I got my truck running again last night but now I notice the temp needle is soild at 190* on the freeway compared to in the middle of 140* and 190* fluctating like before. On city street, it's slightly left of 190*. So it definately running hotter then before.

The things I changed out between the period .. KDP, BHAF, 16.5*, silence ring, waterpump, new rear tires, valve adjustment, and I'm currently running on 85% distilled water/15% Toyota red coolant to clean the system (before running 50%/50% with Toyota red coolant, still Ethylene Glycol base .. doesn't smell like urine like the green stuff). I will threw in a new thermostate sometime next week when I drain the coolant out to a 50/50 mixture.

The only mods I can see that's cooling system related is waterpump (replace it with a Cummins one), 16.5* timing (maybe), and coolant mixture (never had an issue running it with other gas cars.)? Any idea?

 

I wouldn't worry about it. Mine ran there at just under 190*, til I put in a 180* tstat.

 

If you changed the thermostat during all that, it's probably that. The old themostat has been superceded by a newer part number, I think because the fluctuations in the temp gauge with the old one scared some people.

 

IMO, as long as it`s not overheating don`t worry bout it, besides the warmer it runs the better (within reason of course). If I might ask, why the Toyota Red? I use it also, One (and most importantly) because it`s a very good coolant and Two...I get all I can use for ...ummmm...not alot of money...OK, it`s free.

 

Woohoo .. fixed the problem today. Over the weekend, the temp gauge needle barely moved pass 140* .. while driving on the freeway or idling for 20 minutes. I ordered a new OEM thermostat & temp sensor and I got it installed today. The temp needle goes to 190* and then drops back to the middle. It's a good feeling knowing the cooling system is working properly .. especially with 100* temp days expecting in the Bay Area.

As for coolant, I like Toyota Red because it doesn't smell like pee (prestone green coolant does one it's used) .. it doesn't leave a residue or film on the coolant system parts .. it doesn't corrode the cooling system (but again, that's because some people use tap water .. and for some reason, I typically see bacteria growth in the coolant system with green coolant if the motor has sat for 3-4 months but NEVER with Toyota's engine with Toyota Red .. and there's something about Toyota Red using less silicone (or something) so it doesn't destroy the gaskets like the green stuff .. got that off the MR2 board.