Overheating 3VZ-FE...or is it?

[GRANDE,GRANDE!!]

ive heard about diffferent types of overheating cars... most common types are 1 - driving at low speeds seems to overheat but pushing the car higher speeds seems to lower the heat and return to normal? and no 2 - driving at lower speeds wont over heat but higher speeds it does.

My friends i seem to have the second issue... but with a twist...

i know with my V6, if the engine is getting hotter then normal, the hydraulic fans kick in heavy and the car fan begins to sound like jet or something - very very loud fan.

Whats happening with mine is, on cold days (22 degrees celcius or under) my fans wont kick in no matter what i do, they dont need to - runs like a beauty! but anything over that and especially weather in the 30's.. and my fans begin to start blowing like mad.

Now the fans kick in, but the temp guage wont move. Stays where it should be but i know from experience, that when my fans get to this level in mild weather.. a problem is arising...

What could be wrong? My radiator is def not blocked, as its only 2 years old and i change coolant regularly.. even stuck a garden hose in ther to see if the water was flowing properly and it was. No coolant leak either .. why is it doing this?

[hill8570]

For the lurking USA audience, 22 C = 72 F; 30 C = 86 F .

How clean are the radiator fins? Assuming you've got A/C, the A/C condenser is in front of the radiator proper -- if airflow through either the condenser or the radiator are blocked with "stuff", you can run into overheating at high heat loads. You can always backflush the fins (from the engine side with a hose to clean out the fins.

If you've got crappy or old hoses, you can run into problems with the hoses actually collapsing when the water pump is going full blast -- hot temperatures make this more likely, since the hoses will be softer.

[buci]

Originally Posted by GRANDE,GRANDE!!

ive heard about diffferent types of overheating cars... most common types are 1 - driving at low speeds seems to overheat but pushing the car higher speeds seems to lower the heat and return to normal? and no 2 - driving at lower speeds wont over heat but higher speeds it does.

My friends i seem to have the second issue... but with a twist...

i know with my V6, if the engine is getting hotter then normal, the hydraulic fans kick in heavy and the car fan begins to sound like jet or something - very very loud fan.

Whats happening with mine is, on cold days (22 degrees celcius or under) my fans wont kick in no matter what i do, they dont need to - runs like a beauty! but anything over that and especially weather in the 30's.. and my fans begin to start blowing like mad.

Now the fans kick in, but the temp guage wont move. Stays where it should be but i know from experience, that when my fans get to this level in mild weather.. a problem is arising...

What could be wrong? My radiator is def not blocked, as its only 2 years old and i change coolant regularly.. even stuck a garden hose in ther to see if the water was flowing properly and it was. No coolant leak either .. why is it doing this?

So...22 celsius is considered a cold day? Down under? Down up in Toronto right now is a beatifull -12 outside, we are going to see +22degrees in July...hopefully, right now we are just dealing with the snow and the salt. Jokes aside, if the gauge shows that it's overheating you have a problem, asuming the gauge and the sensor works. If the gauge shows normal temp then you'r ok.Did you ever see your car overheat? If the gauge shows normal then temperature is normal. Maybe you only have a problem with the fan making the noise.
Ps: 22 degrees is a cold day he says.

[GRANDE,GRANDE!!]

Oh i see but theres one thing i forgot to mention. My head gasket had a tiny crack in it and was leaking a small amount in my cylinder and i poured some head gasket sealant into it and it stopped the leak, but now the fans come on?

[hill8570]

Originally Posted by GRANDE,GRANDE!!

Oh i see but theres one thing i forgot to mention. My head gasket had a tiny crack in it and was leaking a small amount in my cylinder and i poured some head gasket sealant into it and it stopped the leak, but now the fans come on?

Probably should have your cooling system checked for flow. Head gasket sealant is fairly non-discriminatory about what it seals. Guess you could check the temp sensor for the fans before that, but I can't imagine that getting messed up by a sealant.

Did you have the thermostat out when you did the sealing? Most sealants I'm familiar with have instructions of something like (1) Remove thermostat (2) Completely flush system of coolant so there's nothing but water (3) Add sealant (4) Run for a day or so (5) Drain and flush system (6) Refill system with antifreeze mix and replace thermostat. If you kept the thermostat in place while you were sealing, and the t-stat hasn't been replaced since then, it might be worth changing it out with a new OEM thermostat & gasket -- if your thermostat isn't opening fully, it could be restricting your coolant flow.