Hello all, just joined this group today in hopes someone can point me in the right direction!
Last week driving around town, noticed the engine fans go extremely loud and the temp sensor started creeping up past 90
Was able to get home before hitting approx 110 degrees. There were no visible coolant leaks, the reservoir was showing mid way between min/max and no error codes/lights came up on the dash
Admittedly, I'm a novice in this game and learning as I go with YouTube and FCP Euro videos
The water pump was replaced approx 2yrs ago, so was assuming if anything it might be the thermostat
Fast forward to today
After much anguish, I found the thermostat was not replaced when the W/P was, so learned how to get to the t-stat, replaced and just finished re-installing the supercharger this morning
Started engine (bit sluggish to start possibly because air box hasn't been put back yet), and hopefully bleed the air out of the lines with the 2 screws on top of S/C
Came up to temp (90 ish) fans came on like normal, upper rad hose turned warm, then fans went back into beast mode and temp started to rise again... insert choice words here
The W/P has a vacuum nipple connected (I think) to a solenoid valve just to the right of the pully wheel which i disconnected thinking it was activating the shroud around the impellers..., no change
I don't see any visible coolant loss, and the reservoir fluid seems clear
Not sure what else to check before starting all over again!! HELP

 

Two thoughts come to mind:

1. Have you scanned the vehicle with VCDS?

2. Thermostat was a good guess. But did you use a vacuum filling tool like an Airlift? You could have air in the cooling system.

 

Thx Silver TT
I did a full scan with VCDS, other than a right rear speaker fault nothing else showed up
Dont have a vacuum tool, just went up to 2k rpm, cracked passenger bleed screw then drivers side.

 

What brand thermostat is installed?

The vacuum actuated waterpump is for faster engine warm up during winter cold temps especially below -18C and colder. It should have little to no effect when ambient temps are above -10C. The default state of the collar around the impeller is in the retracted position to ensure max coolant flow during warmer ambient temps.

Vacuum Airlift systems are definitely the way to go with the 3.0T among other engines and that is what I use exclusively. I have never had a problem with airlocks in cooling systems when using an Airlift.

 

Thanks AATW!
I’ve tried finding tech sevice manuals that note the info you just provided to no avail!
W/P was done by a local Euro VAG shop, but I wouldn’t know the model # of the replacement unless I can find it on the external casting
looks like Walmart has an airlift in stock for 55…, will pick up tomorrow and give it a shot

 

My bad…, t-stat came from NAPA model TMH-HT185857

 

I will try some solutions:
1, make sure those coolant pipes are conneted properly.
2,remove W/P to double check.
3, Drain coolant and flush with distilled water untill clear for couple times, then fill with concentrated coolant.
4, also check the temp sensor.check 2 temp sensors reading.
5, testing T-stat is easy, put in boiling water to see it open.

 

Thx Jasonfire, was hoping there was some easier test sequences to try before ripping all apart and starting over. Will try the airlift idea today and see if things change

 

Just read it again, did try feel the bottom pipe ? is it really warm to touch ? if it's so, the T-stat and W/P should be working properly.
Did you try to turn the heater on? is it blowing warm wind ?

What color is the coolant ? I presumed that whoever fixed your W/P should have flashled it ?

 

Thanks again Jasonfire!
coolant is clear and will touch lower hose today
cant confirm if system was flushed when WP was replaced
before bleeding yesterday using supercharger plastic screws only, was blowing cool temp on high heat setting
after bleeding it did blow warmer, but not hot