2000 Buick Century Heating Up

[davidinlaveen]

My 2000 Buick Century is heating up, but only in the morning.


I live in AZ. The Buick runs and cools fine, even throughout the the 115° F summer. Now that the weather has cooled (say 75°F at 7 AM), it is having slight cooling issues that its never had prior.


Here's the symptoms:
I'll drive to work - 30 miles. No problems until I get off the interstate and pull into the parking garage. It takes me 2 minutes from interstate to garage.

Once I slow down and get into the garage, about 10 MPH, and drive up 2-3 levels, the engine suddenly heats up as much as 3/4 of the temp gauge (still outside of the red, but close). If I am able to speed up, it will slowly cool down again.


This symptom is repeatable, and happens almost every day.


No issues going home (although I probably don't have the opportunity to slow down that much, but always keep at least between 25-70 mph speed).


No issues at stop lights, I can also idle for 20 minutes or more w/o problems.


Also, it runs rich when its first started (I can smell rich exhaust).
Also, when it is at operating temperature, the idle can be intermittently fast - maybe as high as 1200 rpms.


No change in coolant levels, no air comes out of the coolant bleeder valves, no change in oil levels, and no puddles. I'm not able to hear any vacuum leaks (but those are tricky). it starts, runs, rides like a dream. (Not that this matters, but looks brand new as it was always kept in the garage or covered parking).


It has 130k miles on it.


This seemed to start after a radiator flush and thermostat change in August at the local mechanic.

Sorry about the long info dump, but wanted you to have all the info.
Any ideas?

Thanks

[Blue Bowtie]

Are the fans running as the temperature increases?

[davidinlaveen]

The fans run on "low" speed during the above mentioned episodes. They do function on high at other times however.