Temp Sensor

[xupkid2]

I am in the process of rebuiling a motor. The car is an 87 and the block was shot so I replaced it with an 84 block since they are the same besides the Autotensioner. I also found out that it has a different temperature sensor. I am wondering if there is any way to buy the pre-86 sensor and still be able to hook it up to the current 87 temp gauge. They dont seem to have the same connections. Any help would be appreciated.

Thanks
Brian

[drew1]

What's different besides the connector? Are the threads different?

[Dean924s]

Yes the two sensors are interchangeable. Wait, are you talking about the one for the gauge or the DME?. The gauge one is in the head. The pre 85.5 ones are small little things. The post 85.5 are much larger in diameter. Your gadge should work with either. If you are going to use the head from the 87 on the 84 block you dont need to worry about this. I think the DME sensors are the same pre and post 85.5 but better let some one else confirm this.

[xupkid2]

The DME temp sensors are the same however the gauge one is not. The gauge one isnt in the head but is right next to the DME sensor. Attached is a pic of the pre 85 and post 85 sensors. I'd really like the gauge to work so I dont get myself in trouble if something goes wrong.

[Razorback1980]

IF required, adapt the threads to use the one that was in the car originally. That's all you should have to do.

[xupkid2]

The only issue with that is the new style one went through into the coolant (ie a hole in the block) where as the old style just sits in the block but doesnt go through to the coolant. They also both are different sizes in diameter

[Razorback1980]

What you are saying is true. So, you have two maybe three choices. You can drill and tap the threads to the new size and drill a hole for the newer sensor to stick through to reach the coolant or you can use the old temperature sensor. (Not sure how to control the drill shavings though unless you have the head off and can clean them up..or maybe a vacuum while drilling...and I'm not sure of the tap size but you can figure that out) Or the last and more difficult option would be to make an adapter that sticks up higher for the new sending unit to screw into although I'm not sure there is room for it. The temperature sensors work the same and the gauge will read the same no matter which one you use. The second wire on the new sensor is for the the red light on the dash panel. If you need that red light, then you can't use the old sending unit. If you can drive and watch the gauges, then you can just tape up the sending unit wire that drives the red light and connect the other wire to the sending unit and be done. To find which wire goes to the sending unit and which goes to the light, hook one of the two wires to the old sending unit and if the gauge moves up, then that is the right wire. If the gauge doesn't move, then you have the red light lead instead of the sending unit lead. I think the connectors may be different, but I'm sure you can find a way to work with that. Hope that helps but if I confused you, please let me know.

[Dean924s]

So it looks like I have mixed up my sensors? I ran into this when I put the 83 motor in my 87. I swear that the two sensors were both just screw in to the head but now I am not so sure. I will have to take a look again.

[Razorback1980]

I am going off memory too Dean, so hopefully I haven't mixed anything up, but I think the one on the head is for the DME and I do believe those are the same. I believe the temp gauge one is on the block and the pre 85 blocks didn't have a hole going into the cooling system area around the cylinders and was a different size and only had one wire. Cross referencing between years is not my strongest attribute so I hope I'm not misleading anyone.

[xupkid2]

You are exactly right. I can live without the red light so Ill just figure out which wire activates the gauge and hook it up. Sounds like a great solution to me. Thanks for all the help.

Brian