Coolant temp sensor replacement

[gmcman]

Paid a visit to the dealer and picked up my sensor.....and noticed the lengthy wire lead.... Well, I can see it tucked in behing the alternator..... so my first question is.....can it be removed from underneath?

How much coolant will bleed out?

 

[Wooluf1952]

From all the accounts I've read, it's very very hard to do it with out removing the alternator. I don't remember anyone doing it.

There is very little coolant lost.

 

[davenay67]

Having just replace the CTS a couple of weeks ago, I myself certainly wouldn't try this job without removing the alternator. Even if you could reach it from the bottom, unless you have the special socket (with a cut-out like an O2 sensor socket) or make one yourself, you are going to be using an open wrench at an angle....and that requires the full amount of working room that only a relocated alternator can provide.

I also hit my old sensor with a shot of PB Blaster in advance of removal to give myself the best fighting chance of getting the old sensor out with the minimum of hassle.

 

[Mark20]

When I replaced my CTS the new one came with too much teflon tape on it. 2-2.5 wraps is more than enough. The extra balled up on me and leaked requiring me to pull the alternator a 2nd time (once you know what your doing, its easy). While the CTS was out getting its threads cleaned and re-wrapped about a gallon of coolent came out. Not immediately though. It pours over so much of the frame even if you put a catch pan there its going to get contaminated. If you can have someone plug the hole while you clean the CTS, that might be the best way to go.

Get a 15mm (or whatever the alternator bolt size is) stubby ratcheting flex head wrench for the lower alternator bolt.

 

[barron03]

Just did mine .

 

[gmcman]

Get a 15mm (or whatever the alternator bolt size is) stubby ratcheting flex head wrench for the lower alternator bolt.

Yes....that works great. Be sure you don't back the wrench out to the A/C line like I did....ha. I don't have a switch that reverses the direction and the line would absolutely not give enough to release the wrench.....I had to loosen ther A/C compressor to remove the wrench.

 

[Enderbygrandpa]

When I replaced my CTS the new one came with too much teflon tape on it. 2-2.5 wraps is more than enough. The extra balled up on me and leaked requiring me to pull the alternator a 2nd time (once you know what your doing, its easy). While the CTS was out getting its threads cleaned and re-wrapped about a gallon of coolent came out. Not immediately though. It pours over so much of the frame even if you put a catch pan there its going to get contaminated. If you can have someone plug the hole while you clean the CTS, that might be the best way to go.

Get a 15mm (or whatever the alternator bolt size is) stubby ratcheting flex head wrench for the lower alternator bolt.

did you have the rad cap still on or was it off. just did mine left rad cap on only lost a little puddle.

 

[gmcman]

CTS is replaced, all is good. Gauge reads just before 210 and scan tool shows 195.....at idle now.

Since most repairs don't always go as planned, the signal lead to the alternator has 2 wires. One being slightly brittle decided to break at the connector leaving me a generous 1/4" to work with. The wire had 1 strand holding on before I even moved the alternator...had the kids been home they may have learned a new word.

Had to bust out my extra pair of hands but it's soldered together until I get a new harness.

 

[Tofer76]

Yes....that works great. Be sure you don't back the wrench out to the A/C line like I did....ha. I don't have a switch that reverses the direction and the line would absolutely not give enough to release the wrench.....I had to loosen ther A/C compressor to remove the wrench.

get her loose and then use your fingers to finish

 

[gmcman]

get her loose and then use your fingers to finish

Wasn't happening when I pulled it for the thermostat. I had dressed it with anti seize and it would turn easier this time.

 

[Mark20]

did you have the rad cap still on or was it off. just did mine left rad cap on only lost a little puddle.

I'm pretty sure I left the cap on since I had already flushed the system. And it didn't come out right away, did so while I was cleaning the CTS threads.

 

[KNBlazer]

Snap on makes a socket which makes this swap easier than changing an o2 sensor... their website shows a price of $46.00.... the size of the socket is 18mm, I used a crow socket, I think that's the name of it...took me almost an hour, combined removal & installation...

 

[Mark20]

Snap on makes a socket which makes this swap easier than changing an o2 sensor... their website shows a price of $46.00.... the size of the socket is 18mm, I used a crow socket, I think that's the name of it...took me almost an hour, combined removal & installation...

That's what I used the second time around, a crow's foot socket wrench, to get torque on it.

 

[KNBlazer]

This is what Snap On sells, which makes it a lot easier, of course you can hack a regular 18mm socket and end up with a tool that gets the job done, but it won't look as nice as this...

P/N: FRXM18
View attachment 18721



This is what I used, turning about 1/8 at a time is why it took me so long...


View attachment 18722