[ee.engineer]

On what became my last drive of 2013, my exige's temperature reading seemed really off. It was about 20 degrees outside, and it constantly kept rising to about 240F (or 232, don't quite remember now). The reading starts flashing, the radiator fan turns on, and the temp won't go down. I checked the engine bay, and there was no smoke, no smell, nothing to indicate the car was overheating. I verified the temperature with my OBDII reader to make sure that it wasn't a guage cluster problem. I also checked my coolant reservoir and it seemed alright. That was the last time i turned the car on.

Anybody know what might be causing this? a bad thermostat? I'm going to look in on it later to see exactly what temp it maxed out at, or if it magically fixed itself .

Thanks

 

[holmz]

The sender unit or wiring determines the electrical aspect of it.
So either it was an electrical issue or it was real.
The OBD uses the sam sensor so the same numbers will be there.

One of the hardest things to teach pilot is to trust their gauges.
This could be the same issue.

 

[<@¿@>]

If a connector is bad (high resistance), would that give you the false high reading. That is, the higher the resistance of the sensor, the higher the temp reading... Just a thought...

 

[holmz]

Which means probably get a new sender unit...

Take the sender out of the car.
Get a new sender from the Toyota shop.
Boil a kettle of water.
Make a cup of tea.
Drop the two senders into the water, bring to a boil.
Locate the volt Ohm Meter.
Measure the resistance of the new and old senders.
Get a bowl of ice.
Drop the senders into it.
measure the resistance of each.
Post the hot and cold values back here.
Even if you only do it with the old sender, someone will advise if the values are correct or not.

 

[ee.engineer]

Thanks for the response.
Does this mean i have the take the right rear wheel off, alternator etc to get to the sender unit?

 

[holmz]

dunno on a toyota...
I would probably start by seeing what the temp says with the engine cold.
if it is fine (<80C or what ever it says in F) then you could assume that the sender is good.

So you either test the sender, or figure out if it is making sense or not (on the cold end of the scale).
Running the engine until the gasket fails, the head gets cooked, and the water blows out is sub-optimal.
If it makes sense on the cold side, then it is probably your thermostat or the water pump is spinning on the shaft... Something is limiting water flow(, or air flow).

 

[Ked67madison]

The easy way would go to harbor freight. Buy a 8.00 lazer temp reader. Point the lazer to the block, read the temp. Then point the lazer to the head. If both are the same don't mess with the temp sender. Buy an aftermarket thermostat and gasket. Toyota thermostats are known to go bad.. Easy easy easy

 

[ee.engineer]

The easy way would go to harbor freight. Buy a 8.00 lazer temp reader. Point the lazer to the block, read the temp. Then point the lazer to the head. If both are the same don't mess with the temp sender. Buy an aftermarket thermostat and gasket. Toyota thermostats are known to go bad.. Easy easy easy

I like that idea, i already have a laser temp reader (for food). I might give that a try once i get a chance to go out.
If i do have to take the sender out and test it, we are talking about the thermostat, right?

 

[holmz]

I like that idea, i already have a laser temp reader (for food). I might give that a try once i get a chance to go out.
If i do have to take the sender out and test it, we are talking about the thermostat, right?

Chricky... I thought you were a EE?

The sender is the dimmer switch or rheostat in EE talk, which has a wire or two hooked up to it.

The thermostat is the "water valve" for a hydraulic engineer or plumber, and sits inside a housing (usually with a hose going into/from it)... And there are no wires.

If the IR sensor says that the head and the block say 240, and the instrument cluster says 240... Then your problem is not electrical.

 

[ee.engineer]

Chricky... I thought you were a EE?

The sender is the dimmer switch or rheostat in EE talk, which has a wire or two hooked up to it.

The thermostat is the "water valve" for a hydraulic engineer or plumber, and sits inside a housing (usually with a hose going into/from it)... And there are no wires.

If the IR sensor says that the head and the block say 240, and the instrument cluster says 240... Then your problem is not electrical.

, i'm the type that does math and programming :thwack:. I'll give that a try though and see what i uncover. thanks

 

[ee.engineer]

:facepalm:facepalm:wallbang::wallbang::wallbang:
Started it up let it sit, watched for about an hour, it got to 194 max, and stayed there

 

[Gunpilot]

I'm thinking Thermostat.......But I have no experience in this.

There is a guy on here that can help you out with hair loss, Smart cars and weddings though!

 

[ee.engineer]

How is it possible that it had a problem in Dec. and nothing now?