1999 automatic Overheating at idle?

[ReconcileUs]

Edit May 2022: Fan Clutch replacement (AISIN) solved overheating issue

Gonna break down exactly what has happened, looking for ideas. Loosing coolant somewhere, but nowhere that's obvious.
1999 automatic with 208,000 miles on the clock.

June 16, 2021 Wednesday

Drove over an hour mostly highway and some city. Temperature gauge normal. Idled in a parking light in sunlight for about 30 minutes, 80F degree day. I noticed temperature gauge near red line, a hair below, immediately drove across the street to gas station to be in the shade & Shut off engine, checked overflow reservoir it was about half full. Let engine cool down a bit, drove 1-2 miles to the nearest Auto Parts store, bought some Vavoline Red Zerex, filled up the overflow reservoir to the fill line. Drove over an hour on the highway back home, everything normal, temps normal. Checked overflow again later that day, level went down, filled it some more.

June 17th Thursday

Before I began my day, checked overflow reservoir, the level dropped back down to half full. Filled it again. Opened the radiator cap and it was full.
Extensive highway and city driving and idling this day, drove 80+ miles, watched the temperature gauge like a hawk, everything seemed normal.

June 18th Friday

Drove 20 minutes on highway, idled in parking lot for 30 minutes. Noticed the temperature in the middle of redline and shut the car off. 70-80F Degree day. Checked overflow reservoir, level was back down to half full. Filled it back up, let the car cool off a bit, drove 40 minutes highway and city to my mechanic, temperature normal the entire time while driving.

At this point, from the brand new 4 quart/gallon bottle of Zerex Red I've added 1.25 quarts to the overflow reservoir back to the fill line each time.

Vehicle History
Acquired 2/2019 at 171,000 miles

Parts replaced that are related to cooling system

5/2019 172,000 miles for all parts below

Radiator Cap Brand: Stant P/N: 10241 <- possible issue?
Radiator Brand: Toyota OEM
Radiator Hose Upper Brand: Toyota OEM
Radiator Hose Lower Brand: Toyota OEM
Thermostat Brand: Toyota OEM
Thermostat Gasket Brand: Toyota OEM
Water Pump Brand: Aisin OE
Water Pump Gasket Brand: Aisin

 

[brillo_76]

Mostly that's thermostat. If you turn the heater on full blast does it start coming back down..


If all those parts good. I would verify the radiator is clean and the radiator itself is not plugged up.

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[alumarine]

Could be your fan if it only overheats at idle.

 

[spartacus]

You are loosing coolant. Got to figure that out. check hoses for leaks. White smoke from the exhaust. Check your spark plugs to see if they have discoloration or chalky residue'or rust spots. The fan should be really loud at first startup. Test the fan clutch.
courtesy of [MENTION=10169]TheDurk[/MENTION]
Testing the fan clutch:
If you have reason to suspect that the fan clutch is defective, here is the recommended procedure to verify the condition of the fan clutch.
1. Start the car (cold) with the hood open and note if the fan is turning, increase the engine RPM and note if the fan turns faster and the noise increases, if it does, first good indication, if it does not increase speed/noise, clutch is bad and needs to be replaced. (Remember, this must be tested after the car has been off for and extended period, over night etc.)
2. Leave engine running and note if the fan starts to slow down after 2-5 minutes, speed/noise should diminish and even raising the RPM, the fan should not make as much noise as when first starting, if it does slow, this is the second good indication. If speed/noise does not decrease, clutch may be “frozen” and should be replaced.
3. Leave the engine idle and watch the temperature indicator. When normal operating temperature has been reached, some increase in fan speed/noise should be noted, in particular when the RPM is increased. If temperature is fairly stable and the fan noise/speed increases or cycles, third good indication. If temperature indication continues to increase, with no increase in fan noise/speed, clutch is defective and should be replaced.
4. After the engine is at normal operating temperature or above, is the only time that the “rolled up newspaper” test that many people talk about should be performed! Take some newspaper and roll it up into a long narrow tube. Be careful, keep hands and fingers away from the fan while performing this test! With the engine at full operating temperature and idling, take the rolled up paper and insert it on the back side of the fan and try to reach the hub of the fan avoiding the blades until close to the hub. Push the rolled paper at the fan increasing the friction to the hub area of the fan. If the fan can not be stopped easily this is the fourth good indication, if it can be stopped the clutch is defective and should be replaced. Again, this test can only be performed when the engine is at or above full operating temperature.

Testing can be performed in any order but just make sure the conditions during testing are those that are specified for that specific test.
Do not continue to operate the engine if the temperature continues to rise and certainly stop if the temperature approaches “redline”.

 

[ReconcileUs]

Mostly that's thermostat. If you turn the heater on full blast does it start coming back down..


If all those parts good. I would verify the radiator is clean and the radiator itself is not plugged up.

Sent from my SM-J337V using Tapatalk

These parts were replaced preemptively, to avoid issues like these. Also, if the thermostat was defective, like not opening properly, wouldn't I overheat during driving as well? If I had to guess I would guess fan clutch, it's original.

I just read the reviews on Amazon for the Aisin FCT-013 fan clutch and one of the reviewers said this

 ‘01 4Runner is running better than ever! Also fixed an ongoing issue where during the hot summer days,
idling with my A/C on full blast my coolant temperatures would rise beyond normal. Once replaced with new fan clutch, that happens no more!

This is a common denominator for my issue too, the A/C on at idle. Although I am not sure why this person is specifically mentioning coolant temperature instead of engine temperature. (If I had to guess I would assume that possibly the coolant temp is actually what is being measured meaning the term 'coolant temperature' would be technically accurate)

 

[ReconcileUs]

You are loosing coolant. Got to figure that out. check hoses for leaks. White smoke from the exhaust. Check your spark plugs to see if they have discoloration or chalky residue'or rust spots.

I think my plan at this point is to just throw a fan clutch on it regardless. Mainly because I gave the truck to my mechanic already and I don't want him to test it and it's bad and then he uses a local parts store brand instead of using an AISIN clutch, so I need to have the AISIN clutch ready on hand either way, so at that point might as well just install it. Also, I JUST (6/17 Thursday) had the A/C serviced for average/below average performance (at idle - worked great driving) which I just learned from reading here on T4R also points to the fan clutch.

And then hopefully he can chase down the reason I am losing coolant. -- My truck will be sitting untouched until the middle of next week until my mechanic gets some time. So, I wonder, if it sits for days and the overflow coolant level is the same level, does that for sure mean it can't be leaking, and therefore it must be burning/entering engines somehow or is that too presumptuous?

As a side note though, I question/wonder if the coolant thing is actually a minor issue, because if I was really truly losing a significant amount of coolant I would have a bigger (more clearly apparent) problem on my hands, yes? A constant overheating whether I was driving or idling. Drove this thing hard, 80 mph on the highway for an hour no temp issues while driving. I just pray to God I don't have a serious issue with the coolant loss.

 

[brillo_76]

These parts were replaced preemptively, to avoid issues like these. Also, if the thermostat was defective, like not opening properly, wouldn't I overheat during driving as well? If I had to guess I would guess fan clutch, it's original.

I just read the reviews on Amazon for the Aisin FCT-013 fan clutch and one of the reviewers said this

 ‘01 4Runner is running better than ever! Also fixed an ongoing issue where during the hot summer days,
idling with my A/C on full blast my coolant temperatures would rise beyond normal. Once replaced with new fan clutch, that happens no more!

This is a common denominator for my issue too, the A/C on at idle. Although I am not sure why this person is specifically mentioning coolant temperature instead of engine temperature. (If I had to guess I would assume that possibly the coolant temp is actually what is being measured meaning the term 'coolant temperature' would be technically accurate)

When mine overheated at idle only it was my thermostat. I changed only the thermostat and issue went away. Very possible the fan clutch not working properly too.. This is why I suggested it and how to test with the heater.

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[JoeT4R]

[MENTION=342150]ReconcileUs[/MENTION] I pray that this is my opportunity to share some knowledge I recently acquired from another user here on the forum. Based off of everything you've stated in the aforementioned posts, I'm led to believe that you need to replace your fan clutch. Prior to replacing mine, I had the SAME exact issue. Idling in park, warm/hot temps, with A/C on (for me), my coolant temps would rise greatly. Once I replaced the fan clutch, I can sit in park with A/C BLASTING on 90+ degree days and my coolant temps stay between 184-190. It's glorious. I bought this Aisin clutch for $80, and honestly I'm gonna tell you that you should replace it asap. Here's the link to it!

Amazon.com: AISIN FCT-013 Engine Cooling Fan Clutch: Automotive

 

[JoeT4R]

[MENTION=164664]brillo_76[/MENTION] Hahahaha that's MY Amazon review! How ironic!

 

[brillo_76]

[MENTION=164664]brillo_76[/MENTION] Hahahaha that's MY Amazon review! How ironic!

That's funny. I just know I never hit H and when I verified no leaks my clutch fan was spinning. So I ran around with the front and rear heater on that day. As it was very hot outside. I had a thermostat on hand. So it was a quick fix in my instantance.

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[ReconcileUs]

[MENTION=342150]ReconcileUs[/MENTION] I pray that this is my opportunity to share some knowledge I recently acquired from another user here on the forum. Based off of everything you've stated in the aforementioned posts, I'm led to believe that you need to replace your fan clutch. Prior to replacing mine, I had the SAME exact issue. Idling in park, warm/hot temps, with A/C on (for me), my coolant temps would rise greatly. Once I replaced the fan clutch, I can sit in park with A/C BLASTING on 90+ degree days and my coolant temps stay between 184-190. It's glorious. I bought this Aisin clutch for $80, and honestly I'm gonna tell you that you should replace it asap. Here's the link to it!

That's your review huh? Good ol' T4R.org, if you smell talk of a 3rd gen anywhere best believe one of you swell bastards are involved. That makes me proud. Well I ordered it last night, when I read the review. Great review! I read them all actually and yours is the only one containing detailed information.

Since I've already replaced the thermostat at 172k miles with Toyota OEM I'm gonna bet on the clutch first and I'll let you guys know what happens next.

Basicially, when I bought this truck it was a family car being passed around to different family members and it was severely neglected. Everything original, driving around with a broken rear shock for who knows how long. I replaced a whole lot of things preemptively based upon the information I found on this forum. Fan clutch was on the list of things I KNEW I should've replaced, based on mileage, but didn't. Here's my records.

 

[brillo_76]

Somehow I missed the loosing coolant part. How much are you loosing and how fast?

When you start up from cold does it smell like antifreeze out the tailpipe. If your head gasket bad sometimes the coolant will spray into the cylinder and when its cold the engine will run slightly rougher and you have a white mist hanging around.

If not burning the coolant or you have a leak your coolant system might not be building the proper pressure it may not be able to suck the coolant out of the reservoir Thus making your issue worse.

Possible coolant leaks locations:

The rear heater lines if your 4 runner is equipped.
Near the Throttle body.
Your oil cooler area
In the valley between the two valve pans

One thing you do not want to do it run any Toyota engine up to H... If you do , you run a very high chance of warping the head and blowing the head gasket. Being these are cast blocks and aluminum heads you want to keep the engine as cool as possible. So if you have to run the heater to cool it down and roast yourself. It may save you from doing a head job.

Hope this helps. If nothing else future readers of the thread.

 

[JoeT4R]

@ ReconcileUs Yeah buddy, that’s me. Not sure if I posted pics or not, but the removal and installation is pretty straight forward. Four nuts holding on the clutch and that’s literally it. Then you remove the fan, etc etc. [MENTION=120071]mtbtim[/MENTION] made a MUST WATCH tutorial on the replacement job itself. You’ve gotta watch it, phenomenal video. Took me an hour and a half from start to finish. Please do follow up once you’ve installed the new one and hopefully it’ll yield the results you’re looking to get!!

 

[TheDurk]

@ ReconcileUs Yeah buddy, that’s me. Not sure if I posted pics or not, but the removal and installation is pretty straight forward. Four nuts holding on the clutch and that’s literally it. Then you remove the fan, etc etc. [MENTION=120071]mtbtim[/MENTION] made a MUST WATCH tutorial on the replacement job itself. You’ve gotta watch it, phenomenal video. Took me an hour and a half from start to finish. Please do follow up once you’ve installed the new one and hopefully it’ll yield the results you’re looking to get!!

Ya want pics? I got pics.....

1998 3.4 Auto 4Runner, Overheating Issue, Suggestions? - Page 4 - YotaTech Forums

This led me to realize I have more time and miles on my replacement (2010) than I did on my failed factory unit. Might have to do this again before too long.

 

[ReconcileUs]

Update:

Mechanic said "Installed the new fan clutch, replaced some hose clamps that leaked under pressure, replaced the radiator cap because I did not like how it felt or what it was doing... I let the car run about an hour temp just under the middle - $120 total"

Haven't fully confirmed whether the issues are resolved because I immediately developed a separate engine issue that I posted about that's prevented me from driving the truck. But once that is fixed if this issue (overheat+coolant) comes back I'll update.

Edit May 2022: Fan clutch solved overheating issue.

 

[JoeT4R]

Update:

Mechanic said "Installed the new fan clutch, replaced some hose clamps that leaked under pressure, replaced the radiator cap because I did not like how it felt or what it was doing... I let the car run about an hour temp just under the middle - $120 total"

Haven't fully confirmed whether the issues are resolved because I immediately developed a separate engine issue that I posted about that's prevented me from driving the truck. But once that is fixed if this issue (overheat+coolant) comes back I'll update.

I don't know if I should like this post or not, but I hope it solved your 4R's problem. On this separate engine issue, that's a bummer to hear about

 

[hairbrush]

I have an overheating issue at idle, so I can definitely check the fan clutch. The problem is sometimes there is missing coolant from the reservoir. I just got a new radiator (old one had a crack in it causing it to externally leak) along with new hoses and thermostat and pressure tested. The vehicle did overheat a tad bit before, but those components were swapped, and it still drives great only that slight problem.
What could explain the missing coolant if there are no external leaks?

 

[phattyduck]

I have an overheating issue at idle, so I can definitely check the fan clutch. The problem is sometimes there is missing coolant from the reservoir. I just got a new radiator (old one had a crack in it causing it to externally leak) along with new hoses and thermostat and pressure tested. The vehicle did overheat a tad bit before, but those components were swapped, and it still drives great only that slight problem.
What could explain the missing coolant if there are no external leaks?

Head gasket or bad radiator cap. Obviously one is easier to check than the other. Use an OEM cap only...

What year and mileage? How much maintenance history do you have? Old coolant eats head gaskets...

-Charlie