Oil pressure light stays on for one second after starting

Pops_20

I changed the oil and filter on my Nissan 180sx with SR20DET engine and noticed that the oil light is staying on for a split second after startup.

Before the oil change, the light went off immediately on startup. Now it takes ever so slightly longer, but while its on you can hear a bit of rattle/roughness from the engine, almost as if its running dry. When the light goes out, the noise stops.

Couple of things that I have noticed,

1) Before the oil change, the oil level was a bit over the 'High' mark. It wasn't that much over, maybe about 1 cm.

2) The car is meant to take 3.7 litres of oil, but it only took 3 litres to bring it exactly to the High mark on the dipstick. I am assuming this is due to residual oil left over.

I'm concerned about two things:

Why would the oil light be staying on for a second after startup, when it was perfectly fine before the oil change? I've been doing my own oil changes for years and I've never had a problem.

Could this damage the engine in some way? The oil light never comes on while driving. It only happens at startup.

Thanks!

Atlantic Dawn

Have you rechecked the oil level from when you originally changed the oil, usually there's some settling of the oil and it may go down from the original reading.

Gravelly

I had the same problem with a celica I had a few years ago and it turned out to be caused by the cheap filter I used - it effectively blocked the flow of oil for a second or two on startup. Changed to a genuine filter and the problem disappeared.

Pops_20

@Atlantic Dawn - yes I checked it 4-5 times times since changing it. The level hasn't changed. Still bang on the high mark.

@Gravelly - I'm using a genuine Nissan filter so I was hoping that wasn't a problem. These are meant to have an anti-drainback valve so I don't think the filter emptying out is the problem.

Maybe the oil was overfilled before for a reason? Would it be any harm to overfill slightly again or not?

Gravelly

Pops_20 wrote: »

@Atlantic Dawn - yes I checked it 4-5 times times since changing it. The level hasn't changed. Still bang on the high mark.

@Gravelly - I'm using a genuine Nissan filter so I was hoping that wasn't a problem. These are meant to have an anti-drainback valve so I don't think the filter emptying out is the problem.

Maybe the oil was overfilled before for a reason? Would it be any harm to overfill slightly again or not?

Might be worth dropping the sump if a filter change doesn't work to make sure the uptake pipe isn't blocked.

*Edit* I'd be slow to overfill the oil - can lead to problems.

alta stare

Is there an oil level sensor in it? Maybe you inadvertently damaged it when doing the oil change.

mullingar

Get the running oil pressure checked via a pressure gauge.

Most of those oil sensors are a basic pressure switch, most are triggered at around 1 bar.

You could have either one of 3 problems.

1. Pressure switch, this could just be getting slow to respond if oil pressure is good.
2. Poor oil pump, resulting in low oil pressure and not building up pressure quick enough on start up
3. Worn Crank/big end bearings, too big a gap in the bearings which prevents oil pressure to build.

Wheelnut

You are probably OK in so far as the rattle at start-up will not cause any damage. However I understand why you are worried and agree that you would be better off without the rattle.

Have you changed to a heavier grade of the oil? For example, have you used a 10w40 oil instead of a 5w40? I have had experience of this in a Nissan and it was cured by changing to 5w40.

Pops_20

I'm using 5W-40 at the moment, not sure what grade oil was in it before.

UPDATE: The oil light goes out immediately when the engine is warm. For example if the engine is up to temperature and you switch it off, come back after 15-20 minutes and start it again, oil light goes out. It seems to only be a problem on cold starts.

Is it possible that I am reading the dipstick wrong? There's a hatched area that I assume is where the oil needs to be - between the lower and upper line. Right now its sitting on that upper line.



Before the oil change, the level was up around the letter H, maybe a little bit higher, which I think was overfilled.

But the engine only took 3 litres of fresh oil, and the capacity is meant to be 3.7 litres.

biko

There is often old oil left in engine when you change. This is fairly normal. I change oil when it's hot so often get more out but usually not everything.

As you said, the oil should be between the Low and High crossmarkings
The oil is not overfilled until it is well over that H.

5w40 should be fine http://mywikimotors.com/sr20det/

Pops_20

Do you think it would be OK to add more oil to bring it up to the H mark?

I'm thinking about doing this based on the fact that there wasn't any issue with oil pressure when the oil was above H, and it only took 3 litres. 700ml seems like a lot of oil to remain in the engine when the drain plug is open.

If doing this seems like overfilling then I won't be doing it though!

Gravelly

Pops_20 wrote: »

Do you think it would be OK to add more oil to bring it up to the H mark?

I'm thinking about doing this based on the fact that there wasn't any issue with oil pressure when the oil was above H, and it only took 3 litres. 700ml seems like a lot of oil to remain in the engine when the drain plug is open.

If doing this seems like overfilling then I won't be doing it though!

If there is already sufficient oil in the engine, then adding more won't cure the problem.

whizbang

2. Poor oil pump, resulting in low oil pressure and not building up pressure quick enough on start up

A heavier oil will often respond better with worn oil pump. The thinner oil will squeeze past the gears, where a heavy oil will tend to 'self seal' in the pump.

Oil stabiliser treatments will help here.

jca

Another thing to try. With the engine stone cold, first start of the day. Start the engine and the light goes out, stop the engine and immediately switch on the ignition without going to the start position, it should take a few seconds for the oil light to come back on. It isn't exact science but the longer the engine "holds" the oil pressure the better condition it's in. I think it's a faulty filter myself, it can happen.

megafan

Pops20... Not familar with your model of car but as others have said it may be your oil filter.... Worth getting the genuine filter which may have a non-return valve fitted as depending of orientation of your filter it may drain if your car is stopped for a while & has to re-fill at startup (causing oil light to remain on while pressure builds up)...

Just a thought!

shietpilot

OP, make sure that the dipstick in the car is the correct one for that engine! Maybe it is not the original one and it was overfilled for a reason?

Cee-Jay-Cee

If it were me I'd change the oil again. Drain out the old oil, jack the car from the side the sumo is on first then change it to the other side then jack from the front and then the rear to make sure you get all the old oil out. Do this when the oil is warm and therefore thinner as it helps it drain easier when it's warm/hot. Get a new filter and new oil, preferably the recommended grade for the engine.

I had a Silvia with SR20DET engine years ago and was always surprised at how little oil it took during servicing.

Pops_20

Thanks everyone for the suggestions.

The dip stick looks like the correct one from a quick Google search.

I'm already using a genuine filter with non return valve. I'd be willing to swap this out if there's a chance that it's faulty.

It makes sense that if I'm using a thinner grade oil now that it might take longer to build pressure if it can squeeze past the pump. The old oil was definitely a thicker grade, it didn't run off the dipstick as easily.

I'm willing to try all of the above, but without wanting to be too pedantic, my real question is, can any damage be done by that oil light staying on for one second on every cold start?

sandydan

apart from checking dipstick ,or getting oil pressure checked, id check if sump is dented, usually recommended oil quantity is accurate . a friend bought a toyota hilux and it took less than the recommended amount of oil at oil change, a few months later engine packed up under load. when sump was removed they discovered oil jelled in sump. the garage concluded some previous owner had exceeded mileage drastically or used incorrect oil. but they fitted good engine in lieu free of charge, you can get an additive that you add to oil pre changing to help flush out sump, but i have no experience of using one.

megafan

Pops_20 wrote: »

but without wanting to be too pedantic, my real question is, can any damage be done by that oil light staying on for one second on every cold start?

Well POPS 20 if bearings running dry yes.... it's oil lubricates the bearing shells & keeps them apart hopefully some residual oil will remain to lubricate & the shorter time it takes for oil to reach the bearing the better.... & if your hearing rattling before oil light goes out it's not good... hope new oil & filter solves problem....

Wheelnut

I have already said (in post #8) that I don't think the rattle is going to cause damage.

Correct me if I'm wrong, but I believe your engine has hydraulic valve tappets. That means that they adjust themselves by having the oil pressure pump them up to the correct clearance.

I have read your description of the noise and I believe the rattle is caused by the tappets being slow to pump up. That indicates that the oil is slow to reach the tappets. In this case the instinct of people is to go for a heavier oil but what you need is a thinner oil that will flow quicker and fill the tappets quicker.

It's a quirk of engine design that the camshaft and valve tappets have the highest lubrication demand but are farthest from the oil pump.

In your case you say that you have used a 5w40 oil and a Nissan filter. The problem started after an oil and filter change. The oil is probably light enough which leaves the filter. You can change it if you like but I think it will be OK.

Pops_20

Wheelnut wrote: »

I have already said (in post #8) that I don't think the rattle is going to cause damage.

Correct me if I'm wrong, but I believe your engine has hydraulic valve tappets. That means that they adjust themselves by having the oil pressure pump them up to the correct clearance.

I have read your description of the noise and I believe the rattle is caused by the tappets being slow to pump up. That indicates that the oil is slow to reach the tappets. In this case the instinct of people is to go for a heavier oil but what you need is a thinner oil that will flow quicker and fill the tappets quicker.

It's a quirk of engine design that the camshaft and valve tappets have the highest lubrication demand but are farthest from the oil pump.

In your case you say that you have used a 5w40 oil and a Nissan filter. The problem started after an oil and filter change. The oil is probably light enough which leaves the filter. You can change it if you like but I think it will be OK.

Thanks Wheelnut. Yes this engine has hydraulic tappets/lifters.

I have tried to pinpoint the noise by getting someone to start the engine while I listen with the bonnet open, but I can't hear exactly where it's coming from. It sounds more like a fan belt squeal than a rattle sometimes, but the engine definitely sounds slightly rougher for that one second when the oil light is on.

I will let it run as it is for a few 100 kms and if it doesn't improve or gets worse then I'll change the oil and filter again.

I'd be disappointed if it's an issue with the genuine filter as it costs 13 quid. Alternatively I could just go for a Blueprint filter next time.

martyc5674

Similar issue with a different car turned out to be hydraulic tensioner on timing chain.
Marty.

jca

martyc5674 wrote: »

Similar issue with a different car turned out to be hydraulic tensioner on timing chain.
Marty.

Could easily be the op's problem, the lazy tensioner was masked by a heavier grade oil.