Temperature question on 86 Iroc 305 TPI
08-05-2017, 11:57 PM
#1
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Temperature question on 86 Iroc 305 TPI
I'm trying to figure out if the cooling system is working as designed or if I've got an issue.
I did a tour of Mt Rainier here in Washington a few days ago. Ambient temps were right about 90 degrees. My drive started at a few hundred feet elevation, all the way to Paradise on Mt Rainier at around 5300'. 2-lane winding road, heavily congested.
With it being summer, there were a lot of visitors, and there was road construction. Read: Lots of stop/go, speeds 15-20mph on winding grades, in full sun, trans shifting up and down (locked out in D, no overdrive).
My fan usually kicks on right around 220. The car has AC, and the fan will kick on with the AC at times below 220. Temperature with good airflow on the freeway is at the 1/4 mark-ish on the temp gauge, so I'm guessing between 160-180.
During THIS drive up the mountain, temperatures started climbing fast. 220 came and went and the car was running closer to 230+, dangerously close to 240 at one point. Seemed every time I was about to pull over, the road would open up or the grade would flatten out, so I kept going.
I turned the heat on full at the highest fan setting (that was fun...) and I was able to get the temp down about 10 degrees. Still above 220 though.
Wondering if maybe the ECM or a temperature switch wasn't working correctly, I turned on the AC to see if I could force the fan into high-speed or whatever (is there even a high-speed?). It had the same effect, took it down from 230 slightly. I figured it wasn't wise to run with the AC on, so I turned that off.
The car didn't lose any coolant on the trip, but it did seem to run suspiciously hot.
The hoses look newer, the coolant is a nice vibrant green color, water pump looks stock, and the fan looks stock. Radiator fins are in good shape, no blockages, and the air dam is in good condition underneath the vehicle. Radiator cap is aftermarket but seems to hold good pressure.
I'm just curious if it's normal to expect 230-240 degree temps on a stock cooling system like mine or if I need to give it some attention, and should otherwise expect it to not really climb above a certain temperature unless in Death Valley type conditions of 110+ degree weather?
I did a tour of Mt Rainier here in Washington a few days ago. Ambient temps were right about 90 degrees. My drive started at a few hundred feet elevation, all the way to Paradise on Mt Rainier at around 5300'. 2-lane winding road, heavily congested.
With it being summer, there were a lot of visitors, and there was road construction. Read: Lots of stop/go, speeds 15-20mph on winding grades, in full sun, trans shifting up and down (locked out in D, no overdrive).
My fan usually kicks on right around 220. The car has AC, and the fan will kick on with the AC at times below 220. Temperature with good airflow on the freeway is at the 1/4 mark-ish on the temp gauge, so I'm guessing between 160-180.
During THIS drive up the mountain, temperatures started climbing fast. 220 came and went and the car was running closer to 230+, dangerously close to 240 at one point. Seemed every time I was about to pull over, the road would open up or the grade would flatten out, so I kept going.
I turned the heat on full at the highest fan setting (that was fun...) and I was able to get the temp down about 10 degrees. Still above 220 though.
Wondering if maybe the ECM or a temperature switch wasn't working correctly, I turned on the AC to see if I could force the fan into high-speed or whatever (is there even a high-speed?). It had the same effect, took it down from 230 slightly. I figured it wasn't wise to run with the AC on, so I turned that off.
The car didn't lose any coolant on the trip, but it did seem to run suspiciously hot.
The hoses look newer, the coolant is a nice vibrant green color, water pump looks stock, and the fan looks stock. Radiator fins are in good shape, no blockages, and the air dam is in good condition underneath the vehicle. Radiator cap is aftermarket but seems to hold good pressure.
I'm just curious if it's normal to expect 230-240 degree temps on a stock cooling system like mine or if I need to give it some attention, and should otherwise expect it to not really climb above a certain temperature unless in Death Valley type conditions of 110+ degree weather?
08-06-2017, 01:21 AM
#3
Re: Temperature question on 86 Iroc 305 TPI
Seriously? It's generally considered normal to hit 240* F on a third gen?
I hate the high temp set points. I have mine set down to 200 in the ECM with a 180 thermostat. Even when it was 105* F a few days ago I was still below 220 on the gauge. Still makes me nervous that the system can't reject enough heat at 75 mph to maintain the thermostat. I'll be swapping to a aluminium radiator, high flow water pump, and whatever else I can do to keep temps exactly where the thermostat opens.
GD
I hate the high temp set points. I have mine set down to 200 in the ECM with a 180 thermostat. Even when it was 105* F a few days ago I was still below 220 on the gauge. Still makes me nervous that the system can't reject enough heat at 75 mph to maintain the thermostat. I'll be swapping to a aluminium radiator, high flow water pump, and whatever else I can do to keep temps exactly where the thermostat opens.
GD