Oil pressure light

[TimLamb]

I went to start the engine tonight to charge the batteries and warm things through a bit (2nd night of severe frost). The engine started as usual but the oil pressure light stayed on. Is there anything obvious about severe cold that could cause this, or does it sound like I might have something to worry about?

Thanks

Tim

 

[JimMcMillan]

The most likely cause if the engine was fine before is that the oil pressure switch is inoperable because of the extreme cold and will recover or oil is not being circulated in the engine. I take it that oil level is correct and that the oil is viscous(i.e.not so thick that it wont flow?) Best of luck!

 

[mtb]

sounds like the pressure switch is sticking !! due to cold easy solution to see if it's that is pour, not boiling but hot water over it .
What engine is it , did you let it warm up , some engines refuse to start with cold weather , they turn over very slow , most people start off thinking it's the battery but it can equally be the oil needs changing . Long stroke engines suffer with this , the oil just slows it all down .

A posh way to cure all these winter ill's is to fit a Kenlow pre heat system , the system is not cheap, but after ten min's and your engine will fire up straight away but miss out on all the wear that a cold engine suffers when cold .
Actually to be really really posh set the system up using a thermostat so it comes on at a certain temp for a given period .
I have one of em fitted to my Landover and you would never believe the difference it makes in the mornings.
Cheers
Mick

http://homepage.ntlworld.com/boats
I need a couple of oak tree's .. for me trawler

 

[vyv_cox]

It is not good practice to run your engine for short periods under no or low load. You will almost certainly be doing it more harm than good.

It would be very unusual for a pressure switch to remain on simply as a result of the cold, as trucks and cars all over the world start every day in far colder conditions. There is a remote chance that there could be condensation in the switch that will short it to earth.

The temperature is nowhere near low enough to prevent the oil from circulating. The pour point of a monograde is less than -10C and of most multigrades may be as low as -30C. I suspect a mechanical problem.

 

[Plum]

Re: First thing to do...

There is only one thing you can do to be certain about what is going on before you start to worry about engine problems:- check the oil pressure with a gauge. I know this may be difficult to arrange, but a visit to a good car accessary shop or a good engine mechanic should get you a gauge on a flexible tube connected to an adapter that screws in in place of the oil pressure switch.

I had the same problem a few years ago (but not in the cold) and the gauge confirmed that the oil pressure was OK and I needed to buy a new switch (14 pounds).

Or, you could go and buy a new switch anyway and try that, but having a gauge will be a good investment for future diagnostics once you know what the pressure is today.

 

[charles_reed]

I'd lay £1 to €1 that it's the transmitter switch.

You could go and buy a replacement or, as suggested, check with a mechanical gauge on a flexible hose.
The latter is likely to be fraught with opportunities for disaster, so I'd probably forego the test.

As Vyv has already pointed out - the quickest way to reduce a diesel to scrap is to run it under no-load conditions; so I'd suggest resisting the temptation to see if the thing still works consider starting it with either a big alternator or being in gear (at least that keeps prop-fouling down).

 

[stubate]

Go back to basics.
the light says no pressure !!!
we know that the pressure transmitter switches are prone to failure however are you willing to bet 5-6 grand by fannying around running the engine in a v cold situation where the oil circulation system is not at its best ? if you are sure that oil levels are ok etc and that the oil filter has not burst (ive seen that before now in cold conditions) go and buy a guage and adapter to check that you do have oil pressure or get someone who knows what they are doing to check it. all the rest of the advice to warm the switch or change it involves more and more running without being sure if the outcome and possible damage to the engine.

on a different note can anybody prove the urban (or should it be boating ) myth that running the engine under no load "destroys" it? i have worked in the oil industry as maintenance supervisor, looking after diesels of all sizes and makes and know that after they have been "run in" have been able to leave them ticking over from daylight to dusk with no ill effects. cases that spring to mind are diesel welding sets using the perkins 4108 engine. we started them on the morning and they ran all day on tick over until welding was required, caterpillar side boom tractors were started at 6 and ran at tick over all day ( we were working in africa where if you left the batteries on they were nicked so we started them in the morning and switched off at night) we changed the oil and filters regularly as in monthly and had no probs even in the bush where heat and sand was a major prob. also what about the famous london cabs, run all day without switching off?
come on guys give me some proof other than " every one knows"
s

 

[vyv_cox]

There is a great deal of knowledge that bore glazing is more prone to occur on tick-over than under load. This is also influenced by engine design and some are definitely worse than others. Increased levels of fouling by carbon deposition is most definitely a problem with lightly used engines.

Quote from Caltex website.

Bore Glazing A phenomenon that results in loss of oil consumption control. Bore glazing as contrasted to bore polishing is characterised by a deposit or coating on the bore/liner of the engine. Bore glazing is believed to occur at low speed and light load operations.

Bore Polishing Characterised by a clearly defined area of bright mirror finish on the cylinder bore. It is caused by local mechanical wear of the surface, resulting in loss of oil consumption control. Believed to be brought about by build up of carbon deposits in the ring area.

Quote from Fina website:
You should note thatuse of incorrect oils in lightly loaded engines, especially Lister LT1 and TS/TR can lead to problems with bore glazing, excess oil consumption and excess carbon build-up.

 

[stubate]

proof not word of mouth or hearsay, proper lab tests, dates and who did it. if you were in uni and handed a paper in with that sort of proof it would be handed back with a flea in your ear.
the point i am trying to make is that the myth is perpetrated from person to person and yet no real proof is offered, i have gone thru the university of life and have first hand knowledge of it over the years. my machines didnt suffer from blowby, hi oil consumption or get "destroyed in a very short time" because they had their engines left ticking over.
s

 

[brianrunyard]

When did you last change the oil, is there a lot of moisture in it?
If the problem happened suddenly it's unlikely to be due to wear.
Could be:
1. faulty switch
2. Blockage in the switch, (dirt or frozen condensation)
3. Wire off the switch, shorting to earth
4. Low oil level


Brian
http://homepage.ntlworld.com/brunyard

 

[ccscott49]

Ticking over and revving on no/light load are two different things, I agree with you in Alaska, we never switched engines off, even changing oil on the run, but when the engines were revved, they were under load, which is how it should be. left ticking over, doesn't seem to hurt most engines, in my experience, a good blast when they are used and all the carbon goes straight out the exhaust. So I tend to agree, but higher revs and no load, does undoubtedly cause bore glazing, I've seen it a lot on underused small generators. Reccomendations from Fischer panda, generators should be loade to at least 50% of rating when being run. We also use engines which tickover for very long periods in the oilfield, only coming on line when required.

 

[tr7v8]

Possible problem that no others have picked up is that of oil pump drive failure which can occur with very thick cold oil, but agree most likely cause is sender failure.

Jim
----------

 

[stubate]

thank you,
good to see some real life experience helping to prove my point instead of the repeatal of the myths.
the problem is of course that those folk who havent had the experience that we have had or seen these things in real life tend to believe the arm chair repeaters of the urban myths.
the debate opens up,
ill go on the record
start her up, let it tick over for a few minutes to get the oil circulating, speed her up a bit to get to working temperature quickly (most important) then you can throttle back and let it tick over, if it doesnt get to working temp quickly get the thermostat sorted, they are the biggest cause of sludge and wear related probs. also you can never change the oil and filters enough. as ccscott says a good blast will soon blow any excess carbon out of the cylinders.

 

[vyv_cox]

Well, I don't propose spending hours of my time proving something that is very well documented in the literature, just to satisfy your unwillingness to search it out for yourself. Every engine manufacturer and lubricant supplier has years and years of experience in research and operation to back up the kind of statement made in the websites I quoted. I.Mech.E, ASME and SAE conferences have been nearly swamped with papers on these topics for the past 20 years plus. If you choose not to believe it, more fool you.

 

[stubate]

as i said before "everyone knows" doesnt prove it i have seen and repaired more diesel engines than you will ever see, and what my own personal experiences prove to me are worth more than any arm chair pontifications.

 

[ccscott49]

I often agree with you, but I'm afraid this time your wrong, the fact that an engine ticks over half its life, does not glaze bores, high revs or medium revs and no load does, that is the facts. Diesel engines need to be loaded to make them run efficiently, but an engine ticking over will come to no harm, as long as it is worked hard occasionally and it remains at full working temperature all the time, he's right.

 

[Avocet]

Re- oil pressure - is it possible that the oil pressure relief valve has stuck open? it might have opened further than usual when the oil was very thick and has now stuck in this position. I agree with whoever advised you to connect a good mechanical oil pressure gauge to the place where the switch is tapped into the engine. This will resolve the issue once and for all. Alternatively, another oil pressure switch might be cheaper - just try one and see.

 

[Mirelle]

Thank you

That is what I have done with my very ancient very simple little Volvo MD2, once a week in winter, for years - start, run up to operating temperature, in gear, at moderate speed, then leave it ticking over on alternator load only to make sure everything is warmed through and batteries are fully charged.

 

[charles_reed]

Marine diesels ;-)

Tend to run colder than the engines to which you are referring.

The results of running with no load are:

1. Increased acidic combustion deposits in the lubrication oil.
2. Glazing of the bore, resulting in loss of compression and lack of oil retention
3. Increased carbon deposits on the head.

I'd suggest that normal practice in the oil-industry shouldn't be confused with good practice in normal life. After all there's a pretty cavalier attitude to oil companies' property amongst most rig-workers.

 

[ccscott49]

Re: Marine diesels ;-)

That sir, is not only not true but downright insulting! I would have expected better from you!
Who has to repair the equipment, normally in not the best conditions if it screws up? Isn't it easier to look after your engines/equipment and then be able to sit in the shade, rather than sweat your balls off over a hot engine which needs to be up and running yesterday, to repair it. I don't think you know what you are talking about, we take a great pride in our engines/equipment and there health in the oil industry, to suggest any different shows your lack of knowledge of our industry!