Trying to find the coolant sensor on my car. '87 GT (not that it matters) with a 3800 n/a S2 out of a 2000 Bonneville. I can't get the Toms digital temp gauge to read anything but 255*. I've run a ground wire from the motor to the grounding pin on the gauge to no avail.

Its right below the thermostat on the lower intake manifold- LIM. Kind of sits down under.

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

Thanks. Do you have a picture of it?

The connector right under the thermostat. The thermostat is located right under where the upper radiator hose connects to the engine. You can see the connector wire between the exhaust pipe and the valve cover.

Most NA 3800s were equipped with a 2 pin CTS. That doesn't support an external temp gauge. So most swap the two pin CTS for the 3 pin CTS & temp gauge sender combo.

This is the three pin CTS & temp gauge sender combo



This is the two pin CTS

[This message has been edited by phonedawgz (edited 02-21-2016).]

Thanks heaps. Unfortunately, it looks like you have to get to it from UNDER the motor. I don't have a lift so it looks like I'll need to find someone to swap out the sensor.

quote Originally posted by Monkeyman: Thanks heaps. Unfortunately, it looks like you have to get to it from UNDER the motor. I don't have a lift so it looks like I'll need to find someone to swap out the sensor.

You can access it from above. I recently had to reseal my temp sensor and was able to get a wrench in there to loosen it. It is made easier by removing the exhaust crossover tube which gives even more access to it. Should be a relatively quick repair.

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Project L67 Fiero

I'll look into that. Anybody have a part number for the 3 pin sensor?

I always search for the one on a 1998 Pontiac Grand Prix GTP. I'm assuming that some models only had the 2 pin to run an idiot light but the GTP's all had gauges...

Let's see if the RockAuto link gets you there:
https://www.rockauto.com/en...sender+/+sensor,4748

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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel
My HUD install thread
Modified stock air canister and base to 3.5 inch for 3800na

Thanks. I just ordered one based on your suggestion. Hope it works.