Oil pressure light randomly pops ups

15011 Views 22 Replies 6 Participants Last post by voxmagna, 12 d ago

Executive

Discussion Starter · Apr 23, 2021

Got my oil changed a few weeks ago at this place and now I've been randomly getting the oil pressure warning. At first it did it once a few days after one night soo I stopped and checked everything looked fine soo I started it back up and everything was good for nearly a week. Now it's coming on a little more frequently, doesn't stay on but usually flashes every 5 or 10 minutes, but if I cut the car off then back on it'll stay of for either a hour or soo or the whole day. Can idle the car for 24 hours and never get a light. However my oil is black now. It was changed at 53k miles and I'm just 54k.

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voxmagna

· #2 · Apr 23, 2021 (Edited)

Is it low oil pressure or a low oil level warning? Have you used the dipstick to check the oil level? You shouldn't assume 'everything fine' if warnings come and go. Normal engine running oil pressure is about 65-80 psi. Low oil pressure warning comes on at <10psi! Engines run at just above the low oil pressure trip level will wear out or get damaged very quickly. Oil color is not a relevant factor.

The ECU should have stored the oil pressure or level warning fault? Get a diagnostics scan done to learn more and read back the the oil pressure and levels, or keep driving on assumptions and risk burning out the engine.

Executive

Discussion Starter · #3 · Apr 23, 2021

The red low pressure warning.

voxmagna

· #4 · Apr 23, 2021

The red low pressure warning.

I'd worry about it until the oil pressure was confirmed good or bad. Perhaps they screwed up on the filter part fitted, their change work, or the oil change event is just co-incidence of an unrelated problem?

Executive

Discussion Starter · #5 · Apr 24, 2021

Pressure when sitting still and slightly revving is around 40. I'm thinking it could be a bad pressure switch or filter (which is a ecogaurd conventional filter by the looks of it)

voxmagna

· #6 · Apr 24, 2021 (Edited)

Pressure when sitting still and slightly revving is around 40

The normal engine oil pressure is lower than I said and that seems ok if you checked it with the oil hot. The filter should have a non-return valve built in but I can't think of that causing low oil pressure and the switch looks like the best bet. Not sure how you are testing oil pressure, but you need to be absolutely sure it's not something else intermittent and the warning is real.

After trying a new pressure switch/sensor, if the problem comes back you can only confirm by doing a diagnostics scan to read back oil pressure whilst the oil pressure light is flashing. That's one advantage of carrying your own diagnostics in the car, you can get hard evidence at the time of a problem, which the garage might take a long time searching for.

doregan

· #7 · Apr 24, 2021

Executive said:
Got my oil changed a few weeks ago at this place and now I've been randomly getting the oil pressure warning. At first it did it once a few days after one night soo I stopped and checked everything looked fine soo I started it back up and everything was good for nearly a week. Now it's coming on a little more frequently, doesn't stay on but usually flashes every 5 or 10 minutes, but if I cut the car off then back on it'll stay of for either a hour or soo or the whole day. Can idle the car for 24 hours and never get a light. However my oil is black now. It was changed at 53k miles and I'm just 54k.

Here's a link to removing and testing the oil pressure switch. Read the entire post because another poster mentions a much easier method that does not involve as much work.

www.vwvortex.com

2.0T FSI Oil Pressure Switch Replacement (2007 Eos)

Oil pressure warnings are scary, and should not be ignored. You can damage the engine if you don't head to the warning. If you've checked for low oil level and large leaks/broken oil pan, the next step is to check the oil pressure switch. The part can fail and cause a false warning. You will...

www.vwvortex.com

www.vwvortex.com

Years ago I had an Audi 4000S and it had an oil warning light as well as an audible buzzer. First time it went off I was on a highway (start and stop hot Summer driving) and I almost pooped my draws. Turned out it was nothing. Just low rpm and low oil viscosity. Oil level was fine. I think I started to use a slightly higher viscosity oil or maybe added an oil viscosity enhancer like STP or Lucas oil. My VW mechanic recently recommended using Lucas oil treatment in my 2007 Eos as a general recommendation (I'm not having any warning light problems). You should research whether these treatment options are OK for your full synthetic oil.

voxmagna

· #8 · Apr 24, 2021

You can get more oil pressure from a worn oil pump, engine bearings or a clogged oil pickup strainer by using thicker oil to put out a warning light. A good oil pressure switch usually cuts out when oil pressure is above about 10 psi or whatever threshold is set. But that low pressure doesn't get the oil around to some critical parts where it's needed and that's the valve gear and camshaft oil supply. A fault scenario some discussed on VWvortex for this starts with an intermittent oil pressure warning, then the engine MIL light on, followed by a clatter from the valve gear and valves smashed into pistons. V.W specify which oils should be used in their engines by year and VIN. Before an oil change, it's worth checking what oil will be used as some of the newest V.W oil specs are not backwards compatible for their older engines. If it was a V.W dealer doing the oil change, they should have used the correct oil.

Many garages now use the quick and easy 'suction up the dipstic' method to remove old oil. You will remove more sludge and old oil by opening the oil drain, plus you might spot any suspicious metal or 'gray oil' in the outflow.

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Executive

Discussion Starter · #9 · Apr 28, 2021

I changed the oil pressure switch and it hasn't came on since. Even did some spirited driving and nothing yet.

voxmagna

· #10 · Apr 28, 2021

Keep you fingers crossed and hope it doesn't come back. I looked up what diagnostics actually measures: Apparently there isn't a linear oil pressure sensor or readout and oil pressure has to be confirmed with a Tee piece and gauge. Diagnostics only stores the two thresholds - low oil pressure and normal which isn't very useful.

Executive

Discussion Starter · #11 · Aug 24, 2021

Soo I changed my oil, Pennzoil 5 40 euro and a stp filter and put in a new duralast oil filter. This morning the oil pressure warning came on again, soo half way to court then all the way home it was on and off. Checked my oil it was fine, went to a shop nearby while the light was still flashing and they said the actual pressure was ok. Cut the car off for a while then left again. And from about 4pm until 8pm I've driven around and now no light has came on. I really don't know what it could be, and if it is just the pressure switch going out, I don't know what would cause it.

Or maybe it's something that was an issue previously and that's why the original owner got rid of it. As it turns out the car had a branded title and was eventually brought back under the lemon law, but I can't find out what the problem was that couldn't be rectified.

voxmagna

· #12 · Aug 24, 2021 (Edited)

You are blind to what may be going on with the life blood of your engine so why guess? It could be innocent like an oil pressure switch problem, or something more serious and the warning is real. Ask yourself: "Do I want to take risks staying blind and what will it cost for a replacement engine"

Even did some spirited driving and nothing yet.

What did you think that would achieve apart from making the engine worse? If there's an oil pressure problem measured at idle, then there is a problem!

You've done some work changing oil and filter (non V.W!) so that DIY work cannot be excluded. Presumably the oil pressure warnings were not there before you did the work?

If you don't want your car written down for a bad engine, talk to an independent shop about fitting an oil pressure gauge you can monitor inside the cabin. There are some aftermarket electronic gauges sold that only need wires not pipes to link to the gauge. You could temporarily plug it into the accessory socket. Then if the oil pressure is around 45 psi when the light comes on, you have confirmation of a faulty switch.

Now, you may be thinking I'll change the pressure switch and the problem may go away? Wrong! A new oil pressure switch may not trip a warning at the higher end of its spec. e.g 12-15 psi and that is what you will be driving with. Unfortunately diagnostics doesn't measure absolute oil pressure because the only engine sensor is the low pressure switch, but it can measure oil temperature.

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Executive

Discussion Starter · #13 · Aug 24, 2021

I may actually have to get a digital gauge installed, probably a voltage gauge too. But I took it to a shop and the dealership the other time it did this. Both times they said the pressure was fine and the switch was bad. I even checked it myself with the little bs gauge I got from AutoZone. The independent guy actually monitored the pressure while driving and he said it never dropped below spec. It also won't do it at idle ever, I can sit for hours and even rev the engine and it will never come on

voxmagna

· #14 · Aug 24, 2021 (Edited)

Trust others and what they say who won't pay for a new engine, or trust what you do and see for yourself. If your engine grenades you'll have no voltage to measure so that seems superfluous.

There is discussion of a problem on some V.W engines where a hexagonal shaft driving the oil pump can wear and slip around. Do some research just in case it might affect your engine - now you see oil pressure, the worn shaft slips, - and now you don't.

Executive

Discussion Starter · #15 · Sep 21, 2021

Think I've figured it out. The light came back but was on almost immediately when I started driving. I wiggled the wiring going to it and it went away. Spun it again and it popped back up. It was laying across the alternator soo I used a zip tie to hold it up, haven't seen the light since

tomgadgets

· #16 · Sep 21, 2021

It is probably a worn connector. Our EOS is known to have some of these cable/connector problems. I swapped out my steering wheel clock-spring wires so that I get back the horn/steering wheel controls, and also re-pin my throttle position sensor cable connector to get rid of the dreaded EPC light....

Executive

Discussion Starter · #17 · Sep 21, 2021

Clock spring is probably next on my list. Horn hasn't worked for while though everything else on the wheel does

Joe Tapper

· #18 · 5 mo ago

Bought a 1 owner 54K 2012 Eos a year ago. The low oil pressure light comes on intermittently. Usually for a second or two. Had a VW dealership as well as an independent master mechanic resolve. They haven’t yet. So far I’ve replaced the sensor, the oil pump, the instrument cluster. no dice. The VW dealership changed the oil and the filter. Mechanic wants to use heavier weight oil. Thoughts?

voxmagna

· #19 · 5 mo ago (Edited)

Before replacing anything I would have attached an external oil pressure gauge to measure what the oil pressure was doing when the engine is started both cold when hot at normal temperature and how pressure drops when the engine stops. Make sure the warning is oil pressure and not oil level. There are thousands of these engines running with V.W spec. standard oil without oil pressure warnings worrying their owners. I would suggest you still have an unresolved problem of which you have very little hard information. Changing things is hit & miss, costs you money and doesn't tell you what is wrong. IMHO that is what I would expect a master mechanic to do first then tell you what results they got? If they didn't do that then question their competence?

If you get an oil pressure warning when the engine is restarted hot, changing oil viscosity (thickness) isn't the answer because even standard multigrade oils will be thicker when cold.

So, this is what your 'Master Mechanic' should do and I'm not one:
When the engine is showing the startup oil pressure fault, fit an external pressure gauge and monitor what happens in the first few seconds of engine cranking and start. Oil pressure should rise very quickly and from memory settle at around 40-45psi for these engines. Even slow speed cranking should produce some oil pressure. As oil pressure goes, by design that is relatively low for engines and the warning will be more sensitive to any pressure loss. Most oil pressure warnings are given below 10-15 psi. Confirm with the external gauge that when the light goes out the oil pressure is actually reaching the normal high pressure and is maintained fairly constant. Just because an oil warning light goes out, doesn't mean it's at correct working pressure. Confirm this happens for both a hot & cold engine.

If correct pressure is being reached and maintained fairly constant at idle that's re-assuring. If oil pressure doesn't get there even on idle, that suggests a problem to fix. If oil pressure does reach normal pressure at idle but is slow to get there during which time the warning light is lit, that suggests something to look at? Watch engine oil pressure when the engine is stopped. It should drop slowly over a few seconds and not crash to zero immediately.

Many oil filters are now fitted with integral back flow prevention valves. These ensure the filter can, pump and sump pickup stay full of oil after the engine has stopped, the oil pump doesn't drain and remains primed. If the warning light comes on when the engine is restarted after running at normal temperature that might suggest oil is draining down from the pump and filter?

There are several reasons why oil pressure may be low and it's important to know if the oil pressure can reach and stay at it's normal level at idle and higher rpm, for a hot and cold engine. If that is proven then look at the behavior of oil pressure during the start up to idle phase and whether pressure is slow to come up past the warning pressure or lagging? Confirm what pressure the warning goes out. Oil pressure warning switches work over a tolerance range.

After confirming real pressure behaviour with a gauge, faults that might be relevant are:

The wrong type oil filter fitted without a backflow valve if that is required by V.W spec.
Blocked oil sump pickup filter, pickup tube, or a faulty seal.
Worn engine bearings.
Blocked oil feed gallery (s).
A pump or cover gasket failure causing loss of oil pressure.
Turbo oil seal or pressure metering valve/jet faulty allowing too much oil to bypass back to the sump.

In order to reduce cost and space, some engines incorporate high pressure oil feed galleries cast in their timing covers. This design relies on gaskets or 'O' rings to ensure they are sealed and oil under pressure won't leak back to the sump. If this type of timing cover warps, oil pressure can be lost past seals which you cannot see. Check oil is reaching valve gear under the top rocker cover after the engine has been left standing. It may take a few seconds to wet these parts after a restart with oil but not much more. A consequence of oil draining back when an engine has been left standing is usually dry valve gear and more valve noise at start up which takes some time to go away.

Good Luck.

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Reactions: 1

Joe Tapper

· #20 · 5 mo ago

voxmagna said:
Before replacing anything I would have attached an external oil pressure gauge to measure what the oil pressure was doing when the engine is started both cold when hot at normal temperature and how pressure drops when the engine stops. Make sure the warning is oil pressure and not oil level. There are thousands of these engines running with V.W spec. standard oil without oil pressure warnings worrying their owners. I would suggest you still have an unresolved problem of which you have very little hard information. Changing things is hit & miss, costs you money and doesn't tell you what is wrong. IMHO that is what I would expect a master mechanic to do first then tell you what results they got? If they didn't do that then question their competence?

If you get an oil pressure warning when the engine is restarted hot, changing oil viscosity (thickness) isn't the answer because even standard multigrade oils will be thicker when cold.

So, this is what your 'Master Mechanic' should do and I'm not one:
When the engine is showing the startup oil pressure fault, fit an external pressure gauge and monitor what happens in the first few seconds of engine cranking and start. Oil pressure should rise very quickly and from memory settle at around 40-45psi for these engines. Even slow speed cranking should produce some oil pressure. As oil pressure goes, by design that is relatively low for engines and the warning will be more sensitive to any pressure loss. Most oil pressure warnings are given below 10-15 psi. Confirm with the external gauge that when the light goes out the oil pressure is actually reaching the normal high pressure and is maintained fairly constant. Just because an oil warning light goes out, doesn't mean it's at correct working pressure. Confirm this happens for both a hot & cold engine.

If correct pressure is being reached and maintained fairly constant at idle that's re-assuring. If oil pressure doesn't get there even on idle, that suggests a problem to fix. If oil pressure does reach normal pressure at idle but is slow to get there during which time the warning light is lit, that suggests something to look at? Watch engine oil pressure when the engine is stopped. It should drop slowly over a few seconds and not crash to zero immediately.

Many oil filters are now fitted with integral back flow prevention valves. These ensure the filter can, pump and sump pickup stay full of oil after the engine has stopped, the oil pump doesn't drain and remains primed. If the warning light comes on when the engine is restarted after running at normal temperature that might suggest oil is draining down from the pump and filter?

There are several reasons why oil pressure may be low and it's important to know if the oil pressure can reach and stay at it's normal level at idle and higher rpm, for a hot and cold engine. If that is proven then look at the behavior of oil pressure during the start up to idle phase and whether pressure is slow to come up past the warning pressure or lagging? Confirm what pressure the warning goes out. Oil pressure warning switches work over a tolerance range.

After confirming real pressure behaviour with a gauge, faults that might be relevant are:

The wrong type oil filter fitted without a backflow valve if that is required by V.W spec.
Blocked oil sump pickup filter, pickup tube, or a faulty seal.
Worn engine bearings.
Blocked oil feed gallery (s).
A pump or cover gasket failure causing loss of oil pressure.
Turbo oil seal or pressure metering valve/jet faulty allowing too much oil to bypass back to the sump.

In order to reduce cost and space, some engines incorporate high pressure oil feed galleries cast in their timing covers. This design relies on gaskets or 'O' rings to ensure they are sealed and oil under pressure won't leak back to the sump. If this type of timing cover warps, oil pressure can be lost past seals which you cannot see. Check oil is reaching valve gear under the top rocker cover after the engine has been left standing. It may take a few seconds to wet these parts after a restart with oil but not much more. A consequence of oil draining back when an engine has been left standing is usually dry valve gear and more valve noise at start up which takes some time to go away.

Good Luck.

Thank you so much for the detail

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