I’m getting ready to do a coolant drain in 2.5 weeks on my new to me G37S Sedan with 70k miles.

What other things should I do while I’m doing that.

-I’m replacing all hoses with Z1 silicons
-new high pressure cap
-metal bleeder valve

I’m considering installing new thermosat while in there. What brands and who sells them? Does it come with gasket?

Water Wetter?

What about a 75/25 water/antifreeze mix? I live in San Antonio, I’ve lived here my whole life and it’s never gotten below 0F. I think once it’s was in the twenties for a whole week.

Lastly should I replace the coupler? I think I’ve read threads about it disintegrated. Where can I get a replacement? Maybe better than oem?

Any other ideas?

 

when you say "all hoses" you mean upper and lower rad and heater?..good call

when you say "metal bleeder valve" that is the replacement for the coupler(s) that disintegrate on the heater hoses( assuming you're talking about the Z1 replacement here: https://www.z1motorsports.com/coolin...e-p-11190.html) ...depending on the year you have you may have two or only have one (or none maybe)... but I would suggest replacing all of that even if you didn't mention it

thermostat is best go with OEM they are cheap...

I would NOT put any water wetter in the system

stick with 50/50 mix

I would also suggest replacing all the OEM spring clamps on the hoses...they tend to lose their tension and should be replaced with the hoses...a lot of people skip it and end up with leaks..

 

What size clamps do you need for the radiator and heater core hoses? Or is it best to buy a kit with many sizes?

is the Oem thermostat the one made by Aisin and made in Japan? I saw it in a video and it looked very well made

Yes, the z1 coupler is the one I’m talking about

 

As a long-time Houston resident, I never felt the need for Water Wetter except when I was running my Senta SE-R on the track. It had a design problem that made overheating somewhat common when driving hard for any length of time.

I've tracked my G several times and it never made indication of overheating.

 

Which Thermostat did you end up with? Saw on Amazon someone saying Aisin is OEM, but can’t find anyone confirming it. Plus it seems there are two model Aisin on Rockauto, not sure which to get THN006 or THN014?

Thanks!

 

Interested as well.

Can I ask why you're changing your thermostat? Are you having issues or just preventative maintenance since coolant will be out? My has 2011 has 87k and I'm getting ready to drain/fill and the thermostat seems to be fine however in IA I am heading into winter. My previous experience with Japanese thermostats is the original one often lasts well past 120k.

-Eric

 

Just preventative maintenance. Ended up ordering OEM from eBay for $21 shipped after that $3 coupon they had. Will do coolant project over long weekend since too many other responsibilities in life right now.