Engine/Transmission (1994 - 1998) Temp gauge problem

[CumminsPower98]

Three times now when towing up steep grades my 1998 12 valve temp gauge would be sitting at 210º when all of a sudden it would instantly spike to the peg and the check gauges light comes on and the chime. Shortly after it will come back down to 210º. Once it wavered around a little bit above 210º after spiking but then came back down. This looks like an electronic problem to me as I see no reason for it to spike that fast. I have never boiled over and I have never seen it go past 210º other then when it spikes. I have not lost any coolant either. When it does this I have always just kept on going becaue by the time I was about to pull over each time it would come back down. Has anyone ever had anything like this happen? Does it need a computer flash maybe? I know I must need a recalibration for the oil pressure because I have replaced the sender twice now and it is still dropping to 0 some times at a hot idle then bounces back up. Any ideas?

 

[CumminsPower98]

No one has any ideas? Maybe I will have to install a gauge.

 

[tp0d]

Sounds like you have a temp sensor that is failing. From the conditions described, sounds like its shorting out once it gets past a point in temp. Shouldnt be too $ of a fix, and if you've never messed with it, then its probably bad.



Before buying a new one, you can try removing the connector, cleaning both sides of the plug with good electronics cleaner (I prefer radioshak's tv tuner cleaner, works wonders on TPS's heh). If you can get ahold of a small wire brush for the male end, and the female end can be slightly crimped using the tip of a knife or a multimeter probe. I -think- the sensor is right up at the front next to the alt, but I could be wrong. Never messed with mine. .



good luck



-jerry

 

[CumminsPower98]

I hope the sender isn't bad as they are over $70 I think from Napa. The sender is on the left rear corner of the head and kinda hard to get at. I'm quite sure it's an electrical problem though the way it spikes all of a sudden and quite posibly is the sender acting up. So now I have an oil pressure gauge that drops like a rock and chimes and a temp gauge that pegs. Oh what fun. I have never changed the sender and I have close to 173k now. Thanks for posting.

 

[SSkinner]

You could check the wiring by removing the temp sensor connector and see which way the temp needle points. Then jump the the two wires in the connector and the temp guage needle should read fully in the opposite direction. Temp sensor is next to the t-stat housing. This would verify the wiring is fine. This needs to be done with key in the run position. Have also see issues with the t-stat also.

 

[Berrigan]

Cumminspower98

Ditto, my 98 does the same thing with temp and oil pressure. I havent pulled heavy this summer yet so i have not changed the sender but thats what Im gonna change when I get time. Bill

 

[biggy238]

With that many miles, you might want to consider swapping your thermostat if it hasn't been changed already. They have a rubber band material that separates and gets lodged in the tstat sticking it open. When I pulled mine the band had come apart just exactly like the picture of the one that was posted here. It's like the band has a factory defect that fails.



I don't know about your particular case, but my truck ran at 200* until I ran it hard and then would see a spike. Now, I can stand on the pedal for miles and miles and it will never come off of 180.