1994 Overheats with AC on

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vinlc562

vinlc562

Joined
Jun 29, 2024
Threads
4
Messages
36
Location
Long Beach, CA
Hello,

My 1994 80 series overheats between the middle line to red line when AC is on when I’m on the trail especially climbing up. I’m from LA and I hit the Lytle Creek yesterday and right away in the entrance temp sensor when up between red and middle line. (For those who been there, you know it’s not steep, just rocks.)

I turned off the AC and started driving and temp is back to normal. Coolant is in full line, no leaks, nothing and vice versa when going down the mountain, AC is off, temp is normal.

I recently did my head gasket couple weeks ago and I just want to test it out to see how it will hold.

35s
New HG, thermostat, rad cap are OEM.
Radiator is from CSF.
Followed FSM for HG job.
New OEM oil cooler and cover
Drove 500 miles in the FWY, no coolant loss.
It does not overheat when driving in the fwy.

One thing I didn’t do tho is timed it, I just set the cams to dots but didn’t use timing light.

Do you all think I need a second fan to let the air out?

Thanks in advance.
 
vinlc562 said:
Hello,

My 1994 80 series overheats between the middle line to red line when AC is on when I’m on the trail especially climbing up. I’m from LA and I hit the Lytle Creek yesterday and right away in the entrance temp sensor when up between red and middle line. (For those who been there, you know it’s not steep, just rocks.)

I turned off the AC and started driving and temp is back to normal. Coolant is in full line, no leaks, nothing and vice versa when going down the mountain, AC is off, temp is normal.

I recently did my head gasket couple weeks ago and I just want to test it out to see how it will hold.

35s
New HG, thermostat, rad cap are OEM.
Radiator is from CSF.
Followed FSM for HG job.
New OEM oil cooler and cover
Drove 500 miles in the FWY, no coolant loss.
It does not overheat when driving in the fwy.

One thing I didn’t do tho is timed it, I just set the cams to dots but didn’t use timing light.

Do you all think I need a second fan to let the air out?

Thanks in advance.
Click to expand...
Well, sorry when I turned off the AC started driving up the mountains, temp is lil bit higher than the middle line but no too high.
 
check your fan clutch. sounds like it's getting weak.
 
Some people add hood spacers to the hinge but not sure how much of that is really needed. Maybe a blue hub fan clutch mod?
 
The system should work without hood spacers.
Is the shroud well fitted to the new radiator and the fan?

Any AC work completed recently?
1720230567932.webp
 
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Rusty Marlin said:
The system should work without hood spacers.
Is the shroud well fitted to the new radiator and the fan?

Any AC work completed recently?
View attachment 3670852
Click to expand...
Yes, it’s well fitted.

No, no AC work since I’ve owned it 4 months ago. PO said the LC is been sitting for couples years before he got it from the PO prior to him.

I’ll try to get an additional Mishimoto fan to let the air out. I’m thinking that the 35s, no re-gear is kinda lil bit too much for 1FZ but then I’m just guessing. Just want to know if people encounter this before.
 
Rusty Marlin said:
check your fan clutch. sounds like it's getting weak.
Click to expand...
And even a new, un-modified fan clutch can prove inadequate. Before getting into that, is your temp gauge stock? Or does it have the Raventai temp gauge mod? If stock and you're seeing movement at the top, it really is getting hot, so your cautions are wise.

My LX 450 is at 325,000 miles, but had a new Toyota motor installed about 40,000 back. I have some limited documentation and it did get a new radiator, water pump, etc but no mention of the fan clutch ither new or modded, so I assume it's original. As this first summer of ownership heated up, running at highway speed showed it getting warm per the ScanGauge, although it never moved the needle on the then un-modded temp gauge. I decided to add some goo, bvut never could get the last 2 screws out after finding the first 2 pretty loose (perhaps a sign of what failed). I needed a new fan cclutch quick and Auto Zone (2 blocks away) had one of their store brand Duralast fan clutches for me the next morning,, advertised as providing same as OEM fiunction.

Against my better judgment, I decided to install it unmodded. It was a definite improvement, but the ScanGauge indicated running too hot for my taste at highway speeds (210+ at 70 mph with AC on). This did not move the temp needle at all, so added some 20000 shock oil after draining a bit of the original fill from the Duralast clutch. That brought it down under 210, in fact usually a little over 200. Planning on adding more goo, though, as my old 80 would run in the 190 to 193 range all day long with its modded fan clutch.

Not advising against adding an aux fan, but would advise gaining what you can with the fan cluctch first.
 
Last edited:
greentruck said:
And even a new, un-modified fan clutch can prove inadequate. Before getting into that, is your temp gauge stock? Or does it have the Raventai temp gauge mod? If stock and you're seeing movement at the top, it really is getting hot, so your cautions are wise.

My LX 450 is at 325,000 miles, but had a new Toyota motor installed about 40,000 back. I have some limited documentation and it did get a new radiator, water pump, etc but no mention of the fan clutch ither new or modded, so I assume it's original. As this first summer of ownership heated up, running at highway speed showed it getting warm per the ScanGauge, although it never moved the needle on the then un-modded temp gauge. I decided to add some goo, bvut never could get the last 2 screws out after finding the first 2 pretty loose (perhaps a sign of what failed). I needed a new fan cclutch quick and Auto Zone (2 blocks away) had one of their store brand Duralast fan clutches for me the next morning,, advertised as providing same as OEM fiunction.

Against my better judgment, I decided to install it unmodded. It was a definite improvement, but the ScanGauge indicated running too hot for my taste at highway speeds (210+ at 70 mph with AC on). This did not move the temp needle at all, so added some 20000 shock oil after draining a bit of the original fill from the Duralast clutch. That brought it down under 210, in fact usually a little over 200. Planning on adding more goo, though, as my old 80 would run in the 190 to 193 range all day long with its modded fan clutch.

Not advising against adding an aux fan, but would advise gaining what you can with the fan cluctch first.h
Click to expand...

Temp gauge is stock.
 
In that case, it was really hot, because that's what it takes to move the stock gauge.
 
vinlc562 said:
I’ll add additional fan and put insulations behind the hood.
Click to expand...
Reset your fan clutch and increase the viscosity and possibly volume of oil in it.

I bought a new Aisin and it was horribly low on oil and with a thin oil. I adjusted the opening point and installed 15K oil of 55 ML. I don't have the problem with any overheating at all now.
 
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@vinlc562 , Your fan clutch is the problem, it doesn't matter if its new. It's the problem.
I urge you to follow the advice of @BILT4ME and @greentruck.
An Aux fan is not necessary with these rigs.
 
BILT4ME said:
Reset your fan clutch and incears the viscosity and possibly volume of oil in it.

I bought a new Aisin and it was horribly low on oil and with a thin oil. I adjusted the opening point and installed 15K oil of 55 ML. I don;t have the problem with any overheating at all.
Click to expand...

I see, I have no idea it can be adjusted. 😅 I’m learning as I go. I’ll search it up how to adjust it.
 
The fan clutches are one of the things that I insist on OEM for. I don't think I have ever installed an aftermarket fan clutch that even cam close to being what it needed to be to work properly. I quit even trying years ago.

I can not think of anything that I will happily use a Duracrap product for. And the fan clutch is absolutely NOT one of them.

Mark...
 
vinlc562 said:
Yes, it’s well fitted.

No, no AC work since I’ve owned it 4 months ago. PO said the LC is been sitting for couples years before he got it from the PO prior to him.

I’ll try to get an additional Mishimoto fan to let the air out. I’m thinking that the 35s, no re-gear is kinda lil bit too much for 1FZ but then I’m just guessing. Just want to know if people encounter this before.
Click to expand...
I'm not in a hot climate, but it has been in the 80s here lately, my stock 1FZ-FE on 35's with stock 4.10 gearing isn't overheating. I'd look closer at your fan clutch. Even a new stock Aisin blue hub can benefit from adjustment/tuning.
 
CharlieS said:
I'm not in a hot climate, but it has been in the 80s here lately, my stock 1FZ-FE on 35's with stock 4.10 gearing isn't overheating. I'd look closer at your fan clutch. Even a new stock Aisin blue hub can benefit from adjustment/tuning.
Click to expand...
Would you happen to know if there is a thread on how to adjust these Aisin fan clutch? I cannot seem to find one. It’s my first time.
 
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