temp gauge rising and falling frequently.

[98mitsubishigst]

So i was driving back up to my college, its 50 miles total at about 40 miles i turned my heat off because i had it on whole way and it was hot as shit, and i noticed my temp gauge go up a little over middle, not 3/4 of way but close, then it went back down.. not sure if it went back down because i turned heat back on or not.

I then parked the car after the 50 mile trip, and i sat in driveway for 10 minutes in park on idle and it never rose back up..

I ended up going back outside and taking the rad cap off for a few minutes and let any bubbles come up, the coolant levels are topped off, i don't smell any coolant so i don't think I'm leaking any.. and the fan is working.. i then took it for test drive for 6 miles and it would do the same thing, it would creep up a little over halfway and fall very frequently..

Then i tried sitting at a stop sign, i put it in drive, and i would hold the brake pedal down while pushing the gas to ilke 2000 rpms and it would do this…

Wtf - YouTube


I also noticed when I'm cruising going down a hill and i let off the gas, sometimes my temp gauge would go up slowly then fall back.. also when i put the heat on it seems to help lower the temps.

What could it be?

 

[Breezio69]

I'd just drive it around and see what happens with it. If it continues then next thing I would check is the sensor itself.

 

[Derk_272]

I'd just drive it around and see what happens with it. If it continues then next thing I would check is the sensor itself.

I think your good to go to. Just drive it as normal and see if your all fixed.

 

[Whophlungpoo]

Hmmm - YouTube

^^ Video

Replaced the thermostat, and the rad cap.. i replaced the thermostat with a 170 degree one as well.. what do you all think? it has a little stream moving along at idle so I'm assuming that means the pump is pushing coolant through.. Also you can see me rev it up it'll bubble up and out! so its definatelly pushing..

No bubbles, i let the car idle and sit while i put more coolant in to burp the system, isn't leaking anything, and still has full coolant.

What do you all think?

It might be the toaster that you used to film that video with but that coolant doesn't look too fresh. haha

Flush that system. Get a multimeter or cheap infrared temp reader and verify actual coolant temps.