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I have transferred the sending unit from my original '73 block to my rebuilt replacement engine. The location was on the right side of the engine near the rear.
I'm baffled though as I have the same opening on the left side of the block and I can't remember taking anything out of there when I tore down the engine:
Right now my new block has a plug in it as did the other side. What did I take out of there and do I need to put something in that spot in my new engine?
That is the water temp sender. Install it where it was, and plug the other side. The heads all have it cast in.
Water Temp. sender? Not the oil pressure sender? This is the engine when I took it out and it was clearly in the spot I installed it in my new engine. I can't make out what was on the driver side though but there was something in the hole that is in the old block now.
As the AIM shows, the two-pronged sender is the TCS switch and it is installed between cylinders 6 & 8. The temp sender is installed between cylinders 1 & 3.
As the AIM shows, the two-pronged sender is the TCS switch and it is installed between cylinders 6 & 8. The temp sender is installed between cylinders 1 & 3.
Got it now. I'll take the sender out of where I put it, put the plug back in and move the Temp. sender to where the plug is on the driver side of the engine.
Since I've switched to a 2004r transmission I don't think that TCS switch is even needed, right?
OK. Something still does not make sense (to me) The sender that is screwed into the block on the passenger side (where I took the plug out of and installed) is the same ONE PRONG sender that was in the same spot on the original '73 engine when I took it out. But.. the AIM is saying it should be on the other side? This is definitely NOT the TCS switch. I think I'll wait for some more feedback before I move it again.
Last edited by KLUTZ; Sep 28, 2015 at 11:10 AM.
Reason: confused
Got it now. I'll take the sender out of where I put it, put the plug back in and move the Temp. sender to where the plug is on the driver side of the engine.
Since I've switched to a 2004r transmission I don't think that TCS switch is even needed, right?
OK. Something still does not make sense (to me) The sender that is screwed into the block on the passenger side (where I took the plug out of and installed) is the same ONE PRONG sender that was in the same spot on the original '73 engine when I took it out. But.. the AIM is saying it should be on the other side? This is definitely NOT the TCS switch. I think I'll wait for some more feedback before I move it again.
All chevys had the temp sender in the left head, never in the right head. There will be a green wire in the alternator wiring harness that plugs onto the sender.
You may have the original engine but someone has had it apart before and possibly put the left head on the right side. Chevy never painted their valve springs with orange engine paint.
On my 73 there are identical single contact sensors on the left and right sides. The left (driver side) has the wire connected, the right does not and there is no wire visible to go there (???) The P.O. did have the heads reworked and cam put in, other than that the car is unmolested , had it for 18 yrs.
OK. Something still does not make sense (to me) The sender that is screwed into the block on the passenger side (where I took the plug out of and installed) is the same ONE PRONG sender that was in the same spot on the original '73 engine when I took it out. But.. the AIM is saying it should be on the other side? This is definitely NOT the TCS switch. I think I'll wait for some more feedback before I move it again.
To add to the confusion, here's what my Chevrolet Service Manual states:
The TCS system temperature switch used with Corvette is located in the right cylinder head between the number 6 and number 8 exhaust port. For vehicles other than Corvette the switch is located in the left cylinder head between the number 1 and number 3 exhaust port on Small V8 and between the number 3 and number 5 exhaust port on Mark IV V8.
On my 73 there are identical single contact sensors on the left and right sides. The left (driver side) has the wire connected, the right does not and there is no wire visible to go there (???) The P.O. did have the heads reworked and cam put in, other than that the car is unmolested , had it for 18 yrs.
The service manual states that there were three different TCS system temperature switches used with the V8 engines: one for the gauge package; one with Corvette vehicles; and the third type for all other applications.
The Corvette switch is a three-position control. The switch used with the gauge package is a two-position single terminal control. On all other applications except Corvette and the gauge package, the temperature switch is also a three-position double terminal unit.
Auto trans cars did not use TCS ..and all its associated parts ... 73 and 74 four speed cars had the tempature switch screwed into the pass side head ..it was part of the TCS system for those cars. It's not the same function at all of the left side engine temp sending unit. Pass head on auto trans car was plugged .
The pass side TCS correct screw in temp switch is a mega HTF part .
Last edited by LS4 PILOT; Sep 29, 2015 at 06:04 PM.
I have a '71 auto car that has the TCS system. From the Chevrolet Chassis Service Manual, there is no delineation between auto and manual cars, as far as the TCS system is concerned. The only difference is how the transmission 'tells' the system that it is in the higher shift ranges.
Sending unit on '73 engine block.. Driver side?
Yup. 
