HELP! Cooling system troubleshoot and or mods??

[91MazdaNava]

Ok, so its summer. The other day, it was hot. The Navajo overheated. I took it into the shop that I'm very loyal too because they've been great so far. They said they spent two hours messing with it, couldn't get it to overheat, said there was nothing wrong that they could see/diagnose and charged me for an hours worth of labor. Fast forward a couple weeks. Pretty hot again. Overheats! Then the tranny starts slipping! (I think) The heat fried this part of the tranny (shifting modulator?) so I take it in again and say besides the tranny, please find the heat problem. They fix the tranny ($300)...can't find the heat problem.

I DO NOT want to live in fear of another overheat and more expensive repairs. What should I do? Are there any performance low cost cooling parts like lower temp fan switches or thermostats? Or even any good, although more expensive options, like a performance fan or better aluminum radiator? What should I upgrade first? Please advise. Thanks guys. Appreciate it.

 

[Anime]

It helps if you pay attention to what's happening when it's overheating. Does it overheat because you have the A/C on full blast and the cooling system can't keep up at idle? Does the temp gauge needle just go to the "L" in NORMAL or it goes way past that and you have to shut off the engine to prevent damage you know will happen?

It's fairly common for the A/C to make the temp gauge needle go to the A or L, sometimes even past it. If it keeps climbing it's trouble and time to pull over and shut the engine off (or shut the A/C off first) and drive conservatively to let the engine cool down.

Cooling issues tend to be associated with a thermostat that is slowly going bad and won't open all the way, or possibly with old coolant or a dirty cooling system that isn't efficiently transferring heat. Sometimes the fan clutch even starts going out, or the water pump gets worn down, which both make it harder for the cooling sytem to work.

If you don't know when the last time the coolant was changed is, or never had a thermostat put in, maybe have the shop do a coolant change (Zerex Green or G-05 coolant are good choices here) and install a new thermostat (Motorcraft or maybe a Stant superstat) at the same time.

 

[91MazdaNava]

Thanks! And Yes, I did have the AC on. Although def not on full blast. Coolant flush&change sounds good as well as the thermostat. Anything else, guys!? Thanks!

 

[91MazdaNava]

Oh, how about a lower temp thermo as long as it fits our applications here? Would that help by turning on the cooling system sooner and keeping it on longer??