how accurate is the oil pressure factory dash needle? when I first did my oil change with the delvac 1500 miles ago it was toward the high side, now its staying near the low and doesnt go past the Mid part of the gauge, is it worth it to install an oil psi gauge? I saw them for like $30 at advance auto, and if this is indeed the route to go, where do you put the actual "sensor" for the new gauge?

 

not worth a damn bud. after market gauge is the only way to go. and your oil pump, no matter what rpm will only go so high. it peaks out. and you would put the sending unit (will be a tiny white/clear hose that runs to the gauge. you put it on the back of the block, right against the firewall facing straight up.

 

oh okay, whew coming back from a lawn customers house today and the gauge was almost pegged at the low mark, scared the heck outa me, my goodness I need to get some more lawn contracts going lol always money money money

 

ya, you can get the install kit from autozone or kragen right off the shelve. im sure harbor freight has the gauges too. i know joef350 got a voltage gauge from there.

 

Its not a gauge in anything after 1987, its an idiot light. Seriously, it uses an on/off pressure switch that turns on at 7.5 PSI and switches off below. The slow rise to pressure that you observe when you first start the truck is made possible by a thick grease that slows the needle down.

Older trucks have an actual diaphragm connected to an internal potentiometer to provide the variable signal. Rangers evidently started doing this even before the F series. I found an 85 ranger that used a switch style sensor even though it physically looked identical to a diaphragm version.

So, yes mine does read a little better and varies a little based on operating conditions but its still not really telling me a lot. I put a really low end electric oil pressure sensor kit in my sister's diesel ranger and holy crap what a difference!

Rev it up cold and it pegs at 100 PSI. Idling hot, 20-25 PSI. Cruising in the mid range, 40-50 PSI. My gauge never resembles that kind of variability based on operating conditions. Hers is practically almost like a tachometer. Electric gauges also respond more quickly than mechanical gauges since you don't have the long thin line from the engine to the cab to get pressurized before a valid reading shows up. Also no risk if filling your lap with crude oil if the line pops for some reason.

 

M for oil pressure means what?

M for coolant temp means what?

My factory ameter has never moved from day one, so what it says don't mean anything either.

Aftermarket oil pressure, coolant temp and a volt meter that have numbers on them is a much better way to go if you want to know what your engine is doing.

Mechanical or electric gauges, the choice is yours.
They both have advantages and draw backs, but at least you have numbers to work with insteadsof O or one of the other letters.

 

Thanks for the tips guys, I think I'm going to go with electronic gauges