What is this?

[Pop's Z]

Hi all, I have a 1973 (build date 6/73). I am refreshing the cooling system and found the thermostat cover is a bit corroded (see pics #2&3). It appears that a cover for this build date is NLA. My question is what is this electrical part (see pic #1)? It appears to be a thermo control of some kind and it fits in this cover w/ pipe threads (see pic #2). It is not the water temp sender as that is in the thermostat housing itself. The only thing I have discovered is that it might be a thermo controller for the automatic transmission, however I have a manual transmission. As far as I know it never had an auto trans. The real question is: Can I use a thermostat cover from the earlier model and eliminate this part? The original owner removed all the air emission stuff and replaced the carbs/manifold with '71 roundtops and manifold including the cleaned-off balance tube. Any help from the Z gurus would be appreciated. Thanks, Mike

[Arne]

I assume that there has been nothing connected to it for quite some time? If so, I see no reason you couldn't use an earlier housing.

On the other hand, if you have had wires connected, it might be prudent to trace them to see what they send their temp reading to.

I know the later injected ZX motors had something similar, but don't know when this started. Neither of my '71s have it.

[240znz]

Mike,

Was it connected to anything?

Maybe it is a thermo switch for an electric radiator fan???? Strange place to put it but it's been done before.

Have you tried running the car without it connected?

[Pop's Z]

Thank you Arne and James for your responses. I decided to look in the FSM I have on CD from Courtesy Nissan (well, duh) and lo and behold...all my questions were answered. The part in question is a thermo switch to activate the E.G.R. If I had an auto trans it would also do someting with the distributor. The switch was added to 3/73 240s and 260s to meet U.S. emission standards. (James, could you look on your 73 parts car to see if it's there on the thermostat cover? It may not be as you have a non-U.S. car. Did it have the flat top carbs?) Becuase the PO removed all the emission stuff I have no E.G.R. so I'm guessing the switch activates nothing. I'm going to eliminate it and see what happens. I'm guessing nothing will happen. Once I get my new radiator on I'll be able to tell. Thanks again. Cheers, Mike

[240znz]

Parts car had 44PHH's onto a L28. The original L24 was chucked long ago. Thermo cover is a lot different than yours but I can't recall seeing a thermo switch there. I'll have a look when/if I ever find it amongst the crap in the garage.

[240znz]

Mike,

Parts car has no provision for the same thermo switch in top portion of the thermostat housing. However, the bottom housing has the temp sender and a threaded bung. Not sure if that was ever intended to have anything in it and there is no way of telling if someone had replaced the whole assembly when the L28 was installed.

There are just too many modifications to the car to ever assume that anything is stock.

[Bonzi Lon]

Mike: This is a photo of my 7/73 that has the coupling in question connected. Mine was a roundtop conversion done at the dealership and they removed some and disconnected other emisions stuff. The wires just left hanging are a solid green (long wire on right) and the shorter one is black with a yellow stripe, don't know what they went to.

Just wanted to show one close to your build date and how the dealership delt with it.

Bonzi Lon

[Pop's Z]

Lonny, Thanks for the pic. Mine looks just like that. I found out it was a temp. control for the E.G.R. Not used any more so I'm going to leave it off. I've already wire-tied the wires back to the hareness and taped them up. I have a new thermostat cover (70-3/73) coming from MSA and it has no threaded opening for the temp control. I'll post when the cooling system re-do is all done so there will be an answer to the question "will it work without this temp controll device". Cheers, Mike

[Pop's Z]

Here's the final answer to the question...will it work without this part? YES. Because all the air emission stuff had been removed including the E.G.R. this part (the "what is this?" of this thread) is no longer necessary. I finished the cooling system rebuild with a MSA 3-core radiator, new hoses, fan shroud, new thermostat cover (from the earlier model), new 160 degree thermostat, and new water intake. I thoroughly flushed the block, put it all back together, and added new anti-freeze in a 50/50 mix with distilled water. Took it out for a test drive today and: no leaks, no drips, no errors. It stays cool with the guage needle to the left of center. The heater works. I am a happy camper.

Cheers, Mike