Sorry for the late response, but I have been traveling and not near my parts.

The TS6 sender is electrically correct, but is not a direct replacement for the original CV sender for the gage. The original is a smaller diameter. But electrically, they work the same.

The original sender is AC PN 25036234. I have not found a direct replacement for this PN.

Tell me more about your Cosworth. Is it a 75 or 76? Where did you put the TS6, as it will not be a direct fit in the original sender's location. The Cosworth came with 3 temp senders - the one on the right in the picture is the CTS that feeds info to the efi computer. The one in right center is a temp switch the feeds the "Temp/Press" idiot light on the dash. The left center one is the sender for the gage. The left one is a TS6.

On all CV's the idiot light sender is located between the #1 & #2 exhaust ports and the CTS is located on the bottom of the thermostat housing.

On 75 CV's the gage sender is located on the intake side of the head below and between the #3 & #4 intake ports. On 76 CV's the gage sender is also located on the bottom of the thermostat housing next to the CTS.

Can you specify where you installed the TS6 sender on the engine. Also, you didn't mention what the gage read when the engine was cold. These two pieces of information would be helpful troubleshooting your issue.