Overheating

Tiny
JOHNNY WILLIAMS2
  • MEMBER
  • 2006 CADILLAC DEVILLE DTS
  • 4.3L
  • V8
  • AUTOMATIC
  • 155,200 MILES
I changed the catalytic converter, thermostat, water pump and temperature sensor. It still overheats also flushed the radiator. It was pristine. What else could be causing this issue?
Thursday, July 8th, 2021 AT 11:40 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,748 POSTS
Hi,

Does the overheating happen at highway speeds or does it occur only when driving in town (stop and go)?

If it is only happening in stop-and-go traffic, confirm the cooling fans are operational when it starts getting hot.

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

If that isn't the case, it could be something related to a failing head gasket. Take a look through this link and let me know if anything mirrors what you are experiencing.

https://www.2carpros.com/articles/head-gasket-blown-test

Let me know if you have questions or what I can do to help.

Take care,

Joe
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Friday, July 9th, 2021 AT 9:56 PM
Tiny
JOHNNY WILLIAMS2
  • MEMBER
  • 2 POSTS
It overheats faster idling but it overheats moving as well stop and go and highway speeds but there are no fluid transfers and no leaks it just boils up the coolant and water mixture and steams out the purge valve on the reservoir.
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Friday, July 9th, 2021 AT 11:01 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,748 POSTS
Hi,

You have replaced just about everything related to the cooling system. By chance, does the check engine light stay on when the engine is running? If it does, have you had the computer scanned for codes? I recommend having the can-bus scanned. CAN stands for controller area network. Basically, all the computers/modules are tied together via a few wires. This type of scan will retrieve codes regardless of what module holds them. Here is a video showing it being done:

https://youtu.be/u-4syLc-ifQ

Now, there are other things that can cause the engine to run hot. For example, engine timing, excessive fuel to the engine, an excessively lean fuel mixture, and so on. That is why I am recommending the scan.

Also, was anything done recently to the vehicle which seems to have led to this issue? Have you ever noticed white smoke from the exhaust?

When the engine is cold, try this. With the engine cold and off, remove the radiator cap. Start the engine. Do you see any bubbles in the coolant or does the coolant shot out?

Let me know.

Joe
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Saturday, July 10th, 2021 AT 8:45 PM

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