It started with 3FE temp gauge

[oestlarsen]

Wanting to know how my 92 3FE was cooling I installed an Autometer digital temp gauge. Although I like it, warning to those with OCD tendencies...you WILL obsess with temperature and i think MR. T was likely smart installing wide range gauges. The 3FE stock gauge shows "normal" operating temp in all kinds of situations, including before the thermostat really opens up.

Ok, here are facts before my question:

1. Coolant flush with distilled 3 times. Only did radiator flush, and looking pretty good.
2. Toyota red
3. New oem thermostat in last year
4. Aisin green 10k fluid change (i had hoped had more effect)
5. Shroud was showing gap as missed tab...corrected and no gaps
6. Likely original radiator and water pump
7. 125k miles
8. Npt sending unit is fairly close to radiator...inline with the large upper hose

Idles up to 200 degrees...it was 80 outside yesterday...can be lower. Can spike to 207 very briefly or so when thermostat opens. Freeway ranges 196 up to 200ish... Not towing anything these days. No leaks.

Am I running too hot or can I let it go and sleep at night

The gauge, btw is great if you are looking at 3FE aux gauge options, imho.

 

[oestlarsen]

I think I have the answer.... Yes, the 3FE is running too hot.

This weekend I had to cross a mountain pass in 95 degrees. Towards the top I finally saw the stock gauge move up...and my digital gauge into 230 range. This lasted fairly briefly as I shortly after was going down and temps settled back around 200. No issues rest of the trip. Truck ran great.

Should I redo my fan clutch with 15k/20k or should I attack radiator next?

Thermostat is new.

Thoughts?

 

[half k cruiser]

How old is your radiator ? If its got enough deposits in there then its not going to be moving fluid as well as it should.

If it makes you feel better my Jeep always runs at 205 or better

 

[tominboise]

Where did you get your gage setup? Looks pretty nice....

 

[swampfoxSC]

I see you have 6000 and 10000 fluid. Did you mix them? If so you may be at stock viscosity depending on the ratio of mix. I assume you used pure 10000.

 

[oestlarsen]

Thanks all:

I used the 10k fluid with a smidgeon top off with 6k

Radiator is original and i had some rust in coolant when i got the truck

I got the autometer digital gauge on amazon...around $100 i think. Great quality.

I may just bite bullet and get radiator barn replacement radiator to rule internal clogging out. Any concerns with that approach?

 

[94SRUNNER]

It may be time to bite the bullet and pick up a replacement radiator. Be it a OEM or an aftermarket unit. Be sure and pickup a new OEM radiator cap.

It looks like you have covered most of your bases. I would recommend a heavier oil for you fan clutch, try 15K. I would also strongly recommend going through and replacing your old coolant hoses when you replace the radiator.

 

[CJF]

You need a new radiator.

 

[rghouse]

Hi I came upon this thread searching for a normal operating temp for a 3fe. I suspect I'm running too hot. In the first 3 months I owned the vehicle (before weather got hot)i never overheated but the gauge started cutting out. I have performed the following work which started with faulty temp gauge:
1. Replace sender- fixed gauge
2. Flush cooling system add new dex cool
3. Replace all cooling system hoses on top(not bottom hose yet)
4. Replace thermostat (not oem)

The outside temps here are 95+. I just drove home 30 miles and the temp was holding steady until my street when it went up from the normal 9 o'clock to about 10 o'clock(a/c blowing). no problems this am on the way to work. the truck has r134 refrig retrofit from dealer. The radiator was replaced at 135k, it's at 168 now.
My main question is, is this normal for the temp to creep up like that. It seems dangerously close to the red. Please help...

 

[maddss]

Where did you get the blue radiator adapter ?

 

[rghouse]

ok lets strike that last one from the record, not sure which blue radiator hose you are referring to?

I checked further down the list on the "running too hot" triage in the Haynes manual last night, and found myself pumping the upper radiator hose like a fuel bulb. Limp. I will run it hot again in the 95-105 outside temp range (only takes about 5-10 miles in town) and then check the water pump pressure with the radiator hose again-last nights check was only at idle after sitting 2 hours.

Here is an interesting tid-bit also. I suspect the old thermostat gasket either disintegrated or was left out last time. Perhaps there was a model with no upper ring-gasket? Not sure but nothing came out.

 

[jrmudder92]

ok lets strike that last one from the record, not sure which blue radiator hose you are referring to?

I checked further down the list on the "running too hot" triage in the Haynes manual last night, and found myself pumping the upper radiator hose like a fuel bulb. Limp. I will run it hot again in the 95-105 outside temp range (only takes about 5-10 miles in town) and then check the water pump pressure with the radiator hose again-last nights check was only at idle after sitting 2 hours.

Here is an interesting tid-bit also. I suspect the old thermostat gasket either disintegrated or was left out last time. Perhaps there was a model with no upper ring-gasket? Not sure but nothing came out.

I have installed a mechanical coolant temp gauge. So I can get a better reading. I put it in the factory temp sender spot and, then put the factory on in the upper hose. Its been in the high 90's here. Ive been around about 200ish. I also know that the jeeps 4.0L damn close to ours normal operating temp is 210. So it makes me feel good that my cruiser is running cooler then a jeep. Not sure this helps... but never know!

 

[jonheld]

ok lets strike that last one from the record, not sure which blue radiator hose you are referring to?

I checked further down the list on the "running too hot" triage in the Haynes manual last night, and found myself pumping the upper radiator hose like a fuel bulb. Limp. I will run it hot again in the 95-105 outside temp range (only takes about 5-10 miles in town) and then check the water pump pressure with the radiator hose again-last nights check was only at idle after sitting 2 hours.

Here is an interesting tid-bit also. I suspect the old thermostat gasket either disintegrated or was left out last time. Perhaps there was a model with no upper ring-gasket? Not sure but nothing came out.

I am not understanding anything in this post. Radiator hose "firmness" has nothing to do with water pump output. What causes the hoses to become firm is the buildup of pressure within the cooling system from thermal expansion. That's what the radiator cap regulates.
As the engine comes up to temperature, pressure increases in the system until it reaches the limit of the cap. I keep forgetting the number, but it's like 13 or 15 PSI. The cap bleeds off excess pressure and coolant into the overflow bottle. When the system cools and pressure goes negative, the cap allows the system to draw coolant back into the radiator, keeping a constant level.
This assumes that the coolant level in the system is correct to start with. The radiator should be filled up to the filler neck and the overflow bottle should be filled 1/3 with coolant mix.

The thermostat has to have a gasket or it's not doing its job correctly. I would replace it with OEM and replace the paper gasket between the halves of the housing and the rubber gasket on top of the stat.

 

[LS1FJ40]

I am not understanding anything in this post. Radiator hose "firmness" has nothing to do with water pump output. What causes the hoses to become firm is the buildup of pressure within the cooling system from thermal expansion. That's what the radiator cap regulates.
As the engine comes up to temperature, pressure increases in the system until it reaches the limit of the cap. I keep forgetting the number, but it's like 13 or 15 PSI. The cap bleeds off excess pressure and coolant into the overflow bottle. When the system cools and pressure goes negative, the cap allows the system to draw coolant back into the radiator, keeping a constant level.
This assumes that the coolant level in the system is correct to start with. The radiator should be filled up to the filler neck and the overflow bottle should be filled 1/3 with coolant mix.

The thermostat has to have a gasket or it's not doing its job correctly. I would replace it with OEM and replace the paper gasket between the halves of the housing and the rubber gasket on top of the stat.

Last I checked it is 13 PSI for the OEM radiator cap.

Worth noting that a malfunctioning radiator cap can be the source of problems. They cost about $10 from Toyota.