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.

[CDeutsch]

Are you running the AC? That will also cause the temp to rise.

[john]

The ac was removed and the car keeps heated when the fan is going. I let it sit a few minutes to see if it would get to the red, but it just stays at the high mark. I will try to see if I can find the pocketlogger when I get home from work tonight. I cant use mt dsmlink right now.
Thanks

[sleepydsm]

I'm having the same issue. I hope more peaple chime in about your issue so I can fix my car too! (Not trying to steal thread haha, I'm just along for the ride)

[john]

I guess James posted all of this under my name... I tried letting air bubbles out by running the car with the cap off for 1-2 mins when the gauge would fly. The fan is working (on) when the car is getting hot. FYI, there are two belts that run off the water pump. One that runs to PS and another that runs the alternator and crank. I will check the tension for him.

[Shane@DBPerformance]

We bleed the system by letting the car for a while with a big funnel thing full of coolant mix attached to where the radiator cap goes. What is your coolant mixture like? You should be 70% water/30% coolant at the min with this weather. You could go even more with the water percent. Don't run pure water though on a street car, it can ruin the water pump due to a lack of lubrication. Your radiator could be bad too, make sure there aren't any cooler spots on it.

[unreal808]

I have a special funnel that I use to get the air out.
Is it a NAPA water pump?
How is your coolant cap, It could be leaking into the overfill the system and not holding presser.
Is your timing correct?
Try switching the cooling fan relay with a different one.
Try a different thermostat.

[john]

The fan works. It is a napa pump I believe. Timing is set fine. It is a new thermostat. Radiator cap holds pressure. I would guess his mix is close to 50/50, not sure though. He put it in but it was fine... How long to bleed the system??? I do not want the car to overheat while trying.

[unreal808]

New does not mean good. New stuff goes to shit all the time. Especially NAPA stuff in my experience.

[unreal808]

How do you know the cap is holding pressure? do you have the overfill hose off?
What happened that started the car overheating in other words, what did you do to the car last before it started to over heat off and on. Was the car overheating before the new stuff?

[john]

I assume it is holding pressure because it isn't losing any coolant what so ever. The overflow hose is connected. The waterpump is a rebuilt stock one from bumper to bumper, not one of the really generic ones. The thermostat we got yesterday is from there also. The other one I pulled out looked different. It had the cylinder thing going down with a spring on it. The new one had the same top part but it also had a bottom part that looked the same as the top that was a little thinner. It was a lot longer than the one that was in there and thepart that sitcks out farther can be pushed in and out. The first one was solid. I was thinking it might have came off the first one, but it looked like it didn't have it. The car didn't overheat until I did the 6 bolt swap. I assume timing it good because Mike did it and base timing was set correctly. I will try another relay.
Thanks for all the help so far.
This is James again under Carlos's name.