Good Morning
I'm a newbie and need some help.
Own a 97 F150 XLT, 100k miles. Starting last winter, when I first start, the temp. quage will climb to normal and then fall back to cold for a couple of seconds, blows cold air, then shoot up to overheat for about 10/15 seconds, blows hot air, then fall back to normal. When this happens I shoot coolant out the overflow at the filler bottle and my add oil warning light comes on but goes off when the temp. falls back to normal.
This has my mechanic buffaloed and is driving me crazy.
It does not seem to happen in the summer, only cooler winter months when I am using the heater.
Any ideas or suggestions would be greatly appreciated.
Thanks
pdubs4143

 

Test your coolant for correct mixture and freeze temp. If something like a heater hose or radiator hose is plugged or freezes it could do exactly what you said.

 

Thanks for the come back. Additional info.
Replaced thermostat and radiator last spring. Coolant is at proper mix. and temp. Have not had heater hoses checked. Ran truck this morning and had no problems. I backed temp. control **** off to about warm/cool and shut down heater control ***** to off position. When temp. guage read normal turned everything back to on and full red on temp. control **** and evrything worked fine. Not sure if my problem is intermittent or not at this point in time. Also wondering if an air bubble in the line would cause this problem.

Thanks again.
pdubs4143

 

Have him test for exhaust gasses in the coolant.

JMC