So I've run into some issues with my new truck and a little help diagnosing this would be excellent.
I purchased the truck and immediately had to replace the front main oil seal. So, Monday I disassembled the front of the engine; Tuesday I replaced the Front main seal, timing belt, water pump, thermostat, idler pulleys, t-belt tensioner, and distributor cap and rotor. I started the truck up, and it ran beautifully, I idled it in the driveway and checked over the engine and found that the alternator was bad. I replaced the alternator this morning and took the truck for a drive. I warmed it up to normal operating temp, tried to bleed the cooling system and took it for a drive. The temp immediately headed towards overheating. I got it back to the house and removed the rad cap, it burped out a ton of air and coolant so I topped it up figuring it was bled and tried again. Same result.
Symptoms: The rad top hose firms up and gets hot. The top of the radiator is warm. The bottom is ice cold, but I don't know if this is because it's the A/T cooler portion and I didn't drive long enough for that to get hot. The lower radiator hose is cold yet full of fluid and the thermostat housing is very hot.
I replaced the radiator tonight (Got one for $112 bucks at pep boys!) but it didn't fix the problem. What is going on?!
The water pump is an Asin and the T-stat was the OEM manufacturer that Toyota used.
I'm going to start with removing the thermostat when I wake up and testing it on the stove while I make breakfast. If this is bad I'm gonna pop the old one right back in there with a new gasket and finally get my DD on the road.

 

Did you put the T-stat in backward?

try running it with out the T-stat....

got heat from the blower?

 

stat is in correctly, I don't think it'd fit in the housing backwards and the jiggle valve is clocked correctly. I have very hot heat in the blowers.

 

I'm not trying to say you're stupid so please don't take it that way, but did you put the belt back on the water pump?

 

Good idea to test the thermostat suspended in a pan of water with a thermometer....just be sure thermostat and thermometer is not touching the pan itself.

Did you fill the block with coolant through the upper radiator hose?

To get the air out, idle the engine with the radiator cap off and the radiator at the highest point, heat on high and the fan on high. Start engine and let it warm up. Add coolant as necessary to the radiator. Keep an eye on the engine temp too.

Now, fill the overflow tank with coolant to the cold line. Monitor the cold overflow tank level and add more coolant if it drops below the cold add line.

 

That'd be the timing belt, so yes I did. I am concerned that It is not working, though. It seemed to be in order when I put it in and it's an Aisin. I don't see how it could fail when being brand new and with no visual defects. has anyone ever heard of a dead brand new water pump?

Thank you for the advice on keeping the stat suspended in the water, I didn't know that and I'll definitely try and burp this sumbitch real well.

 

Idle the engine with the radiator cap off to get the air out.

:wabbit2:

 

X2 on this, no need to blurp, just run the engine until OT and rev a few times (with heat control on red) to push the air up out of the radiator. Once the t-stat opens you should see the coolant moving in the radiator from the water pump.

Also did you replace the radiator cap? This could cause overheating as well.

 

Haha, I'll be the first to call myself stupid on this one! I'm sure plenty of people are thinking it! I really don't know anything about the 3vze. The only Toyota I've ever really worked on (mine) has a 22re. I'm just trying to think of stuff that could be wrong.

 

No worries, Sparks I appreciate the help! It turned out to be a bad t-stat. Lesson learned: always test them before you put them in. I replaced it with the old one and it runs like a top. I just drove the ~300 miles back to VT.

 

I'll do a little research before I comment on anymore 3vze threads lol.

Can anyone tell me why you should keep the t-stat suspended when you boil it? I just swapped mine out the other day and boiled the new one before I put it in, but it wasn't suspended in the water and I didn't have any issues with it.

 

Touching the bottom of the pan that is right up against the burner can heat the thermostat to a temp that the water is not at. So the thermometer in the water is reading a temp different than what the thermostat may not be at.

 

So will that result in damage to the t-stat or just give an inaccurate temperature reading for when it opens?

 

Don't know if it will damage t-stat. Yes, it can give inaccurate temp reading for opening.

The FSM shows the t-stat being suspended for the opening test procedure so that is how I've always done it along with the thermometer not touching the metal pan.

 

the issue has returned... I think there must be an air bubble behind the thermostat not allowing it to heat up enough I'm going to go try to burp the system. Cooling systems and I don't have a great history.

 

What I found last weekend when I replaced my t-stat and hoses was to leave the radiator cap off with the engine running and squeeze every hose you can. Squeeze it gently until the coolant reaches the top of the fill neck and the let go quickly. Keep doing this with each hose until no more bubbles come out. Make sure to keep refilling when the coolant gets below the fill neck. You don't want to reintroduce new bubbles into the system. I did this this past weekend and it worked great. I didn't have to park on an incline and bounce the front of the truck to work the bubbles out the way a lot of people on here have recommended. And make sure that when you put the cap back on that you have plenty of coolant in the reservoir.

 

Thank you, Sparks I will do that. I'm going to replace the thermostat again because it's the same exact symptoms as before when it was bad. I will bleed it through thoroughly as I can. I'm doing this in the morning before work tomorrow and it'll determine whether I go back to my family's home for Christmas or not. I hope it works out! updates will come and pics in the build section soon, hopefully.

 

Hilarious, all the burping and squeezing just to fill a radiator.
Real mechanics would starve to death if they spent days filling a cooling system after a repair, By now you should realize you have more going on than just a little air in the system.

 

"Hilarious, all the burping and squeezing just to fill a radiator.
Real mechanics would starve to death if they spent days filling a cooling system after a repair, By now you should realize you have more going on than just a little air in the system."

Do you have any suggestions related to Cheezs issue?

So Cheez, let me get this straight, you replaced the water pump, t-stat, radiator, and, coolant and your truck still overheats. Have you tested or replaced your rad cap like I suggested? They are like $10 and play an important part in maintaining the correct pressure in the cooing system, which also affect the boiling point. They also allow coolant to overflow to the reserve tank and back to the engine.

I don't know what to tell you if you've replace all the crucial cooling system parts. Did the truck have any desire to overheat before you did the front end work? No head gasket issues? Perhaps your coolant temperature sensor is bad, but that would probably affect you engine performance.

To check your t-stat, leave it in the truck, start it up, run until normal temp, then rev to 2500 rpm until the t-stat opens or not (with rad cap off) if the t-stat opens you will see the coolant moving from left to right in the rad which will confirm if your water pump is doing its job. Good luck!

 

I have gone over it on this forum and explained the proper way, but nobody listens.