Overheating

NASER NASER

MEMBER
2008 TOYOTA TUNDRA
V8
2WD
AUTOMATIC
268,000 MILES

Was sitting in the parking lot waiting on a customer and I noticed the A/C started to cool worse, looked at temperature and it was climbing 3/4, turned it off. Looked under the hood and the side plastic overfill reservoir was boiling and some of the water came out of it. Belt looks good. Mechanical fan has good resistance when turning by hand.

7 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

I would start with replacing the thermostat. It may not be opening causing the fluid to get too hot.

https://www.2carpros.com/articles/replace-thermostat

Beyond that, is the fan pulling air through the radiator while the engine is running?

https://www.2carpros.com/articles/engine-overheating-or-running-hot

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

Roy

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Wednesday, June 3rd, 2020 AT 9:02 AM

NASER NASER

MEMBER
836 POSTS

Yes, fan works, and A/C is very cold, can the thermostat get stuck closed even after I drive it and its at operating temperature? How do I replace it on this one, it's a v8 4.7l.

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Wednesday, June 3rd, 2020 AT 9:06 AM

ASEMASTER6371

MECHANIC
52,797 POSTS

It is under the truck where the lower hose attaches to the thermostat housing on the block.

This is an easy one.

Yes, it can.

Roy

REMOVAL

HINT: If the thermostat was not installed, cooling efficiency would decrease. Even if the engine tends to overheat, do not remove the thermostat.

1. REMOVE NO. 1 ENGINE UNDER COVER (See: Engine Oil > Removal and Replacement > Replacement)

2. DRAIN ENGINE COOLANT ()

3. REMOVE THROTTLE BODY COVER SUB-ASSEMBLY (See: Intake Manifold > Removal and Replacement > Removal)

4. REMOVE AIR CLEANER HOSE ASSEMBLY (See: Intake Manifold > Removal and Replacement > Removal)

5. DISCONNECT WATER INLET

imageOpen In New TabZoom/Print

(a)Remove the 3 nuts, and disconnect the water inlet from the water inlet housing.
6. REMOVE THERMOSTAT
(a)Remove the thermostat.
(b)Remove the gasket from the thermostat.

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Wednesday, June 3rd, 2020 AT 9:10 AM

NASER NASER

MEMBER
836 POSTS

Removed the thermostat first to see if its going to do it. Am I supposed to see a change in speed in the mechanical clutch? Like at operating temperature? I tried the stick test and it works, it is turning hard, not freely, so I know it is good, just don't know if she will change speed or not. I am watching to see if temperature is going to rise or not now with thermostat out.

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Wednesday, June 3rd, 2020 AT 2:02 PM

ASEMASTER6371