Why does the temp gauge... [Archive] - GrandAmGT.com Forum

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jeffescortlx
07-15-2004, 01:20 PM
On the 95 GA-GT 3100 after it's warmed up and been running for a while the temp will sit in the middle like normal and be fine as long as I'm moving. When I sit in traffic the engine temp goes way down, all the way cold. WTF? I have never heard of a car to go cold sitting in traffic, 100 out side with the A/C on.

It worry's me, it's been doing this for a couple of month's now. The coolent is fresh and full, the termostat is only about 6 months old, and the fan relay is now wired to be on when the car is on. (Fan stopped comming on with A/C).
The LIM gaskets are about 6 month's old also.

The gauge will usally wiggle and twitch as it goes colder. But when I'm driving at highways speed's it a steady as a rock, just under the middle mark.

HotLikeFire
07-15-2004, 01:23 PM
I don't know but I wish mine did that! My biggest fear is to be sitting on 169 and over heating during rush hour.

Panacea
07-15-2004, 01:29 PM
Maybe you have a bad temp. sensor?

Dr_Kyle
07-15-2004, 01:37 PM
the fan relay is now wired to be on when the car is on. (Fan stopped comming on with A/C).

So the fans are always on? Don't you think that would cause it to be a little cool? Like I dunno, say 100 or so? :)

The fan's being on will only affect the car when sitting still, otherwise the air will be forced through/over the radiator because you're driving.

The fans being constantly on is my guess.

jeffescortlx
07-15-2004, 02:36 PM
So the fans are always on? Don't you think that would cause it to be a little cool? Like I dunno, say 100 or so? :)

The fan's being on will only affect the car when sitting still, otherwise the air will be forced through/over the radiator because you're driving.

The fans being constantly on is my guess.
I really dont think it's the fan, than why is it when I'm cruzing down the freeway at 70mph (fan is still on) it stay's normal temp, but when there's just the fan pushing air at probly no more than 10-15mph it get's cold. Would'nt you think that 70mph air would make it run cooler than 10-15mph air?

When sitting in traffic it will dive alll the way cold, as if you just started your car after sitting over night..that cold.
It'a all back-asswards.

I'm afraid that it's not really cold when it say's it's cold, but at the same time I dont want to start to replace random parts untill the problem goes away.

No body else has had this problem?

jeffescortlx
07-15-2004, 02:39 PM
I don't know but I wish mine did that! My biggest fear is to be sitting on 169 and over heating during rush hour.
Hey, dont worry, my car will be right along side of 169 in ruch hour broken down with your's.
You must of noticed I'm from MN to.

2002AmSE
07-15-2004, 04:21 PM
Sounds like when the engine gets hot past a certain temperature and your thermostat opens and gets stuck open so it gets cold. Even if the radiator has cold fluid in it the engine won't get any colder because the thermostat stops/slows the flow unless its at normal operating temperature. ...unless the temp sensor is indeed bad, but it sounds like a stuck thermostat

2002AmSE
07-15-2004, 04:23 PM
Hey, I'm from MN too, yeah temp gauge = way up on 169, but its fine and it will go back down if you turn the air conditioning on for a minute or two or get moving in traffic. Lol, my closest to running out of gas was on 169.

HotLikeFire
07-15-2004, 04:33 PM
Finally.... some Minnesotans. Yea.. I noticed so I knew you'd understand the 1-6-9 rush hour..which has its moments.

2002AmSE
07-15-2004, 04:55 PM
It's not just the 169 rush hour, but that highway is the Cop Joy Speedtrap of the area, especially north of fleet farm and including night time. I have 6 friends who have gotten tickets on 169.

jeffescortlx
07-22-2004, 12:00 PM
UPDATE

I hooked up a temp-probe/multimeter directly to the front head. The temp would climb like normal to 218 and sit there steady as a rock while moving or sitting in traffic with the A/C cranked on a hot day. While the temp gauge in the dash would jump from all the way cold to 220. So it seem's the cooling system is fine, so that would leave only the temp sender, guage and wiring. I have a feeling it's the sensor since it seem's fine cold but act's up as the engine heats up.

95-GT
07-22-2004, 12:03 PM
Not sure if you know, but the 95 3100 has 2 temp sending units. 1 for the dash thats on the rear head, with a single green wire, and the other for the ECM/PCM on the lower intake near the t-stat.

jeffescortlx
07-22-2004, 02:23 PM
Not sure if you know, but the 95 3100 has 2 temp sending units. 1 for the dash thats on the rear head, with a single green wire, and the other for the ECM/PCM on the lower intake near the t-stat.

I did'nt even notice that the temp gauge was on the back head, I assumed just the one on the T-stat housing did it for both the gauge and the ECM. Good thing it's seperate, other wise the ECM would be going nut's.
I found the single green wire, and I think it's safe to say that was the problem. I gave it a slight tug, I mean a slight tug and it poped off. The only thing holding the wire to the sensor was the rubber boot. The wire had broken off at the crimp, probly got pulled on too much when I did the LIM.

Thanks for the tip :boogie: