4.3 Temperature Sensor

[jeb6294]

Our temp gauge doesn’t budge when we’re out. I grounded the wire from the sensor and the gauge pegged so I’m guessing I have a bad sensor. Can’t find any cross reference to take to the local auto parts store for a new one. It’s just a 4.3 GM motor so surely it’s not Mercruiser specific.

1987 Starcraft with the 4.3/175hp

 

[alldodge]

Need more info on the motor. What is the serial number?

 

[jeb6294]

Need more info on the motor. What is the serial number?

B649365

 

[alldodge]

Thanks for the S/N, it uses P/N 860490T and original number was 97257A1

Marine senders use 240 ohms (cold/low) to 33 ohms (hot/high)

You could try auto parts stores with a ohm meter to try and find one in the right range for cold, but unable to verify hot.

This is one for $15 using older number
https://www.amazon.com/Engine-Water-Temperature-Sensor-Mercruiser/dp/B07SLYHN6M

 

[Scott Danforth]

Many automotive senders are 0-90 ohm, so most likely you wont find what you want at your FLAPS, except maybe a NAPA

 

[jeb6294]

Amazon had free shipping and it’ll be here tomorrow so I went ahead and got the right one…Amazon

 

[jeb6294]

Well crap…. Clearly, the new sender will not work. I will say, everything I saw talked about the sender being in the t-stat housing, but this one was in the intake manifold. Pretty sure it was the right one though because it had the brown wire on it and the gauge pegged hot when I grounded the wire. The second picture shows the only numbers I could see on the old sender.

How often do these go bad? This one had a plastic washer on it to isolate the wire from the sender that looked like it was cracked. Could it be as simple as putting a new plastic washer on it?

 

[alldodge]

It depends on which thermostat housing so there could be two options

Use same sender and go to hardware store and get a 3/8 to 1/2 brass bushing. Screw sender into bushing and bushing into intake

If the thermostat housing has a 3/8 plug in it at the correct location, put sender in there and put old sender in original location to plug hole