: '06 DTS Overheating Problem - NOT Thermostat

John F
05-28-13, 04:59 PM
My '06 DTS is constantly running hot, even at highway speeds. Changed the thermo but problem persisted, and even checked the new thermo again. At lights there is little or no heat, step on it and heat blasts. Restricted heating core? If so why would that cause engine to run hot? Where exactly is it located and how big of a job to replace? Thanks.

05-28-13, 10:03 PM
Are you sure you're not low on coolent. Check drivers side front for water on the floor under the water pump. Mine went at 70,000 mi.

05-29-13, 02:08 AM
How "hot" is it running?

If the coolant is not low, I would suggest checking the purge line for flow.

05-29-13, 07:53 AM
Yep, what MoistCabbage said. No heat at idle indicates air in the line. Changing your coolant will do this. When I changed my thermostat my car did the same thing. The purge line was clear but the car started getting overly hot. I let set until it was cold. I turned the heat to max and then I removed the reservoir cap and started my car. I let it run until it got almost to running temp and then put the cap back on. If I remember correctly, I could see the air bubbles escaping. This resolved my problem. This may not be the correct way of doing it but it worked for me. Good luck.

John F
06-05-13, 01:23 PM
I appreciate the input however low coolant level and air doesn't seem to be the problem. The other night it got hot again to the point I had to pull over (was on the highway) and let it cool. Lots of noise from the heating core and....not a drop of heat from the vents even with the heat on. Common sense is telling me the problem is in the heating core but still don't understand why that would cause the engine to overheat. Going to have the entire system flushed - maybe that will work. If I'm looking at a core replacement how big of a job is it? Thanks.

06-05-13, 01:51 PM
Just my two cents worth, overheating engine and NO heat from HVAC is classic symptom of low coolant level or air trapped in system.

06-05-13, 11:28 PM
it's popcorn time

06-06-13, 01:52 AM
Lots of noise from the heating core and....not a drop of heat from the vents even with the heat on.The noise you are hearing is air in the cooling system. Again, check your purge line. If it's clogged, the system won't be able to purge itself of air, and the engine WILL overheat.

Don't get a flush. It's unnecessary unless someone's poured some kind of stop leak product into the system.

06-19-13, 07:07 PM
So, :pop2: did you fix your "air-lock" problem .? .? .
cause your thermostat does not like to function
with an 'air pocket':suspect: around it - as the coolant.