Oil pressure

Hi
I've only had the car a couple of months, oil pressure seems low and after it gets warm and the pressure gauge rides near the bottom of the normal range, we hooked a real gauge and when cold it has good pressure and as it warms up looses it and warm it's barely within specs, what I am wondering is why is it so strong when cold, is it because the oil is thinner cold and easier to move?...And as time goes by the pressure looks to be maybe getting better, I know the car sat for awhile and maybe the oil pump is a little cloged up? I don't know, just asking becaues I am using a half of a Marvel Mystery oil with the last oil change and the pressure looks like it might be getting better, diffently higher when cold and when cold I have less valve clatter...Is there something else I could add to the oil to clean the pump, if this sounds right.

Oil pressure is always better when cold because the oil is thicker, not thinner. If you've added anything to the oil as far as a cleaner ect. I would suggest changing the filter at least once between normal oil changes and top off with oil. I doubt that your oil pump is 'plugged' as it would be caught at the pick-up screen first and once able to flow through that...the filter would grab it. Hence the needed mid-scheduale filter change.

When you see a pressure drop at normal opp. temps it (usually) suggests that you have either bearings or cam bushings or both, that are on the fringe of specs.

Oil is thicker when cold and more resistant to flow, which is why the pressure is higher.

I doubt the pump is clogged. Pressure is a measure of resistance to flow. The only way to get higher pressure(forget the pressure relief valve) is to reduce bearing clearances (less flow) or increase viscosity (more resistance)

How many miles does the engine have on it? What grade (weight) of oil are you using?

Have you looked under the valve cover to see if the clatter is due to a worn cam?.

Assuming you are using the proper weight oil, low oil pressure could be due to excess wear in bearings. What readings did you get when the oil was at operating temperature?

The engine has 105,000 on it, it has 10w-30 and I forget the readings as we did it when I first got the car to make sure it was ok, but if memory I good I remember around 60 at idle cold ~1500 rpm and warm it dropped to like 30 I think, but holding the rpm's at 2000 warm it was ~40 which I read is low but within range.

Have not looked under valve cover...if I do that much I have to replace all that I can while I am there, that's just the way I am, and that seems to me to be quite a bit of work/money and times being tough, I don't want to do that unless I really need to.

Ford spec is 40 to 60 psi oil hot @2000 RPM. Every Ford I have had has run on the low side of that spec..... low 40s @2000 RPM with oil temps 180 to 210 deg.

I used to have a '62 Ford that idled 13 lb of oil pressure hot and never got over 25 lb hot no matter what the RPMs were... as A 18 year old kid, I couldn't kill it and sold it to old guy that ran it a couple more years before the transmission died(I had killed the orig trans and had one from a '58 Ford in it)...

Since your in Florida where it never really gets cold, try some 10W-40 oil and see if you get better pressure when it's warm. Like Jeff K said, 40lb pressure when warm is not too unusual for a TC with some miles on it.

Thanks for the help!

Originally posted by TurboCoupe50:
I used to have a '62 Ford that idled 13 lb of oil pressure hot and never got over 25 lb hot no matter what the RPMs were... as A 18 year old kid, I couldn't kill it and sold it to old guy that ran it a couple more years before the transmission died(I had killed the orig trans and had one from a '58 Ford in it)...

gotta love the old ford slushomatics! :p