Overheating while at idle and driving

C

cashmoney

New member
Pretty certain I know the issues but wanted to run it by y'all first. Driving to work in traffic this morning and noticed the needle was at the red box. Flipped the heater on and it dropped a touch. Started moving and it dropped some more but then it went right back up. Couple of times it would drop half way and the heater would quit blowing hot. Then it would go right back up to the red box. Did this all the way until I was consistently driving 60+ and even then it was only a hair below the red box and kept bouncing up and down. Here's my plan of attack:

1. Purge the system of air
2. Thermostat
3. Confirm fan clutch is good and if not then replace
4. Complete flush and fill

Water pump was done last year. Anything else?
 
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Sounds like a good plan. My guess would be clutch fan or thermostat. I don't see how air bubbles could get into the system unless it wasn't purged when the water pump was changed (and you would have seen overheating at that time).
 
That's what I'm leaning towards as well. And of course the cooling system is the one system I didn't inspect when I bought it.
 
One thing I found interesting is no light ever came on the dash even when the needle went in to the red zone. I would think it would do something to alert you to that.
 
cashmoney said:
One thing I found interesting is no light ever came on the dash even when the needle went in to the red zone. I would think it would do something to alert you to that.
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Thats what the needle and the red zone is for,,, to alert you
 
Ya I get that and hence I watch it but they don't build vehicles for people that watch those things. They build them for people who don't realize they need to change their oil hence warning lights or buzzers.
 
Your truck is 15 years old. If you want a buzzer or warning lamp, buy a newer one. thermostat control parameters, coolant temp threshold readings all can trip warnings now.
 
You may have a blown head gasket. Driving that long with it "a hair below red" may have warped your heads.

My recommendation would be to not drive it anymore until you can properly diagnose the issue.
 
BlackCat914 said:
Your truck is 15 years old. If you want a buzzer or warning lamp, buy a newer one. thermostat control parameters, coolant temp threshold readings all can trip warnings now.
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Again, I get it. Just thought it was interesting it didn't have one. That's all.
 
Im guessing this came out of the blue and no recent work was done to the cooling system?

If that is the case then take it to a good private mechanic that focuses on Toyota.

If you want to do it yourself use the FSM. You can find it by using the How To Search link in my sognature below. Basically you need to do an alternate search to find those threads because FSM is only 3 chars and the forum search only responds to 4 or more char searches.
 
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Got some time at work right now and popped the cap and reservoir open. Ton of brown sludge. Looks like someone mixed coolant at some point and I didn't see any in the radiator. Pulled the trans dipstick and fluid is fine there and the oil looks good as well. Looks like a full flush, scrub, and t-stat replacement is in store. Looks like I'm going to be paying for my mistake on this one.
 
I'd check the coolant system with a pressure tester. Brown sludge sounds like oil mixed with coolant. You would probably have coolant in the oil if it's that bad, but I'd pressure check it anyway (borrow tester from auto parts store like O'Reilly's).
 
Did you drive with some speed at all and see if it went down?

I would put decent money on the fan clutch. You clearly have fluid flowing and usually the air bubbles will hide in the heater core and you have hot air..
 
Got an OEM thermostat and cap on the way. Going to pick up some coolant flush stuff tonight and start flushing this crap out and hope it's not to late for everything. First things first I'm adding coolant to the radiator before I drive home tonight.
 
Just poured an entire growler into the radiator. Got a flash light and looked in the overflow bottle and sure enough there is green coolant in there. It's dirty as hell but it's at least green and not brown like the residue on the cap so maybe there's some hope.
 
cashmoney said:
Just poured an entire growler into the radiator. Got a flash light and looked in the overflow bottle and sure enough there is green coolant in there. It's dirty as hell but it's at least green and not brown like the residue on the cap so maybe there's some hope.
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I don't see how you could change a WP and not change the coolant, and I don't see how new coolant could turn into brown sludge in one year. Clearly you need a good flush and fill. Something is in there that shouldn't be there. I wouldn't drive more than a few seconds with the needle in the red, you don't want to warp a head or blow an HG.
 
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