What temps do you consider "dangerous" on a 1fz-fe (1 Viewer)

[Marvelicious]

Since there are a ton of hot engine threads currently, and the level at which people seemed concerned varies widely, I'm curious what people consider "too hot". I know the AC is designed to shut off at a certain point (couldn't find the exact figure), but does that mean the engineers thought that was a hard limit and panic time, or does that have a bit of padding, just to be safe?

I didn't find a hard number in the FSM, but maybe I missed it... if so, let me know and I'll delete this whole mess.

Edit: to be clear, Discussion is fine, but for the purposes of the poll, I'm not asking what point you start watching it, or what point should be normal, I'm asking what point you go, "Oh, #$&*! I need to figure out what to do right now."

 

[Cruisers and Co]

I believe the AC shut off is 226. I start watching closely around 210 and start backing off at 220. 230+ definitely a no go. Realistically with a healthy cooling system you should never see above 210.

For reference my 80 is usually 7,000 lb or more if not closer to 8,000, fully armored, 35s, 4:10's and turbocharged.

Turbocharged or NA your temps should stay in check around 210 +- a little even on the hottest of days with a healthy cooling system. Most the time running around my turbo truck runs 195

 

[tmxmotorsports]

I believe the AC shut off is 226. I start watching closely around 210 and start backing off at 220. 230+ definitely a no go. Realistically with a healthy cooling system you should never see above 210.

Is that a turbo 80?

 

[Cruisers and Co]

Is that a turbo 80?

Yes I updated my reply see above

 

[tmxmotorsports]

Yes I updated my reply see above

I would really like to drive a turbo 80. Not that I can put one on my obd1 80 and my girl definitely doesn't need one on her 95 she drives fast as it is...

 

[Cruisers and Co]

I would really like to drive a turbo 80. Not that I can put one on my obd1 80 and my girl definitely doesn't need one on her 95 she drives fast as it is...

Let's not derail this one

But yes turbo 80s are great!

 

[tmxmotorsports]

Let's not derail this one

But yes turbo 80s are great!

Yeah I would be tripping if my 80 got up to 250 or tye ac shut of because of the heat.

 

[Cruisers and Co]

There was recently a turbo'd 1FZ that hit 228 without damaging it. He was in Cali in that brutal heat wave about a month ago. 115 degrees F ambient pushing it hard with a small trailer behind his fully loaded decked out 80.

 

[LC4LIFE]

I start paying attention at 200, really worry at 210, uhhh wait, I never see 210, so I guess I never really worry about my temps.

 

[OGBeno]

226.

 

[use2bn83]

Before I ditched the CSF rad, I’d regularly see 210-215 going up the i70 corridor in Colorado.

 

[Marvelicious]

226.

So, if the AC kicks off, it's time to find a safe spot to pull over and figure out the problem? I'll admit, if the engine is getting that hot due to the weather, and the AC kicks off, I probably WILL stop. Still, most of the reading I have done on aluminum head engines in general seems to indicate that a bit higher is generally okay. I acknowledge that the 1fz is a bit of an odd duck in a few ways, but I'd honestly be amazed if Toyota's engineers weren't conservative with that 226 cutoff: they're always a bit conservative, that's why the engines last so well! Still, it's probably a pretty safe rule of thumb - if the AC kicks off, you've got a PROBLEM.

Honestly, it's all academic for me at this point. I haven't seen over 200 yet. Still, it seemed like a worthwhile discussion to have this time of year, and I'm glad to see some of the forums "elder statesmen" weighing in.

 

[ChaseTruck]

Turn that engine off when temps are high - and then watch the temperature really climb!

That hunk of iron stores an amazing amount of heat. At that point I found it best to let the cooling system try to do its job without a load on the engine - i.e. A/C off, revs to ~1200, perhaps a spray of water in front of the truck for a little bit of evaporative cooling.

As for the original question, I'm starting to get concerned when temps in the '93 go above 210 and stay there. This is not to doubt the wisdom of Toyota engineers; it is because that truck doesn't normally do that.

 

[jonheld]

The below statements assume that the ENTIRE cooling system is functioning correctly and within design parameters.
The OEM thermostat (90916-03117) starts to open at 180F (82C) and is fully open at 203F (95C).
Once the thermostat is fully open, the cooling system is at it's design limit and has no more headroom.
If the load remains constant at this point, the temperature will continue to climb as the ability to cool has been surpassed.

IMO, anything over 203F is pushing the system beyond what it was designed for. I would back off the throttle first and cut off the AC if it didn't drop a bit, but that's the way I roll. I'd rather err on the side of caution rather than push the issue on a 30 year old engine while in the middle of a road trip.

All that said, I recently did a 1300 mile road trip in 90F+ ambients with the AC set to 75 and highway speed around 65mph. Temps stayed fairly consistent around 194F for the majority of highway travel rolling 35s with a 4" lift and loaded with crap for a 4 day trip with my wife.

 

[ZackR]

Came here to say the same thing as @ChaseTruck . When it gets hot give it a chance to cool down, reduce the heat load on the engine while increasing the amount of cooling.

I wasn't driving but my wife said the AC stopped about a month ago when she was stuck in construction traffic and it was 106F out (super hot for here). She said as soon as they started moving again (30+ mph) the AC came back on.

First thing I checked was if the AC was actually set to on and recirculate, which it was, so perhaps it got hot enough to turn off. I showed her the high idle, listen for the fan roaring tip in case in comes up again. Fan clutch upgrade is now on my to do list.

 

[Marco Lau]

230F for a whole week at the Rubicon and Fordyce with broken fan and radiator last year. But fortunately, its a 91

 

[Marvelicious]

Turn that engine off when temps are high - and then watch the temperature really climb!

That hunk of iron stores an amazing amount of heat. At that point I found it best to let the cooling system try to do its job without a load on the engine - i.e. A/C off, revs to ~1200, perhaps a spray of water in front of the truck for a little bit of evaporative cooling.

As for the original question, I'm starting to get concerned when temps in the '93 go above 210 and stay there. This is not to doubt the wisdom of Toyota engineers; it is because that truck doesn't normally do that.

Yes, absolutely. I should have been more specific... to me, "STOP" in an overheating system means shut off AC, pull over and switch to neutral, open hood... anything you can do to reduce strain on the engine and get it to cool. If that doesn't work and it continues to climb... well, it's going to shut off one way or another sooner or later!

Probably some other thoughts worth mentioning. If you're just driving along in relatively normal weather and your temps just shoot up like a rocket, you've probably got some sort of serious and immediate failure with your cooling system... should go without saying that your system isn't going to cool if it's dumping all your coolant on the ground.

It also depends on what's happening... am I driving on an extended road trip? Or am I doing a normal commute that includes a couple of steep hills? Or am I stuck in a traffic jam? Or wheeling? If I know my loads are going to decrease significantly just as soon as I peak this hill, I'll push it a lot higher than I would in the "family road trip" scenario. If I'm crossing Death Valley, I'll probably be keeping an eye on it anyway. Incidentally, I did that in an Isuzu Trooper with family when I was a kid and I honestly had no idea how hot it was outside until we stopped. Getting out of the AC was like getting punched in the chest!

@jonheld No disrespect intended, but I don't entirely agree with your analysis of the cooling system capacity: the coolant and the load aren't the whole equation. Airflow is also a major factor. 203* at a standstill is very different from 203* moving. Also, the thermostat is fully open at 203, but is your clutch fan pushing maximum air at that point? Sure, if nothing else changes, then theoretically the temps would continue to climb. To my mind, the odds are on some other factor changing before you're in truly dangerous territory, or as you said, you can change a variable or two yourself (slow down, etc). What I'm trying to get a handle on is what is considered truly dangerous. If you are saying you aren't at all comfortable pushing it past 203, then fair enough.

 

[GeoRoss]

226.

Mine is OBD I. I use the AC cutoff switch as a high temp indicator. If the AC shuts off I should let things cool off for bit. Happened only once stuck in a traffic jam coming down I17 in Black Canyon.

 

[ZackR]

A a quick data point I just got home from a 50 mile drive to town and back and with the Toyocom OB1 plugged in my range was between 195-203F, mostly around 199F, 203F going up a long hill at highway speed. Outside temp in the low 90's, AC on. Seems about right for the conditions.

 

[Marvelicious]

A a quick data point I just got home from a 50 mile drive to town and back and with the Toyocom OB1 plugged in my range was between 195-203F, mostly around 199F, 203F going up a long hill at highway speed. Outside temp in the low 90's, AC on. Seems about right for the conditions.

A little bit warmer than I see in similar conditions, but you're at higher elevation, which probably makes a difference. Plus, it's probably pretty dry over there. Moist air feels hotter to us, but moist air blowing through a radiator has more capacity to absorb engine heat, if I have the science right in my head.