Random Temperatures while driving 03 at

[green240sx93]

G35 sedan (AT) Recently my car has been acting a bit funny. I can be driving in the street and all of sudden my temp gauge goes to the 2nd highest line and eventually goes back down to normal. On the freeway, it will go up and then go back down right away. Should i begin to worry more

What is weird is that this begins after a while of driving and it has become an annoyance having my gauge go up. Any idea what it could be?

Already replace the thermostat and had a cooling flush done,but still does the same thing.....can someone please help me?

[SteveTheTech]

If the car heats up too much on the while cruising you may want to check for any debris either in front of the condenser and/or radiator. Also the 2003 has a mechanical fan and the clutch may be starting to go.Another possibility is that when the coolant was originally flushed if the system was not pulled into a vacuum of at least 18"hg and the crucial step that many people overlook is purging the feed line before allowing the system to begin refilling.

To start I would see if the engine temperature is actually increasing if all the above things are known to be in good working order. A wise investment may one of those infrared digital pyrometers if you plan on doing this yourself as you will need an accurate reading at several places throughout the engine bay.

[fixer]

sounds like you might have an air pocket in the cooling system, you can use a vacuum type refiller or you can bleed the system manually. Does the heater blow hot when idling engine? if not there is a bleeder on the heater hose. attach a fill bucket to the radiator opening and fill bucket with coolant mix. run engine to warm up and rev to 3000 rpm for a few more minutes, shut off and bleed air from bleeder. repeat steps several times until all the air comes out.

[green240sx93]

Took it to dealership,they flushed it again, still did the same thing so they told me it could be water pump or the radiator clogged. I replace the water pump, and waiting for after-market radiator to come maybe that will do the job. The car always had heat. take like 40min of driving or it to happen. Took the radiator out of the car when i replace the water pump,there was alot of debris in between rad and condenser. Hook up the hose to the the top of the radiator the flow though the radiator was slow.