How to check if oil cooler on 1999 Cadillac Deville is working properly.Or where is the oil temp. Sensor

SOURCE: 1999 cadillac deville overheating

my husband did everything that everyone else did that had this overheating problem. It was so weird that my engine cooled at a light and heated up going down the road. I have a north star 4.6 engine and this is natorious for happening. my check engine light also came on and so I had a diagnostics done which told me my #1 injector wasn't firing , car ran like **** as well. After putting in a new water pump and plugs,ect. and realized injector was good a friend told him we could have a blown head gasket. So just to see if this was the problem I went to buy a bottle of glassbeads and the auto parts guy told us to purchase a bottle of BARS STOP LEAK BLOCK SEALER NOT RADIATOR BUT BLOCK SEALER $31.99 . He followed the directions and we waited 24 hrs. before driving it. What ever the problem was has stopped my car runs like brand new and I am loving it again. no over heating no injector problem, runs great.......I hope this helps. I know its probly a temperary fix but its a fix and now we know what the problem was. SASSY

SOURCE: 1999 cadillac deville air wont work

There's a blower motor (fan) under the hood and up against the firewall near the center of the car that takes some work to remove. It has gone out in the last 2 of my 4 Cadillacs. Turns out if you're not real careful with the positioning of the spark plug wires they will brush up against it, and if one of them gets cracked or brittle it will "arc" and short out the blower motor. The a/c compressor should still come on (you'll hear a click when it engages) but you won't get any air blowing into the cabin, hot or cold.

The part was like $200 stock (year 2000 prices) and it took about an hour to remove it. My Caddy at that time had this damn strut bar going across the engine bay which we eventually removed to get to the blower motor.

SOURCE: thermostat location on a 1999 cadillac deville concours

looked it up online and looks like it's on the front of the water pump in a thing called the coolant inlet housing. one end of it looks something like the letter y and the other end, where the thermostat is round. hope that helps

SOURCE: location of coolant temp sensor

where can locate the engine coolant temperture sensor.

SOURCE: Cadillac 1999 DeVille Battery goes dead after

You should check for voltage draws when the vehicle is off... Disconnect the negative battery termal, Pull dome light fuse,and connect a light or volt meter between the two.

common offenders are alternator diodes. These fail and cause drain.

Then you have to check, circuit by circuit, until you find the offending system.

Also, before doing anything, disconnect negative terminal and see if the battery is still fully charged after a few days...