Oil Pressure Question

I have had my car for a year. In November I installed the spin on filter adapter. Warmed up car idles a needle width under the 2BAR line. Cold winter starts the oil pressure would always go up to 5BAR. Running Motul 5w40. IDLE = 1.9BAR 2000 RPM = 3BAR 2800 RPM highway 5th gear @ 70mph= 3.8BAR 4000 RPM = 4.6 - 4.8BAR 5000 RPM = 4.6 - 4.8BAR Maybe its just me, but the car no longer seems to hit the 5 BAR line @ 5000+ or cold start.... and I could swear it did prior? The car was driven all winter, but right now this is really the first time I am driving it in temps above 60F, since installing the spin on filter. I am not sure if this not hitting 5BAR is a recent change, or if I am just being hypersensitive to it. Car is going to my indy anyway on Friday for 6mth (3800miles) oil change, but just figured I'd ask if this is normal or should the motor def be hitting 5BAR? Thanks in advance.

Normal to not hit 5 bar at operating temp . Discussed further here: https://rennlist.com/forums/996-foru...-start-up.html

You�ve always been running the same 5-40 Motul? My car behaves like yours used to. If the only thing you changed was the spin on filter, the only way to know if that was it is to go back to the old filter housing and try it. If the oil brand or weight has changed at all, then it�s the oil most likely. What oil was in the car before you had it? You might not know. It could have been thick. Even if you did an oil change, there could be some old, think oil in there. Final comment - the oil pressure gauges are not super accurate. I�ve seen the gauge off by 1/4-bar just by turning the car off and on again - the needle sometime sits at 0.2 bar when off, sometimes at -0.1 bar. So I sometimes hit 5.2 bar or sometimes hits 4.9 bar

Sounds pretty normal to me. Might go up a bit after the new oil change, but I wouldn't worry about it. In addition to what Murphy says above the sensor can is not all that accurate, either.

Most likely what your seeing is before with the OEM set-up, you had a filter system with a bypass valve that open when you had a cold start and bypass oil and you had a higher pressure then, now you have the L&N filter adapter that uses the oil filter with no bypass and now reading slightly lower pressure. same happen with when I did the swap and I'll stick with the no bypass L&N system, no reason to go back to the original system, you know now your getting clean oil to the rest of the engine.

When i bought the car last may, i did a fresh oil change to motul 5w40 right away. I do not know what PO ran as i got it at a dealership. I changed the oil in November, and added the spin on filter. Since installing the spin-on filter, during the colder months i remember the pressure going to 5bar immediately upon start. Now its going to 4.5. It will go to 5bar when revving to 3000 and the oil is still cold. I will see if the oil change restores it to "normal". I was just used to seeing the needle at 5 more. Now as the ambient temps are improving, i am noticing it stays lower. I checked a picture from when i bought the car last yesr, my highway cruising pressure @70mph is the same as now. Then again my sender could be going...lol.

Quotes source post: 14961971

If your sender goes bad, like mine did...you will know it. Dash goes "ding" and when you look down to see no oil pressure on gauge, then it pops back up to normal, then zero and dash now says "oil sensor failure"(or something to that effect). After you catch your breath and clean out your drawers you realize it is just a bad sensor...hopefully!

Quotes source post: 14961956

Technically this is correct - the oil pressure almost certainly MUST be lower, even if only 0.001%, because 100% of it must go through the filter, which causes a slight drag (friction). However, any oil pressure that cannot make it through the filter and get delivered to the engine can still be bypassed from the oil pump to the oil pan directly. The result could be very slight oil pressure drop, although I�m not sure if anyone ever noticed it, or if the oil pressure drop would actually register.

Quotes source post: 14961971

What are your ambient temps? How hot is it getting? I still have 5 bar even if it�s 90F outside on cold start. And over 3,000 RPM. I don�t think oil senders go bad all the same way. I would keep an eye on it. If you really want to check apples-to-apples, then put the old filter and housing back on without changing the oil or anything else. Also, I�m sure it�s rare, but if the filter is defective or collapsed, or there�s a blockage, well, that could cause a pressure delta, although I would only check that if the old filter had higher pressure after your swap.

As long as you have oil Pressure, and therefore Oil Flow, does it really matter whether the gauge shows 4.8 bar, or 5? If everything else seems normal, doesn't sound like something I would worry about.

Quotes source posts: 14962426, 14962511

I am going to try and get the car in for an oil/filter change on Weds... but to be honest unless the filter failed I am not expecting any change. Tonight on the commute home, I def noticed the sender/pressure gauge seems alot less responsive then usual. A rev will be very "laggy" to register on the dash, much more then I remember in the past. And will rarely just jump to 5 out of nowhere. If you just turn the ignition key but do not start, the gauge sits @ 1.2BAR. My suspicion is the sender is slowly failing. Your probably right, but my oil pressure gauge is definitely acting different past week or two. M96 shell shock syndrome...It will bother me until I fix it.

thanks for this thread, as it confirmed for me about the right oil pressure the car ought to be at. i was a bit concerned seeing it all the way at 5bar on (cold) start up and not dipping til temp has gotten to where it should be (at 12 o'clock position).

Oil changed today....made no difference. Indy didn't seem too concerned when I asked about it, said my pressure was good. I will replace the sender next month to see if that gets it back to 5. If that doesn't do it, might drop the sump next oil change just to sanity check that nothing is obstructing the oil pickup screen. Good news is that they cut open my old filter and said it was clean inside, no metal. And I have an oil sample going to the lab. I will update thread when I replace sender for anyone interested.

Dumb question, but why not change the one thing that was changed that caused the change in pressure? Why change other things to rule out the problem?

Quotes source post: 14968171

Fair question. I checked my service folder, and I installed the spin on filter adapter Oct 31,2017 (4000 miles ago). The oil pressure reading has been perfectly consistent since I bought the car in May 2017....up until a week or two ago. I had the spin on filter installed almost 6months, and had no difference until about 2 weeks ago. Oil gauge does some strange things. Every other week or so, driving down the highway the pressure gauge will randomly shoot to 5 for a split second (has done this randomly since I bought the car). When its idling just about up to temp.... the gauge will start bouncing up and down between 2-3 fast (also since I bought the car). But pressure levels starting, etc were always consistent. Seems like a good case to put a fresh sender in.

I see, so it wasn�t directly related to the LN adapter. Makes sense now.

I would install a updated oil pressure relief valve and spring first. 5 minute job. it helped my car.

John i have read about that but didn't know if it would help. Thanks I will do some searching. What was your experience before and after changing it?

Here were my results. https://rennlist.com/forums/996-foru...il-change.html

Quotes source post: 14968847

Ha other then the wheels our cars are nearly identical. Grey cab / grey top. Thanks for the info. Question, do you have to drain the oil to remove the oil pressure relief valve?

Some guy's can do it quickly, I prefer to take my time and look over everything, with oil drained... i have no problem draining good oil and reusing it.

WOW!! I am glad my paranoia got the best of me. In doing research I found a few threads of others having strange OIL pressure readings....That had AOS issues. So went outside and started the car. Two things. 1) My AOS was replaced 11months ago when I did my IMS! 2) I just started the car, then pulled off the OIL cap. Cap was very hard to remove. Once I did....Car immediately started choking and sputtering.... (AOS Diaphragm??) Have appt with my INDY who did the AOS last May on Weds.

AOS was fine, pressure sender was fine. Oil pressure relief spring snapped in half, and coiling in on itself. Cheap fix I will take it! And got my first oil analysis back and everything was average.

Oil pressure relief spring and piston replaced. Problem solved.... back to 5bar on starts and any rev over 3k!!!! If you oil gauge is very laggy and delayed response when you hit the gas...and slowly losing maximum pressure on cold starts and rev's.....you want to get your relief spring checked ASAP. @johnca58 Good call man!