Evan Roska

Hello all!

I've been dealing with cooling issues this past month and I've gotten a lot of help addressing them.
I would cruise on the freeway at damn near 220*F with the needle noticeably moving and on TS showing me *Danger Red* lol.

I've replaced my ebay rad with a SuperMiata Crossflow rad(1.1 bar OEM rad cap), Mishimoto oil cooler, and 30/70 clt/water and water wetter. Minor ducting and undertray with Rtheory hood vents and going WOT 1-3 I don't even go above 207*F! BUT That was after replacing my generic napa replacement CLT sensor with an ACDELCO one from Rockauto.
The ACDELCO sensor really read 10 degree cooler than the NAPA sensor which I thought was odd. In MS they both matched my GM IAT after sitting over night. My aftermarket (ebay/chinese) CLT gauge would even be within +/-3 degrees of the NAPA replacement. Weirdly enough comparing the aftermarket gauge to the ACDELCO at lower temps they would be within 2 degrees of each other but then the ACDELCO would stay considerably cooler lets say it sits at 205*F on MS and then the gauge on the it would say the CLT is at 215.

For example I took it to the track today at T-hill and the gauge said it was hitting 235*F but I logged that run and on MLV it says I BARELY scraped 207*F until I got off the track and the temps kinda jumped to 215 and instantly cooled off.

I guess what I wanna know is, do I trust the megasquirt telling me im running way cooler than I was or should I trust an aftermarket gauge and sensor? (I've ordered a glowshift one and installing tomorrow to confirm if the gauge is straight dooky or not)
I drove it home with the gauge blaring that i was cruising at 240*f ( didnt log it because I didnt think it'd happen on the freeway)

I dont know I just want to know if I'm right to be kind of concerned with the discrepancies between MS and my gauge
thanks, I'm a bit new to this but I've learned much on this forum and I'm ready to learn more! lol

Gee Emm

You can test the sensors by taking them out, and calibrating them against a decent thermometer using a pot of water brought to the boil on a stove. Likewise the thermostat, if you want to do the job properly. A multimeter can also give you values to check against the tables used in the ecu in producing its readings/warnings.

If you are seeing 240*F, wouldn't it be boiling coolant out to the overflow tank, even at 1.1 bar - any signs of that at all?

Not sure what you mean by minor ducting, but unless you are doing all-of-it, you are probably wasting your time and money, Bonnet vents need to be in the right place, or they can make things worse by becoming inlets, not outlets.

Evan Roska

I'll actually try the boiling water thing tonight.
By minor ducting I mean by putting all of the stock undertray and air guides back in because it didnt have any, I sealed off some gaps between the AC heat exchanger, rad and a little bit of the intercooler, and sealed the rad and rad support.

And exactly! It isn't boiling at all, not even seeping a little bit out of the rad cap or overflow. I suspect the ebay temp sensor is junk but I do want to test just for science