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429CV23 · 12-15-2014, 02:56 PM

The PO installed a mechanical temp gauge, which is no good - only drops to 190* when cold.

I assumed the sensor would be in either the t-stat housing, or in a fitting at the front of the intake. There are plugs occupying both places, but I see no free wire to connect a sensor. PO installed the mech gauge in the left head, but I don't see any available connection there either.

If I can find the wire, I can at least test the stock gauge's operation. Worst case I'll install an aftermarket gauge if the stock one is bad.
I'll be installing a tach and a trans fluid temp gauge as well.

Phobos · 12-15-2014, 03:11 PM

I'm not sure on a big block, but on a small block Chevy, the temp sender is on the driver's side in the cylinder head. Up near the front, about 2nd cylinder back.
I assume the 454 is going to be in the same basic place because of the wiring harness on the vehicle.

429CV23 · 12-15-2014, 04:07 PM

Thanks, I'll center my next search in that area.

429CV23 · 12-16-2014, 07:09 AM

I found the green temp sensor wire zip-tied to another harness; verified it is for the gauge, gauge seems to work fine.
Now the question is; what sensor is correct? All the sensors I've seen online have the 2-wire harness connector, and what I have is a single green wire with a spade connector. All I've seen with a spade connector are temp switches.

Edit: NAPA lists it ... shoulda checked there first.

Part number is TS6640.
Of course, no stock on hand; found one on ebay for less than $11 shipped.

Phobos · 12-16-2014, 07:56 PM

You might try to search for a Temp Gauge sender, not a sensor. The sensor would be for the computer if it had one. That's probably what's messing up your parts search.
If you still need to, try a search for a temp sender for an 1985 Chevy 1 ton truck or something similar that would have a 454 as an option. I don't think it will matter much though, I have a feeling the gauge senders are all the same for a GM of that vintage. They're pretty generic units.