car overheats

[john]

The car has a new waterpump already installed about 30 miles ago, has plenty of coolant, a new thermostat as of yesterday and a slimline fan that is working. The car drives perfectly fine, but sometimes the temp guage randomly goes higher. It can be right in the middle, jump up to the higher mark on the guage and out of nowhere just fall back to normal. It doesn't get to the red on the guage, but it is close to it. The idiot lights turn on (battery, coolant) as it is hotter. I don't think another fan would really help as it was driven at 9:30 last night and it wasn't too hot. Coolant isn't leaking either and is full. Any ideas?

[blageo23]

Im not the smartest guy but maybe the sensor is messed up. Have you checked the connection maybe its wack. Like I said I dont know much but maybe this will put a thought in a some who know exactly what they are talking abouts head.
Mike

[john]

It is connected right. I wouldn't even know how to check if the sensor is messed up though.

[TheBlizzard]

Check your belt tension to make sure that its not slipping. Does the car have a front mount of anything obstructing the flow of air to the intercooler. And I know you said the fan is working but how do you have it wired in? Is it hard wired with a toggle switch or into your existing wiring?

[Shane@DBPerformance]

Could be a large air bubble trapped in the system.

[Enes]

i was always currious how would you go about removing large air bubles out of the cooling systems?

[TheBlizzard]

Burp it.

[john]

buuuuuuuurrrrrppppp. The bubbles are out now. Does letting it run with the thermostat housing cap off get bubbles out? The car has a big greddy FMIC and the fan is wired to the original harness. The high and low were both wired into it. What belt tension should be checked? I know when I start driving it, one of the belts squeels a little when I shift into gear. Do you think the belt might be slipping slowing the waterpump down?
thanks

[Matt D.]

Use a logger of some sort and monitor the temp. If it's erratic that would mean the sensor is bad.

Check the tension of the only belt that's on the water pump pulley...

[TheBlizzard]

Yeah thats the belt I was talking about, who knows maybe when a load is put on your alternator it will slip causing the water pump not to function properly? Erratic temps does not always mean its a sensor. I had pretty erratic temperatures in my 2G after I put my Apexi Skyline FMIC in it. The temp would jump up past half and then cool down on its own. I just figured it was because of limited airflow that the radiator was seeing because of it. Then when the fan would kick on then it would go back down to normal.