HitTheHole

I recently had the Rally Pack gauge cluster installed in my 1970 Olds Cutlass Convertible 350 2bbl. Everything works as it should with one exception - the Temp gauge is showing hotter that it actually is. I the temp sending unit designed for warning lights was replaced with an AC Delco G1852 designed for gauges. When the car is started cold, the temperature gauge goes up as the engine warms but it eventually hits beyond "H" when the engine is definitely not overheating. Could this be a grounding issue? Faulty or wrong temperature sending unit? Anyone else ever experience this type of problem with Rally Pack gauges or temperature in general? Not sure how to troubleshoot this one.

69'442

If you put teflon tape on the sending unit that could be the problem.

Lady72nRob71

A lot of times it is the sensor.
Is this a repro rally pac or an original?
I had that issue and I had to add series resistors to bring the needle down some.
I have a thread here on calibrating the gauge. If you can post the temperature of the engine (from IR thermometer or mechanical gauge) AND a resistance reading across the sensor (with wire removed) I can see if it measures close to mine.

Unlikely but possible as the threads would cut through the tape as the taper makes them tighter as it is turned. However too much tape could cause it not to screw in far enough.
To check this, take a piece of wire to short from the body of the sender to the engine block, unpainted metal section. Then see what the gauge does.

HitTheHole

It is a repro Rally Pack from OPGI. I'm going to try a Borg Warner WT203 sending unit first. I've read some success stories after using this part. If that doesn't work, I guess I'll ask my auto-electric mechanic to try adding resistors. I wish I had know this would be such a pain in the a**! Thanks for the suggestions.

Lady72nRob71

Yes, the BW part may help. Do you know the real temp of the engine?

HitTheHole

The Borg Warner sending unit was installed and it functions better than the AC Delco or Standard parts I previously tried. However, under normal driving conditions the temp reads at 3/4 (halfway between center line and "H"). Not really sure if this is where it should be. Seems to me the needle should read a little lower under "normal" operating conditions. Overall, I'm pretty disappointed with the Rally Pack conversion. Illumination of this gauge is very, very poor while speedometer and tick-tock-tac have acceptable illumination.

Allan R

Have a look at Robs thread on Rally Pac stuff. There's information about how to brighten the display. Basically the inside of the pod needs to be painted white and the back of the front trim bezel painted with a light sky blue. Not hard stuff at all. But I agree that there's no excuse for producing them like this. My rallye pac is OEM and the inside of the pods were painted white from the factory.

Lady72nRob71

Sounds like your gauge is reading correctly given that reading and assuming the engine is running at 190*. This is what mine did and I have the BW sensor. A 180 t-stat put mine below that line between center and H, and a resistor inline can bring it down to where you want it.

As Allan pointed out, I did brighten my gauges up a lot by painting them inside. I also agree, this mod should not be needed!
See my link on rally pac stuff below for details.

m455sx

I have a rebuilt unit in my 442 and it reads close to center line for the temperature and if it goes above it will boil over in the hot summer day with no A/C on. My Cutlass sx has never been restored and has factory gauges and never get close to the half way mark with 180 thermostat unless at a stop light with A/C on. I have changed the rear end to a 3.23 gear and it runs half way all the time, keep in mind its in the mid 50s now.

My442

The Rally Pack gauge is non linear.

The first mark (1/4) is approximately 180 degrees.

Half mark (1/2) is approximately 200

Three quarter mark (3/4) is 220

I used an IR thermometer to verify.

The Lectric Limited is the most accurate.

m455sx

Where is the best place to point the IR thermometer , Thermostat housing or intake near the sending unit. Also I have replaced radiator and heater core.

My442

I point it at the thermostat housing.

That is what the thermostat is reacting to in terms of temperature.