Low oil pressure - should I be concerned

OK - I've done a search, but my heart rate/blood pressure is still high. I need some reassuring words.

I was bringing the car home today (it's been away getting some work done) and got stuck in Rush Hour traffic. Really horrible traffic. The good news is - water temp hung in right at 195 and oil temp at 210. Here's what almost caused me to have a heart attack.

While idling (and hot) - oil pressure hovered between the first hash mark (42 psi) and 0. Seemed closer to 0. Never low enough that the red light came on, but too close to zero to make me feel good. The brief minute traffic moved, pressure would come up between the 42 psi mark and the 85 psi mark - about halfway betweed (I guess about 60-65 psi)? Then I fet better. But at idle - sheesh....

Anyway - got home, and added some oil, figuring it might be low. It wasn't - which is another problem I'll now have to fix. By the way - car is running 20/50.

Did a search and I see that inaccurate Veglia gauges/senders are a common problem. It still doesn't make me feel better.

So - what's the "operating pressure" typically? My car is idling steady at 800-1000 rpm. I know you don't need much pressure to get things oiled, but that low was killing me? Also - I realize that it's not a problem. It took me an hour to get home, and there was a lot of idling. If it was a real oiling problem, the engine would have cratered.

I'm so tempted to order the sending unit from Superformance right now.....

Please stop me.

 

Test with a mechanical gage and proceed from there. Also check along your oil cooler system for leaks.

The oil sending unit is separate from the low pressure warning switch. Without the light going on I would blame the sender but still test it mechanically to verify

 

Agree with above. Mine would never go 85 even cold at rpm. Used to sit at about 20 hot idle. Hooked up a mechanical gauge and it was sitting at 85 cold idle and 40+ hot idle with immediate climb to 85 off idle hot.

Swapped sensor with a new one and the gauge reads much more accurately. It was little bit of a pain to get a wrench on the sensor but it can be done. Just be patient.

 

You should read your owners manual.

 

Glassman - I'm assuming you are referring to pages 60 and 61? yeah - I see that.

SteveG/MNExotics - thanks. I see now it's p/n 100343, located up near the oil filter.

I think I need to verify the pressure of the system, and probably order a new sender.

 

But the owners manual specifically states that the oil pressure behavior you noted is normal and acceptable?

Low oil pressure at idle when the engine is fully warmed up is not unique to Ferrari - all engines have lower oil pressure at idle, some quite low. As long as the pressure jumps above idle, you're fine. This is one good reason, though, to never lug an engine (ie drive at large throttle openings at very low rpm, ie 1500 rpm or lower)

 

Gordon. Sure - that's why I was only worried when I was sitting there idling in traffic. Seeing that gauge close to zero made me nervous. Knowing that it was jumping up to 60 or so psi while driving - less worried.

My gut feel is that it's the sender. My car doesn't leak oil. I don't blow blue smoke all over. I'll get one from Superformance and see what happens.

 

Same here with my 208GT4, close to zero at hot idle and climbing with the revs. I also note that when I turn the lights on the pressure reading increases a little bit, which make me assume there is a electrical issue with the gauge and/or the sender. Running for three years like that, so do not worry

 

Seems normal to me. On my (ex GT4 ) starting and cool temps were fine. Once hot, the gauge is scary.
The Veglia senders are crap and it is well documented here.
Order a new sending unit by all means, but the replacement will probably be just as inaccurate.
I'm here to tell you, if the oil pressure on my car was as low as indicated, and the way I drove it, there would be 308 engine parts scattered all over the So Cal highways!
You must have faith in Ferrari .

 

As MNE mentioned, check it with a manual gauge. That's the only way to be "comfortable." The manual gauge will tell you what the pressure REALLY is. If you 15-20PSI at idle with the engine hot and the appropriate idle speed - 1000RPM - , that's plenty. Beyond that, if there is 10PSI for every 1000 RPM, that's also plenty. Any more than that won't hurt but it is just a waste of HP!

 

Pretty much what he said.

If you are looking to make the Veglia gauge accurate that can be a real exercise in futility. On a couple of cars we have spent a good deal of time and money trying to get it to read correctly throughout the range and the bottom line is that the gauges and senders are just trash. For a number of years now the senders are nowhere near what we got for them back in the 80's. Even substituting a quality non OE sender and calibrating the Veglia gauge to it really only makes it better but not really good. A common method of reaching a usable scenario is to just get a good idea what it really is with a mechanical gauge and note where the OE gauge is under the same conditions and mentally correct it.

I have considered just installing a complete matching set of quality gages in mine and just being done with it.

 

Yep sending units are crap. I changed mine a few years ago after the original one would intermittently stop working - first time was a grap key, kill engine at 70mph. The replacement reads like 15ish when hot ille and 45 when doing 7K rpm. Old unit was at 45 at idle and 85-90 at 7K rpm. Used a mechanical tester to make sure there were no issues, all is fine except for the sender.

I changed out for the second time with no change and said no more. I wish Ferrari had used a mechanical set-up originally.

 

I just had this problem.

I had the air box off to adjust the carb linkage and I think I disturbed the sender connector just below the carbs. I ended up replacing the sender. When I went to take the old one off I noticed the connector was very corroded. I cleaned it up and used some Oxguard when I put it back on. Pressure is now back to normal.

I think it may have just been the corrosion but replacing the sender made me feel much better about it.

Here is a test you can do to make sure your gauge is good. Disconnect the connector and jump the gauge line to ground, then turn the ignition on. The gauge should peg to max. If not then you have a problem with the wire/gauge. You can also clean up the connector at that time and retry to see if that solves your problem.

If you do replace the gauge, do yourself a favor and buy a gasket for the oil filter fitting. To get the gauge on/off you will need to remove the oil filter fitting (three bolts). Otherwise getting to the sender nut is next to impossible.

The sender needs a crush washer as well so make sure you order that too.

Good luck!

 

Excuse the dumb question but where is the connector and what does it look like?
Thanks.

 

Sender is on bottom of oil filter housing on the carb side. Trace the wire and it should lead to a white connector. It's damn tight in there. Good luck.

 

Thanks.
I may have a leak at the oil filter housing so it sounds like a good time to check it out.

In the last year the pressure reading has dropped when hot. Never below half way though.

Would the weight of the oil effect the reading much?

 

I had the same leak and just fixed it also. Was just the sender in my case luckily. New sender and crush washer was the fix. Was the most major source of my leaks ; )

Oil weight will absolutely affect pressure. How much depends on the oil, temp, and oil system in question. I have not experimented on oil w this engine so can't give you any data points. I run Castrol Dino 20w50 and get similar readings to what the manual suggests is normal. But my gauge also cuts out intermittently. Have to swap that next. Also have a leak from the oil cooler return line...projects projects : )

 

Thanks.
Sounds like we should note what oil we're using when posting on this thread.

 

An idling engine can sit on practically zero. 8 psi per 1000 rpm is what my engine builder used as a fail safe on the dyno cell back in the day.

 

The sender lead is about 6-8 inches long and is routed under/between the carbs. Follow the wire from the sender and you will find it.

 

Grazie

 

Ken, just saw this thread.

My 75 GT4 (same engine as yours, essentially) displays almost zero oil pressure at idle when the engine is warm. Then jumps up when off idle. The 77 GT4 has almost exactly the same behavior.

I'm not saying there isn't a problem with the sender, but it seems like this is normal behavior.

 

What's your oil consumption like?

 

Frankly, I haven't driven the car for more than a couple hundred miles, but oil consumption seems normal, which is to say that I haven't seen much consumption at all. I would expect to see about a quart used every 500 or so miles; I'd have to check what the manual says is normal.

 

Sounds like the engine isn't suffering from the low pressure (readings).