I just purchased a 1998 F-150 Super Cab 4X4. Drove it home from the used car dealership and noticed that the truck was leaking water? (odorless, colorless fluid) from underneath the fromt passenger side of the truck. With the truck idling in the driveway it is a continuous drip. I noticed that if I turn off the heater it evenutally stops and if I turn the heater (blower) back on again it starts to drip rapidly (A/C is NOT on).

I unfortunately know nothing about cars/trucks and am really worried I just purchased a $19,000 problem. Is this problem with the heater core, head gasket, other? I did a few searches on the forum here but couldn't find an exact match for the problem. At the rate it leaks I can't believe this is normal.

Please advise, I'm going to have a hard time sleeping tonight! Purchased the truck as-is, no warranty, can't afford an expensive fix. Thanks!

 

Sounds like your A/C system is actually on. Don't go just by switch position. Pop the hood and visually check to see if the compressor is cycling with the "Heater on".

If it is (99%) then cycle the switch marked "A/C" (push button?). Did it stop?

Yes, you've solved the problem (check the led or lightbulb for the A/C switch).....

No, next step. Now move the air position switch to "Heat" (idiogram showing a guy seated with an arrow pointed at his feet). If the cycling stops, the system was either in "MAX" or "DEF". These two positions automatically cycle the compressor on. They help in certain conditions but if you don't watch it, you'll end up wasting a lot of fuel and putting excessive wear on your A/C system.

Read the owners manual (if you have one). This will tell you all about the different switch positions.


Larry

 

Sleep well my friend, it IS normal.
The AC compressor operates in ALL modes except PANEL and FLOOR.

1999 F150 4x2 Lariat RegCab Shortbed
5.4L 3.55LS Tow pkg

 

Larry, Raoul,

Thank you both for the quick and accurate response! Found my owner's manual under the seat and it confirms exactly what you've both stated. Truck is running great so far; really enjoying it. If I ever have questions in the future I know where to turn (and yes, I'll read the owner's manual first!).

Thanks again,

Brad