Temp sender question

[Thealien]

Does anyone know the resistance/ohms of our temp senders?

The reason I ask is I am swapping an LS engine in and am looking for a temp sender that might screw into the LS head without an adapter that would work with our factory gauges that I am keeping (for now)

I know some of you smart guys have a good answer'

[68gmsee]

ttt for you.

I looked through my mnauals and couldn't find the answer to that one. Probably would be just as easy to buy one and take a reading off of it. Local auto parts store has them for about $5.

Or ask them to take a resistance reading on one for you. If you do a lot of business with a local parts store they usually will try to help you if they're not super busy.

[Thealien]

Originally Posted by 68gmsee

ttt for you.

I looked through my mnauals and couldn't find the answer to that one. Probably would be just as easy to buy one and take a reading off of it. Local auto parts store has them for about $5.

Or ask them to take a resistance reading on one for you. If you do a lot of business with a local parts store they usually will try to help you if they're not super busy.

Problem is they are all 17 year old if I don't have a part number or year and model they can't find it kids !!

I also think the ohm reading is at like 160-200 degrees so reading them cold won't help.

The answer is out there and when I find it I will help others and tell them!!

Thanks BTW

[john]

Heres a link to cutting a 1/2 npt down to 3/8 npt to keep from using a bell reducer adapter. Also some of the trucks have put them in the intake manifold.
There has been more posts on cutting them down, I just haven't found them.

http://67-72chevytrucks.com/vboard/s...d.php?t=196755

[OhOneWS6]

Most aftermarket guages use a range of 33 to 240 for all the gauges. Many OEMs are a different range. Not sure what the range is for the factory truck sender but it would not surprise me if it is the same range as the factory LS temp sender.

[Thealien]

Originally Posted by OhOneWS6

Most aftermarket guages use a range of 33 to 240 for all the gauges. Many OEMs are a different range. Not sure what the range is for the factory truck sender but it would not surprise me if it is the same range as the factory LS temp sender.

I sure whish that was the case but the LS temp sender is wired to the PCM instead of the gauge. If it were that easy (I really hope/wish it was) I think the few places doing the swaps would be using just a sensor instead of using all the adapters. On LS1tech there is a guy that had his turned down and threaded 12 X 1.5 mm that the thread for the sensor is but his was a newer engine with a smaller sender. The smallest part of my sending unit is 13mm+ which is bigger than the 12 mm hole.

[Thealien]

Originally Posted by john

Heres a link to cutting a 1/2 npt down to 3/8 npt to keep from using a bell reducer adapter. Also some of the trucks have put them in the intake manifold.
There has been more posts on cutting them down, I just haven't found them.

http://67-72chevytrucks.com/vboard/s...d.php?t=196755

Old post, too bad he wasn't still active?

No putting them in the intake of the LS engines, they are plastic with no coolant running through them.

[OhOneWS6]

Originally Posted by Thealien

I sure whish that was the case but the LS temp sender is wired to the PCM instead of the gauge. If it were that easy (I really hope/wish it was) I think the few places doing the swaps would be using just a sensor instead of using all the adapters. On LS1tech there is a guy that had his turned down and threaded 12 X 1.5 mm that the thread for the sensor is but his was a newer engine with a smaller sender. The smallest part of my sending unit is 13mm+ which is bigger than the 12 mm hole.

Forgot about the PCM. Looks like there are a couple of threads here with people selling senders that work with the factory gauge but have been turned down to fit the LS head

[Thealien]

Originally Posted by OhOneWS6

Forgot about the PCM. Looks like there are a couple of threads here with people selling senders that work with the factory gauge but have been turned down to fit the LS head

Been looking/searching. There was a guy turning them down for the TBI swaps 1/2 inch to 3/8 but I hadn't seen any turning them down to 12 X 1.5mm if you see one please post it.

The guy turning them down to 3/8ths hasn't been on in over a year?

[eagleuh1]

Drill and tap the head for the larger sender. Its been done by members on LS1 tech.com. Also, on my 96 Blazer I used an older model f-body sensor that hooked up and worked on my guage. Can't remember what year it was for but I got the idea off ls1tech.com also. Both ideas were for the passwenger side head, leaving the sensor for the computer in the drivers side head. Good luck. JIM

[Thealien]

Originally Posted by eagleuh1

Drill and tap the head for the larger sender. Its been done by members on LS1 tech.com. Also, on my 96 Blazer I used an older model f-body sensor that hooked up and worked on my guage. Can't remember what year it was for but I got the idea off ls1tech.com also. Both ideas were for the passwenger side head, leaving the sensor for the computer in the drivers side head. Good luck. JIM

Thank and I know about that option. Did you know the head bolts are single use only on LS engines (unless you change to ARP) so there is the cost of headbolts and the cost of a headgasket, intake gaskets. And my engine has 5 miles on it, I really don't feel like breaking the factory seal on an engine with 5 miles on it.

There is also an idea to drill and tap the brass block heater plug. A temp sensor is just a resistence that changes due to temp. There has to be one out there somewhere that will screw into the 12 X 1.5mm head hole and work with our gauges!

[OhOneWS6]

Originally Posted by Thealien

Thank and I know about that option. Did you know the head bolts are single use only on LS engines (unless you change to ARP) so there is the cost of headbolts and the cost of a headgasket, intake gaskets. And my engine has 5 miles on it, I really don't feel like breaking the factory seal on an engine with 5 miles on it.

There is also an idea to drill and tap the brass block heater plug. A temp sensor is just a resistence that changes due to temp. There has to be one out there somewhere that will screw into the 12 X 1.5mm head hole and work with our gauges!

The more I think about this the less I think you are going to find one. By the time US auto manufacturers went to metric threads they were using PCMs. The chance of finding a sender with the correct resistance with metric threads is going to be pretty slim.

When I googled this I did find one comment stating that NAPA had the resistance values for all the senders in their catalog. It lead to a dead end for that person as well.

I found a couple of other threads where people were turning down other senders but now I can't find them. I don't remember what I searched for but I was searching with google.

Good luck on this. If I find anything I will post it back.

[Thealien]

Originally Posted by OhOneWS6

The more I think about this the less I think you are going to find one. By the time US auto manufacturers went to metric threads they were using PCMs. The chance of finding a sender with the correct resistance with metric threads is going to be pretty slim.

When I googled this I did find one comment stating that NAPA had the resistance values for all the senders in their catalog. It lead to a dead end for that person as well.

I found a couple of other threads where people were turning down other senders but now I can't find them. I don't remember what I searched for but I was searching with google.

Good luck on this. If I find anything I will post it back.

Thanks and I really apreciate the effort. I try to even think outside the box. Foreign vehicles of the same era would most likely have metric threads. I wonder what their resistance values are? These things aren't all that complicated, there is a thremistor with a set value installed into a brass piece (either epoxied in or?). I have ordered a couple of the ones for our trucks and will take it apart when I get it. With the help of some of you smart people, the internet, and a little persistence I believe I will find something.

[jaros44sr]

Wouldn't it be easier to build an adapter to go from 3/8" NPT female to a 12 male, you could start with brass octagon stock(to put a wrench on) and build it from there.

Wire size, or ballast resistor, could be used to change to the required value. Electrical section might be of more help on this problem...REALLY smart guys down there!

[OhOneWS6]

Originally Posted by Thealien

Foreign vehicles of the same era would most likely have metric threads.

Thought about that as well. Most OEMs use different values than each other by design. The OEMs do not want you to use a sender from another make. Most aftermarket uses the same values. The aftermarket wants to be sure if you have a chance you will buy their stuff. IE: replacing a SW gauge with a AutoMeter. If you had to buy the sender as well it may sway your decision.

[OhOneWS6]

Check this site. It's a little hard to find but they have NPT adapters from 12mm to 1/8-1/4-3/8, or 1/2-inch NPT There is also an article on a 5.3 swap into a truck. I know you didn't want to use an adapter. I would call them and see what they say. Seems that they have done several of the swaps.

http://www.hotrodlane.cc

[Thealien]

Originally Posted by jaros44sr

Wouldn't it be easier to build an adapter to go from 3/8" NPT female to a 12 male, you could start with brass octagon stock(to put a wrench on) and build it from there.

Wire size, or ballast resistor, could be used to change to the required value. Electrical section might be of more help on this problem...REALLY smart guys down there!

There are adapters and I don't want to use one (might have to). First they look like an afterthought? Second they stick out quite a bit and I don't like the look and I am afraid at some point I or someone will snap it off causing a coolant leak and something broke off in the head.

My sensor that I removed is too large to have turned down on a lathe to fit. The sensor part is larger than the 12 mm hole (about 13.5mm). I ordered a couple of sensors online and maybe the newer aftermarket ones will be able to be turned down?

[Thealien]

Originally Posted by OhOneWS6

Thought about that as well. Most OEMs use different values than each other by design. The OEMs do not want you to use a sender from another make. Most aftermarket uses the same values. The aftermarket wants to be sure if you have a chance you will buy their stuff. IE: replacing a SW gauge with a AutoMeter. If you had to buy the sender as well it may sway your decision.

I agree to a point but I don't believe every manufacturer was checking the resistance on the temp sensor to make sure chevy people weren't using ford, toyota, chrysler gauges? I beleieve it was more of an engineering design with different engineers coming up with different answers to the same problem?

I do believe the aftermarket gauge manufacturers think this way as that is their only business.

[Thealien]

Originally Posted by OhOneWS6

Check this site. It's a little hard to find but they have NPT adapters from 12mm to 1/8-1/4-3/8, or 1/2-inch NPT There is also an article on a 5.3 swap into a truck. I know you didn't want to use an adapter. I would call them and see what they say. Seems that they have done several of the swaps.

http://www.hotrodlane.cc

Thanks, very aware of their offerings and have read a bunch of their stuff. I am trying to avoid adapters for the reasons stated a post or two up.

[jaros44sr]

Originally Posted by Thealien

There are adapters and I don't want to use one (might have to). First they look like an afterthought? Second they stick out quite a bit and I don't like the look and I am afraid at some point I or someone will snap it off causing a coolant leak and something broke off in the head.

My sensor that I removed is too large to have turned down on a lathe to fit. The sensor part is larger than the 12 mm hole (about 13.5mm). I ordered a couple of sensors online and maybe the newer aftermarket ones will be able to be turned down?

Can you drill and tap the head, coolant passage, not to much of a risk getting shavings in the oil

[Thealien]

Originally Posted by jaros44sr

Can you drill and tap the head, coolant passage, not to much of a risk getting shavings in the oil

I am not the luckiest guy in the world. I am afraid I would get a few chips in the coolant passage and mess up my water pump or?

I have emailed manufacturers and companies that deal with nothing but temperature sensors and nobody is able to come up with anything. I guess first I will see the sensors that I have ordered and maybe they will be able to be turned down to the 12 X 1.5mm thread. If that doesn't work I "may" turn my engine on the stand so where I have to drill is on the bottom, put grease on the bit and tap and use a vacuum also?

[eagleuh1]

Try the 98 LS1 temp sensor. You'll use only the guage pins on it. The other pin goes to the pcm. I tried to get a pic of mine like i said on LS1 tech, but the thing is so tightly packed in my s10 Blazer it was a no go. The sensor fits in the passenger head without adapters. It is most likely same resistance as you're original sensor. Good luck. Jim

[eagleuh1]

This is for a 99 Ls1 Camaro.http://cpwstore.carpartswholesale.co...DETS10076.html

[clay68c10]

You can change the calibration of the gauge by changing the resistor on the back. I did this on mine because my 454 tends to run around 200 and that was in the red on my factory calibrated gauge. I think the original resistor is 66 ohms and I changed to a 75 ohm resistor. It put the needle in the middle at 195, where my stat opens. That was 2 years ago and i didn't write down my test values, DOH.

I used my laptop to read the temp value in my ECU and hooked in a variable resistor to the gauge to 'set' it where I wanted it. Then it was just a matter of installing the right ohm value resistor on the back of the gauge.

I bet this would work for your LSx, or any temp sender for that matter.

[eagleuh1]

Sorry, i used the 99 Fbody temp sensor, not 98. Jim