Oil light ON, advice needed

2011 8V Tenni, rollerised. Used Motul 10-60 for 2 years in a row. Last oil change 800km ago. Beetle map, and custom exhaust-open.

Today, after 3 weeks i finally start my bike. Everything looks normal, but oil light comes ON and stays ON. I turn it off, wait for 10 min, and checking the level, it says above MAX.

Can anyone give me right direction, what should i check? What are the possible problems?

i guess the MG do not like the oil level above its max, I believe you should not fill with more than 3.1 liters.

It was filled exactly as it should be, 800km ago. I was riding it, and it was perfectly fine,no oil level exceed and no oil warning light, until today.

Note that the oil light is a pressure warning, not a quantity warning. The level, as long as there is *some* in there is irrelevant.

Now the most likely cause is the warning light sender switch. These are a common failure point so first thing is to replace it. Being a 2011 you'll probably need to go aftermarket as Guzzi, for some reason known only to them, changed the thread pitch and electrode fitting at about this time and their solution was to require a huge, clumsy, adaptor to screw into the block and this quite often meant that the switch fouled on the alternator. There are aftermarket switches with both the correct thread pitch and electrode fittin. You just need to match it up at an auto parts store.

If it isn't the switch then you need to look elsewhere. The spacer gasket between the block and sump spacer can blow out but this rarely triggers the light as the switch works on such low pressure. The oil pressure relief valve may of jammed open or fallen out but this is unlikely. Or the oil pump gear may of stripped its teeth which is even more unlikely!

My money is on the switch.

Ok, after few hours rest, i again checked the level. It is above MAX. Oil is good, smooth and color is ok, but there is a smell like petrol in it.

I started the bike, working in Neutral on side stand for 2 min, everything ok. I do some rev above 1500rpm,and OIL light comes ON, and stays...

Have you lost fuel from the tank?

On older designs fuel can drain into the cylinders and past the piston rings into the oil.
The fuel makes the oil too thin to pump properly - so the pressure remains low.

This should not be possible on a fuel injected bike but if you have lost fuel from the tank i would replace the engine oil and filter before running the bike again

Unless there's an over-fuelling problem, it's usually short trips, cold ambients & not reaching normal (already low) operating temperature that build up unburnt fuel diluting the oil - comes directly past rings as fuel & round the blowby circuit as fuel/oil emulsion in bottom of sump. I'd focus on the switch (& the gasket) !

I think the alarm bells went off for me when the oil level increased. Thinks it's either over-fuelling, or has a leaky injector.

Petar and I have had a chat on social media. He's going to pull a plug and send me a pic. He's running a custom pipe with my GT Pipe map.

I really doubt that dilution of the oil alone would cause the oil light to behave as it is. Also it should be remembered that in most cases the pump won't leak fuel through its spigot and thence to the injectors if the ignition is off.

Pull your tank. Sit it on the floor. Most won't drip or flood. That would mean that for a huge amount to bleed through there would have to be both a faulty pump valve and a leaky 'jeckter. Not impossible but unlikely.

I'm still pointing the bone at the switch. They're a known weak point..

I agree re the oil switch. However, the oil level never goes up. That, plus the petrol smell is what concerns me.

You may recall I have some experience with this situation.

Yeah but we know what caused that.....

Keep it simple!  I'm with Pete on this one.  I had the same exact issue.  No change in engine noise that indicated low oil or oil pressure or smells of overheating, but the light came on, luckily, 1/4 mile from the house on my daily drive home in 2015/2016 timeframe.  I had seen it blip on previously during a ride home and then go off.  I did the usual internet investigations and came up with the oil pressure sending unit which, conveniently, sits right in between the cylinders .  Hardest part is that the fancy slip on connector for the stock unit will have to be snipped off and you'll have to wire in an old school female  spade connector for the male spade connection on the new sending unit.

Here's the link on AF1 with note on the bottom, like Pete said, "*Moto Guzzi Owners: Please note: The 1000cc, 1100cc, and 1200cc engine can have an M10x1.0 oil pressure switch (like the one in this ad) or an M12x1.5 Oil Pressure Switch. Check your switch before ordering to be sure you select the correct one."

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P.S. FWIW, I had an oil leak from the sending unit with my stock sending unit failure.

I had one fall apart on a Cali 1100 many years ago. I was on a tour, so had to scrounge around the hardware shops for a short bolt and sealing washer to fit. Oil leak fixed, and replaced the sender after arriving home.

Is the bike in a secure area. Oil level increased? Something else is in there, sabotage or fuel?

Bike is in garage, super secured. Not even my wife has a key in my garage

It is the first time ever to have OIL light ON. Never before, not blinkinkg, not ON and OFF.

Bike was Serviced 800km ago, oil filters, new spark plug caps, new wires. After service everything was perfect.

Stored 3 weeks ago, and sent the seat for a leatherwork. The moment the seat arrived i went for a test ride, and than, OIL Lightning happened.

Several times tested, OIL level is indeed increased, it was in the proper level, now is above maximum.

On startup, everything is nornal. After 1500rpm rev in Neutral, light comes ON. Also, if i shift in gear, the moment i release the clutch, the light comes ON. In both cases, it stays ON until shuting down.

No abnormal noises, no leaking, no visible traces. Checked bike visually 100%,several times.

So fsr, i havent got time to do any action in detecting the problem.. I'll start in yhe next few days by draining the oil, check its quantity, consition etc.

How are you checking the oil level?
Manual asks for the bike to be upright on a level surface - this is difficult to achieve in day to day life.
Do it once to check, the put the bike on a level surface using the side stand. Check again and mark the dipstick with the new reading.
Don’t forget that when talking oil level readings the stick in not screwed in just pushed square onto the opening.

For fuck's sakes you muppet several people have told you that the most likely culprit is the fucking oil pressure sender switch! Change that out and then see if the light problem goes away.

If it doesnt go away then We can start looking at whether your bike has an overfuelling problem.

Stop sticking your head in the sand and start listening otherwise??? Well? Fuck!

Nobody is going to sprinkle unicorn horn/fairy-dust over your motorbike over the Internet. If you aren't interested in following advice? Bugger off and cry in someone else's bloody beer!

You must have misunderstood me, its easier to speak than to write it down... Sorry if you, or anyone felt insulted, i am extremely grateful for the contribution to reply, and point me to any direction.

I accept that most people directed me to change of oil pressure sender switch, which is already ordered online, but meanwhile i wanted to check the oil, since it will be changed anyway, no matter if the problem is solved by the switch or not.

Steady on, Pete. He’s a chemist, not an engineer.

Yes, I'm sorry. I'd just had a very frustrating day and it seemed that the obvious suggestion of the switch was being ignored. I didn't see any mention of a new one being sourced. That sort of thing happens a lot and drives me bonkers!

If you want to vent, direct it at me. Petar and I have communicated off-forum. This is what I said:

Quote :

What year GRiSO? Pre 2014 models with the sump spacer can have the spacer gasket blow out, causing the oil pressure light to come on. The oil pressure sensor can go bad, or have a bad connection. That's the first place to look - the connector on the sensor.

Please remove some oil. You should never run more than 2/3 oil level, otherwise you run the risk of blow-by forcing oil into the airbox and throttle bodies.

Petrol smell may mean you're over-fuelling, causing the oil to thin, washing your bores, and, as a consequence, causing oil pressure issues. Hence the light. Have you remapped it?

Don’t forget I fix MRI’s and PET/CT’s for a living. My nerd brain always goes straight for the obscure.

Yup, when I hear hoof beats, I think of zebras.

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Removes the oil pressure sender switch, now i have to source new, because Piaggio canceled my order due to unavailability.

While reading cross refferences, i found BMW Series 1,have similar or maybe same. Can anyone recommend a cross reference?

I have recorded these as a successful alternative.

Duralast PS158 (thread M12 x 1.5)

Autozone PS486

Or use Google to find others.