I just switched back from a clutch fan setup back to the original factory electric fan setup on my '84 T/A (with the HO option). With a new cooling fan switch installed my factory gauge told me it was coming on around 240* and off around 230*....

To double check this I removed the temp gauge sender and installed a mechanical temp gauge that I had sitting around and warmed up the engine. According to the mechanical gauge the fan came on at 225* and off at 215*- much closer to what I had expected......

So I removed the mechanical gauge, replaced the sender to the factory temp gauge with a new one and did the whole thing over again- this time the gauge ran all the way up to 250* without the fan coming on.......didn't give it a chance to hit 260*, I shut the engine down before it got there (yea I know, it's not REALLY 260*).....

Once, some years ago the engine overheated - the engine seems to be ok from the ordeal, but since then the temp gauge has always seemed to be a bit off but I was never sure until now. There's a place in town I can have it recalibrated at but I was wondering if this is normal for factory gauges to go out of adjustment like this?

Thanks!

 

The factory guages suck. The temp guage is also non linear. If you want it accurate switch to autometer or some aftermarket guages. The temp sender probably isnt good or accurate either.

Matt

 

Non-linear? That would explain a few things- it seems to get worse as the temp goes up.....


I don't need it to be pinpoint accurate- in the higher temp ranges it's off by at least 30*- if I can get it down to about 5* I'd be happy....

 

It's a long shot, but you can reposition the needle in the gauge.

 

Good idea, but it won't work in this case since the gauge is non-linear... I'm going to pull the thing out tomorrow to see if there's a linearity adjustment on it.....

 

It's a stock gauge, isn't it? the internals of the gauge rely on the needle itself for a stop when the power to the gauge is cut (ignition off). I know this becuase I've had my cluster open before when I tried the DIY whiteface gauges mod and rotated each gauge by hand to see which ones had stops and which don't. The speedo, tach, and I think the fuel gauge all have stops and the others are free-set. It sounds to me like the temp gauge is set too low for what the engine is sending to it. Remove the needle, get the engine to a known temp using the aftermarket gauge, and then set the needle. that's all there is to it... Might be that someone in the past f***ed with the cluster or the cluster was replaced and not set properly. If you are the only one who has owned you F-body, than I am wrong, but that's the best cause I can see for the problem.