2002 Temp Gauge Skyrockets In Prolonged Idle and Coolant Gurgles at Shutoff.

[Squigs]

Hey guys,

So my 2002's temp gauge will creep to the max if I idle for any period after running for more then 10 min or so. It also will idle rough sometimes, (jump between 800 and 1500 rpm.) When I shut it off I hear a gurgling sound coming from the radiator/coolant reservoir. My reservoir level is slightly below the MIN line and dosent move even at full running temp/redlining gauge. I was thinking maybe its just a low coolant issue? Or a thermostat problem? I have a 270 mile roadtrip on Monday and need to figure this out ASAP.

Thanks.

[RacerXXL]

I'd take a look at the fan to ensure it is turning and at the correct speeds. May be time for a new fan clutch.

[RacerXXL]

Also is this the original radiator cap? How many miles on the truck? May want to replace the original cap as over time they wear out and allow the truck to overheat more easily.

[Squigs]

Original cap, 110,000 on the truck. The fan seems to be running normal and its blowing cool air. As soon as I start moving again the temp gauge creeps back down to mid range and only goes up when stationary or in park.

[Squigs]

Also the coolant in the reservoir dosent fluctuate at all when the truck is hot or cold. It stays a hair below the bottom mark and dosent move. The top radiator hose gets pretty hot too.

[ShiftingSkys]

Ok so this is an idling problem only.
I would Check Things in this order.
#1 Check coolant level or better yet Drain the coolant and refill with a new blend to ensure proper blend AND see what comes out with the coolant.

#2 Check the radiator cap. Replace it since they are cheap and it is old.

#3 Check the Fan clutch to see if it is spinning as it should.
Rev the engine to 2-3K and see if the fan is spinning as such. Also Note whether your bottom Fan shroud is still in tact.

#4 Leave the X overnight and in the next day check the thermostat. Drive the X until it completely warms up. Time the amount of time taken to warm up to proper operating temperature. It should be no more than 10 minutes. I would also suggest that you just change the thermostat since it is cheap and relatively easy. Failing to warm up after 10 minutes is an indicator of sticking open. usually the indicator of sticking closed is overheating usually at idle.

If these do not solve the problem then let us know.

Also Do not take much stock in the reservoir. My brother has a 1994 F150 and the reservoir was full. when I asked him to check his coolant since it started to overheat he came back saying it is full. I go out remove the cap and the radiator was near bone dry. Needless to say a proper fill and bleeding did a world of good. No more overheating.

[RacerXXL]

Also are the radiator fins clear of debris? Has it been mudding lately?

[Squigs]

Ok guys so I opened up the air relief screw and topped off my radiator like RacerXXL said and she took a lot more then I thought she would. Problem solved. Got the air out and got my coolant levels back to normal. Just took a 300 mile trip back down to school and she didnt skip a beat. Thanks for the help!