Losing anti freeze.

AlanS · Post by **AlanS** » 14 May 2025, 14:18

Was noticing antifreeze on my driveway...and on the frame rail on the pass. side. To save me time, I had my mechanic do a water pump, belts, etc. It was time...water pump was original 2006. Still noticing anti on my driveway and on frame rail. Did a through inspection, could not find the source. Not the antifreeze reservoir (as I hoped it would be). The engine is dry...the tank loses antifreeze after very long trips. I have a cap for the reservoir that I put a shredder valve in. If I want to pressure test...what is the procedure? I don't want to blow a gasket. Any help would be great! PS...it does not appear to be the heater coil. Dry inside.

Post by **jonesg** » 14 May 2025, 18:52

the coolant cap is usually rated around 12 psi, so 10psi would be ok.
Its very possible for the coolant bottle to be losing coolant and show nothing when you look because it evaporates very quickly.
When the system is pressurized spray soapy water on the bottle, they crack on the molded corners, I changed mine last yr.

Vova585 · Post by **Vova585** » 14 May 2025, 19:55

Based on quick search green color cap is rated for 1.5bar which is 21psi. As far as I remember correctly lots of rental tools dont have volvo specific adaptor. Adaptor is about $45. You might get lucky with buying something from harbor freight and maybe in their master set there is correct adaptor. I think at this point I much rather pay dealer $180 per hour of diagnostic and drink coffee in their waiting room or enjoy a loaner for a day. To buy adaptor +shipping+tax +plus trying to find correct pressurizing tool+ time to get the tool and return it+labor(it might be way easier to see this problem in a lift)..long story short I dont think this job is worth your time u less you are particularly passioned about doing it yourself (180- 45(tool that you likely would never use again)-10 for shipping..)

Post by **volvolugnut** » 15 May 2025, 08:37

I have taken an old cap, drilled a hole, tapped for 1/8 pipe thread, and added connection to pressurize with air. With a gauge in the connection, you can monitor initial pressure and bled off.
volvolugnut

Post by **DavidE7** » 18 May 2025, 18:22

Finding the coolant leak(s) can be very tricky. The crimp and gasket joint between the aluminium center fins and plastic end caps has failed on 2 or 3 of my cars after 200,000 miles. The bleed nipple on the top of the expansion tank has also failed a few times. The hose from under the expansion bottle to the back of the engine was a recent failure. I had a pin hole in a radiator that wasn't visible until after the radiator had been removed because it was behind the fan shroud. Looked for milky white-blue-green dried coolant near each of the junctions. The worst leak is when the cooling system is pressurised, spark plugs removed, and you turn the engine over and some blue-green liquid splashes out of a spark plug hole...

I did the same thing as volvolugnut and drilled an old Volvo coolant cap, tapped for a brass fitting, and made my own adaptor. You have to disassemble/unsnap the green top part of the cap off the black bottom part to access the area for drilling and tapping the threads. I had a little leak after finishing so I roughened the plastic a little and sealed it with JB Weld epoxy.