Cooling system pressure test

[SimLyons]

I was intending to pressure test my cooling system this week. The local parts places (2) will loan me the tool kit with 4 or 6 adaptors. The problem is that none of the adaptors work on the Volvo screw on threads on the reservoir. Have any of you seen a way around this? Not sure I have a leak yet, but last month I suddenly lost about a pint of coolant. It was good before and seems tight now no loss since mid-December. I definitely don't want to take it to the dealer for this!

[jimmy57]

I use a T fitting with a short section of hose. The pump goes to one branch, the short section connects T to tank on another branch, and the hose taken off tank fits on the the last branch.

This setup allows pressure testing and the cap can be tested if the gauge on the pump is trusted. You pump it up and see at what pressure the cap hisses and then release cap and pump it up to something a bit lower than that.
The cap should be about 18 PSI and a continuous 16 PSI is a good test pressure for discovering leaks.

[SimLyons]

Thanks Jimmy! Sounds like a great idea. I have plenty of hose and a few tees around! I was thinking it would be around 15 psi but I'll go until I hear the hissing and back off a couple of lbs.

[db130]

if you have a green-colored radiator cap, that's rated at 22 psi

if you have a gray-colored radiator cap, that's rated at 18 psi(..and you should upgrade to the green cap)

so i'd first check to see if the pressure tester that they are lending you can go up to 22 psi to simulate actual conditions.

i have a friend who was a dealer technician who lent me his Mac coolant pressure tester(looks like a rebranded Stant unit) - i bought a stant Volvo adapter for it and it worked well to find my leak.

part number for the Stant volvo adapter is 12018 and the best price right now is on amazon:

https://www.amazon.com/Stant-12018-Threa ... 596&sr=8-1