i put a 170F thermostat in the car and running an aftermarket coolant temp gauge, it hangs around 180F usually idling, after cruising and getting on the car a little bit it slowly creeps up to 200F but im trying to see where i should worry. I had a buddy that said 210-220 is still nothing to worry about as the motor runs more on the hot side but most cars i've owned they usually were around 180-190F tops but some motors are different than others. Any advice/help would be much appreciated!

 

mine runs at 190 all the time basically, 92 SC400

 

Dude,


180F to 200F is perfectly normal while cruising, assuming you mean on the open highway driving 55 to 75 mph.




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Well, the cooler the better, period.

BUT, I just always remember 212 degrees is the boiling point for water so depending on the coolant mixture you're running it should never get more than maybe 230... Aka, long as the coolant isn't boiling, you're good.

 

you also get some headroom from boiling from the pressurized cooling system, most stock rad caps are 1.3 bar. i know i have run my coolant over 230F a few times sitting in traffic when my fan failed and nothing bad happened

170 is pretty low, you will lose gas mileage a bit at that point, i would try to keep it over 180, but if it's a race car then 170 is totally fine too to give you more headroom.

 

Are you guys running non-dummy coolant temp gauges?

 

Nope, not on this car, I'm just comparing to my old DSM days when I had 400+ WHP and they were known for temp issues. I was always told by the tuner to not let it go over 235ish. You can always turn the AC on to kick on the fans if they are not already on but otherwise you should hit the highway at a cruising speed or just turn the car off.

 

Dude,


My '95 sc300 uses a 0.9 bar/13 p.s.i. cap (88 kPa to be exact). My '87 MR2 and '87 Toyota truck also run 0.9 bar/13 p.s.i. caps. Other Toyota engines use 1.1 or 1.3 bar caps.

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actually i mean on the road not highway, haven't really taken it on the highway too often

 

is that right? hmm well im running the pink toyota coolant with some distilled water to top it off but it doesn't go to 230, I just wanted to make sure i wasn't in overheating territory, I'd like to be able to cruise and not have to stare at my coolant temps worrying but i just want to make sure. and how will i know it's boiling?

p.s. i do have a 1.3bar cap

 

I'm curious to hear what others have to say... I wouldn't think many people are running actual coolant temp gauges unless they've done serious engine upgrades and need to monitor things closely, which doesn't really sound like the gist of this thread. Are people just estimating temperature by the marks on the factory gauge?

Mine never gets above the ~40% mark on the gauge and probably never will, barring major cooling system failure, with the addition of the big hood vent directly behind the radiator.

 

i should've noted it's a 1UZ in my AE86, running a rx7 radiator, dual fan setup as well, should be enough capacity to cool the motor properly it's a 3 core rad aftermarket one, my buddy who has a SC400 said 200-220F isn't overheating but i just wanted to make sure

 

the dummy gauge in the cluster doesnt move from the center when engine temp is between 90C and 110C, i can verify that, at least the 97 sc300 gauge cluster that i am using. when that starts moving up then you're in real hot territory.

 

Makes more sense now. Gotta keep an eye on all the non-factory stuff being fitted together.

Those numbers puzzled me at first glance, then I noticed the units... That's 194-230 F, which is a pretty wide range. No wonder the needle never moves! I guess that answers whether 230 is considered dangerously hot, if that's the upper limit of normal operating range.

 

ah i see, so how do you guys feel about 220F still too hot or maybe on a fine line?