Snizzlesticks

I've had my 88 F 150 300 in line six for about a month. When I turn anything electrical on my oil gauge will rise a bit. If I turn the heater on it will rise over thirty seconds or so to max it out, and it tells me the engine is running hot after a minute or so. Turn the heater off and all snaps back to normal. What could it be? Since it's even on 20 degree mornings I don't think it's for real. Any ideas or warnings?

memoniz

When I changed my a/c compressor, it seamed that my truck was spiking electrically. Someone said that a diode needed to be replaced. After ignoring it, the alternator went bad. Since I had bought one with a lifetime warranty at Autozone, I got a new one and have not had a problem since. I did not change the diode, and my temp gauge was running high before the new alternator. My battery gauge was also bouncing like crazy.

Oh, and when I turned on anything electrical, the gauge would drop. If I turned on the a/c, it would spike. Maybe check for diodes.

Snizzlesticks

A diode in what? Mine doesn't have an AC and the alternator keeps checking good.

memoniz

Your truck being an '88, I don't know the wiring system. I gather you don't have a power distribution box under the hood. In my '96, in the box, I have a diode. What for I don't know, never had to mess with it. The a/c one I was told is inline. You can check the schematics in a Haynes book to see if there is one somewhere.

Or maybe the heater core was replaced and they wired it wrong? Wish I could be more of a help but I'm not that good an electrician.