Cooling Woes

ElPolloBlanco

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Oct 27, 2011
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Hanford, Ca
 
I know I know, another cooling thread, but I’m just looking for a little guidance as I’ve already read most of the other threads, and still don’t know what to do next. First off, a little back ground. 1997 with a little over 166,000 on the clock. Head gasket was replaced by a previous owner. I had some cooling issues in the past. Last summer, I did the oil mod in my black fan clutch with 15k oil. I also replaced the thermostat, did a flush until the water coming out was so clear I thought about drinking it, and put new Toyota red in it. My temps afterwards were good. On a long steep climb that normally pushed temps into the 210+ range I was right around 200-205. Daytime temps in the CA Central Valley top 100 almost every day. I was in the 190-195 range driving around town. It was great. Now though the temps are starting to rise again. Just the other day I was waiting for my food to come out in the parking lot, since you can’t go inside anymore. It was 52* outside, kinda of rainy, I had the defrost on low with the temp setting just about the halfway mark. Sitting there for about 10 minutes my temps got up to 212 degrees. I feel that was way too high for the situation. My question is what should I look at next? I’m positive it’s not the thermostat because it cools down as soon as I drive. I’d like to say it‘s not the fan clutch, but I honestly think that’s the issue. I don’t think it’s the water pump, I replaced that when I first got the truck. The radiator is clean on the outside and looks to be in good condition.

So what do you think? Should I just suck it up and replace/upgrade the fan clutch? No amount of new oil is going to repair a worn out clutch, right?
 
Joined
Aug 26, 2009
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flat earth Midwest
 
 
While the radiator may look good, I R&Red ours because internally it was blocked up from years of faithful service. If yours is original, it's probably a lot like ours. Check it to see if there are cool spots vs warm ones. If you have a remote measuring thermometer, this works best, butyou can do it by hand if the motor is (of course) off
 
Joined
Sep 15, 2016
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Chattanooga, TN
If it cools down well when you start driving that does seem to indicate good radiator flow and cooling capacity. Decent amount of room for there to still be issues in most parts of your cooling system based on just reading your description of this but typically with what you've said I'd focus on the fan clutch exclusively until you know it's working properly then move on through the cooling system to make sure all else is well.

There are a few adjustments on a fan clutch. One is the temp at which the ports open and allow the fluid to flow out and sheer/drive the fan. The other adjustments are the fluid weight/thickness and quantity. It's pretty easy to pull the fan clutch and check/dial these in. It's free to adjust the clutch opening temp and cheap to change/add oil which are also good reasons to start with the fan clutch.

Good luck
 
Joined
Oct 10, 2018
Messages
119
Location
Texas
Is your thermostat OEM?

I agree with the above, next option is new blue fan clutch, and swap in 15K fluid. Don't change any settings when you have fan clutch open.

Is your radiator the original? if so, probably time for a new one regardless, call it a win with 25 years of service.

Just for reference- I have 280K+ miles on my 1995, I swapped all new hoses, new radiator, new coolant, new fan clutch, new thermostat, and I am sitting at 182 when idling, and 186 when on highway (based on scan gauge). So yes, your temps are high in comparison.
 
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Phoenix
 
 
 
Depending on your choice, radiators are cheap. I've fought with overheating for years before changing the rad, and regretted waiting so long.
 
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Oregon
 
 
 
Last summer, my temps were much higher than I liked when going out to the desert. I bit the bullet and replaced the water pump, thermostat, fan clutch, and radiator. Also did the fan clutch mod with 30K oil. I did it all because I've seen so many threads where people did a little at a time and they never seemed to nail it on the first try. For me, perhaps I changed a few parts that didn't need replacing, but parts were relatively cheap buying most parts from Rock Auto (Aisin pump & clutch) and getting the TYC radiator from Amazon (gets thumbs up from a number of the Arizona folks). So far, I haven't seen temps above 186, but it hasn't been warm yet. However, I have high confidence that high temps are a thing of the past. Think I was into everything, including new hoses and belts, about $350. For me, it was worth it to do it all at once.
 

Howard705

TLCA 5505
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Feb 1, 2013
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Central Illinois
 
If it cools after you start moving- it's the fan/clutch. I've driven cars without fans installed or electric fans working before and they are fine until you slow/stop. The air pushes through very well.
 

LandCruiserPhil

Peter Pan Syndrome
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Mar 10, 2004
Messages
24,662
Location
Scottsdale Arizona
 
 
 
Is your thermostat OEM?

I agree with the above, next option is new blue fan clutch, and swap in 15K fluid. Don't change any settings when you have fan clutch open.

Is your radiator the original? if so, probably time for a new one regardless, call it a win with 25 years of service.

Just for reference- I have 280K+ miles on my 1995, I swapped all new hoses, new radiator, new coolant, new fan clutch, new thermostat, and I am sitting at 182 when idling, and 186 when on highway (based on scan gauge). So yes, your temps are high in comparison.
Last summer, my temps were much higher than I liked when going out to the desert. I bit the bullet and replaced the water pump, thermostat, fan clutch, and radiator. Also did the fan clutch mod with 30K oil. I did it all because I've seen so many threads where people did a little at a time and they never seemed to nail it on the first try. For me, perhaps I changed a few parts that didn't need replacing, but parts were relatively cheap buying most parts from Rock Auto (Aisin pump & clutch) and getting the TYC radiator from Amazon (gets thumbs up from a number of the Arizona folks). So far, I haven't seen temps above 186, but it hasn't been warm yet. However, I have high confidence that high temps are a thing of the past. Think I was into everything, including new hoses and belts, about $350. For me, it was worth it to do it all at once.
Smart AZ guys use 25-30k in blue hub clutch
Smart AZ guys use TYC 1918A radiator

With that said I use an Eaton fan Clutch with 17.5k 🤷‍♂️
 
Joined
Nov 9, 2012
Messages
8,882
Location
Olathe, KS, USA
 
If I recall correctly, the most famous overheating thread of all turned out to be loose fan and alternator belts.



Check that and check to make sure your radiator isn't clogged with grass / mud / debris where it won't sufficiently cool.


Typically these trucks overheat at speed because that' where it needs the airflow, not at idle and slow speeds. That indicates that you could be getting reduced flow, which again points to loose belts.
 
Last edited:
Joined
Nov 20, 2013
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886
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PA
 
I end up playing in the mud when out in the woods. When I replaced my rad a couple years ago, it was packed with dirt. I am currently parting out that truck, and the "new" radiator is pretty mudded up. I never had this problem in the past with my other trucks, but the LC system seems to hold onto dirt. Unfortunately with the AC condenser in place, it is difficult to get a good look at the radiator.
 
Joined
Aug 26, 2009
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flat earth Midwest
 
 
SNIP

Typically these trucks overheat at speed because that' where it needs the airflow, not at idle and slow speeds. That indicates that you could be getting reduced flow, which again points to loose belts.
With the radiator being original or very old. it's worth checking the state of the seals around the radiator. If these have been trashed, you get lots of airflow around the radiator rather than through it. Not helpful and could contribute to what BILT4ME is discussing here.

That said, some neglect to refresh the seals when R&Ring the radiator. Instead, look at it as a good time to freshen them.
 

ElPolloBlanco

SILVER Star
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Oct 27, 2011
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Location
Hanford, Ca
 
I may have figured this out. I checked the coolant level the other day and realized it was pretty low. I do remember bleeding the heater core of air when I did everything before, but I don’t think I did the rear heat. I think using the rear heat over the winter might have refilled that system and drained the cooling system. I added about half a gallon of distilled water to the radiator and overflow bottle to top then off. Since then I haven’t gotten above 190.
 
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