Oil Pressure goes up and down

What a coincidence Ron, my oil pressure gage jumped around on me Sunday & then finally went to zero. I had pulled over & checked the oil level at the first signs of trouble, the oil level was OK, so I knew it was either the oil pressure sender or the wiring behind the gage. If my pressure were truly zero, my lifters would have collapsed & made a terrible racket.

PCV valves won't help oil pressure, 2 valves are unneccessary, one good one is enough. Pull it out of the valve cover grommet & shake it, you should hear the little check valve inside rattling, if not, replace it.

Its not likely your oil pressure would fluctuate as you describe unless you were cornering at high "g's" or the oil level in the pan was low. As long as your oil level is OK, check the gage wiring and the wiring to the oil pressure sensor on the back of the engine block first, Amigo. Make sure the connections are all clean & snug.

George

Thanks for the briefing Gran Prix George Pence! What a truly brilliant analysis and plan of approach. This is the perfect project for me right now in the dog heat of summer. Just enough action to get me doing something needs to be done and feel good about it. Maybe not even break a sweat since I kept the garage door open to cool the garage.

I'm a gauge junkie and constantly glance at them going down the road.

Thanks again Amigo, and sorry I missed getting together with you at Coz's, but it's really hot there and here too. So hot there were nine (9) truck tire treads laying in the freeway, just coming back for 7 hours. Mr. Gauge Junkie ran over one because a car was driving in my blind spot for 20 minutes checking out my cat and I couldn't change lanes. Broke the GTS spolier up front, 2" crack, so I'll be learning fiberglass repairs shortly too.

Thanks again GP,

Ron

Ahem,

Ron....in case you haven't noticed....you live in a DESERT amigo!!!! And....it happens to be the middle of SUMMER!!!!

Seriously, sorry to read your spoiler was "munched". Hope all is well otherwise.

You know where I'm at if you need moral support, just holler.

George

Thanks George, us single and divorced guys hang together, and if all these single women would just stop calling and coming by at all hours of the day and night, life would be worry free....

Seriously, you were right, my Pantera pucked out half a gallon of antifreeze, and the little nut on the oil pressure sender was not so tight as it is now that I knew where to look and tighten. The little GTS spoiler is a scarificial lamb. It isn't munched, just cracked right in the middle, so a little fiber glass underneath and some bondo on top and a little glazing, some sanding and painting, and it's a weekend project. Without the spolier, the curled (now flat) truck tire tread would have dented my radiator screen, and maybe punched it loose and put a hole in the radiator. So, they said the GTS spoiler doesn't do anything, I disagree as you see. It's protection for the radiator. A truck tire tread shield - flatener.

It was worth it to go see an old buddy. Coz is at the top of his Pantera restoration and upgrading game. I learned a lot. How to polish my ZF myself, how to install a new bushing in a steering rack, how to lay down my radiator and use simple little parts from the hardware store for under $1, how to install sucker fans. Really George, Coz is into it and even if you sleep on his couch, it's worth the trip to visit a Pantera brother, even deep in the desert, in the middle of the Summer. If you want a road trip destination and just hang with the guys, work on Pantera's and drink beer or what ever, these folks in Phoenix are truly friendly folks. Coz and all the two dozen total strangers I talked to are actually quite outgoing and talkative folks.

Don't forget your sunglasses. I went outside mid-day without mine and I got a headache right around the eye sockets, it's that bright outside in Phoenix. Heading down into Phoenix from the tiny mountain towns is the most gorgeous canyon road with long sweeper turns, and once that BMW convertible sponsored me by passing at 100 mph, clearing all the cops free for me, it was a terrific drive. Hardly any traffic, no brakes in any turns, just G-force on my neck. My new 7/8" sway bar in the rear holds the front tires to the ground in the turns, no more understeering. Nice testing opportunity, all of course, within the confines of the speed limits, and all the laws, I assure you.

I'd go again, in the middle of Summer, well maybe not this Summer, at least not until another 3 day weekend.... Coz extended you an invitation, he means it. If you want to come to Albuquerque, you have a place to stay here too. Are you thinking ... Road Trip? It's good for the head, and not so hard on the wallet, and there's great people for you to meet. Freedom, once the home town is not visible in the rear view mirror anymore, no worries! Well, presuming all the gauges are working OK!

We will meet up one day and share a few jokes, it's a plan, definitely Vegas '04 (unless I get the Shelby Cobra GT500KR convertible and I am in the process of restoring it!! Never know...)

Ron

It was really great having you here Ron.
I look forward to getting together again soon brother. Your always welcome in my home and as part of the family.
Maybe when it cools off, we can get George to swing through Arizona, hook up with me and we both can drive out and spend a couple of days with you.
BTW, when you told me about your oil pressure after getting home, my first thought was possibly your oil pump may be having a problem.
Maybe not, but it was a thought.
One more thing, talked to Gil and I'll pick up your shirt at the next POCA Arizona meeting 7/13 and will send it off to you :-)

quote:

Originally posted by veryfast italain:
My oil pressure goes up and down. It's always between the middle (top) and the left (low), but not extreme left hash marks.

Oil pressure seems to go down when I'm going up a long mountain or when accelerating hard. Oil pressure seems to go back up when going down hill or on a long flat straight.

At times, in hot weather (over 105 degrees outside and closer to 125 degrees on the pavement surface) the oil pressure seems to jump around a little, even at steady speed (80 mph, 3200 rpm), flat, level roads. Oil pressure goes from middle location (35 psig) to the lower lever (17.5 or 20 psig).

What the heck is causing this? If I put a new PCV valve in will that steady out the oil pressure? Is it a good idea to put two PCV valves in the line?

Should I be concerned? I'm just guessing at low rpm, the vacuum is low and the oil pressure is higher, and at higher rpm, there's more vacuum and less oil pressure. Is there any relationship between vacuum and oil pressure? What's too low or too high for oil pressure with a stock 351-C? Thanks.

Ron, in the last 4 plus years of ownership I too have experienced the "bouncing needle" oil pressure gauge that makes one nervous. I tried two different oil weights, 10/40 and 20/50, various oil filters and even went as far as replacing all rod and main bearings.........all without a change.

Then last week I did my oil change and installed my Pure Power filter that I got "a deal" on while at SEMA. The oil pressure has been steady since the install, and I mean rock solid and consistant between the last hash mark and the 70 point. You can install these either with a bypass valve, or a block off plate so all oil must be filtered, I chose the latter. Note that the Pure Power filter flows 90% more per area than a conventional filter.

Could it be that the oil pressure flucuations are caused when the typical paper filter can not allow enough oil to flow through (oil pressure then drops) until the pressure inside the filter generated by the oil backing up causes the built in bypass valve to open (the pressure then goes up), this process repeats itself over and over giving us the bouncing needle syndrome.

Keep in mind this is just theory, but the filter itself is the only parameter that changed. Is anyone else running this filter that could provide feedback?

Ron

Could be oil filter, could be oil gauge, could be engine problems. One suggestion - the only way to know for sure is to install a mechanical oil pressure gauge.

I had flaky readings in my GT5-S, sometimes decent pressure, sometimes not, and I couldn't really establish any pattern. I installed a mechanical pressure gauge in parallel with the stock one and notice that the two readings are as diffferent as night and day.

I've spoken to other people who have noticed significant differences between the stock gauge and a mechanical one. In the end, I left the mechanical gauge permanently installed since it wasn't hurting anything and seemed useful. It's hidden in the engine bay to the passenger's side of the engine screeen.

I'm a gauge watcher as well and it drove me nuts to see low oil pressure. Now I am much more confident and comfortable driving.

IMO it's the only way to know for sure...

Charlie,

You are correct in your comments on having a secondary mechanical gauge, which I do. At rest I can check both gauges and they do concure with each other witch is why the needle flucuations REALLY made me nervous. But as I stated in my previous post, with the new filter all is well.

Ron