Pressure Test Coolant System

[actionstan]

Hello All,

I have a 1999 Saturn SL1 that loses a small amount of anti-freeze over a long period of times.. Just millimeters over the period of months. This is a closed system and shouldn't lose any anti-freeze as far as I know.

Typically to find a leak i'd pressure test the system and call it a day.. however a Saturn does not have a radiator cap, and only an expansion tank cap.

I believe most auto part stores pressure testers only include 2-3 adapters for testing the most common types of radiators.. does anyone have any other tips on how to either verify the leak? Or where I can get a tester that will work with a Saturn?

I believe I have located the leak at the intake manifold near the 4th cylinder, but would like to verify before jumping into anything.

All help and advice is welcome, thanks!

 

[kschachn]

The $68 (with coupon) pressure tester set I got at Harbor Freight has a bunch of adapters, it even had one for the expansion tank on my BMW. It is really well made for the money.

That tool was something I went without for many years, not really seeing the need. But since I have bought it I have used it several times, and located leaks that if I waited till the engine was reassembled would have been major headaches to fix.

Originally Posted By: actionstan
Hello All,

I have a 1999 Saturn SL1 that loses a small amount of anti-freeze over a long period of times.. Just millimeters over the period of months. This is a closed system and shouldn't lose any anti-freeze as far as I know.

Typically to find a leak i'd pressure test the system and call it a day.. however a Saturn does not have a radiator cap, and only an expansion tank cap.

I believe most auto part stores pressure testers only include 2-3 adapters for testing the most common types of radiators.. does anyone have any other tips on how to either verify the leak? Or where I can get a tester that will work with a Saturn?

I believe I have located the leak at the intake manifold near the 4th cylinder, but would like to verify before jumping into anything.

All help and advice is welcome, thanks!

 

[Realtech214]

You could throw in some dye

 

[actionstan]

Originally Posted By: Realtech214
You could throw in some dye


I was considering this.. It would be cheaper than buying the Harbor freight kit, I wonder if it would work ok on a slower leak?

 

[Gabe]

Your small leak might become a moderate leak after the pressure test.

I would leave it.

 

[MarkM66]

Originally Posted By: Gabe
Your small leak might become a moderate leak after the pressure test.

I would leave it.


If you don't put more pressure in it then what the rad cap states, I don't see how this would put anymore stress on the system.

But really, I wouldn't even worry about loosing that much on a car that old.

 

[kschachn]

It won't, unless you pressurize it more than you should.

But I think the dye is a good idea, it is easy and would show small leaks over time. A UV dye is best if you have access to a black light.

Originally Posted By: MarkM66
Originally Posted By: Gabe
Your small leak might become a moderate leak after the pressure test.

I would leave it.

If you don't put more pressure in it then what the rad cap states, I don't see how this would put anymore stress on the system.

But really, I wouldn't even worry about loosing that much on a car that old.