Running hot...realtime help please

[RavenTai]

WTF???

I'm doubting what I'm reading here; you ran your 1FZE for multiple hours with the engine coolant gauge in the red???



Curtis

red range with a stock gauge is 248-260,

red with the modified gauge is a not near as hot but still well above wide open thermosat temp, ranging 217 to 226, (now confirmed)

 

[RavenTai]

Will an obd2 reader read tranny temp? I just plugged in my snap on MT2500 and it did not give a tranny temp?! I was like WTF. I think it should. Does the tranny have a factory temp sensor?

it has a thermistor in one of the transmissioin lines, it connects directly to the ECU but I am not sure if it is available to the OBDII port.

 

[CJF]

red range with a stock gauge is 248-260,

red with the modified gauge is a not near as hot but still well above wide open thermosat temp, ranging 217 to 226, (now confirmed)

Ah.

I feel a *little* better now. Still, this is not good (duh)...

Good luck,

Curtis

 

[Rich]

Will an obd2 reader read tranny temp? I just plugged in my snap on MT2500 and it did not give a tranny temp?! I was like WTF. I think it should. Does the tranny have a factory temp sensor?

My '97 has a transmission fluid temp sensor that feeds direct to the ecm.

 

[IdahoDoug]

Rick,

I think you're aware of this, but if the tranny's putting enough heat into the radiator via the tranny cooler to actually overpower your cooling system's capability then the tranny's getting SERIOUSLY hot.

I'd consider a couple things and I'm sure you've attended to them, but I'm mentioning them since even the best of us will make mistakes when under duress.

What's the status of your fan clutch? Your radiator? Are all 4 of your tires same wear/size etc? Does your rear heater work? What does the tranny fluid look/smell like? These are basic things that I'm guessing you've already checked into, but as I said we all tend to ignore the obvious, or make unwarranted assumptions when under pressure.

I don't know how the tranny could be the culprit here, actually, so I'm going to cast some doubt on that. If, for instance, there were debris in the new (rebuilt?) tranny that blocked the tranny cooler then the tranny would indeed get hot, but it would not neccessarily transfer more heat to the cooling system than normal simply due to reduced flow. If you reversed the hoses, again the tranny would get hot but I can't see it transfering more heat to the coolant this way, either. You'd have hot tranny fluid in both cases, but improper flow through the cooler.

So, I'd look to the basics of the cooling system integrity first. Just as an overheated tranny will elevated the coolant temp, a suboptimal cooling system will overheat a tranny. Which one do you have? Dunno, but I feel things point more at your cooling system than the tranny - which seems to be operating correctly, no?

DougM

 

[landtank]

First , the temp only goes into the red pulling a 4k lb trailer through the mountains in 100* weather. That is where it cuts out the AC. Pulling the trailer along the highway not under that kind of load it sits just below the red.

As for the cooling system, 3 core brass radiator 1.5 years old, new blue fluid coupler 1 year old and a new Stant t-stat.

When the truck is idling the temps are stable and normal. When driving around town they are elevated maybe 2 needle widths. It does seem to be a little better than when I first initially started to drive the truck right after the swap. but that may be wishful thinking on my part.

 

[Erratic]

My '97 has a transmission fluid temp sensor that feeds direct to the ecm.

Have you read it with a scanner?

 

[Rich]

I don't own a scanner. In researching pc software based scanners several spec out that they can monitor transmission fluid temp for Toyotas (and also a number of other Toyota "enhanced OBD II" parameters).

 

[landtank]

Well, had some time to look at the truck today with a clear head.

Took it out around town with only a slight increase in temp. So following the FSM took it out on the highway at 60mph and checked out the TC lockup function. The TC is definitely locking up. But as I was driving the temp slowly rose to the red once again. I got of the highway and drove around town and the temps didn't drop. Now I'm not towing the trailer so things seem to be the same with less load.

I then had a clear moment and pulled over to the side of the road and popped the hood. NO ROAR!!! The temp was around 220* and the fan was as quiet as ever.

So I turned off the truck and watched the fan coast to a stop and when I tried to move it it spun almost completely free.

CDan might have records but I don't think there is 1 year on this BLUE fan coupling. I went down to Advanced Auto and ordered a replacement. This is the second fan clutch I've had fail. Last time I got a Torqflow which ran fine for 3 years until I read about this blue dual stage wonder and replaced it as a kind of insurance.

The coupling won't be in until Friday but I'm leaving for work anyway so it'll have to wait until then.