high oil pressure 550 98

I glanced at my oil pressure yesterday and noted it was higher than I expected for mid to low rpm's. Think I saw a 7 reading around 3k rpm.

 

I experienced the same problem a couple of years ago on my 550, at about 25,000 miles. The indicated oil pressure kept going up. It turns out that the problem was a failing pressure sensor at the front bottom of the engine. Replacing the sensor completely eliminated the problem.

 

I have mentioned this before. The sender seems to not like a lot of revs.- i.e. high oil pressure. Most of my mileage is on the track with the engine between 5 and 7K+rpm and I have gone through 4 senders in a year. The last time it decided to show no pressure at all, rather than the usual overly high reading, so I made the decision to change to a mechanical gauge.

 

would you tell me mileage? since i have only 6000 on my 2000 and have had it on track only one day(550) any oil pressure problems are good to know about

 

The issue is there are no oil pressure problems, the sender just gives bogus readings.

 

What is normal Maranello pressure per RPM?

 

It varies depending on the temp and viscosity of the oil e.g.
Cold Warm Hot Very Hot
Idle 7+ 5 3 1.5
7K ?? Max 6-7 4-5

 

I have the same problem with a one week old new sensor!! Or is it possible that the engine actually HAVE too high pressure? The car runs perfect!
View attachment 2888791

 

I believe the sensor is upstream of the filters. Too high a pressure might indicate partially or fully blocked oil filters.

There appears to be a pressure adjusting valve on the pump. The workshop manual has this dire warning:

Pressure is determined by the preload of spring "4" [in the valve]. This value is set during engine design and must never be altered.

 

Is it possible the sender is in contact with the sway bar causing a short to ground? Failing motor mounts will cause this.

I have remoted my sender, it is a simple task, you can put it anywhere you want with a bit of hose.

 

Something like that about to happen would have been noticed at the time the sender was replaced.

The contacts on your new sender are clean. Try cleaning the connector. And once this is sorted out, get John Cribb's oil pressure sender boot available at Ricambi America: Oil Pressure Sender Cover

 

I replaced the sender with a new one from Superformance last week. Just did a trip from Monaco to Venezia, up to Milano for a having a look at the awesome Alfa Romeo museum, and back. It is pretty strange how the needle act. Idle when warm shows about 2 bar of pressure. At 2.900-3000, it shows around 5 bars. But just over that, around 3.100-3.300, the needle bounce up to 10 and more revs sometimes show less and sometimes way beyond the scale at «12». I called the seller, and they can offer to refund and send me a new one If the one I send in is faulty..... It is quite a bit of work to change it as the car must come up, undertray down, stabilizer bar come off, both front wheels come off, old sender out (and the oil pours out too). Really anoying bow when I did all this myself and I have to do it over again.

 

Sounds more like you have a short or bad contact somewhere in the wiring or gauge. Works fine up until a certain voltage from the sensor, and then goes bad.

 

Thanks. I have noticed that the vibrating sound from the high pressure dry sump oil pump is sometimes more present than before. Or it is just that I notice it more. I don’t know actually... Why is it making that sound? Is it some kind of over pressure relief valve that opens up? Both my oil filters are just a couple of months old. I can’t understand why the engine can have more oil pressure than normal. And it is quite strange that a brand new original sensor will fail after a few days.

 

Is the oil temperature ok? If there was a blockage somewhere, I would expect unusual pressure and temperature.

There is a pressure relief valve, but I don't know what it does with the oil (dumps overboard or recirculates). Might be a good idea to at least check the filters for contamination and recheck oil levels. I assume the magnetic gearbox plug was checked on your last oil change.

 

I changed oil and filters in October and have done 7.000 kms. since. Should be no reason for two (both) clogged filters. Both level and oil temp is normal. The gearbox oil magnetic plug you mention is at the rear gearbox, and I would guess those are two different oil systems separate from each other? I have actually bought a new gearbox oil filter, and will change it soon.

 

Sorry, yes, you are correct. Not sure why I said that

If your temperature is ok, then I would lean towards an(other) indication problem or pressure control. Have you been using the recommended oil type?

 

I used Castrol Magnatech 10W40 full synthetic.