hi, A few times over the past few weeks upon starting my 2001 f-150 the oil pressure guage drops to to the lowest position and the red oil temp light comes on at same time.This only happens after truck sits over night.I shut her off right away then restart and same thing happens upon 3rd restrart all is normal.oil leval is fine but i have noticed a higher than normal usage of oil (about one quart in 600 miles) lately but am not dripping any on the driveway.Could these two problems be related and where the heck is the oil sending unit located on the 4.6? Thanks for everyones help,Andy

 

A qt/600 miles is not a good sign but...

How many miles on the truck and what have you been using for oil?

 

112000 miles,5-30 high mileage castrol,plugs have never been changed

 

Replace your oil sending pressure switch. It screws into the oil filter housing.

Oil consumption rate is getting up there, do keep an eye on it. Probably worn rings.

Steve

 

how big a job is repacing the rings$$$$$$$

 

A ring kit + labor, your looking at several grand. I know on a friends car his PCV valve was bad and it went through a lot of oil. Put a new PCV valve on and no more oil consumtion.

Do you have black smoke out of your tail pipe? Deos it leak any oil? If so, where is it leaking?

 

No does not leak oil to ground, i will have to check on the smoke,thanks

 

Changing the PCV valve is a good idea. Besides the rings, the next thing that will cause oil consumption are the valve guide seals. If the valve guide seals are bad, you will get a puff of blue smoke (NOT BLACK AS PREVIOUSLY POSTED) when you first start it after sitting overnight. So, have somebody
watch your exhaust, after sitting over night.

 

After changing out the pcv, your next step would be a leak down test. If you're lossing oil via the valve guides, or valves, or rings, I would think it would show up as a decrease in compression somwhere. This would show on a leak down compression check.

With 112K, if the oil has been done regularly with the 5-30 you mentioned above I would'nt think it's related to valve seals, valves, or rings. However there has got to be some reason you're using a qt/600 miles. How hard on the gas peddle are you?

 

A leak down test will test for ring or valve problems, but not valve guides & valve guide seals.....

 

Right Bob. Got a little carried away.

 

We have a 1997 F-250 LD and every once in a while when we go out to start it a cloud of blue smoke occurs. It doesn't do it all the time. It doesn't use any oil either. Should we be worried? I've notice my F-150, my step mom's Taurus, and my sister's Taurus do this also.
-Matt

 

That puff of blue smoke usually indicates the valve guide seals are leaking.

This is a pretty minor annoyance for the most part. Oil consumption due to this is not very significant until the problem gets really bad.

Steve