Loss of coolant..

[16g Spoolin TSi]

Every couple of weeks i'm noticing my coolant overflow tank being low on coolant, never bone dry however if i fill it to the max line its alomost half way down the tank. I work at a service center and for the last two weeks i've had my car in the air on the ground searching for leaks... can't find anything. the car is running way to good to possibly be a head gasket issue, i see no oil in my coolant and no coolant in my oil, my heat works the balls same as the defrosters, no blue smoke no scent of coolant burning... WHERE THE HELL IS IT COMING FROM?!? haha im going crazy. One night i did notice a drop i mean a DROP a trace lets say of coolant around my belts, so i wiped it off and haven't seen anything since. Anyone have any ideas they lend to help me find this out.
Thanks
Johnny

 

[unlikely hero]

Just to be safe check your compression. You might be surprised.
=Jason-

 

[GSXanimal]

with that slow of coolant loss the head gasket could probably be the cause.

 

[16g Spoolin TSi]

What should compression be across all four cylinders min and max?
~Johnny

 

[16g Spoolin TSi]

and with the head coming off do u need to do the t-belt or can it be slipped off, i just had one done less than 15k?
thanks
~Johnny

 

[Defiant]

Originally posted by 16g Spoolin TSi
WHERE THE HELL IS IT COMING FROM?!? haha im going crazy. One night i did notice a drop i mean a DROP a trace lets say of coolant around my belts, so i wiped it off and haven't seen anything since.

The water pump is starting to head out, you probably have about three months to go on it. Do belts at the same time.

 

[crankbender]

The water pump is deffinately a possible cause. Also most people don't know but your car runs the coolant at a temperature that has a very high vapor pressure. If you coolant cap has a leaking gasket on the pressure seal you will slowly boil the coolant off. It is an easy fix they are about 5 bucks and it never hurts to have new caps even if it isn't the problem.

Personally I have had this be the problem 3 different times on 3 different older cars.

 

[16g Spoolin TSi]

crankbender thanks a bunch i never knew that, i hope its not the head i really don't want to do a head gasket job :thumbdown

~ Johnny

 

[GSXanimal]

If you did see a drop by youre belts then I would definately watch the water pump.

 

[16g Spoolin TSi]

did a compression test today while at work
cyl #1: 175psi
cyl #2: 175psi
Cyls 3&4: about 175/6psi hard to read but close to it..
max psi 178
min psi 133

seems to be no signs of leakage or significant wear.
i also replaced the rad cap the old had a very weak spring.
~Johnny