Overheating problem on 3sgte,need help PICS

[3sgte]

As others mentioned, a thermostat is necessary for operation. Without a properly fitting one, with a plate to block the bypass when hot, coolant can loop continiously through the bypass, never seeing the radiator.

[BrianRA23]

If your engine is overheating you are not getting cooler water into the engine so your problems are esentially limited. It would be good to know how quick it overheats and unde what conditions. What is the state of the engine- both modified and tuned alterations.

1. Radiator blocked or fan not working (I think you said you turned the thermos on full time so radiator is next option)
2. Water pump not working - impellor not moving with the pulley (yes it does happen on new pumps even) or
3. Thermostat not working - try remove it or alter the old one to allow some flow and take for a drive (definitely not a long term fix)

This assumes nothing else has changed from when it was fine, but if it has then that is the first thing to change back to the previous setting. Once this is done and problem still exists then work through the these possible faults.

If you think the head gasket is blown (in your case communicating with the cooling system) then my previous suggestion of using the screwdrivers into the combustion chamber should help you eliminate the problem.

When trying to sort out the problem, I would be running either straight rain-water or distilled water. It is not going to cause any corrosion on the short time you are going to to troubleshoot and water has far better heat transfer properties than any other coolant. Also it is cheap and environmentally friendly to dump between eliminating different possible faults.

[BrianRA23]

3SGTE (from Canada)

Are you saying a hot thermostat will prevent flow through the bypass system, by some technique other than having an easier route through the radiator?

[kingmick]

few things you can do to check outside the engine if it still gets hot with a new thermostat.
get it up to operating temp, then feel the oulet hose from the engine to see how hot it is and the the inlet hose to make sure it is cooler and not dead cold,squeeze the pipes a bit and you will feel the flow. run hand gently over radiator to check for hot spots{blockages}. then the system needs to be prssure tested to see if there are cracks inside the head.

[Aust162]

yeap...

1. retorque head yet?
2. 100% sure that coolant is flowing?
3. all hoses are good? heater core leaking?
4. When you did your HG did you pressure test the head?
5. sort out all the thermostat?
6. when cold, start car and take out the radiator cap.. any bubbles?
7. coolant temp sensors?
8. fans spinning the right way? not reversed or anything?

to a lesser extent
. from the plugs i can see it's not running lean, make sure it's not though
. Is your timing too high advance?
. shaved the head when u did HG?

the comes the harder issues

. does the water pump spin freely? if u have to remove the timing belt
. worse case scenario, take out the head and do a pressure test again

that's all i can think of at the moment...

Thanks for the list mate
1.havnt done this. i've been told by the mechanic that assembled the block/head that is will be ok. im going to take his word at this stage + i dont want to touch it.

2.i've removed the thermostat now and i'm goign to check the water is flowing.the heater in the car is getting warm, so that might be a sign the coolant is circulation..go more testing to do.

3.all hoses are fine. double double checked it.heater core seems to be fine.no leaking inside the car.

4.reading off the receipt:head was swirl,strip and report.degreased,cut seat reface valve,head surfaced (min), cleaned and assembled. this was done 3000kms ago by a reputable shop.

5.got another toyota 82degree thermostat.didnt fix it.

6.going to check.

7. grabbed a thermosensor and temp switch from pinch a part.

8.fans spinning fine,and in right direction. put a new relay in too.

Timing is at about 15-16degrees at idle going by the hand controller.

I tried to spin the waterpump by putting my fingers through the thermostat housing. wouldnt budge. so i'm guessing the shaft isnt stripped. (timing belt still on)

[Aust162]

BrianRA23 - going to pull the radiator of again and get it checked by a shop. fans are good. and the thermostat is out atm. i have the bypass hose clamped shut, so that the water doesnt keep circulating the motor and not the radiator.

Kingmick - will check the hoses for temp and pressure.

Thanks alot for your time guys. will let you know the lastest

[Aust162]

I've run the car without a thermostat and it ran fine, never went over 94d. i replaced the thermofan sensor on the thermostat housing at the same time. The thermofan's turning on properly now. (i have a feeling this was the original problem)

I went and spoke to the workshop that did the tuning on my wolf. we were under the impression that the thermofan's were controlled by the plug and play wolf3d, but there not. i will eventually hook it up that way.

So the plan is to refit the new toyota thermostat i brought and see how it runs. I'm hoping it was just the sensor and a slightly faulty thermostat all along.

[Robbos_Toyotas]

I've run the car without a thermostat and it ran fine, never went over 94d. i replaced the thermofan sensor on the thermostat housing at the same time. The thermofan's turning on properly now. (i have a feeling this was the original problem)

I went and spoke to the workshop that did the tuning on my wolf. we were under the impression that the thermofan's were controlled by the plug and play wolf3d, but there not. i will eventually hook it up that way.

So the plan is to refit the new toyota thermostat i brought and see how it runs. I'm hoping it was just the sensor and a slightly faulty thermostat all along.

It shouldnt get up to 94" celsisus!!!

[3sgte]

3SGTE (from Canada)

Are you saying a hot thermostat will prevent flow through the bypass system, by some technique other than having an easier route through the radiator?

Not what I meant to suggest.




When the thermostat is hot, and it opens, the disc I circled on the rear of the thermostat moves back and blocks off the hole in the housing (also circled)

Thermostat shown isn't for a 3SGTE, so don't worry if it looks different.

[Aust162]

yep,thats simular to my thermostat(s). are they called a 'two stage" or something along those lines?

I just noticed another thread popped up about cooling issues on a 7m. funny that.has almost the same symptoms too!

[3sgte]

yep,thats simular to my thermostat(s). are they called a 'two stage" or something along those lines?

I searched for a picture, and wound up also finding a good explanation of a two-stage thermostat, along with the "why".
Go here:
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat
(sorry for the tangent)

[tooch]

Finally got my car back last night! I noticed though on the way home, the engine temp rose to about 95-96 deg and I dont think the thermofans came on, so I need to check the sensors and shit. I did notice though that the heater wasn't warm at all, the pipes going to it didnt seem hot either, any clues?

[BrianRA23]

Aust162 - did you get you overheating problem sorted? Updates??

tooch - what was telling you the engine temp was 95-96 degC (ie are you sure the engine is getting hot) and can you confirm this with another test?

Is the radiator getting hot, because if it is not then the thermofan should not be expected to come on?

[tooch]

Aust162 - did you get you overheating problem sorted? Updates??

tooch - what was telling you the engine temp was 95-96 degC (ie are you sure the engine is getting hot) and can you confirm this with another test?

Is the radiator getting hot, because if it is not then the thermofan should not be expected to come on?

That reading came from the Wolf3d handset, the stock temperature guage sat on its normal halfway level though. The radiator was hot, both upper and lower hoses. Unless it's possible that the wolf's temperature reading is incorrect? I have to check again today, still don't understand why the heater wasn't hot tho

[-==L=a=N=c=E==-]

That reading came from the Wolf3d handset, the stock temperature guage sat on its normal halfway level though. The radiator was hot, both upper and lower hoses. Unless it's possible that the wolf's temperature reading is incorrect? I have to check again today, still don't understand why the heater wasn't hot tho

you bring up an interesting point there.

most aftermarket ecu's have calibration data for any sensors it uses in the system. It could be possible the calibration is wrong.