Low oil pressure shutdown?

[Runs With Scissors]

re: linking to oil pressure sensor
Not the same really, you could have just enough oil for pump to supply oil BUT not the VOLUME needed to properly lube AND cool the engine.
One analogy is a well. Great volume and pressure all spring, then in mid summer,low water table = low volume of water, even though pressure is great, you 'run out of water'...until well refills.

You need xx GPM @ yy PSI to keep the engine 'happy'. If either go below minimum, bad things can happen.

I agree, the oil pressure sending unit is not a perfect long term solution for certain situations, however for an event like this, I bet it would have helped.

I mean who knows how long that light was on for? ...........2 seconds or 5 minutes?

I'm betting it was closer to the latter.

Just an idea, I got no proof either way.

 

[RBsingl]

Runs With Scissors is on the right track, if the oil level drops low enough that the pickup is getting mostly air then the pressure IS going to drop. You can see that happen with some wet sump engines in high performance cars where the high G force will cause an oil pressure drop in sustained very high G turns, one of the reasons for using a dry sump design.

I am most familiar with GM since I did some consulting work with their former Powertrain division and a number of vehicles had a low oil level sensor BUT this was only active at the point of start-up. During operation it wasn't used because it would otherwise generate multiple false alerts during driving. As long as there is sufficient oil that the pickup isn't starved and picking up air, then pressure will be sufficient to maintain the film that prevents bearing damage.

Most (maybe all) GM vehicles will activate a warning chime in addition to a light if oil pressure drops too low; immediate engine shutoff COULD be done via this system but isn't because that would be a liability issue if the artificial shutdown caused an accident. If the customer/driver chooses to ignore the warning then the liability (and also repair cost) belongs to them.

One of the shutdown controls on my diesel powered standby generator is for low oil pressure; the controller gives it a few seconds after start where the sensors are ignored and then lack of proper oil pressure causes immediate shutdown. I haven't looked to see how GM handles it on my current GMC diesel pickup but my 1995 had a fairly low tech approach with a pressure sensor in series with the lift pump; during cranking the contacts were bypassed with a relay but once it started if there wasn't sufficient oil pressure then the lift pump shut down and the engine would also.

Rodger

 

[6869704x4]

Wonder how loud this thing is

Perkins M92 Low Oil Pressure Alarm

A quality 12v Low oil pressure warning buzzer for Perkins M92 bulkhead mounted warning alarm, to be used in conjunction with an oil pressure switch.

www.parts4engines.com

 

[Hkb82]

I can’t wait to hear what the second opinion has to say. Sorry that ya had to learn a lesson the hard way but hopefully you can get off lucky. Be nice to know where the oil level was at after you added the oil.

 

[GreensvilleJay]

how loud ? 97db, so you will hear it, unless you're playing tunes the way kids do today
Piezo sounders are loud and don't draw much power 20-50ma
but...
no mention as to WHAT pressures the switch activates on and off at.
Agree it could be useful,maybe it can be wired in parallel to the 'idiot light' on the dash ?

 

[D2Cat]

I think on many Kubota engines the oil pressure light activates at 7PSI. Going the last 300ft with oil dripping is not a good decision, but because the light was on doesn't mean it was without oil pressure.

If it was my tractor I send a sample of oil and see what you learn. Then I'd probably add a quart of Lucas and see how it goes.

 

[TheOldHokie]

Runs With Scissors is on the right track, if the oil level drops low enough that the pickup is getting mostly air then the pressure IS going to drop. You can see that happen with some wet sump engines in high performance cars where the high G force will cause an oil pressure drop in sustained very high G turns, one of the reasons for using a dry sump design.

I am most familiar with GM since I did some consulting work with their former Powertrain division and a number of vehicles had a low oil level sensor BUT this was only active at the point of start-up. During operation it wasn't used because it would otherwise generate multiple false alerts during driving. As long as there is sufficient oil that the pickup isn't starved and picking up air, then pressure will be sufficient to maintain the film that prevents bearing damage.

Most (maybe all) GM vehicles will activate a warning chime in addition to a light if oil pressure drops too low; immediate engine shutoff COULD be done via this system but isn't because that would be a liability issue if the artificial shutdown caused an accident. If the customer/driver chooses to ignore the warning then the liability (and also repair cost) belongs to them.

One of the shutdown controls on my diesel powered standby generator is for low oil pressure; the controller gives it a few seconds after start where the sensors are ignored and then lack of proper oil pressure causes immediate shutdown. I haven't looked to see how GM handles it on my current GMC diesel pickup but my 1995 had a fairly low tech approach with a pressure sensor in series with the lift pump; during cranking the contacts were bypassed with a relay but once it started if there wasn't sufficient oil pressure then the lift pump shut down and the engine would also.

Rodger

Every car I have owned for the last 20 odd years has had a low oil level warning light. First ones were a couple Ford Turbo Coupes followed by a couple Cadillac Cateras, and now a pair of BMW 3 series. The Fords were prone to false alarms. The BMW oli level sensors are as accurate as a dipstick. It has to be because there is no dip stick. I routinely check oil level as I am cruising the interstate. Right now I am about 3/4 of a quart low. The light will come on at a quart low.

Dan

 

[GeoHorn]

Thanks everyone. I’m going to get a second opinion before I do anything. I actually called the service people where I took it when it would not start and they advised me to put 4 quarts in it just to get it started so I could get it on my trailer. That’s why I thought it had a kill switch. I don’t know how much oil it actually needed. I only bought 4 quarts. I thought that’s what it held. The dipstick didn’t show any when I looked the first time. When I had gotten it to the traileri turned it off to get everything situated. When I went to start again it died so I assumed it had a low oil kill on it so I wasn’t worried about it at the time. So ya I guess I know better now. The battery was having a hard time turning it over so I assumed it was the kill switch. I put the oil in and jumped the battery to get it started to get on the trailer. The battery had been weak lately so I thought maybe it has finally died. It started right up when I jumped it. I guess looking back I should have done everything differently but honestly didn’t know any better. I still think all engines these days should have a kill switch if it will destroy an engine. I need to go to the dealer to grab it anyway so will update when I know more. You guys have been great. Thanks for all the help. I will update when I know more.

This thread reminds me of an old ”Brother Dave Gardner” album… when he shouted out “Rastus! You leave that wheel-barrow alone! You know you dasn’t know nuthin’ about machinery!”

 

[Hkb82]

how loud ? 97db, so you will hear it, unless you're playing tunes the way kids do today

Have a look at this. I guess kids will always be kids today and also yesterday.
The article it’s from http://www.farmworldonline.com/news/NewsArticle.asp?newsid=33692

 

[Jday]

Thanks I was wearing ear buds so unfortunately the noise wouldn’t help. Definitely a live and learn thing for sure. Hindsight 20/20 I have no idea how long the dummy light was on for but I didn’t think that long. I will update yall when I know more. Appreciate all the help.

 

[cthomas]

What tractors, cars, pick-up trucks, etc. do?

Ford/International trucks that are diesel, as the injectors are triggered via an high pressure oil pump.

 

[SDT]

This 5 year old machine has already had an engine replacement. That seems strange in itself but apparently the engine is not seized. It holds 8.5 qts of oil and was down 4 so you did not run it bone dry.

If it runs and operates normally just use it. Get a good oil pressure gauge and monitor oil pressure. If there was significant damage pressure will be low and in all likelyhood will continue to drop pretty quickly with continued usage. If you see that you know things are significantly damaged and tanking fast.

I certainly would not be condemning it as long as its still running OK and has decent oil pressure and normal power.

Dan

How do we know it was only down 4 qts?

Apparently, the pressure lamp was on for an extended period.

 

[SDT]

Sorry about your troubles.

Out of curiosity I have to use a wrench to take off my filters. Knocked it loose with a branch? Maybe broke the filter off or punctured it? I'm interested in the back story

Bingo.

 

[SDT]

Thanks I was wearing ear buds so unfortunately the noise wouldn’t help. Definitely a live and learn thing for sure. Hindsight 20/20 I have no idea how long the dummy light was on for but I didn’t think that long. I will update yall when I know more. Appreciate all the help.

Yet another reason why I always operate all of my machinery without anything covering my ears.

Always want to be able to hear my machinery.

 

[SDT]

Ford/International trucks that are diesel, as the injectors are triggered via an high pressure oil pump.

Obvious exception to current issue.

 

[The Evil Twin]

Man, it would be bad to have an oil pressure/ level sensor that shut off an engine. There is a reason they don't do that.

 

[TheOldHokie]

Man, it would be bad to have an oil pressure/ level sensor that shut off an engine. There is a reason they don't do that.

Yeah but when that light comes on and your significant other keeps driving and it siezes up or grenades on the interstate at 70 MPH the result is very similar. Some sort of limp mode seems to be a modern and appropriate way of dealing with these scenarios.

I know for a fact my two daily drivers (BMW 3 series) do that for cooling failures.. You get a VERY loud and persistent alarm and about one minute grace to pull over before power gets chopped to about 10%. At that point it will shutdown if temps keep going up.

My son just had the same scenario with transmission overheating due to lubrication failure on his POS Ford Focus. It initially goes to limp and then shuts off entirely. Turns out thats a chronic problem with the double clutches in those cars. Fortunately he had wartanty coverage that paid the $12K repair bill.

Dan

 

[TheOldHokie]

How do we know it was only down 4 qts?

Apparently, the pressure lamp was on for an extended period.

We dont know that but it does not change my advice.

Dan

 

[mikester]

Wonder how loud this thing is

Perkins M92 Low Oil Pressure Alarm

A quality 12v Low oil pressure warning buzzer for Perkins M92 bulkhead mounted warning alarm, to be used in conjunction with an oil pressure switch.

www.parts4engines.com

View attachment 117672

If you can't hear it put a light on the dashboard. Put a funny pictographic in front of the light so operators get confused and can ignore it.

 

[GreensvilleJay]

high tech method...

For about $25 Cdn, you could hookup the sensor to a transmitter that sends a signal to your smartphone. An 'app' on it would then blast 'Shut off the tractor NOW' into your earbugs, then return to whatever music you have playing...

low tech method...
Get into the habit to visually scan the entire dashboard every few minutes. Something every pilot is taught and becomes second nature.