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ray_mcavoy · 12-03-2017, 04:39 PM

According to some of the old parts catalogs I have, there are a couple sending units that have the correct temp vs. resistance curve to work with the stock 79 gauge. One is GM #8993106 and has 1/2" pipe thread, the other is GM #8993146 and has 3/8" pipe thread.

So you should be able to use one of those #8993146 (or equivalent) sending units in the stock location in the 89 engine. I wouldn't recommend placing the temp sending unit in the water pump since that is on the "cold side" of the system ... in other words, the coolant that is flowing through the water pump has already passed through the radiator and will be cooler than readings you'll get at either the cylinder head or intake.

12-03-2017, 04:39 PM	#3
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,354	Re: Temp gauge question According to some of the old parts catalogs I have, there are a couple sending units that have the correct temp vs. resistance curve to work with the stock 79 gauge. One is GM #8993106 and has 1/2" pipe thread, the other is GM #8993146 and has 3/8" pipe thread. So you should be able to use one of those #8993146 (or equivalent) sending units in the stock location in the 89 engine. I wouldn't recommend placing the temp sending unit in the water pump since that is on the "cold side" of the system ... in other words, the coolant that is flowing through the water pump has already passed through the radiator and will be cooler than readings you'll get at either the cylinder head or intake.