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Tech Editor's DeskProjects, papers, writings, thoughts, musings of our technical editor Joe Padavano. To begin with, he will be making threads and can approve posts to it if he wishes. This can be changed in the future if it does not work out well.
Am I the last one to find out these are available? Four Seasons P/N 84809. One tapped port and one blank bung that can also be drilled and tapped.
Yes, of COURSE they're imported. Still, this seems like a better solution when you need an extra sensor port than the fitting that splices into the upper radiator hose.
Yes, I have one on the way. About $16 delivered from Amazon.
OK, follow up. The part arrived very quickly, but I've only now had time to run out to the shop and test fit it. Summit is right, this is an AMC part. The hole spacing is slightly wide for the Olds manifolds. That's easy to fix with a die grinder. Unfortunately, that's not the biggest problem. Once you do slot the holes, the bolt heads are now closer to the body of the housing. Correct Olds housings have grooves cast into the sides to clear the bolt head and wrench. This one does not, and I doubt there's enough meat to cut them in. You'll have to use socket head capscrews and grind a flat on the washers to clear. Still not the end of the world. The biggest problem is that the port at the rear of the housing that comes pre-drilled doesn't work with many Olds intakes. Any sensor you install there will hit the frontmost runner on any factory manifold and most aftermarket ones. You should be OK with a Performer RPM or Torker or an Air Gap, but each of those already have three threaded bungs in the water crossover. Stock manifolds, O4Bs, and Performers won't clear. And then you have the problem of interference with the fuel line and inlet fitting on any 1968-newer Qjet. This means you'll have to drill and tap the blank top port to use it. The housing does come with a pipe plug for the rear port, so there's that. And yeah, the casting finish is very rough. Nothing a little time with the glass beader won't fix, and I would paint it anyway, so not a big issue. Still, if you need an extra temp sensor port, I think this is cleaner than the fitting spliced into the radiator hose.
OK, follow up. The part arrived very quickly, but I've only now had time to run out to the shop and test fit it. Summit is right, this is an AMC part. The hole spacing is slightly wide for the Olds manifolds. That's easy to fix with a die grinder. Unfortunately, that's not the biggest problem. Once you do slot the holes, the bolt heads are now closer to the body of the housing. Correct Olds housings have grooves cast into the sides to clear the bolt head and wrench. This one does not, and I doubt there's enough meat to cut them in. You'll have to use socket head capscrews and grind a flat on the washers to clear. Still not the end of the world. The biggest problem is that the port at the rear of the housing that comes pre-drilled doesn't work with many Olds intakes. Any sensor you install there will hit the frontmost runner on any factory manifold and most aftermarket ones. You should be OK with a Performer RPM or Torker or an Air Gap, but each of those already have three threaded bungs in the water crossover. Stock manifolds, O4Bs, and Performers won't clear. And then you have the problem of interference with the fuel line and inlet fitting on any 1968-newer Qjet. This means you'll have to drill and tap the blank top port to use it. The housing does come with a pipe plug for the rear port, so there's that. And yeah, the casting finish is very rough. Nothing a little time with the glass beader won't fix, and I would paint it anyway, so not a big issue. Still, if you need an extra temp sensor port, I think this is cleaner than the fitting spliced into the radiator hose.
I think I'd murder the TCS system and take its port.
I think I'd murder the TCS system and take its port.
Unfortunately not an option on older motors that only have one port in the coolant crossover. Olds even used a TVS that spliced into the J-hose on a few applications.
That's a good idea, better than the main hose. It's unfortunate some things need binary light style sending units and some things need gauges. One could double up on the electrical, otherwise.
That's a good idea, better than the main hose. It's unfortunate some things need binary light style sending units and some things need gauges. One could double up on the electrical, otherwise.
GM actually has oil pressure senders that have independent idiot light and gauge senders in a common housing. I haven't found a similar sender for temp, however.
GM actually has oil pressure senders that have independent idiot light and gauge senders in a common housing. I haven't found a similar sender for temp, however.
Didn't the 9 code 307 engine in the 442 G body cars have a temp sensor that included a thermistor for the temp gauge, and a thermal switch for the TEMP warning lamp?
I haven't read all the entries to this thread, so maybe the Gbody stuff is irrelevant to this discussion. I do know from reading electrical questions on the square body truck furies GM played a lot of games with temp sender resistance ranges. People have spent lots of time and effort “fixing” overheating issues that aren’t really there simply because the gauge scale isn’t accurate.
Didn't the 9 code 307 engine in the 442 G body cars have a temp sensor that included a thermistor for the temp gauge, and a thermal switch for the TEMP warning lamp?
Hmm. Good question. It has two terminals. Now I'll need to investigate.
EDIT: you are correct. Good call. Now I'll have to figure out what the resistance swing is on this sensor.
For the G-body temperature sensor w/gages. Sensor shown above in Joe's post, GM p/n 25036628. This is the inboard dual-purpose sensor found on driver side next to T-stat housing. There was a green and green/white wire plug going to this bad boy on the G-body. The green/white one goes to the gage, and the green one goes for the light (green turns to green/yellow going to the dash lamp and bulb test at ignition switch). Unfortunately I don't recall which prong goes to which. I want to say the inside prong is for the gage, but then not sure. I'm too lazy to get off my butt and go to the shop and see.
The CSM wiring diagram shows the gage coolant sensor 1365 ohms @ 100 deg F, and 55 ohms @ 260 deg F. The idiot light part shows closed above 258 deg F.
As an aside, for the G-body ECM temperature sensor (new style), GM p/n 12146312 which is interchangeable with p/n 15826386. This is the outboard sensor on the driver side front corner. I did find some Delphi tech data on this one:
April 3rd, 2022, 03:03 PM
