Hi guys, looking for a bit of help here. I recently swapped out my stock '84 cluster with non-functioning "idiot lights" (and a mess of aftermarket gauges) for one that has self-contained gauges and everything's been fine except I'm having issues with the temp gauge reading way too hot.

The sending units were replaced as needed. Used a WT359 temp sender.

The ohm readings of the sending unit reads 1600 while the engine is cool (which I've read is normal), at least until it is connected to the green sending wire. It then drops to around 1100. Pulling the gauge out of the cluster (with the wire still attached to the sending unit) brings the ohm reading back to normal. The gauge needle tends to creep up while disconnected and when the key is off, usually only stopping when it finally pegs. It all leads me to believe that the gauge is shot, but I'd like to hear the opinions of some of the Camaro gurus here.

Many thanks!

 

I have an 86 IROC and 3 temp gauges later, none of them have never been accurate. I have a radiator cap that reads the temp and it never reads above 180 but the gauge always creeps up to just a little past the red line. I dont trust those gauges.

 

stock gauges are notoriously inaccurate....

 

@1986tpiiroc: That's essentially what mine is doing. My thermostat kicks in at 180, and by that time, the gauge is already reading well above 260. Then it just kinda hovers over the first red marking while driving down the road.

@travis401: Yes, I'm well aware from previous searches that the stock gauges have a reputation for being prone to failure and inaccurate calibration, however, I'm simply asking if my observations are indicative of a failing gauge or if it could be the sending unit.

 

i was just stating the gauge could not be failing and the sending unit could be perfectly fine, the gauge could just be reading out the wrong temps. you can try a new temp sender or a "new" gauge

 

But that's not what you said. Thanks for the elaboration, though. Sorry if the tone of my reply seemed a little harsh. It's just that I have done a lot of searching on this topic and each question about these things had posts with people stating *all* of the stock gauges are "trim pieces!" and "notorious for being inaccurate" before telling the original poster to just buy aftermarket gauges.

Well, all I can say to that is my "new" stock gauges are reading almost exactly what the aftermarket gauges read before the cluster swap, except for the temp gauge, of course. So to me, an answer like that ignores what could be the source of the problem.

There are a couple things I noticed recently though, which is making me wonder if my problem is somewhere in the cluster itself. Turning the key off after the engine has warmed up (gauge reading ~260) and then turning the ignition back on brings the needle about to where it should be (a little below the 220 mark). After starting the engine back up, it slowly rises to 260 again. And I noticed it will fluctuate pretty in tune with battery/alt load. High/low beams, climate control and engine fan, rear defogger, and the cluster backlights all seem to influence it. It's not a huge difference, but it's the only gauge (other than the volt meter) that seems affected.

I'll tear into the cluster with a volt meter within the next couple days. If anyone can tell me what kinds of voltages to expect at the three gauge contacts (with ignition on/off, engine running) for comparisons, I'd really appreciate it.

 

 

Hi NINA, thanks for the response. Just curious, could I accomplish the same process you describe using plain resistors? I've got plenty of them lying around; I think all I'd need is some sort of ohm -> temperature reference.

 

 

Alright, I finally got a chance to test the gauge with some resistors. Values seem relatively close to what they should be. At 1200Ω, the gauge read just off the 100 line and at 56Ω, it read slightly higher than 260 (close to where the needle hovers while driving down the road). And I just found a nice little chart with ohms -> temp reference points (here). Will try a few more values later today to see how accurate it is with middle values, but now I'm starting to think the sender is either bad or not the right one for this gauge. Just can't help but wonder which one to get when there are so many different models that are supposedly made for gauge use... If anyone is willing to give out suggestions for senders that have proper range for a factory 100-260 sweep gauge, please do let me know.