Hi Everyone,

I have a 2012 G37X with 215K (mostly highway) miles. I bought it last year and the previous owner never changed the coolant so it still has the original factory coolant. I'd like to change the coolant since its long overdue and wanted to know if it's OK to take it to a shop that uses a machine to flush the coolant? I called a radiator shop that told me they use a machine that uses a vacuum to suck out the coolant and they claim they add new coolant in while its under under vacuum pressure to avoid air pockets. Is it OK to use such a machine to change the coolant in our cars? Any risk of damage to any seals or components due to the vacuum pressure used by the machine? I don't plan on changing any other parts, just want to replace the coolant. I'd appreciate any advice.

 

Yes, a power coolant flush is OK for your car.

 

I've always done a drain/fill on mine (new owner, if you're reading this, it's due!!!). When refilling, using a vacuum fill tool does indeed eliminate the issue of air pockets and having to bleed the system.

During operation, the system operates at 15+psi, so I suppose so long as your pressure flushing system is below that, you should be ok.

 

Thanks for the response. My concern is that the cooling system is normally under positive pressure (you mentioned around 15 psi), but the vacuum machine would be putting the cooling system under negative pressure. Could this dislodge or harm anything? I'm thinking about concerns many people have when it comes to doing a power flush on transmission fluid, which most people advise against.

I'm also curious to know how they connect the machine to the cooling system.......do they connect through the radiator cap and then fill up the coolant through the reservoir?

 

Never heard of a vacuum assisted coolant flush. Not claiming it isn't a thing but I'm not familiar with it. I've always just done as @Jsolo mentioned. Drain via peacock, run distilled water (optional), add new coolant, run until fans operate, burp system & top off.

 

Just a quick follow-up, I had the coolant changed by the shop that sucks out all the fluid by a vacuum machine and uses the same machine to fill it back in. The shop owner claims this method eliminates all air bubbles. Aside from some sounds that came from the heater (near the glove box) during the drive home, everything seems to be working fine. No overheating issues.

 

That's odd... If you hear noise from the heater that is only due to air in the system...

From my experience, the VQ37 doesn't have "cooling system air pockets" when you do a simple drain and fill.
Other engines can be VERY difficult to get the air out, but not the VQ37.

 

^^Agreed about the sloshing noises due to air.

Friend who's an auto tech claims the vq37 engines tend to be difficult to bleed traditionally. Recommendation was to use a vacuum filler to avoid the headaches. Something like this . I've used this tool on the G with great results.

Either way, if you're hearing noises when turning, take it back to the shop to have 'em do it right.

 

Interesting... I just use this:

and make sure to pour in the new coolant VERY slowly.

 

Same @SonicVQ . I drained then refilled very slowly and worked like a charm. Followed a member's video from the forum who was/is a tech

 

With a compressor, the vacuum fill method takes 5 minutes to do and ensures no air pockets. No burping needed. Probably overkill for the home repair unless doing multiple cars.