14 replies to this topic

[Island Mini]

Just wondering how long it should take from cold for the oil light to go off in an Auto. Mine probably takes about 5 seconds unless I rev it a bit. Just wanted to know if that sounds realistic.

Cheers

Toby

[Badboytunes]

Mine goes off after about a 1 second or so once the engine has fired. It takes minimal cranking to get started. Being an auto ( in my eyes ) ahould not make a difference with regards how long the light should take to go out.

[Mini Manannán]

Being a auto won't make a difference.  My oil light is lit for 1/2 a second or so, if that.

[ibrooks]

The oil light on a healthy engine should be out almost before the engine has fired i.e. whilst it's spinning on the starter. If yours is staying on for so long then there's something wrong.

 

You are running the correct 20w50 oil aren't you? thinner stuff will work on an older engine but can show problems on an A-Series with average wear and will kill it when the correct stuff would have allowed it to soldier on for many more years. If it's already caused the problem then switching might not get you much longer as the damage has been done but it's worth bearing in mind and swapping if you are running something else.

 

Check the light isn't lying to you and that the oil pressure really is low - a pressure gauge isn't expensive or hard to fit even as a temporary lash-up to make sure of what's going on.

 

Assuming the pressure really is low......

 

Check the pressure relief valve isn't leaking or sticking and that the spring hasn't gone weak and is therefore allowing pressure to bleed away.

 

Check the pump is in good condition and actually able to make sufficient pressure/supply.

 

I'm not sure off the top of my head how different these are on the auto lumps but I suspect they aren't the cheap and easy replacements that they are on a manual. On a manual it's worth swapping these as a first hit precisely because they are cheap and easy (relatively) but the next step is to tear the engine apart and check/replace the shell bearings and regrind the crank. Since you are in there it would be foolish not to have the bores taken to the next oversize and fit new pistons and rings and whilst you are in there......

 

It can rapidly get expensive but carrying on with the problem is only storing up more cost for the future as it's doing more damage every time the engine runs.

 

Iain

[Island Mini]

An interesting read. Thanks guys.

I dont want to start a war but I was always told 10w 40 mineral for autos in hot countries as the viscosity is closer to the older oils. I used to run 20w 50 can't remember if that made a difference to the oil light switching. Certainty helped with oil leaks though.

Surely being an auto would make a difference through simply that higher pressures need to be achieved within the oil system. I would guess I have a worn pump or weak spring realistically. Do the sensors every get covered in gunk? Is it worth pulling it and testing it whilst giving it a clean?

Cheers

[Cooperman]

It should have 10w40 for an Auto.

5 seconds is a long time for the light to go out, but it could be the switch at fault. Change the switch first and if that makes no difference consider taking the engine out, checking/changing the bearings, fitting a new high-capacity oil pump and inspecting the crankshaft journals.

[KernowCooper]

Also worth a look to make sure you dont have a switch which warns when the pressure drops below 25-23psi, they take a bit longer to go out, but not 5 secs longer

[lsto]

My car usually turns over 2 or 3 times before it fires into life, then its usually couple of seconds before the light goes out.

My engine is getting a little tired these days anyway. I had quite a lip on the bores when I did my hg a few months back....

[Lincsminbin]

I've attached an image of the back of the owners handbook for my 1991 / 998 auto for info, it comes from a carb car not an SPI, but may be useful.

 

10w/40 oil seems to be the one for auto's.  It's also worth noting the 'Maintain level to MAX mark when engine is hot' for auto's  I had never heard of this and when I first owned the car used to keep it at the standard 'between max and min'

 

As it only seems to come on when starting and goes of quicker with rev is it possible that it is idling a bit low when cold?  Maybe and Idle air valve issue?

 

Attached Files

•  Rover_998_forecort_data.jpg   38.78K   12 downloads

[Spider]

An 'extended' period for the Oil Pressure to come up can (but not always) mean a worn Oil Pump, however, before selling a Kidney to pay for repairs (that may not be needed), test the Oil Pressure, when hot, if it's within Factory Specs, leave it.

 

The Grade of Oil is also dependent upon Ambient Temps, from the Australian Factory Workshop Manual;-

 

[Rog46]

I seem to recall hearing that the spin on oil filters should contain a non-return valve to stop oil draining when the engine is off, but that some of the cheap replacements don't incorporate this. Could be worth checking !

[Dr s]

I might be in the minority here, but I think it depends how often the car is used 5 seconds on a daily is a long time, if it only gets started once a month or less often then that seems fine to me. The motor in my vdub if left all winter can take 10-20sexonds or so. It's been like it for a longtime.

No panic from me. Wouldn't Rev it or drive it just let it come up.

[Dusky]

Mine(new oil pump and central pickup) goes out before the car starts. Cranking takes a second or 2 before or fires into life with the weber carb, and light goes out after around 4 engine revolutions on the starter.

[Island Mini]

Hmmm interesting. After turning the engine off it seems to hold pressure for about 20 seconds before the light comes back on again. But upon starting its a good 5-7 seconds. I know I have a small oil leak around the head. Its nothing too bad. Changed to a copper head gasket and its obviously not sealing completely. I also have a small sealing issue around the oil canister from where it had been previously overtorqued. Miniscule but still there, the ball valve may be leaking in there as well possibly. The engine runs fine all stem seals have been changed and the cylinder walls looked pretty good when I changed the head. Think it may just be one of those things. Will do the oil level check tomorrow.

Thanks for all the input

[ibrooks]

The stem seals won't make a difference to oil pressure and neither will the condition of the bores. The biggest factor in a worn engine if it's not simply an under-supplying pump or leaking relief valve is the shell bearings. Oil is provided to them under pressure to try to make the surfaces "float" on a layer of oil. When the two wear a little the clearance between them is greater and so the oil escapes faster and therefore the pump can't maintain the same sort of pressure. A blip of the throttle spins the pump faster and makes it supply more oil therefore the pressure comes up - to be honest a single blip to make the light go out is probably doing less damage than letting the thing idle for several seconds with low pressure and metal grating on metal.

 

The head gasket weeping oil won't have an effect - it would be gushing out and you would be leaving a trail everywhere and using as much oild as petrol if it was a big enough leak to show a pressure change.

 

My first car (a MKI Astra) when it got quite hot and the oil was thin the oil light would flicker at tickover - that was cured by a recon short engine after a garage that I trusted to do some work on it managed to crack the block.

 

 

Iain