Running hot and out of ideas.... (1 Viewer)

[devo]

For what it’s worth…

 

[alvarorb]

Like the pieces the arrow points to... I'll try to get in there.

 

[jonheld]

Couple of things after just completing a 1300 mile road trip in 90+ degree heat. Loaded, auto climate control temp set to 75, highway temps steady at 194-198 at 65-70 mph for hours on end.

Denso is NOT the OEM for Toyota radiators. TRAD is the OEM.
Your local Toyota parts department will show 16400-66081 for the 1996 radiator, however 16400-66040 for the OBD1 FZJ80 fits as well and has better cooling capacity. That's what's in my 97 LX450 right now.
The OEM radiator cap (16401-54750 that comes with a new OEM radiator) is critical for proper cooling.
The OEM thermostat (90916-03117) starts to open at 180F (82C) and is fully open at 203F (95C). If your temps remain within this window, then the cooling system is operating properly.

The statements regarding the blue hub fan clutch modifications are also critical and can't be overlooked. Out of the box, a new blue hub is fairly weak and this has been documented multiple times. Both the amount of supplied fluid and port opening temps vary widely.
Several years ago I modded my blue hub according to my typical driving conditions here in the northeast. I would strongly suggest you do the same. Normal driving without AC on she sits at 186 all day. Winter cold/summer heat makes no difference.

I added thin self adhesive closed cell foam to the front side of the fan shroud to get a tighter seal on the radiator.
As previously stated, the upper and lower foam that is supplied with the new radiators is also important to keep air flowing through the radiator as opposed to around it.

Another thing that shouldn't be overlooked is the thin metal pan that sits under the very front of the chassis (51441-60200) and has a cut out for the steering damper mount. This also helps to direct airflow at speed.

NOTE: Some will say (mostly Facebook knuckleheads) that the engine fan does nothing at highway speeds. This is 100% incorrect. These engines cannot stay cool without a properly operating fan clutch at any speed.

 

[RiverCityDave]

if you

it comes with a genuine radiator, napa sells different foams and I'm sure hardware store do also. Make everything really clean before trying to stick it on. sometimes I need to use some superglue too.

here's a diagram of the foam try to make it look like that. the piece on the bottom is even taller then it looks in the picture.

View attachment 3662671

I have the "OBD I" OEM radiator, which was ordered from Toyota in 2021 but did not come with the foam. The dealer parts rep said they don't anymore. There is a long thread about it here somewhere. As already stated, you can use commercially purchased closed-cell weatherstripping to fill the gaps. Any big box store or Amazon can take care of you.

I also used the silicone fluid linked a few threads back. It may seem like someone is pulling your leg, but that is the correct fluid.

Also, @jonheld referenced the correct thermostat; this is also important. They are often replaced with parts store units that may or may not operate as directed by Toyota.

Usually there isn't just one thing that solves all your problems, it's a series of marginal gains.

 

[flintknapper]

Couple of things after just completing a 1300 mile road trip in 90+ degree heat. Loaded, auto climate control temp set to 75, highway temps steady at 194-198 at 65-70 mph for hours on end.

Denso is NOT the OEM for Toyota radiators. TRAD is the OEM.
Your local Toyota parts department will show 16400-66081 for the 1996 radiator, however 16400-66040 for the OBD1 FZJ80 fits as well and has better cooling capacity. That's what's in my 97 LX450 right now.
The OEM radiator cap (16401-54750 that comes with a new OEM radiator) is critical for proper cooling.
The OEM thermostat (90916-03117) starts to open at 180F (82C) and is fully open at 203F (95C). If your temps remain within this window, then the cooling system is operating properly.

The statements regarding the blue hub fan clutch modifications are also critical and can't be overlooked. Out of the box, a new blue hub is fairly weak and this has been documented multiple times. Both the amount of supplied fluid and port opening temps vary widely.
Several years ago I modded my blue hub according to my typical driving conditions here in the northeast. I would strongly suggest you do the same. Normal driving without AC on she sits at 186 all day. Winter cold/summer heat makes no difference.

I added thin self adhesive closed cell foam to the front side of the fan shroud to get a tighter seal on the radiator.
As previously stated, the upper and lower foam that is supplied with the new radiators is also important to keep air flowing through the radiator as opposed to around it.

Another thing that shouldn't be overlooked is the thin metal pan that sits under the very front of the chassis (51441-60200) and has a cut out for the steering damper mount. This also helps to direct airflow at speed.

NOTE: Some will say (mostly Facebook knuckleheads) that the engine fan does nothing at highway speeds. This is 100% incorrect. These engines cannot stay cool without a properly operating fan clutch at any speed.

^^^^^

Excellent. Covered all the critical points.

 

[mudgudgeon]

The fan angle has been pretty well covered.

Only comment i have is in relation to the fan hub color. My opinion is that the colour only represents how long the hub is/ how far it protrudes from the pulley.

I have had a couple of orange hub fan (1hd-t, 1hz) clutches apart, and from what I could tell at the time, they have the same functionally as a blue, black, light blue hub clutch etc etc.

I 'think' the orange hub is what's used with supercharger installation??? Not certain.
The difference is the hub length.

I agree, these things are usually a combination of issues.

Another thing to look at is the radiator cap. As with thermostat, having the correct pressure rating matters. Or, even if it's OEM, it may be worth while replacing it. They aren't expensive, and they are often overlooked.

 

[LandCruiserPhil]

Regular fan clutch. No mod

Number #1 80 heat mod IMO
Blue hub 30,000

 

[80t0ylc]

About three years ago, I took my 96 FZJ80 to a garage inSouthern California for service. On my way there from Norcal, I kept an eye on engine temperature. I always do. The truck ran at 198°F all the time. Even while going up the grapevine. While at the shop, they told me that my radiator was leaking, so I had them replace it with a Denso radiator. When I got the truck back, I noticed the truck would run hot on hot days. Sometimes as hot as 220°F. I only run the truck about 500 miles a year. And when it's cool outside, this is not an issue. Having said that. I need to fix this.

Since then, I’ve taken several steps to fix the issue:

1. Changed the fan clutch.
2. Changed the thermostat, OEM.
3. Changed the temperature sensor, OEM.

Despite these efforts, the truck still runs hot. Before the radiator was replaced
At this point, I’m considering whether to change the water pump or replace the radiator again. Any advice you can offer would be greatly appreciated.

Couple of things after just completing a 1300 mile road trip in 90+ degree heat. Loaded, auto climate control temp set to 75, highway temps steady at 194-198 at 65-70 mph for hours on end.

Denso is NOT the OEM for Toyota radiators. TRAD is the OEM.
Your local Toyota parts department will show 16400-66081 for the 1996 radiator, however 16400-66040 for the OBD1 FZJ80 fits as well and has better cooling capacity. That's what's in my 97 LX450 right now.
The OEM radiator cap (16401-54750 that comes with a new OEM radiator) is critical for proper cooling.
The OEM thermostat (90916-03117) starts to open at 180F (82C) and is fully open at 203F (95C). If your temps remain within this window, then the cooling system is operating properly.

The statements regarding the blue hub fan clutch modifications are also critical and can't be overlooked. Out of the box, a new blue hub is fairly weak and this has been documented multiple times. Both the amount of supplied fluid and port opening temps vary widely.
Several years ago I modded my blue hub according to my typical driving conditions here in the northeast. I would strongly suggest you do the same. Normal driving without AC on she sits at 186 all day. Winter cold/summer heat makes no difference.

I added thin self adhesive closed cell foam to the front side of the fan shroud to get a tighter seal on the radiator.
As previously stated, the upper and lower foam that is supplied with the new radiators is also important to keep air flowing through the radiator as opposed to around it.

Another thing that shouldn't be overlooked is the thin metal pan that sits under the very front of the chassis (51441-60200) and has a cut out for the steering damper mount. This also helps to direct airflow at speed.

NOTE: Some will say (mostly Facebook knuckleheads) that the engine fan does nothing at highway speeds. This is 100% incorrect. These engines cannot stay cool without a properly operating fan clutchh at any speed.

The foam and fan clutch comments are good info, but @jonheld ’s radiator advice is key, IMHO. One thing about the Denso radiator - is it aluminum? If not, it may be a key issue. IME, copper/brass radiators give the same issues you’re seeing. Yes, tune up your fan clutch and install the sealing foam. Those are important details, also.

 

[sbman]

It seems like the obvious thing is to put a factory radiator back in it. It worked OK before with the original OEM radiator and now it is running hotter with an aftermarket Denso radiator. Seems like the first thing to try.

I have found through experience that even something is "Same Brand As OEM" it often is NOT the same part or the same quality. Manufacturers create different products at different price levels for various markets and sales channels, so even a brand match isn't necessarily a product match. As it has been pointed out Denso isn't the OEM manfacturer anyways.

 

[surfpig]

I went to my local Toyota dealer and they are out of the blue oil/silicone. I did however watch a YouTube video where the person replaces the factory oil for an oil he got at a hobby store. My dealer won't have the oil for a week. Any ideas what the oil from the hobby store is?

Alvaro, I may have some at home. Forget what thickness it is...

@jonheld has the most comprehensive list of things to look at, including the radiator cap, often overlooked. I would definitely do the fan clutch mod, including adjusting the temperature at which it begins to open, and when it's fully opened (hot water bath and a GOOD thermometer). I put (I think) 15,000 silicone in mine and adjusted the opening temps, and temps live at 190 degrees most of the time. It goes up on long crawls, but it's mostly happy right around there. Mine lacks the weatherstripping around the radiator. I'll fix that soon.

 

[alvarorb]

New radiator, thermostat, hoses, silicone, and weather stripping on their way. I got 10,000 cst oil.

 

[surfpig]

New radiator, thermostat, hoses, silicone, and weather stripping on their way. I got 10,000 cst oil.

10K is pretty good. I think I did 15K. Out of the box I think the blue hubs are around 6K.

 

[LandCruiserPhil]

New radiator, thermostat, hoses, silicone, and weather stripping on their way. I got 10,000 cst oil.

The cool guys run 30000 cst

 

[lexustruck]

Number #1 80 heat mod IMO
Blue hub 30,000

A blue hub and new silicone can keep the A/C on and cold where the old Eatons can’t keep up and the A/C kicks off - it’s pretty impressive. Night and day difference in my temps and the mod is mandatory, I’ve had milk thicker than the silicone it shipped with

New radiator, thermostat, hoses, silicone, and weather stripping on their way.

Did you buy the weatherstripping that Landcruiser65 linked?

 

[flintknapper]

10K is pretty good. I think I did 15K. Out of the box I think the blue hubs are around 6K.

Did 20K in my 80 series and LX470 but we live in a hot climate (Texas Summers).

Just right for my application.

I wouldn't fool with 10K unless you just need a 'little help'. 15K minimum.

 

[surfpig]

Did 20K in my 80 series and LX470 but we live in a hot climate (Texas Summers).

Just right for my application.

I wouldn't fool with 10K unless you just need a 'little help'. 15K minimum.

View attachment 3663347

We’re in Central Valley California. I agree.

 

[surfpig]

The cool guys run 30000 cst

A blue hub and new silicone can keep the A/C on and cold where the old Eatons can’t keep up and the A/C kicks off - it’s pretty impressive. Night and day difference in my temps and the mod is mandatory, I’ve had milk thicker than the silicone it shipped with



Did you buy the weatherstripping that Landcruiser65 linked?

I tried working with the Eaton for a while. I tossed it. Blue hub, modded.

 

[LandCruiserPhil]

I tried working with the Eaton for a while. I tossed it. Blue hub, modded.

Eaton can work I run an Eaton and use 17,000 cst set at 125 degrees in Arizona

 

[freshspecbluegt]

Only other thing I would add is belt tension. Get a belt tension gauge, they are about 20 bucks and use the belt tension spec in the service manual. The spec for belt tension is way higher than most people’s “thumb” gauge is calibrated to.

 

[surfpig]

Eaton can work I run an Eaton and use 17,000 cst set at 125 degrees in Arizona

Mine just wasn’t cutting it. I forget, are they also internally adjustable too? Might be where I screwed up.