the owners manual for my 'new' truck (1992 with 4.9) says 5 quarts of oil. I just bought a Chilton's today that says 6 quarts.

5 quarts brings it 1/8 inch below 'full' on the dipstick.
Should I just add another quart and scratch a new line on the dipstick?

thanks,
Matt

 

just add until the dipstick reaches 'full'

 

I hope somebody with the same year and engine will give you a definitive answer. Until then, I suggest doing what Donate54 says.

 

I'd go w/the owners manual....I have a Haynes manual that lists the WRONG tranny fluid (Dextron vs. ATF +3) for my wife's Dodge Intrpeid.

I think Chiltons and Haynes are great for the mechanical fixes pics etc, but I don't think they put the same detail in the routine maintenance sections. I have found several errors throughout the yrs about plug gaps, fluid capacities etc.

 

FORD TRUCKS HAVE BEEN USING SIX QUARTS SINCE THE EARLY 90'S PLUS FILTER, CATCH UP TO SPEED MAN.

 

Well since he's talking about a '92 model 'early 90's' may or may not apply... How about catching up on what was asked?

 

Yeah, I know that this isn't a huge problem or anything, its just that I do know that dipsticks, contrary to popular belief, are not scientifically accurate measuring devices...

and while i am sure that 5 quarts are fine, I know that 6 quarts are better.

 

Well, overfilling isn't good either. In fact, in some ways, it's worse because you don't know it's a problem until it's too late. At lease with underfilling, you can hear the engine clattering.

When you overfill, the crankshaft hits the top of the oil and whips in air. If it goes on long enough, the oil turns into a thick frothy whipped up mess that doesn't lubricate the parts and the engine will seize.

If 6 qts doesn't make the level go over the full or max mark on the dipstick, then there shouldn't be any problem, assuming the dipstick is the proper one.

 

What I was saying is this...

that oil pans are designed to hold a certain amount of oil before you get into any foaming problems (crank hitting oil)...this amount is independant of what the dipstick says.

dipsticks are very simple devices that give a 'more-or-less' correct measurement.

I meant that 6 quarts are better simply because that is 20% more lubricant, 20% more 'coolant', 20% more detergents...