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Discussion Starter #1
hi every body, my Deville is 2001 DHS, i need to replacement the coolant sensor, what should i do, thank you. my Deville is used car, the last owner did not tell me the sensor is broke, he use a wire to connect the sensor, so i don't know when i have to change my coolant, and the DIC didn't show me the right temperature.
 

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I'm assuming you're talking about the coolant temperature sensor? It's located in the rear of the right side head (the engine is sideways, so it's in the rear left of the engine compartment). It just unscrews from the head, but there's not much room.

The sensor has nothing to do with when to change your coolant. Coolant changes are done once every 2-3 years. Drain and full with a 50/50% mixture of distiller water and coolant. DEX-COOL or all makes/all models green/yellow coolant, it makes no difference. Fill to the FULL COLD line on the surge tank, check the level in a few days, add if necessary.
 

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I'm betting it's the coolant level float in the surge tank. So the fixes are (1) tap the tank with a rubber mallet (2) remove the tank and clean it out with hot water, or (3) replace the tank with a Dorman unit found on Amazon or eBay. My replacement is scheduled to arrive in the next couple of days. As for temp, does the DHS show actual temperature? My base DeVille doesn't.
 

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No it does not. Devilles either have the all social dash with segmented temp gauge, or analog with digital speedo with analog temp gauge.
 

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Discussion Starter #7
this is the image of my sensor
DSCF3099.jpg
i don't know is this sensor or coolant tank broken,
and i want to use Prestone af850 but the dealer tell me to no need to add water, just use coolant, should i listen to him? but in some video they mix water.
 

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Discussion Starter #8
thank you, my DHS can't show the coolant temp, but is has a red light in DIC when i start the car, and is will disappear is 4-5 second ,you can see the image i just upload, the last owner use wire to connect is, so it can't work well i think, the amazon sale the sensor, but i don't know which is broken the sensor or the tank.

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i am not sure what sensor i talk about, so i upload image, i think is should connect the tank and is next to the positive electrode.

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and one more thing, how many coolant(i mean the 1 bucket or 2 bucket) should i use. and should i mix 50% water or not.
 

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They take a 50/50 mix of coolant and distilled water. Pure coolant doesn't dissipate heat sufficiently and pure water won't provide freeze protection or inhibit corrosion. 50/50 mix of dex and distilled water is just right for all around temperature and protection. it's what's in mine.

If that wire is what I think it is, it connects to the sensor on the bottom of the coolant surge tank. it's likely stuck which would explain the jumper. You can try removing the tank, filling it with hot water and shaking it vigorously up and down. Empty and repeat until no more crud comes out and try installing the tank with the sensor connected. Old seal tab residue and jelled coolant can build up over time and bind the float in the tank. If that doesn't do the trick and you get false low coolant messages, replacement tanks are available online and sometimes over the counter in big box stores.

When I washed mine out I tested the sensor by connecting an ohm meter and using the continuity setting and filling the tank halfway with water. It's a switch and is either open when level in tank is low (no tone) or closed when level is full (tone) If it's "noisy", then the switch/sensor is bad and can cause intermittent false low coolant messages

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thank you, my DHS can't show the coolant temp, but is has a red light in DIC when i start the car, and is will disappear is 4-5 second
The DIC is the single line read out between the steering column and the instrument cluster. If you removed the jumper from the wire you SHOULD see a low coolant or check coolant message there. As far as a red light in the dash indicating coolant level, :confused: I have never seen one in my 2002 DHS and have gone through the same stuck float issue.

Coolant level sensor is in the tank and monitors just that. The coolant temperature sensor is in the rear cylinder head, driver side and monitors coolant temperature only. If your car thought it had a temperature issue or the temperature sensor was jumped, you would have alot more than just a red light at start up going on.
 

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and one more thing, how many coolant(i mean the 1 bucket or 2 bucket) should i use. and should i mix 50% water or not.
Fill the cooling system with 50/50 coolant and distilled water as markmnj said. Then run the engine to about 3000 RPM for a minute or so and top off any that was drained from the tank into the engine (before it starts to heat up and overflow). Then check the surge tank level again (cold) after the next 2 or 3 drives and top off as necessary.
 

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and one more thing, how many coolant(i mean the 1 bucket or 2 bucket) should i use. and should i mix 50% water or not.
Your cooling system uses 12 to 14 U.S. quarts (11.3 to 13.2 liters) of 50/50 coolant. You may use any type you can obtain.

Prestone AF-850 is a pre-mixed 50/50 Dex-Cool coolant. It is recommended, by Cadillac, for your engine - but is more costly than mixing your own coolant from 100% coolant and distilled water.

In any event, change your coolant every 3 years.
 
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