UPDATE: HELP! diagnosing overheating problem!!

[stackz]

got it fixed this afternoon. just had to backfill the system through the upper radiator hose so the head was filled above the level of the waterpump. cooling just fine now.


a female friend of mine has a 1994 4cyl camry that is overheating. At first glance I immediately noticed the radiator was cracked along the plastic top portion and leaking so we replaced the radiator with a new unit.

filled it back up and the car was still overheating and I noticed with the cap off that the water in the radiator really wasnt flowing so I swapped the thermostat for a new one.

STILL overheating, then I noticed the fans weren't kicking on and that there still wasnt flow in the radiator...grabbed the lower radiator line...bone cold, as well as the entire radiator (while the car was overheating ) This tells me that the radiator switch isn't to blame...cant turn on if it cant heat up since it's located at the bottom of the radiator....

The top hose and very top of the radiator was hot though. I pulled the thermostat housing back off and felt inside at the water pump but I feel the blades on it so it doesnt seem like its the water pump.

I checked the thermostat housing and both the radiator hoses and they arent blocked and the new radiator obviously isn't blocked.

I have no clue???

Is this a bubble-less cooling system??

why am I not getting any flow??

The temp gauge is located in that little outlet on the side of the head (for the upper radiator hose) and it gets hot and registers the engine heat on the gauge so I'm assuming that little pipe isn't blocked??

what the hell is going on here??


OH! and I dont think it's a head gasket or cracked head as I checked all of the plugs and they are all the same and have white residue on them which basically tells me they've been in there a bit too long but not wet/clean from coolant burning...

[fe519]

maybe its the switch that turns on the fan. My friend had a integra and has the same problem. Its a sensor that turns the fans on when its hot enough. Also, might want to see if she got a blown head gasket.

[karugs]

No flow? How is the water pump?

[5Sfte]

Could be the pump or you might have an airlock in the system.

[stackz]

I was thinking the pump as well, even went and bought another one to put on.

I ended up taking the thermostat housing off and you can see/feel the pump inside there. All the blades are intact and when the motor is spun over you can visibly see it pumping so I actually think it's ok.

how can I check for an airlock?? I was thinking this may be one of those cooling systems that you cant have bubbles in but I dont see a bleed site hole and my mitchell on demand software doesnt talk about any special bleeding requirements??

I'm at a loss right about now.

maybe its the switch that turns on the fan.

"read", the radiator isnt getting hot enough due to lack of flow through it to even heat up the fan switch.

[chronoti]

i normaly beed the air out by running the engine with the cap off and filling it with water when ever the air gets out, there could be blockage in the engine it self ...... so you can try blasting the engine with water from top to bottom

[stackz]

yeah, I think I'm going to back fill the engine through the upper radiator hose tonight. I noticed that the connector to the cylinder head where the sensors are located was bone dry when I opened it up.

either there's way too much air in the engine itself for that little water pump to push (so that it basically is just cavitating) or there's a blockage in the cylinder head somewhere.

I tried to do that with the air bubbles and the filling of the radiator with the cap off but the water literally didn't move. Hell, it was still clear sitting in the radiator as the car overheated which is a clear indication that it was NOT moving and thus not mixing with the antifreeze that was still in the engine.

[chronoti]

if you think the block is cloged home improvement stores sells this thing that expands to build up pressure to flush pipes out. it's used for uncloging pipes with a hose .... i think it like $7 or so and could help you clear out the engine if it is cloged

[stackz]

what is it?? foam?? liquid?? easy to flush out?? I dont want to create more problems than I already have

[S92GT]

you have been focusing on the top of the car, could the bottom hose have a problem?

not sure if that could be it, but nobody's mentioned it yet, so I figured I'd throw it out there

[chronoti]

it like a rubber boot thing that screws on the the garden hose and dosent let the water flush back out and pushes out what ever might be blocking the flow ...

[stackz]

ahhh ok.


as for the lower hose. yesterday afternoon...in the rain...I pulled the lower hose back off as well as the upper hose and both are clean on the inside.

I also pulled off the thermostat housing and it's clean on the inside as well.

the thing that got me, was that after pulling off the upper hose I noticed that the part it attaches to, (the pipe with the sensors that then attaches to the head), was bone dry...and it shouldn't have been like that considering antifreeze doesnt dry up that quickly without open air access.

I'm starting to think maybe something is lodged or sludged up or that I just have WAY too much air in the system to move it around.

I'm gonna try my back fill idea first and then I'll give that flush idea a whirl. hell, I may even light some insense and chant a bit.

[karugs]

Originally Posted by stackz

ahhh ok.


hell, I may even light some insense and chant a bit.

The flush should be enough

[stackz]

didn't need a flush, I just had to back fill it so there was water "above" the waterpump heh.


its cooling just fine now, thanks for the help guys!

oh and if anyone knows about the cv joints on these cars see reply to this thread for me:

http://www.toyotanation.com/forum/t67943.html

[5Sfte]

Ahh, the dreaded airlock. I recommend always backfilling the system and letting the air bleed out by running the car with the cap open until all air drains. Glad to see that it was an easy fix.