I'd like to install an aftermarket temperature sensor / sender and gauge in my 1994 LT1 (formerly in a Camaro) motor - its a swap into a street rod. I've got great access to the block drain plug on the drivers side. A lot of guys on here use the port on the passenger head between #6 and #8, but my headers are in the way.

Is replacing the block drain plug with a coolant temperature sender on the drivers side a good choice or location? Is there good water/coolant circulation in that area?

 

There are temp sensor ports in both heads, since they are identical (rotated 180-deg side-to-side). Between #1 / #3 on the driver side. Is that accessible?

You want the head coolant temperature, rather than the temperature at the very bottom of the block. It's high head temps that cause detonation and blown head gaskets. SAE Tech paper #920673 provides significant info on the changes that the LT1 reverse flow cooling engenders. At the front of the engine the block is hotter than the heads. At the rear of the block, the block temp drops and the head temperature rises to about the same temperature. The top to bottom profile of the cylinder wall temperatures shows that the bottom of the wall can be about 6-degC (11deg-F) cooler than the top.

I have a second coolant temp sensor installed for my aftermarket engine management system. It is teed into the crossover line from the back of the heads. That produces temperature readings consistent with the gauge and the feed to the stock PCM.

 

Thanks for the reply Injuneer. Currently the car's stock gauge is connected to the port between #1 and #3 on the drivers side -its a basic gauge that does not display the temps. I want to add a second better water temperature gauge that has the temperature demarcations on it, as a backup.

Thanks for the info about the top/bottom cooling -- that rules out using the bottom end drain plug. Sounds like you have the correct solution figured out. I just got the car and I'm still learning about the LT1 - Can you explain a bit more what you did? Thanks!

 

Shoebox has a good diagram of the 1993-94 radiator hoses, from the factory manual. Is the system hooked up similarly in your car?

http://shbox.com/1/93-94_hoses.jpg

The “tee” goes in line #4.

The other line that I bundled (nylon ties) with line #4 with was just done to stabilize things. It is not involved at all with the temp sensor install. That line is the heater return, with air bleed screw, part #4 in this diagram.

http://shbox.com/1/heater_hoses_93-94.jpg

Shoebox has 95-97 hose routing diagrams, but things get complicated in those years because the return from the back of the heads is routed through the throttle body first, and then to the radiator.

http://shbox.com/1/95-97_hoses.jpg

I needed a 2-wire sensor, to utilize the 5 volt reference signal from my MoTeC ECU. The typical dash gauge uses a 12 volt reference, and can be done with a 1-wire sensor, using the chassis as the ground. If you look at the air box behind the coolant temp sensor in the picture, there are dual inlet air temperature censors to feed both the factory PCM and the aftermarket ECU.

 

If that first link won't work, go here, and scroll down to item 16:

4th Gen LT1 F-Body Tech Aids-Drawings & Exploded Views

 

Im having some issues with my temp sensor, I like what you did here. What did you use for the tee and where did you get it if I may ask?

 

Details are faint, did that 24 years ago. Sold the car 2 years ago.

Brass tee is a common item for a plumbing supply store (or even Amazon). Get one that matches the size of your sensor threads (most likely NPT). Then get two hose barbs with the correct size NPT threads on one end and the barb diameter to match the hose diameter on the other end. Install all with teflon tape.

 

Thanks. That helps.