4a-c Ae82 Overheating Problem!!!

[nos4ag]

Gday Everyone!!

I searched for a thread on this topic and couldnt find one, so I thought that I would ask a few people on the forums here.
I am having an overheating problem with my g/f's AE82 4AC Corolla. Here are some details on the car:
- Engine has done 172,xxx original kilometres.
- Radiator was cleaned about 12,000km ago.
- New Thermostat, Belts, Rad Hoses, Heater Hoses.
- Water Pump is still the same since when we bought the car (at 127,000kms ago).
- I use Techtaloy 60 plus coolant all the time, and there have been NO bubbles coming from the radiator when the car has warmed up. Coolant is still green.
- The car only use the tiniest bit of oil and the oil is also the normal colour. It is reguarly serviced every 5000kms.

Now, when I start the car every morning it only takes about 5 mins of standing still for it to reach HALF WAY on the temp guage. It always stays at halfway and never goes below it. But, if the day is a bit hotter (as in degrees) the temp guage goes higher. In the last last 4 months aswell, it has blown the top radiator hose and the top heater bypass hose to the thermostat housing. The car has had the timing checked and is correct.
The thermo fan does not switch on which is also puzzling me. You can physically take the plug off the switch and the thermo will run ok, and it will never go over halfway, but every time I shut off the car I have to physically put the plug back on the switch to turn it off. Its a bit dodgy to me to do it that way, but it works.
The plugs are also the normal running colour as said in the NGK book aswell.

- Why is the car running this hot so quickly??
- Why are the top hoses bursting??
- Is there pressure of some sort in the engine blowing holes in the hoses??

Apart from this overheating problem the car runs beautiful (as much as a 4AC can anyway...hehe).
Any question ask away!!!!!

Any help would be appreciated.
Regards, Ben.

[Vios-GT_07]

looks like the fan's on reverse or something... that or a fuse or connector somewhere is shorted out / blown causing the fan to not work properly..

4A-Cs do run hot, but usually sit below the halfway mark.. also does your thermostat have the correct heat settings?

me thinks water pump is bad on bearings, or somehow the flow of coolant through the engine is impaired..

[nos4ag]

Vios - Thanks for the reply. Which way is the fan suppose to run?? Clockwise or Anti-Clockwise?? Its suppose to pull from the raditor isnt it??
The thermostat is the standard TRIDON 82 degree celcious thermostat that you get from SuperCheap Auto e.t.c
I havent taken the Water Pump off before, but it doesnt leak at all.
Ahh actually, I have been hearing something which sounds like some kind of bearing noise though the atlernator belt!!!
Could that be the water pumps bearings whining?????
What do you think guys???

[Vios-GT_07]

hm.. as long as the fan can pull heat away from the radiator is fine.. not too sure coz i've seen some weird fan designs and directional pulls which work.. clockwise / anti-clockwise is really depending on the blades and direction, best to check another FWD car or similar to see what it's doing sorry i can't help u there.. best to check out why the electrical system for the fan isn't working.. could be wires crossed and doing something stupid..

hm.. the thermostat sounds alright.. and it being new means it's highly unlikely the thermostat is the problem.. water pump bearings whining could be something.. best to check out the pulleys to eliminate any potential problems..

i've seen a tensioner pulley seize up before, and the balls were coming out.. it completely seized and was very lucky i pulled off the timing cover to have a look otherwise it'd have shredded the belt or something serious could've happened.

[RobertoX]

Its strange that the thermofan doesn't come on even though its getting quite hot, I believe these are operated by a temp swich somewhere, maybe check this.

I had a similar problem with my 4ac last summer and a new pump fixed it, it was quite rusted and pitted on the inside when I pulled it out. Before I changed it I tried a full flush, thermostat and new hoses with no luck.
If you are having issues with the thermofan maybe start there as it will possibly be cheaper and is an obvious problem.

[nos4ag]

Thanks for the reply RobertoX!!
I bought a new Water Pump today and will be fitting it this week. I rang Toyota and asked how much a Thermo Fan Switch was and got the reply of $134.50 inc.!!!!!!!!!!!!
I couldnt believe it!! But I might be able to see if I can find and alternative at work!!
I will change the Water Pump and let you guys know what happened!!
Cheers!! Will keep you posted!!

[nos4ag]

**UPDATE**
I fotted the new Water Pump as I thought that there was a squealing sound coming from the bearing of the old one. After I took it off the car, I noticed that there some slight coolant sludge that had been dripping out of the bottom hole of the pump. I dont know how long it was doing this, but I do know that I wasnt losing coolant. Apart from the bearing noise and the coolant sludge, the water pump looked normal.
I installed the new pump and started the car and found that the same symptoms still remained.
The hoses are still very tight when you squeeze them when the car is at operating temperature. Is this normal? The radiatoir cap is never hot though, as I can put my whole hand on the cap after I have turned the car off and its not hot at all. Is this normal??
Also, the car just hovers at half way on the temp guage now, and that is with the thermo fan on all the time when I am driving.
Any more ideas of what could be causing these problem at all??
Thanks Guys

[river]

Hi,

So the thermo fan is running all the time and you've changed the water pump, and there's no coolant leakage, right?

Isn't half-way ok on the temp gauge for a 4AC? Mine runs halfway most of the time.

However, if you think it deserves more investigation then pull out your thermostat and put the assembly back together without a thermo in it.

Technically, it's not good to run an engine without the thermostat 'cos the engine won't reach it's proper operating temp, assuming everything else is fine. Now run your engine and see where your temp gauge goes.

If it still gets too hot then you have a blocked radiator or blockage in the block that's reducing the effectiveness of the coolant. If the temp is too low then it's either all okay or your thermostat was the problem.

To check the thermostat put it in a saucepan of cold water on the stove. The thermo should be closed. Now heat up the saucepan. At 82deg the thermostat should be opened. Remember the thermo has a "range" where it may start to open at under 82deg or it may start to open at 82deg. In any event, I would expect it to be fully opened at under 90deg.

If the thermo isn't opening or opening just a couple of mills then I'd look at getting another one.

seeyuzz
river

[slide86]

it does seem as if there is blockage there somewhere. the fan shouldnt be running all the time. and the radiator cap should definetly be hotter than what you descride.

i think river has a good idea with removing the thermostat. you will definetly be able to confirm the problem if it doesnt get hot with it out. i have seen new thermostats that play up, you may have one of these.

by having very tight hoses, that means that there is a lot of pressure in teh system. is there any difference in the temp of the top hose compared with the lower hose? at operating temp they should almost be the same.

[eviltwin]

i had an issue with my bigport in my 82 in summer, it was overheating and the fans werent coming on, so i went to the wreckers and bought a thermo sensor ( sits just before thermostat ) and that fixed the issue i was having, may be also worth having the radiator out and flushed.

[nos4ag]

Thanks guys! Rep to all of yas!!
The thermostat is definately brand new , so I assume that it is opening properly.
The top radiator hose and the bottom radiator hose are both tight at operating temperature, so that should be ok then. Umm......2 things that I can do then, take the radiator out and get it flushed again.....and get a new thermo fan switch and see whether it turns on or not and keeps the haet down.
Maybe its just cos its a 4AC!! I dunno!! Im puzzled

[Scorpion]

You may have air trapped in the system and this fills up with steam which expands and causes pressure build up.

Do you open up your heater valve when you replace the coolant ?
After you first start your car, put the heater temperature slide on full and see if you can hear a gurgling sound as water enters the heater radiator under the dash. If you hear he gurgling there is air trapped inside.

[cambelt]

Also AE82 temp guages are Aussie poo , they do tend to read on the high side ive found.
Check the temp with a known tested rad temp guage .

[Admiral coFF33]

blocked radiator .... take it somewhere to get it opened up, its probably caved in the middle ?

[nos4ag]

Rep For you guys!!
Ill see what I can do with the Radiator next week some time, but its the thermo switch not turning on that is really bugging me!! Oh, and I will get the temp tested with a different source to see if it reading the right temp or not. Will get back to ya's!!!
Cheers!!