Coolant leak 2003 ALH from below vacuum pump

[MATPOC]

I'm sure it's been covered, can't seem to find it though...
Been loosing coolant slowly (top off once every few months) and I did see some drops on the transmission before but figured it was an o-ring between that pipe and head or something, today I moved the car and there is a whole lota pink snow. It was something like -20ºF overnight and I'm guessing extreme cold shrunk some parts and made it worse. I don't have tools here or lift, got to drive home 170 miles in the morning and I will be passing by ID parts on the way home so I want to pick up whatever is the common failure part that will hopefully take care of this, I don't want to be without a car for days while waiting for parts to show up.
Thanks!

 

[csstevej]

It will probably be that oring between the head and coolant flange…..notorious for leaking there…. I’d get 2 just in case….

 

[MATPOC]

It will probably be that oring between the head and coolant flange…..notorious for leaking there…. I’d get 2 just in case….

Does the flange need to be replaced as well? I know with Audi it's usually never just an o-ring, got to replace entire component, but that's more modern ones...
Hope this is a simple fix, been a bad weekend for leaks, driveway has all the colors of the rainbow: truck left a big red stain of ATF (needs to go back to transmission shop which might take weeks) and snowmobile is leaking green coolant (cracked heat exchanger which is part of the frame)
Yellow and brown stains are from the dog, no fixing that

 

[03TDICommuter]

Does the flange need to be replaced as well? I know with Audi it's usually never just an o-ring, got to replace entire component, but that's more modern ones...
Hope this is a simple fix, been a bad weekend for leaks, driveway has all the colors of the rainbow: truck left a big red stain of ATF (needs to go back to transmission shop which might take weeks) and snowmobile is leaking green coolant (cracked heat exchanger which is part of the frame)
Yellow and brown stains are from the dog, no fixing that

The 5 spd ones have a metal water outlet. Just clean it and re-use. The automatics have a plastic one.

I had to replace mine, but the bulk of the leak actually was from the coolant temp sensor o-ring. After replacing that, the top of my trans was no longer wet.

 

[csstevej]

Yep what 03 said…..it might not be a bad idea to get the coolant temp sensor o-ring and a new clip……just in case….

 

[MATPOC]

The 5 spd ones have a metal water outlet. Just clean it and re-use. The automatics have a plastic one.

I had to replace mine, but the bulk of the leak actually was from the coolant temp sensor o-ring. After replacing that, the top of my trans was no longer wet.

This one? for $12 might as well get new sensor too...

Coolant Temperature Sensor Green 4pin w/Seal and Clip (A4)(B5.5)

Coolant Temperature Sensor Green 4 pin. This is the coolant temp sensor for most later TDIs, including PD engined A4 chassis cars. Check your car before ordering, early cars (98-00) use the blue se...

www.idparts.com

 

[csstevej]

Yep that’s the one.

 

[MATPOC]

Finally replaced the sensor, that fixed one leak...

When I got the car there was a leak between the water pump and engine block, did the pump and belt, that seemed to have fixed it, for a while at least, saw few coolant drops again at the lower timing cover, don't feel like pulling it all apart again so I'll wait to see how much I'm loosing. Wondering if I missed something or it's a common problem, the leak between the block and pump

 

[Tdijarhead]

You have to be real careful when installing the water pump. The bore it sets in needs to be clean and you need to put some lube on the O ring of the water pump so you don’t nick or pinch it.

 

[jakob0327]

Not to hijack this year old thread but does anyone know the torque specs on the water outlet flange? Cracked mine last night and want to make sure I don't break a new one....

 

[MATPOC]

Not to hijack this year old thread but does anyone know the torque specs on the water outlet flange? Cracked mine last night and want to make sure I don't break a new one....

2 year old thread
IDK the spec but rule of thumb is 10mm socket=10 ft/lbs, not exactly accurate as it could be M5 or M6 and M6 could have 8mm head... but after 35 years of wrenching I just know what it takes to snap that bolt. Usually use 1/4" ratchet for small stuff like that and it doesn't take much torque

 

[jakob0327]

2 year old thread
IDK the spec but rule of thumb is 10mm socket=10 ft/lbs, not exactly accurate as it could be M5 or M6 and M6 could have 8mm head... but after 35 years of wrenching I just know what it takes to snap that bolt. Usually use 1/4" ratchet for small stuff like that and it doesn't take much torque

Thank you very much i should have it handled today if fedex comes in!

 

[JETaah]

On the ALH, BEW...
The bolts for the driver's side cylinder head coolant flange are M6 x 1.0 and they get torqued to 7 lb/ft.
Water pump bolts and thermostat flange are M7 x 1.0 and get torqued to 11 lb/ft.