79 320 Overheating issues

[EconomicHustle]

Recently just picked up my car from the auto mechanic to do some general tune-up work I didn't want to take the time to do myself. After getting her back this morning and driving her about a half mile I noticed that the temp gauge was at about 80% so i decided to pull over and take a look under the hood. Car seemed fine, was a bit warm, however, i didn't feel that given the heat the motor was putting off it was anything alarming. At this point though I don't want to risk any damage to the motor.

I'm looking for advice on the quickest way to identify what the underlying issue could be - auto shop advised that they did a full inspection and that everything seemed to be fine. Checked the oil and coolant levels, tune-up and replaced the breaks and rotors. I let the car sit for an hour or so and turned it back over, after running it down the street and back a few times the temp sky rocket again.

Bottom line - whats the quickest and most effective way for me to find the underlying issue. All help appreciated.


I checked additional threads on the forum and found people saying - replace the water pump, ensure its running, check aux fan to ensure its working properly, replace the radiator and everything that comes with it. Rather than putting myself in a position of doing all of that I'd like to just locate the underlying issue. Once again I appreciate the help.

[bwesty]

verify that your water pump and thermostat are in good working order, maybe do a radiator flush too https://www.youtube.com/watch?v=s--5ft5YiHg

[MIKYZZ4]

Test fan operation,
perform radiator/cooling system pressure test.

[epmedia]

Maybe the belt is slipping and maybe it's also crooked from worn alternator mount bushings.

[320iAman]

Use an Infrared Thermometer to verify your having a cooling issue,really inexpensive now, these car gauges vary on voltage and so forth, aim at the coolant hose not metal.

Randy

[epmedia]

Hi Randy, the temp gauge needle position is not swayed by voltage variations - assuming all the electrical connections are good! I forget the terminology for this type of electrical style, but has to do with how the gauge's 3rd wire is attached to it.

[320iAman]

There are tests to confirm that,, As too overheating, it could be a sticky thermostat, clogged radiator-needs a flush,,fan belt too loose and several other items. Its a process of elimination to find the reason for overheating.

Randy

[gsumzzz]

if original, probably the radiator. new ones are cheap. i had same issue when i had first purchased my car. new radiator was like night and day. good luck.

[sgtfury40]

If it was fine before the mechanic, and he replaced the coolant as part of the tune-up, make sure the air is out of the system. This can cause an overheating condition.