originally Posted by nelsonjr20

Hello Bud: I'm having a similar problem with my 2.7T where it seems to be running hot and my fan clutch is constantly engaged because I always hear that wind rushing noise when I accelerate. Have you been able to find a solution to yours?? Please let me know becuse this sound is very annoying and yes the car does feel underpowered.

One more comment: the ECM has a safety function to limit boost if the engine is overheated.

[jenyus425]

Originally Posted by nelsonjr20

Hello Bud: I'm having a similar problem with my 2.7T where it seems to be running hot and my fan clutch is constantly engaged because I always hear that wind rushing noise when I accelerate. Have you been able to find a solution to yours?? Please let me know becuse this sound is very annoying and yes the car does feel underpowered.

still nothing, but i did another pressure test and i can hear a bubbling noise coming from the driver side turbo indicating a coolant leak. 034 motorsports said that it wasn't a significant leak but im not totally convinced.

Originally Posted by Peter Badore

I would expect that the thermostat is stuck closed or is only partially open. If the thermostat is OK then there could be a water pump failure with the original design plastic impeller. My low miles 2.7l 6 speed A6 failed its
thermostat open at 46,000 miles this winter but at 11 years old the original part must have suffered an aging related problem. The thermostat can be changed without removing the timing belt but I always take out the timing belt and change the thermostat, water pump and timing belt system components at the same time. I do all my own work so the labor cost of paying someone else is not a factor. Also if the coolant in your Audi is the incorrect type it is possible that sludge has formed clogging the radiator or other parts of the cooling system. Last are you sure the fan clutch isn't defective as the mechanical fan is a very important part of the cooling system on this generation of Audis?

I should probably just bite the bullet and buy a new water pump and timing belt and tensioner, the previous owner said that that was all done but he was a liar about a lot of other stuff.

i do all my own labor as well, but the cost of the parts still isn't cheap. i flushed out the old coolant, i went through the flush procedure, where you drain it, fill it with water, warm the car up, drain it, and repeated about 7 times until the water coming out was clear. do i need to do more than that? i just ordered a laser thermomoter so that should help me diagnose some of the problems i hope.

when the clutch fan was running, i tried to stop it by applying pressure to the outside of the fan with a piece of cardboard (not sticking it in the fins) and it wouldn't slow down, so i would assume that it isn't the clutch fan. im going to put a 4k CFM fan on it this week and see if that changes anything.

did i also mention that im getting about 10mpg? and that according to my boost gauge its still putting out 7-11 pounds of boost?

Originally Posted by Peter Badore

One more comment: the ECM has a safety function to limit boost if the engine is overheated.

thats good to know! thanks for all your help!