06 Using some coolant

[TNTKNC]

Ok I'm hoping someone here has seen this before, cause I'm baffled.
I have a customer with an 06 Jetta and this is what he is telling me.
The car is using some coolant but only about 1/2 gallon and then it quits. He can fill the bottle to proper level and within a short period of time the add coolant warning comes on, about 20 to 30 minutes of driving. However that is where it stops. He can drive it 20 miles or 100 miles and the car never looses more than about that 1/2 gallon. Also when he pulls the reservoir cap there is pressure in the system. This has been going on with this car for several years now. He took it back to the dealer several years ago under warranty and they replaced the water pump. He said it seemed to work for a little while but picked back up and has continued since. I haven't seen the car yet so I have not been able to look at things yet but he wants to see if anyone else has seen this happen before.

 

[D-Cell_Mekanick]

Thats odd, id be checking to make sure the resevoir isnt cracked first.

 

[Henrick]

Maybe it's the exhaust gas cooler?

 

[TNTKNC]

EGR has been deleted so that's not the issue. My problem with the reservoir being cracked is it doesn't hold half a gallon, and since the system is pressurized if there is a leak it should push all the fluid out. This problem makes no sense to me at all.

 

[scrichy84]

Weird...soothappens had his leak for years out of the water pump seal, when we changed his timing belt and water pump at 100k, it went away...

Continuous leaks can also be cause by the coolant hoses behind the motor getting a pin hole leak in them as oil tends to drip on them from the boost pipe...

It is really weird that the system is staying pressurized, I would be more concered about where the coolant is ending up?!?!

 

[TNTKNC]

Well I don't get to see the car very much he calls and tells me whats going on. Then I'm tasked with trying to figure it out. So I thought I would try here to see if anyone has ever seen this problem. He has had some strange issues with this car and really isn't sure he is even going to keep it.

 

[runonbeer]

Check the small coolant line that wraps up over the tandem pump and goes into the port on the side of the head. I've seen them bubble up and pop a pinhole leak here on several cars.

I just cut it and run a coupler with a shot of new hose.