65 GTO, aftermarket rally cluster, oil/temp gauge

[Lloyd65GTO]

I installed the aftermarket rally intsturment pack manufactured by parts place inc. The temp gauge went out. Replaced sending unit, checked all wires for continuity. Did not find any loose wires. Short of dismantling the dash to take the oil/temp gauge out, does anyone have any suggestions what the problem could be? I have talked to the manufacture and they said they could not help nor could they take the orginal and modify it to aftermarket use. Any suggestions would be sincerely appreciated!

[Larry]

How long did it work before it stopped working? And, what does it now (not) do... pegs up, doesn't move...?

Parts Place sounds like a lot of help...NOT! Don't they have any tech help line at all? Have they offered to replace the unit? I know it would be a pain, but like about everything else today, often you need to go through a couple/few before getting one that works.

[Lloyd65GTO]

Larry,
I initially thought I blew my engine. Coming back from a parade and car show, the temp needle went off the scale. Could not tell if it went to the right or left. Stopped the car, left the engine running and checked to see if the engine was hot. I was able to put my hand on the radiator, so I new it was either the gauge or sending unit or a wire came loose. I have since consulted with an electrical engineer. He ran continuity from the sending unit to the gauge and also did some voltage checks. His initial thought was a loose ground wire, but there was continuity throughout.
Parts Place Inc. are NO help whatsoever. Well they did tell me to check hemmings for intrument services. Their tech deparment would not even talk to me! All they said was: "sorry, you cannot use the orginal unit in place of aftermarket, it will not work".

I am thinking, that as long as I still have my original, and I have the plug-in clips, why couldn't I remove the plastice aftermarket oil/temp cluster, cap the hot lead from the tach, use the the peanut bulbs in the original holes, uncap the pink wire lead from the ignition, connect the green and blue wires to the leads going to respective sending units?? What do you think? The only thing I am concerned about is, will the original cluster holes align with the aftermarket unit!!
It is a real pain to get that oil/temp cluster out of the dash!! Had to remove the radio, ash try, a/c ducting around steering column, glove box to get to the screw holding the heating a/c flume, just to name a few items. Then try to get to the 1/4" screws that hold the unit in place!! No fun at all!!

[Larry]

It sounds like there is no warrenty help available or replacement coming from the supplier. It is very likely the gauge is bad as you have switched the sending unit already and checked all the wires.

I'm not familar with the unit you bought, and tried to find a picture on their web site to no avail. From the looks of some of their prices, I'm guessing this wasn't cheap. It sounds like there might be problems reinstalling your original gauge in their setup. Perhaps it will work with the modifications you describe.

If you are going to try to rig up the old gauges seperate from their connector, you can probably do so very carefully wringing out the appropriate wires... just as if you were installing aftermarket gauges on a car that had idiot lights. Just move carefully. Do you have a schematic to be certain of which wires feed which gauges?

It's too bad you have to go through this. Have you checked to see if The Parts Place has a seperate replacement gauge? If not too ecpensive, it might be easier than rewiring back to your old ones.

Let us know how this all turns out.

[Lloyd65GTO]

When I did the restoration, I put all new wire harnesses in throughout the car and I purchased, (ebay), a color coded wiring schematic that was really helpful. On one of the e-mail exchanges with parts place inc., I asked them if they had seperated gauge for sale and they told me "sorry, the only parts they have are for the rally packs"

I may still spend the money and have my entire original gauges restored. I am thinking I will be money ahead if I have another problem with a gauge.

[Lloyd65GTO]

Hey Larry,
I finally got things back together but still am having a few issues. I modified the back of the original tac unit to accomodate the aftermarket tac. After melting wires a few times, I finally realized that the clips from the aftermarket circuit board were touching the metal of the housing on the inside of the tac case. Finally got that resolved by filing down the metal casing so nothing was touching it.

Another issue I have run into is that the original temp gauge goes to 180 deg. after warm up for 10 minutes. After driving it for 20 miles it goes to 220-225 degs. Is this normal for a 389, tri-power? I have a 4-core radiator in it already as it has factory A/C. What can I do to cool my motor down? A friend of mine asked me if the head gaskets I put on it were specific to left and right, top and bottom. When I had the motor torn down to replace the cam, I did a comparison of the left and right head gasket. I did not notice any specifics!! All the holes lined up with each other and I when I set them over the pistons I could not see where any holes in the block were covered. I have to replace the timing cover and am wondering now if I should go ahead and break the motor down to check and see if I missed something when I put the head gaskets on.
I purchased a temp gauge from NAPA and did a temporary installation. The temp readings are pretty close to the OEM below 180 degs. but when it goes to 220-225 degs, the OEM would go to around 230-240 degs.
Am thinking that I should send the OEM temp/oil gauge to TACHMAN and have it calibrated and restored.
Any input or suggestions from you or anyone else in the forum would be greatly appreciated!!

[Larry]

Sounds like you're kind of in the two steps forward, one backward situation.

Good to hear about the retro-fit of the OEM gauge. Sorry to hear about the high temps. My first question was going to be "do you really know it is hot?" Sounds like you verified the reading with the extra gauge. The reading don't sound far enough apart to warrent rebuilding of the OEM.

Actually you don't know which of the two gauges is most accurate. I remember my Dad using a cooking theromoter in the radiator to get a most accurate reading of the water temp. Just open the cap carefully when hot. You might want to sneak the wife's cooking therometer out of the kitchen for a test.

One thing you don't mention is what the gauge used to read under similar use before all these switch-er-roos. Do you recall? It would be unusual for a rise in temp coincidentially during/after switching the gauges.

Before I would start an engine teardown, I would get a super accurate water temp reading. As a thought, do you have a radiator shroud on your GTO?

[Lloyd65GTO]

Before any of these problems, the temp was right around 210-220 degs. That was before I replaced the dual lobing cam with a new cam grounded to OEM specks for a 389. I thought that if I put in a less radical cam it would do a little better on gas but most of all, was hoping it would not run as hot. The car has a shroud and all the engine compartment baffles that were specific to a factory A/C car. I will try the thermometer idea. Any thoughts on the head gaskets that I mentioned earlier? Can the head gaskets be put on incorrectly...i.e upside down or left on right and right on left??
Thanks

[Larry]

I checked the AllPro "How to Run Cool" book for some more ideas. They state "A car with a 195 thermostat might stabilize at 210 or 215. This is an acceptable temperature. 230 at the tiop of a hill on a hot day with the air conditioning on is acceptable. However 230 for long stretches with no extra load on the engine is too hot." So you're kind of at the top of the limits.

Does the temp go above the 220-225 that it reaches after 20 miles if you continue to drive?

You mention changing the cam. Perhaps you need to advance the timing some more. Retared timing can cause overheating. You didn't change to a different pulley when you changed the can, did you?

I have not ever seen a problem with head gaskets if all the holes were un-blocked by the gasket. Sounds like you did correctly there. Damaged intake gaskets can cause problems too; but, you would probably notice leaking of air or water if not installed properly. Did you check that they did not block any holes?

After tearing down an engine, it seems like thermostats like to act up (or at least have for me). Be sure to check (or remove) the thermostat and also check the radiator cap. It is probably something simple.

Also, does it crank hard and slow when shut off at the top heat mark? If not, perhaps we are back to the "is it really hot?" question.