Oil Pressure - 1974 F 1.5

[Tecagist]

So I recently purchased a "New" 74 FJ40. Oil pressure was within normal ranges on the cluster gauge (dead center). I just changed the oil, oil filter, etc.. and now my oil pressure is borderline high. I have not checked with a manual pressure gauge as everything seemed fine prior to the oil change. I decided to go with CASTROL GTX classic 20w 50 and a K & N Oil Filter. Oil level is right at Full mark. Given the noticeable change in oil pressure and the fact that it is currently borderline - see picture, should I be concerned? My initial thoughts are the oil viscosity of the 20w 50 Castrol or that perhaps there is an issue with the oil filter. Any thoughts would be appreciated.

 

[charliemeyer007]

Its cold in Washington. Once the engine is at temp, I'd bet it reads normal. My 72 never read accuracy even with a new sender. I put in a direct read gauge. I carry a plug for the block in case the plastic line breaks. I also ran fuel hose over the plastic line from the back of the gauge to the engine side of the fire wall - no face full of hot oil if the plastic line broke at the gauge.

 

[Grayscale]

Put on a new filter and hope it goes away? It might be stuck in by-pass, allowing full pressure from the oil-pump to the unfiltered side?

Is this pressure reading with a warm engine?

 

[Tecagist]

Its cold in Washington. Once the engine is at temp, I'd bet it reads normal. My 72 never read accuracy even with a new sender. I put in a direct read gauge. I carry a plug for the block in case the plastic line breaks. I also ran fuel hose over the plastic line from the back of the gauge to the engine side of the fire wall - no face full of hot oil if the plastic line broke at the gauge.

Thanks - I did bring it up to temperature and pressure did not decrease. I just removed some oil to bring it midway between Low and Full with not much of a change in pressure. It may be worth checking the pressure manually and like @Grayscale suggested, try a new filter.

 

[Tecagist]

Put on a new filter and hope it goes away? It might be stuck in by-pass, allowing full pressure from the oil-pump to the unfiltered side?

Is this pressure reading with a warm engine?

Thank you @Grayscale and @charliemeyer007. At start and after warmed up the pressure remains the same. I'll try a new filter and cross my fingers that it resolves the issue. If not, I'll buy a pressure gauge and check the pressure manually. Crossing my fingers. I'm optimistic though given the pressure was fine prior to the oil change.

 

[Tecagist]

Okay, here is an update. Changed the oil filter and warmed up the engine. Still sitting right at the line between normal and hot. Looks like it's time for a manual test. @Grayscale, @charliemeyer007

 

[Grayscale]

Mine would almost go to where yours is, twice last summer. I was running 5W-30, like mid-September, 10,000-feet-above-sea-level. This is where mine is right now at idle. Perhaps if I was using 20W-50 would the needle go up, as it might be more resistant to flowing thru the oil galleries?

 

[mrboatman]

When you put a manual gauge on. I bet you will be around 60psi.

 

[Mark Jennings]

20w50 is a bit much here in WA….maybe in summer eastern Washington. A good 15w40 is pretty normal for this part of the country.

50 to 60 pounds cold, 25 to 30 pounds warmed up, summertime temps. On 100 degree days, a bit lower at idle….

 

[Pighead]

The stock gauges are notoriously inaccurate and slow to react, little better than idiot lights that move. I refuse to drive mine without a real, mechanical oil pressure gauge.

 

[3_puppies]

hard to use the gauge as idea on amount of pressure
the gauge is more of a tell if you have oil pressure

 

[dazerb]

Mine's been pegged at "H" for 17 years... FWIW.

 

[GA Architect]

Hot or cold, with 20W-50, mine rides right here most of the time.

 

[Tecagist]

The stock gauges are notoriously inaccurate and slow to react, little better than idiot lights that move. I refuse to drive mine without a real, mechanical oil pressure gauge.

View attachment 3857145

Had to laugh while reading this. Thank you @Pighead

 

[Tecagist]

Hot or cold, with 20W-50, mine rides right here most of the time.

View attachment 3857218

Thanks! This is helpful.

 

[Tecagist]

20w50 is a bit much here in WA….maybe in summer eastern Washington. A good 15w40 is pretty normal for this part of the country.

50 to 60 pounds cold, 25 to 30 pounds warmed up, summertime temps. On 100 degree days, a bit lower at idle….

Thank you Mark. I’m betting that if I go with 15/40 I see a drop.

 

[Tecagist]

Appreciate all of the feedback and pictures. I’ll monitor it for now and go with a lighter weight oil next time and see how that changes things.

 

[RevISK]

Thanks! This is helpful.

Mine is the same.

 

[Mark Jennings]

Thank you Mark. I’m betting that if I go with 15/40 I see a drop.

I live in south central WA….summer temperature are hot….July and August most days hover around 100. I run Shell Rotella 15w40 year round in my 68 F engine. I also have a Dakota Digital dash that gives a number vs. a line or 2. Cold start, oil pressure indicates 60 psi…..pretty close to the oil gallery relief set point. At 2000 rpm, once the oil is warmed up, I see 35 to 40 psi. At idle, on uber hot days, I’ll see oil pressure down to 15 to 17 psi, on colder days at idle….maybe 25 psi. However, once rolling, she comes right back to 35 to 40 psi. The spec on these old F and F 1.5 is 44 psi, at 2400 rpm, operating temperature with straight 30 weight oil.

 

[B y r o n]

Your oil is new, your filter is new, so you're getting good flow. Being at the high line is not bad. As the oil warms or begins to thin and the filter gets dirtier, the pressure will drop. I'd say you have nothing to worry about. You'd have more to worry about if it started at the low pressure line.