Bleeding the cooling system

[My84terc]

I just put in a new radiator. The temperature stays perfect when I'm driving on the freeway, but when I exit, the gauge shoots up pretty high. I have a new thermostat also. A mechanic friend asked if I bled the system. I can't find where to do this. Any advice would be helpful.

[takza]

Did you make sure the small opening on the thermostat plate was at the top? Is the rad full when you open the cap cold?

[splatterdog]

All my tercs came with a flush tee in the top heater hose. This worked out well as 2 of them came with liquid rust for coolant.

It also makes an excellent bleeder. It's also the highest point in the cooling sys.

[Highlander]

Did you replace the Radiator cap along with the radiator? It should be a 13psi (0.9bar) cap. I had an overheating prob with my '85, tried everything but a cap-Guess What $5 cap solved it. Good luck!

[My84terc]

Did you make sure the small opening on the thermostat plate was at the top? Is the rad full when you open the cap cold?

What small opening? Is this on the thermostat itself? The radiator is full when it is cold.

[Neu]

make sure your fan is popping on.

[Petros]

it sounds like the fan is not working. I have never felt the need to bleed the tercel rad, other cars I have. After I top it up and drive it a bit, I check the water the next day and top it up if necessary.

If it cools good at speed, and not at slower speeds, it sounds like the problem is there in not enough airflow at the low speeds.

Good luck.

[Neu]

If it cools good at speed, and not at slower speeds, it sounds like the problem is there in not enough airflow at the low speeds.
Good luck.

Yeh, same thing happened to me. What i ended up doing was unplugging the fan and keeping it on all the time when my car was one, then I just went to a junkyard and got the sensor out of a wrecked tercel4wd. It could be any 3ac though. I got it for free, cuz I bought a lot of other stuff.

[alex16]

I just recently had problems with my fan switch going bad, it could be that. If you unplug it (it plugs into the switch on the bottom of the radiator passenger side) it will keep the fan on when key is turned on.


I am a mechanic and I have gotten away with this same procedure with every car I have ever seen.


Start the car up cold and top off the radiator with 50/50 mix. Let the car warm up. When it gets to opperating temperature you might have some coolant "burp" out onto the ground and then the thermostat will open. Then you will see the coolant start flowing and the level should go down. Then keep adding until it stops going down. Once it does not go down anymore rev the engine to 1800-2200rpm and add some more (it will go down slightly). Then top it off and put the cap off. As soon as you have the cap back on you can let off the throttle. Its important to flush the cooling system if you see anything nasty in the coolant when you drain it. Remember to have the temperature control set to red or "warm" to allow the heater core to also be flushed/filled. If you have rusty water you want to flush your system out a few times with distilled water with no antifreeze, and then when all cleared out use 50/50.


That is the way I used to do all cars but for the past year and a half I have used my faithful air powered snap on pressure tester and matco cooling system filler.

Part#: MCR101 Price: $164.95
"COOLING SYSTEM REFILLER

Vacuum Venturi Cooling System Refiller.
Eliminates airlocks during cooling system refilling.
Compact design - No need to change hoses during refilling process.
Complete refilling process can be done in 2 - 3 minutes.
Seals directly on radiator or with standard type cooling system adapters.
Operates with shop air, minimum 80 psi required.
Tester comes with a cooling system adapter selection guidebook.
All metal construction: Combination of chrome plated and stainless steel components for a lasting finish."

Pretty much it shoots air threw a valve that connect to where the radiator cap twists on and it pulls a 25 psi vacuum. Once you have 25psi you know you have no leaks after your repair work is good. The kit comes with a 4ft vinal clear hose that you can dump your 50/50 mix into a bucket (its very convient and easy) and put the hose into the bucket, open the valve slightly for the hose and let the coolant get all the way to the top and about to go into the radiator, then shutoff the air pressure and open the valve back up. It automaticlly fills the entire cooling system back up with what is in the bucket. It takes maybe 5 minutes vs 10-15 the other way and you still might find leaks if you don't pressure test it before filling it.

For pressure testing I use this.


Snap-On
Tester, Pressure, Cooling System, Air Powered
Stock#: SVTS263

$205.95

It can go from 1psi to 32psi max. The valve on mine is set at 13psi and i have drilled too small holes 180 degrees from one another and zip tied them to make sure it stays there (makes it easy no adjustments). Put it on the filler neck of the radiator and open the air pessure valve until it reaches 13 psi and then turn the valve off and look for pressure drop/leaks. Easy as that. You might call me lazy but wait until you work on 3/4 ton diesels with radiators, it takes like 20-30 pumps to get them up to pressure. Even more so with the international diesels I work on in comercial trucks.