Troubleshooting coolant vacuum fill failure

[Rendak]

Hey folks. I’m at my wit’s end with the very last step in the comprehensive cooling system overhaul on my 2015 LR4 with 86k miles that I’ve been doing following txfromwi’s extremely helpful video on YouTube.

My problem is that I can’t draw a vacuum greater than about -5 inHg. I’m using the popular OEMTOOLS 24444 Coolant System Refiller Kit hooked up to a Porter Cable C2002 pancake air compressor and I’ve followed the directions in the manual as well as watched videos online to make sure I’m using the coolant refiller kit correctly. I don’t think my air compressor is leaking air through fittings, but I’m not sure I know how to check with the coolant refiller kit. I’ve got another coolant refiller kit coming in the mail to see if the one I’ve got is a dud. And I’ve triple checked all the coolant hoses that I can think of on the LR4.

Anything else that any of you can think of as to why I’m not getting sufficient vacuum?

Thanks in advance!

 

[Rover Range]

I would fill the cooling system, then do a pressure test.
That way you can see where the coolant leak is.

Using WD40 to lube the o-rings is a no no. Some of the o-rings in the cooling system don't like WD 40. That would cause the o-rings to swell up and leak.

 

[powershift]

I've never tried vacuum filling. How does that work? For my pressure test I used the harbor freight hand pump coolant pressure tester and it found a leak.