tempature guage ?????

[jhiggins]

I have a 1988 yj with the 258 in it and when I am going down the highway the tempature will read one mark over the 210 wich this is the way it has always been. But when I shift from forth to fifth it starts rising pushing almost to the read line but if I leave it in forth it stays on that mark above 210. My question is, is it the water pump, thermostat, or the temature guage. Or is it all three?? Has anyone had this problem before ??? Any sugestions before I start tearing her apart???? :-? :-? :-? [addsig]

[bluebelle]

jh,

Are there any other circumstances where your temp climbs like that?

It almost sounds like you have an electrical short somewhere in the sending wiring that would be affected by the position of the shifter.

You're dropping rpm's from fourth to fifth, so what would reasonable result in less heat - not more.

Your thermo shouldn't have anything to do with what you've described.

Your water pump shouldn't either.

If you have the factory manual, do the instrument diagnosis check.

Let me know what you find.

blue
[addsig]

[jhiggins]

It drops RPM's from 4th to 5th but the tempature goes up...But I can't drive in 5th it doesn't carry enough speed..... :-( :-? :-( [addsig]

[bluebelle]

So, when you're in fifth, your engine can't generate enough power to drive?[addsig]

[jhiggins]

not enough to keep it moving fast enough to do the speed limit... :-? [addsig]

[jhiggins]

hmmmmmmmmmmmmmm :-? :-? :-? [addsig]

[MudderChuck]

Just thinking out loud, could be low RPM´s, low flow, through the radiator, for various reasons. Before I tear anything apaprt, I take a small MAG light and hold it behind the radiator and look through the front. You´d be surprised how much dust and stuff is stuck between the layers (low air flow).
Carburator, transistions from one system (idle) to another (high speed) between 1000-2000 RPM´s. If the low speed (idle jets) are a little to lean, messes with the transisiton, usually resulting in a stumble in the motor during transisition. Wide open throttle, introduces a lot of air and the air velocity through the carb is relatively slow. Could result in a lean condiditon. Slightly plugged high speed jets, can also cause a lean burn, especially during wide open throttle.
Could be a faulty sensor, the low HG. sensor is supposed to close the stepper motor some, during low vacumn (wide open throttle). If it doesn´t could be burning lean=heat.

Low coolant volumn flow or restricted air flow in the radiator. Exceptionally lean burn condition. Very slight head gasket leak into the coolant system (bubbles in the radiator) that only shows up during certain driving conditions. Or a little here and a little there, that all adds up.

edited by: MudderChuck, Apr 02, 2003 - 01:01 PM[addsig]

[jhiggins]

um kay sounds good to me, because I am stumped but thankyou for the input I will check it out on friday.... :-O :-O [addsig]