Overheating Problem

Trust|Nobody

Trust|Nobody

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Hello

I took my car for a service yesterday (Toyota Corolla 1.3l, 2001 model).
They replaced the coolant amongst other things.

Now I have a new problem, the car overheats at standstill (temperature gauge goes into the red region), although it cools down when driving.

The radiator is filled with coolant, so the problem is not the coolant level.

Why is the car overheating at standstill?
 
Last edited:
Trust|Nobody said:
Hello

I took my car for a service yesterday (Toyota Corolla 1.3l, 2001 model).
They replaced the coolant amongst other things.

Now I have a new problem, the car overheats at standstill (temperature gauge goes into the red region), although it cools down when driving.

The radiator is filled with coolant, so the problem is not the coolant level.

Why is the car overheating at standstill?
Click to expand...

Sounds like you may have air inside the coolant loop. Usually the thermostat has a bleed hole to mitigate this, but some stubborn ones can sometimes get stuck on the engine side and cause steam pockets when it gets hot. The coolant pump can also not circulate steam as well as it can a liquid, so it ends up overheating as the pump can't get the heat away from the engine quick enough.

Take it back to the shop and have them look at it before it causes damage!
 
PhireSide said:
Sounds like you may have air inside the coolant loop. Usually the thermostat has a bleed hole to mitigate this, but some stubborn ones can sometimes get stuck on the engine side and cause steam pockets when it gets hot. The coolant pump can also not circulate steam as well as it can a liquid, so it ends up overheating as the pump can't get the heat away from the engine quick enough.

Take it back to the shop and have them look at it before it causes damage!
Click to expand...

How is the air creating a problem?
 
Trust|Nobody said:
How is the air creating a problem?
Click to expand...

Air is a poor conductor of heat, coolant (with the correct % of antifreeze) is much better and can wick away the heat much more efficiently than air ever could.
 
Before the service the speedometer wasn't working correctly - it would erratically jump to different speeds. So I asked them to check the cable. They replaced the cable during the service. Turns out the cable is not the fault but the problem may actually be inside the speedometer itself.

The mechanic says that when removing the speedometer the temperature gauge calibration went off, and that this is the problem. That he just needs to recalibrate the gauge. Is what he saying correct?

The fan is actually working btw.
 
Trust|Nobody said:
The mechanic says that when removing the speedometer the temperature gauge calibration went off, and that this is the problem. That he just needs to recalibrate the gauge. Is what he saying correct?.
Click to expand...

That doesn't really sound right to me. A car engine in good working condition shouldn't have wild temperature swings when going from on the move to a standstill. Your thermostat, radiator fan and radiator pressure cap should keep it in the optimum range which is between 87 and 105*C.
 
PhireSide said:
That doesn't really sound right to me. A car engine in good working condition shouldn't have wild temperature swings when going from on the move to a standstill. Your thermostat, radiator fan and radiator pressure cap should keep it in the optimum range which is between 87 and 105*C.
Click to expand...

I took the car to him quickly.
He says the engine is not overheating and that the gauge is not showing the correct temperature.

He does seem confident about what he's saying. I'll most likely have to wait till next weekend to have him look at it because I need to get to work during the week.

It seems this always happens to me.
 
On the radiator there is a pipe on the top and one at the bottom, if the top one is blistering hot and the bottom one is cool then the thermostat is damaged.
 
The engine seems to cool when driving, because the high air flow is cooling the radiator.
When I come to a standstill it starts to overheat, obviously because the air flow is insufficient to cool the radiator.

So I guess the coolant is flowing correctly through the radiator and there are no pump issues. Would a broken thermostat prevent flow through a radiator?
 
Trust|Nobody said:
The engine seems to cool when driving, because the high air flow is cooling the radiator.
When I come to a standstill it starts to overheat, obviously because the air flow is insufficient to cool the radiator.

So I guess the coolant is flowing correctly through the radiator and there are no pump issues. Would a broken thermostat prevent flow through a radiator?
Click to expand...

Which makes the story about an uncalibrated gauge even more suspect. It's not like the gauge is digital or something, I am not sure but if it the normal gauge it will just resets to zero when unplugged, it is in a way self calibrating. Where is the gauge pointing in the morning when the car is started from cold, unless if it is stuck somewhere in the middle?
 
thechamp said:
Which makes the story about an uncalibrated gauge even more suspect. It's not like the gauge is digital or something, I am not sure but if it the normal gauge it will just resets to zero when unplugged, it is in a way self calibrating. Where is the gauge pointing in the morning when the car is started from cold, unless if it is stuck somewhere in the middle?
Click to expand...

I don't think there's anything wrong with the gauge.
The mechanic doesn't know what he's doing.

I think it's either the fan or there's too much antifreeze in the coolant.
 
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