Standard Motor Products TS66

[Deano350]

I have installed a Standard Motor Products TS66 to read the coolant temperature in my 1985 C10. My temperature gauge was reading prior to changing out the heads and having to find a new sensor (3/8" npt). My gauge is no longer working. I have been trying to find out what the TS66 output should be. Can anyone assist me with what output I should see from cold to hot?

 

[idahovette]

What, no foreplay???

 

[Strick]

Welcome in, Deano. The TSU 5 switch is the most common for a GM temp sender for the cylinder head. The coolant temp switch on the intake is 3/8 (I believe) and should not operate the temperature gauge in the dash. Are your new heads not machined for the 1/2 fitting? Also, it appears that @idahovette is ruffin' you up because you didn't make and introduction and post some pics of your Square or your dilemma.

HS

 

[Ricko1966]

I'll add something here across the years there have been 3 different senders for temp gauges on squares. Different resistance values. I've posted the values and years before. So even though a TSU 5 may be most common, I'd compare the values on it vs. the values for my year truck. I'll see if I can find my list. Here ya go.

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[Deano350]

In answer to the question about what my heads are machined for. It is for 3/8" which started my misery when I couldn't just reuse the old sensor which is 1/2" thread.

 

[Strick]

Welcome back @Deano350 . @Ricko1966 has always got good tech info for us folk here in the chat & there are probably others that can assist with the debacle at hand.

HS

 

[xm20k]

In answer to the question about what my heads are machined for. It is for 3/8" which started my misery when I couldn't just reuse the old sensor which is 1/2" thread.

Try and find one of these at your local hardware store and see if the probe will fit. I have done this before.

Pardon Our Interruption

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[dusterdude]

Your hardware store will have a reducer bushing

 

[Ricko1966]

I have installed a Standard Motor Products TS66 to read the coolant temperature in my 1985 C10. My temperature gauge was reading prior to changing out the heads and having to find a new sensor (3/8" npt). My gauge is no longer working. I have been trying to find out what the TS66 output should be. Can anyone assist me with what output I should see from cold to hot?

Okay sir go look at the resistance values I posted. Here are the resistance values for your ts66. If you can find a sender with the specs I posted, you can relocate it to the intake manifold. Not the water neck but in that front water passage. You reading will be 10-15 cold, the head gets hotter. But it will still be a good reference. If you see where it normally runs, then you notice it's running higher, then it's time to investigate.

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[75gmck25]

My heads have a 3/8” fitting and my Edelbrock intake has a 1/2” fitting. I have an aftermarket mechanical gauge and have tried the installing sensor (with an adapter) in both locations. Based on my experience, there is almost no temp measurement difference between the two locations once the engine is warm.

The Edelbrock 1/2” fitting is right next to the thermostat housing, so it gets more coolant flow earlier as the engine warms up. However, once the engine is fully warmed up, the two sensor locations are within a few degrees of each other.

The correct OEM-quality ‘85 vintage temp sensor should be easy to find, since originals are still on the shelf in many parts stores. Older trucks, like my ‘75, use an older sensor that is only available as a reproduction item, and quality is unpredictable.