Vazcular

Hello. I aquired a 1998 4.6 F150 with about 275,000 miles last year. The engine ran cold all the time, even in 90* temps. Barely above the start of the "Normal" range. The past two weeks it has started overheating @ highway speeds. Now if I just let off the gas and cruise it will start quickly dropping. If I pull up to a traffic jam within 20 to 30 seconds the guage is way down to 1/4 the way up the Normal range. Someone told me the thermostat could have been stuck open before but is now sticking closed.

It doesn't seem to overheat until I drive over 50/55mph....

Since I have had the truck if I press the accelerator close to flooring it the A/C stops blowing until I ease up. Not sure if any relation.

I used to hear the water/coolant flushing around. Now I don't hear it at all.

No warning lights have lit up yet. I pull over or slow down before the temperature gauge can reach the red.

Any help or advice will be greatly appreciated.

Thank you

screamineagle

Could be air in the cooling system. Bleeding the system would be a good place to start.

Ratsan_Fratsan

New thermostat, flush the system using a good antifreeze/mix, and check your electrics. Sounds like something is not right. Also Does your coiling fan work and make sure you don't have anything blocking air to the radiator. Some of the fancy grills can inhibit air flow.

Vazcular

Thanks for the replies. I actually checked the oil and it was barely registering on the dip stick. I added three quarts and it's now fine. I lost approximately three quarts of oil in just about 2,000 miles. My oil pan is leaking, but it's just a few drops the size of a couple of quarters. I'm going to check if it's leaking from where the oil filter is screwed in. It's just difficult for me to get under the truck with my bad knee. I'll have a friend check it out.

Gene45

Is the cooling system full?

Vazcular

Yes.