Overheating at idle

Hey there folks. I have a 2006 Toyota Tundra DC SR5. If you remember me i had a problem with my pcv valve recently but that’s not really the point of today’s issue. Here’s the issue, when i’m sitting in line like in a drive-thru or costco gas, my truck will overheat, with the ac on that is. The ac will start blowing warm air as well. Took it to the dealership on a hot day and they couldn’t get it to overheat themselves (or supposedly). The dealer said my thermostat was good as well. Water pump was done at 200k. Note: it did this before the water pump job and continued after. I am currently at 278k. I am out of ideas and i am tired of having to shut off my engine while waiting in line. Your attention to this would be greatly appreciated.

 

Original radiator?

 

fan clutch can do that. Not pushing enough air at idle and overheats where it cools enough when the air flow is increased when truck is moving.

old radiator could be an issue too, they can get clogged inside or the fins get full a crap after many years of driving.

 

@FirstGenVol you are correct about the original rad, but if that was the culprit, wouldn’t it be overheating all the time instead of going away when i drive down the road? Also what about the ac blowing warm air when it overheats?

 

Honestly I don't know but I know those fins work by having air flow across them. So when you are sitting still the truck isn't getting any airflow. Have you check to see if the fan is working? At 278K miles I would replace everything. Your way overdue for radiator and thermostat. I'd do the hoses and flush the coolant too. I'm basically a retard and I did all this myself. You could knock it out in a single day.

I wouldn't let it overheat too many more times or you could have a much more costly head gasket failure.

 

I knew someone would appreciate that.

 

Sounds like a fan issue if it’s only at idle. Motion above 35-40 will do the job via ram air effect. Below that you need a fan. Most cars will shut AC down in the event of an overheat because the condenser generates heat as well.

 

i’m gonna cross off fan clutch because I hear that fan roaring louder than hell when i take off. And for the record, I just want to make it known that I don’t ever let my truck reach the red zone let alone let it overheat even slightly, I shut it off right away to prevent it from happening

 

I am starting to think it’s the radiator because after searching the forums here, they tend to go out after 15 years which is almost my truck’s age…

 

Also the strangest thing happens to me right before it will start heating up, the overhead temp display (i forget what it’s called) will go blank which helps me predict when it’s about to overheat. Not really sure if it is worth mentioning or not.

 

Does your rad shroud have the lower section?

 

@Sirfive hmm, I’m gonna have to check that later. My truck is currently parked somewhere else and I am too tired to walk to it right now just getting back from work. so I will get a picture later to verify that it has that piece.

 

This. There was a thread recently with someone having similar issues. Someone noticed in a picture that the shroud was detached on one side.

 

I had a truck that did the same thing, all the components were inspected, but I finally took the radiator to a radiator shop and turned out it was partially clogged and at idle would overheat. After the clean job, never happened again. Don't know why the dealer wouldn't have spotted it though. Might be worth it anyway. Not much else is left to check. Good luck.

 

My 05 Sequoia radiator bit the dust 3 years ago. Even if it’s not an issue now for your rig, it soon will be imo.

 

That is fed by the Ambient Temp Sensor(2 conductor-Blue and Pink) right next to passenger side horn....sensor, wiring or overhead module are possibilities. Does that have to do with your overheating....plausible, only if you have gremlins in your wiring

 

Does the AC blow cold(ish) driving down the road? Only gets warmer at idle as well?

 

I'd say it could be related. Lose airflow and the sensor is mounted up by the radiator so the excess heat either maxes out the sensor or the sensor is going bad and malfunctions at high temps.

A new radiator and fan clutch should get you squared away.

 

Sorry i haven’t been able to respond. I have been very busy. Anyways, the fan spins, i doubt the fan clutch is the problem. the fan shroud is not missing the lower part. I am out of ideas guys, usually overheating in idle would lead right to the fan clutch. Looks like I am going to have to throw a radiator at it (when I acquire enough money to do so) and see if it will fix this issue. I am tired of this, I have not been able to sit in a drive through for 5 years without turning the engine on and off with no ac…

 

Just because you can hear the fan when starting off doesn't mean it's good though. A fluid clutch can still function but not be working correctly.

New ones are under $50 so it's cheap enough to throw at it either before or during a radiator replacement.

 

Hmm, i like your advice, ok will try to get the fan clutch repaired soon and see what that will do for it….

 

Yeah, it really seems like a fan clutch issue. Can't hurt to have the radiator replaced as soon as you can. OEM Denso installed in my 2000 was $450. Do that and you won't have to worry for another 15 years.

 

brazen, you can test your thermostatic fan clutch to verify that it's functioning properly. With the engine off spin the fan by hand. If it freely spins two rotations it's probably passed it's life-cycle and should be replaced. On the other hand, if it doesn't freely spin at all it's worn out also. The radiator is definitely suspect here due to age also. The Denso unit for these is about $150 and drops right in.

 

Mine free spins about 1/3 rotation.

 

It may be nearing the end. It should go around at least once. If you don't have any issues though you're probably ok for awhile but I'd keep an eye on it.

 

I think its been replaced before. The mount that bolts to the pulley is painted chevy orange.

 

Ok so with the engine off and at cold temperature, I spun the fan clutch. It barely turns and doesn’t make a full clockwise spin. Imagining that the fan and it’s shroud is a clock, the blade was at 10 o clock before I spun it and when I spun it, it landed on 12 o clock. After that I decided to turn on the engine after and let it get up to operating temperature (not overheating temp) and then turned it off. The fan now was more easier to spin and spun a bit further but still didn’t make one full turn. After about 20 minutes I tired again, and the fan would barely turn like the first time I tried it. What do these findings show?

 

Once the motor is up to operating temp the fan should spin 1-1.5 max. If it spins less than a full rotation when the motor is up to operating temp then it is nearing the end of its service-life and I would recommend keeping an eye on its operation. Conversely, if it freely spins multiple times after the motor is up to operating temps then it definitely needs replaced.

 

Brazen, did you ever get this resolved? I have an 05 with the 4.7 doing the same thing.