engine temp sensor/gauge

[eclipsegst8406]

My engine temp. gauge in the dash is always reading just at the boat looking thing or about 3/4ths of the way up. I got my coolant flushed and all of the hoses checked and it all checks out but it still wants to go up to just before 3/4ths of the way up but when i turn my car off and let it cool down through the turbo timer it will immediately go right to the mid of the gauge(its weird). I also had the actual engine temp. through a diagnostics and it checked out at normal. I dont know if its just a bad fuse or something else. does anybody have any suggestions on where to look next?

[spinz4]

Are you saying that it rises when you turn the car off and it is still running with the turbo timer? If so its because your cooling fan wont turn on when the turbo timer is operating your car. Causing the temps to rise. Thats why I dont run one anymore.

[eclipsegst8406]

when i turn my car on it warms up to the boat looking thing on the gauge and then when I'm driving it will fluctuate from staying in the middle of the gauge to 2/3rds of the way up. When i have my turbo timer on, I turn the ignition off but the car still runs for the set amount of time i programed into it to let the turbo cool. The needle always drops to the middle of the gauge saying it is running at normal temp(when the car is in the turbo timer mode).

I have a manual switch that turns on one of the fans that was installed a while ago to try to help solve this overheating(but im thinking now its not a heating problem) but the problem is till occurring.

When Im driving, I almost always have that one fan on and when i let the car cool down in the timer mode i also have it on. (the fan i have hooked up to the switch isnt hooked up to the sensor but the other one is)

[yokotabrat]

Best way would be to log the coolant temperature with a datalogger while the instrument cluster gauge is fluctuating. There are two coolant temp sensors, one for the gauge and one for the ecu. If the ecu temp sensor isn't picking up the fluctuation then there's something wrong with the gauge temp sensor, provided the cooling system is filled completely.

[Dane Becher]

You said the temp checked out OK with a logger? If so I'd replace the sensor that controls the gauge (one of the sensors on the thermostat housing, I forget which one).

Have you replaced your radiator cap lately?

[Kibo]

provided the cooling system is filled completely.
This can be key as well. Localized steam pockets can do some weird things with your temp gauge if your cooling system isn't purged of air. When I had a small leak in my cooling system, I found that the temp gauge's value was directly related to how much throttle I applied when accelerating...the air bubble was covering/uncovering the temp sensor varying amounts depending on how hard I accelerated. :D

[eclipsegst8406]

I havnt replaced the cap lately. Do you think it would help.

The coolant system was flushed and pressure tested for air pockets about a month and a half ago. Im thinking of replacing the coolant sensor and getting the actual gauge fixed or replaced to see if thats the actual problem befor i start spending alot of cash hunting the problem down.

It seems when I push more boost and step on it the gauge reads cooler but when im in a higher gear at low rpms the gauge reads hotter.

[Dane Becher]

I havnt replaced the cap lately. Do you think it would help.

I'm not sure. If it's old and isn't holding enough pressure, yes. You'd probably notice coolant getting pushed out into the overflow. But it's got to be the easiest thing on these cars to replace and they are cheap.

But I also agree with Erik that it could be an air bubble. I know there is a method to 'burp' the system but I don't exactly recall how:confused: . I repeatedly squeeze the upper rad hose as I'm filing and it approaches full. I'm not sure if this helps but I do notice the water level goes down/air comes out.

[eclipsegst8406]

alright thanks ill see about getting my coolant pressure tested again and see about getting a new cap.