Recent Topics
Mobil 1 and ILSAC GF-5 Spec
by Hot_Ajax
08/22/14 06:19 PM
oil and filter for 10k oil changes 2014 focus
by ram_man
08/22/14 05:51 PM
windshield replacement
by lenjack
08/22/14 05:11 PM
2002 Subaru WRX, EJ205 - RT6, 5275 mi.
by oaklandish_wrx
08/22/14 04:57 PM
2010 Camry 2.5, AMSOIL OE 0w-20, 8,611 miles
by Rat407
08/22/14 04:21 PM
Interesting ACDelco article with good pics
by CapitalTruck
08/22/14 04:15 PM
Pinion seal leak - go ahead & get Speedi Sleeve?
by 01rangerxl
08/22/14 04:10 PM
2011 Buick Regal 2.4 NA, 4200 mi., AC Delco 5W-30
by Benzadmiral
08/22/14 04:00 PM
Other 3.6 Pentastar folks going 10K OCI on dino?
by jayg
08/22/14 03:32 PM
A/C System Revival
by zppeterson
08/22/14 03:22 PM
12 Impreza 2.0L (FB20), AMSOIL ASM 0W-20, 6503 mi.
by IveBeenRued
08/22/14 03:19 PM
I got screwed
by y_p_w
08/22/14 02:58 PM
Newest Members
Jay_W, goser, brada, havetoknow13, cjacobs18
51051 Registered Users
Who's Online
92 registered (aquariuscsm, bdleonard, 57ChevyLS, 901Memphis, 01_celica_gt, Bandito440, 11 invisible), 1733 Guests and 234 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
51051 Members
64 Forums
218158 Topics
3439102 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG

Topic Options
#2191704 - 03/07/11 10:32 AM How do low oil sensors work?
callbay Offline


Registered: 05/29/05
Posts: 610
Loc: Ozark Mountains
I have had a couple experiences lately with low oil sensors not stopping the small engine even though there was hardly any oil in the engine. In the last case I drained out only 16 ozs of oil and the manual says it holds 1 1/2 qts. and the dipstick says 2 qts. The wires were attached to the sensor so is something just malfunctioning? It was a 20 HP Kohler 2 cyl (see my recent post on no oil on the dipstick)

Seems like the sensors should stop way sooner or we should not counrt on them to do their job.

Top
#2191726 - 03/07/11 10:53 AM Re: How do low oil sensors work? [Re: callbay]
suspiciousmind Offline


Registered: 12/11/09
Posts: 352
Loc: NC/SC
We should not count on them to do their job.

They're looking for a low pressure situation which occurs when there's not enough oil in the sump to keep the galleries full....it's actually too late then....damage has likely been done.

Keep an eye on the oil level by checking it frequently.


Edited by suspiciousmind (03/07/11 10:57 AM)
_________________________
1990 miata 5 speed
1992 Accord 5 speed
1996 Accord auto
1999 Tacoma 3.4 4wd 5 speed
2002 4runner 3.4 4wd auto
M1 0w/30 in everything

Top
#2191736 - 03/07/11 11:02 AM Re: How do low oil sensors work? [Re: callbay]
punisher Offline


Registered: 09/11/04
Posts: 1904
Loc: snowblind in TX
Most sensors on small engines are a float type with a magnet located inside the float. When the float level (oil level) reaches a certain point the magnet gets near enough to a reed switch and closes it grounding out the coil. More expensive small engines, with a pressurized system) do have a pressure sensor that performs the same function.

The level sensors work for the most part and stop engines when the actual level falls. Pressure type sensors can let an engine run really low on oil as long as the oil pickup can get enough oil to keep the system pressurized. It is normal operation to not have the system stop with low oil levels, as long as there is enough oil to keep pressure up.

Top
#2191738 - 03/07/11 11:04 AM Re: How do low oil sensors work? [Re: callbay]
Texan4Life Offline


Registered: 01/28/10
Posts: 2131
Loc: Texas
Thats a good question. If it is pressure lubed, then it is suppose to alarm at a specific psi setting. Even though it was critically low it could have still maintained oil pressure. ie. the oil pump pickup was still submerged in oil.

On splash lubed engines I'm not sure exactly. I always thought it was a sensor of some kind that could tell when it was submerged or being touched by oil. But when I took apart my gx160 cone it had some doo-dad that I haven't see before. It sits in the bottom of the sump with a tube that goes up to the wires on the side of the block.
_________________________
2005 Dodge Ram 1500, 5.7L
[Current Fill: PP 0w-20][Baldwin B2-HPG]

Top
#2193831 - 03/09/11 08:23 AM Re: How do low oil sensors work? [Re: callbay]
eljefino Offline


Registered: 06/15/03
Posts: 23714
Loc: ME
How would a pressure sensor allow spark during cranking? Any override? Or do you just have to get it going fast enough to fling some oil around and make it catch?

Top
#2195405 - 03/10/11 12:53 PM Re: How do low oil sensors work? [Re: eljefino]
wolfc70 Offline


Registered: 04/13/07
Posts: 360
Loc: Wisconsin
Originally Posted By: eljefino
How would a pressure sensor allow spark during cranking? Any override? Or do you just have to get it going fast enough to fling some oil around and make it catch?


Most have a 15-30 second override to allow the engine to start. On my splash lubed OHV Briggs generator the manual states that the low oil shutdown activates after 20 seconds. It lists that in the trouble shooting section for when the engine starts then shuts off shortly.

Once it is up and running, the low oil cutoff seems to work instantly. I was running my generator (mainly to just run some fuel through it) to power a grinder while I was fixing my laundry lines. The soft ground sank under one wheel causing the gen set to list to one side. I have no idea how long it was like that, I did not notice it until it shut off. I moved it, restarted the engine and it started sinking again. While I was moving it again, I must have lifted the front too high, as it shut off again. I then check the oil level and it was close to full. It is a nice feature, but I could see how on a job site if you do not have perfectly level ground, it could be a big PITA.
_________________________
2011 Honda Accord EX Saloon, Manual, K24Z3, Toyota Synthetic 0w-20, Napa Gold 7356
2008 Pontiac Vibe 1ZZFE, PP 5w-20, Federated LF410F

Top