Coolant Temperature Sensor / Engine Coolant Sensor

[Bergjo91]

Question. Doing Injectors, valve cover gaskets, intake manifold gasket, so thinking changing out these two sensors. In the service manual picture attached (#2) reads Coolant Temperature Sensor, and (#3) reads Engine Coolant Sensor. Trying to find parts and when typing in the two different named sensors I get the same list of parts being pulled up even trying different parts sites. Are these the same sensor or does anyone know what they are called for me to find replacement parts?

Thanks for any information provided!

 

[HotAirWH1]

Rockauto has both - ROCKAUTO.COM

 

[1986 Buick GX1]

Rockauto has both - ROCKAUTO.COM

Does the #2 coolant temp sensor turn on an idiot light or something, maybe tells the computer the engine temp?
Does the #3 engine coolant sensor run a temp gauge?

 

[Anthony P]

#2 is the single wire for the temp switch for the idiot light in the dash.
#3 is the 2-wire temp sensor providing actual coolant temp to ECM.

The "ROCKAUTO.COM" text Dan noted in post #2 is a link to the specific temp sensors/switches for hot air's.

You could pick a Standard Motor Products TS66 for the temp switch and a SMP TX3 for the temp sensor.

Keep in mind that the SMP, Wells (WVE), NTK, AC Delco, and GM Genuine are most likely(like Ivory soap - 99and 44/100) the same part as pictured, built in the same factory, just in different brand packaging and price points.

I see you're working with a print copy of the service manual. to help you find parts in the future, bookmark the following link to the exploded parts diagrams for the car found at webautocats. From the home page and the drop down menu at top, you'll find a lot of different car manufacturers and models.

The Buick Regal exploded parts diagrams (AKA 44W crash book) is found via link below.

Buick Regal > EPC Online > WebAutoCats.com

Genuine auto parts catalogs (BMW, Mini, Rolls-Royce), ETKA (Audi, Seat, Skoda, VW), PET(Porsche), EPC (Mercedes, Smart, Buick, Cadillac, Chevrolet, GMC, Hummer, Oldsmobile, Pontiac, Saab, Saturn).

webautocats.com

Also, if the temp switch and temp sensor are currently working. you might just let them be. BUT, I would pick up a spare for each as these cars are nearly 40 years old and as a result, even some of the aftermarket support parts are drying up. So, if you do remove and replace these, keep the old parts.

if you decide to purchase these parts from RockAuto, remember to go to the website retailmenot.com, type in rockauto in the search bar, to retrieve a 5% off discount code. paste the discount code in the rockauto website sidebar window or cart on the line " how did you hear about us" and press enter. 5% is deducted from your total. codes from retailmenot are always available.

 

[Anthony P]

@Bergjo91,
I wanted to revisit your initial post on this thread.

I re-read your introductory post => 1984 Buick Regal GN over my head

and wanted to look into a few things since you noted in that introductory post you have an '84 GN. There are some changes to the LM9 engine from 84 model year to 85 model year that do not show up in manuals, exploded parts diagrams, etc.

From the service manual pic you posted, sensor #2 image shown looks like the mushroom top sensor while sensor #3 looks like a spade terminal sensor.

The LM9 engines actually built have those sensor locations swapped.
Refer to the pics in this recent post => 84/85 Motors
as well as my pic attached of NOS takeoff intake assemblies.

From those pics, you can see the mushroom top sensor is installed next to the T-stat while the spade terminal sensor is installed below the T-stat.

That mushroom top sensor should be a 2-wire sensor, being it should be the temp sensor for the ECM. The issue is that I don't believe that exact mushroom top sensor is available today from retail stores.

In mid 85 model year or so, that 2-wire temp sensor part changed to what I noted in post #4 as a SMP TX3 or equivalent. The connector from the wiring harness is different for the mushroom top and may not fit the TX3 style sensor.

So let's take a step back to confirm what the two sensors you have on the car look like and their corresponding harness connectors and go from there.

 

[WE2Regal]

I think the replacement for the earlier '84 temperature sensor is marketed by Four Seasons #36401 and Standard Motor Products #TX1. The early and later versions are completely different and do not interchange.

 

[WE2Regal]

I don't know why the parts books don't list them, but the earlier temperature sensor wasn't an exclusive turbo Buick part. Other GM cars, such as the Corvette, used that version up to around 1985. The originals were steel bodied. The Four Seasons and Standard Motor Products replacements are brass.

 

[Anthony P]

I think the replacement for the earlier '84 temperature sensor is marketed by Four Seasons #36401 and Standard Motor Products #TX1. The early and later versions are completely different and do not interchange.

Thank-you for getting that SMP TX1 and equivalents under Standard's umbrella of brands to this thread.

The GM exploded parts diagrams show only the TX3 version sensor which we know is not correct on the '84 model and early '85 model year engines.

I had searched through the sensor/switch/relay e-catalogs for:
'85 3.8L turbo;
'85 3.8 NA;
'84 3.8L turbo;
'84 3.8 NA;

and the GM LM9 diagrams; gnttype.org; and a few versions of 44W crash books before I saw your exacting info last night. Those e-cats/books/publications all lump the '84-'85 LM9 engine into one and only one listing for the coolant temp sensor - the later TX3 variant which is wrong. I would have spent more time this weekend expanding the lookup to other Buick, Olds, Pontiac models trying to help the OP and satisfy my own curiosity. That BOP cross could have wasted more time as you have to get into Chevy and GMC '81-'84 models to see a bunch a TX1 applications. Link to RockAuto listing for TX1 below =>

STANDARD MOTOR PRODUCTS TX1 Temperature Sender / Sensor | Shop Now at RockAuto

STANDARD MOTOR PRODUCTS Cooling System Parts and More for Your Vehicle at Reliably Low Prices. Fast Online Catalog. DIY-Easy. Your Choice of Quality. Full Manufacturer Warranty.

www.rockauto.com

I use RockAuto's site for the broad inclusions of many brands, part pics, and cross references to the GM part #'s. Researching this temp sensor would be a bit of a hunt when the e-catalog's only Buick listings for the TX1 temp sensor are for the 1981 models.

Glad you figured this out. Hopefully the OP sees this when he takes a moment from working his farm.

 

[WE2Regal]

On a side note, they sell the pigtail to change the earlier sensor wiring connector over to the later version. I have no idea why GM decided to update the sensor but it doesn't seem worth the trouble unless your connector gets cracked or broken.

 

[HotAirWH1]

@Bergjo91,

I have several 84 - NOS Temp Sensors in the Ac Delco packages. Let me know if you would like one.

 

[Bergjo91]

Minute to breathe and got to tear into the car some yesterday. You all are awesome and a wealth of knowledge. Attached our pictures of what I have that correlate with what you all are talking about. Next is there a part number to get a new wire plug for the TX1? I am thinking mine is shot.

 

[WE2Regal]

I don't think a replacement pigtail is available for the older TX1 style sensor. If yours is broken, you'd be better off upgrading to the newer style sensor and splicing on the newer pigtail connector. Rockauto has the Genuine GM kit to do it that includes the sensor and pigtail wiring connector under part number 21352 for less than 30 bucks.