Temp sensor - can I tap the threads in the head?
Originally Posted by daniel6718
i did it in the passenger head and it read hot...did it with a 98 sensor in the drivers heat and it still read hot, but the pcm reads fine...
TECH Apprentice
Joined: Aug 2005
Posts: 347
Likes: 0
From: Dover Arkansas
I used the 98 fbody sensor I believe in my 5.3 Passenger head. Didn't have to tap anything. It reads about right on in my S10 Blazer temp guage, 195F. Your guages might require different range sensor though. Good luck.
Originally Posted by eagleuh1
I used the 98 fbody sensor I believe in my 5.3 Passenger head. Didn't have to tap anything. It reads about right on in my S10 Blazer temp guage, 195F. Your guages might require different range sensor though. Good luck.
What year blazer do you have? Was it a one or two wire sensor from the factory?
TECH Apprentice
Joined: Aug 2005
Posts: 347
Likes: 0
From: Dover Arkansas
It was a 3 wire sensor but you only use 1 wire. The other 2 go to the computer if you want to do that. I had to experiment to find which wire to pin to. I think I bought it at O'reillys Auto.
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Originally Posted by daniel6718
i did it in the passenger head and it read hot...did it with a 98 sensor in the drivers heat and it still read hot, but the pcm reads fine...
back when i had the 99 sensor in there and the stock gauge T into it, it read 185 just right...but it screws ip the pcm...
back when i had the 99 sensor in there and the stock gauge T into it, it read 185 just right...but it screws ip the pcm...
Did you try putting the 99 sensor in the LH head? I was consittering moding the LH head to accept the LT1 temp sensor.
Re'
I am having trouble with the same problem. I have a 1981 Blazer that I am using the stock cluster with. I spent hours today trying to find an adaptor to go from a 5/8" thread to M12. There just isn't one out there that would go from the size that the old temp sensors where on the old SB Chevy engines to M12 metric size at the heads. I don't really want to put it in the water pump but I guess I may have to. My sensor is 5/8" wide. Surely somebody has been in the same situation before and didn't drill the head or install it into the water pump??
After talking with some people and researching it a little bit..here is a good way to do this.
Place a second Sensor in the Passenger side Head, that one will read maybe 5 deg. hotter, but it will give you a good idea.
As far as the Wiring goes..pretty much everything 1998 and back uses standard Gauges..they need a Signal to work. This is how you get the Signal to it(same way I did it)..
I wired in a second Conector for that Sensor, placing it so it will work for it no problem. I wired it in to where the Ground(Black) Wire is spliced into the Sensor Ground Wire going to the PCM Connector, since the Sensor is grounded in the PCM(hence the 2 Wires). Then the other Wire coming off of the Connector for that new Sensor goes to your Gauge, that is the Signal Wire. You will have to do a little tracing around in the Harness for this, I'll post the pinouts for it when I get home tomorrow so it makes it a little easier.
I am doin it this way, several others have as well, and it has worked no problems. I know what I said about it being hotter earlier in the thread, but those people found that problem to be bad Sensors.
Place a second Sensor in the Passenger side Head, that one will read maybe 5 deg. hotter, but it will give you a good idea.
As far as the Wiring goes..pretty much everything 1998 and back uses standard Gauges..they need a Signal to work. This is how you get the Signal to it(same way I did it)..
I wired in a second Conector for that Sensor, placing it so it will work for it no problem. I wired it in to where the Ground(Black) Wire is spliced into the Sensor Ground Wire going to the PCM Connector, since the Sensor is grounded in the PCM(hence the 2 Wires). Then the other Wire coming off of the Connector for that new Sensor goes to your Gauge, that is the Signal Wire. You will have to do a little tracing around in the Harness for this, I'll post the pinouts for it when I get home tomorrow so it makes it a little easier.
I am doin it this way, several others have as well, and it has worked no problems. I know what I said about it being hotter earlier in the thread, but those people found that problem to be bad Sensors.
Last edited by the_merv; Jul 13, 2007 at 10:27 PM.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
Originally Posted by wildmanaaron
Surely somebody has been in the same situation before and didn't drill the head or install it into the water pump??
Here is the location of the Wires..this is the one that you are splicing into.
BLUE PCM CONNECTOR- PIN 80, BLACK WIRE
Splice into, run that to the Ground of the second Connector, and the other end to the Gauge.
This is using another LSX Temp Sensor.
BLUE PCM CONNECTOR- PIN 80, BLACK WIRE
Splice into, run that to the Ground of the second Connector, and the other end to the Gauge.
This is using another LSX Temp Sensor.
Originally Posted by G-Body
Yep, I was in the same situation.....I chucked the sender in a lathe, cut it down and rethredded it M12. Looking back on it I could have probably done just as well chucking it in a drill and using a file to cut it down. I remember someone else used a bench grinder to cut it down. The thread in the head is just a regular M12 x 1.50?(IIRC).
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
my gauge seems to read ok, it normally reads just over 200 once the motor warms up and I have a 195 T stat. I haven`t ever had the opportunity to check it against the temp that the computer sees from its sensor.
I too drilled the head rear pass side and tapped it in place. I forgot all about the temp gauge until the engine was already in the car. Its working fine and the bonus is the #7 cyl seems to be the problem area with LS engines and now I have direct input to its temps.
As odd as that is I have twice now recorded near overheat temps on my gauge but the stock LS1 temp sender ( front drivers side head ) was still not even calling for fan actuation. Lucky me I guess I shut it down let it cool and all went back to normal.
As odd as that is I have twice now recorded near overheat temps on my gauge but the stock LS1 temp sender ( front drivers side head ) was still not even calling for fan actuation. Lucky me I guess I shut it down let it cool and all went back to normal.
