oil pressure light

[motodoc43]

Hi all,

 

I just bought a 2002 lemans with 9k on the odo. I checked the fluid levels, started it up, and

went for a ride. After about 10-15 minutes the oil pressure light went on. Crankcase still with oil.

I limped home low RPM (about 2 miles), shut it off, and let it cool down. On restart, the oil pressure light is still on. So, I added a little less than half a litre of oil, now at the max line on the dipstick, and restart- the oil pressure light is still on.

I have read a number of things about it being the pressure switch rather than the oil pump, but am not confident enough to just go ride- not interested in a total rebuild. The bikes history is that it had an oil change about 2,000 miles ago, was checked out and given a clean bill of health. It has since sat for about a year with the exception of one 5 minute ride about 3 months ago.

I am 300 miles from the nearest dealer, and so would really like to be able to handle this without taking it to the shop. I have purchased a motratech oil pressure guage kit which I intend to install.

This is my 3rd Guzzi (an 81 convert, and an 09 cali vintage) and I have never had any trouble with them before.

Anyone with any ideas?

[stormsedge]

I wonder if the screen in your pan is clogged from sitting for so long?

[gstallons]

I have an idea, take the oil pressure switch out,start the engine, if oil shoots out about 10' in a hard stream, you are pumping oil.

P.S. do this outside............

[jrt]

Could be one of several possibilities. The oil pressure sensor turns on/off at very low pressure, so if it truly indicates low oil pressure, you are screwed. It's too late.

1) most likely- the sensor is bad. That's what gstallions is suggesting. I personally would just replace it with a new one rather than spewing oil out in a stream...but, hey- that's just me. Really- this is by far the most common scenario.

2) the pump is bad or there is a blockage in the line. Replacing the sensor won't help. You'll probably need new bottom end bearings as they are the most prone to damage after a low oil-pressure incident. If the sensor is good and you have a low-oil pressure incident....you likely have damaged the bottom end.

3) are you pulling wheelies or doing really hard acceleration? If so, you might be pushing the oil to the back of the crankcase and starving the oil pickup, thus reducing oil pressure. If this is the case, then see 2 above and quit pulling wheelies until you buy a Roper-plate.

I'm sure there are other possibilities, but these are the most common, and of these, 1) is BY FAR the most common. I've run one of my Guzzi's (not the V11) without an oil pressure sensor for 30K miles because the oil pump system is dirt-simple and not really likely to fail. And I'm too damn lazy to wire up a proper idiot light ;(.

Still- it is worth investigating. If there is an actual problem, it will be cheaper/easier to fix now.

[luhbo]

Before you start the engine again, make sure the oil filter still sits tight. For you the easiest approach might be if you remove the pan, first having it drained of course. I would not loosen the hose at the back of it by the way.

Also it might be a good idea to check the drained oil (and the dismounted pan) for metal chips. Not the tiny ones - I mean those which you can really see

 

Hubert

 

PS: I would not start the engine without the sensor. It IS a mess, you won't do your engine a favour and the oil will spill out even when the filter has come loose. No gain to expect here. Should the sensor be defect (what happens quite often - internal corrosion) the light will stay OFF, not ON.

 

Pics here

[ponti_33609]

+1 with check the oil filter! Make sure it is tight and add a "hose-clamp"!

[gstallons]

The switch removal procedure was tongue-in-cheek. If he rode 2 mi. w/the light on, he is probably o.k. You can drain some oil out & look for damages. The oil sender is a machine thread. Purchase or borrow a manual gauge from a mechanic or auto parts store and check the oil pressure.

When lights come "on" you are meant to STOP. These lights are not for your viewing pleasure. It is cheaper to haul your bike home and diagnose it than to spend $$$$$ to fix it after it is toast!

[Mike Stewart]

I am thinking the best way to find the issue is to drain the engine oil into a clean pan, remove the oil filter cover to check the filter for tightness, you may also want to remove the oil filter to make sure it wasn't double gasketed (new filter installed over an old filter seal). If all of above is ok, reinstall the oil filter and cover, reuse the engine oil (that is why the clean oil drain pan). Remove the oil pressure switch, install a threaded flexible oil hose with an mechanical pressure gauge on the end. Fire the engine up to see where the oil pressure really is. This is what a shop would do.

 

It only takes a second to do bad damage to the bottom end. Hopefully, the oil pressure was enough to turn on the light but had enough to keep everything else lubed.

 

Just my thoughts,

Mike

[motodoc43]

Thanks for all the help. I find it interesting that the light would go on at such low pressure that there would be a problem with dammage to the motor form riding home easy. Never have raced anything with an oil pressure light or guage, never had any oil pressure probs with my other Guzzi's (one is 30 years old and the motor has never been open!)- I just change the oil and filter, get the valves checked every couple years, and go. Have owned a slew of Kawis since 1976, and they always recomend getting to a shop as quick as you can ( riding it) if an idiot light goes on- never had any trouble with dammaging a motor. Hopefully I'm not too much of an idiot. So now I will show my idiocy- can someone pos a pic of where the switch/sending unit is? Don't really want to take off the fairings etc... if it is easily accessable.

[luhbo]

.... where the switch/sending unit is? Don't really want to take off the fairings etc... if it is easily accessable.

 

Is this a Texas thing? Really keen on seeing the oil spring up?

[motodoc43]

.... where the switch/sending unit is? Don't really want to take off the fairings etc... if it is easily accessable.

 

Is this a Texas thing? Really keen on seeing the oil spring up?

 

 

LOL- No, I just want to take the thing out and hook up a guage so I don't have to ahul the bike 300 miles if it's ok!

[gstallons]

Remove the oil pressure switch and take it with you to an automotive shop and ask them about borrowing an oil pressure gauge & proper adapter to check oil pressure. As I stated it is a metric machine thread and not a NPT thread.

[motodoc43]

Remove the oil pressure switch and take it with you to an automotive shop and ask them about borrowing an oil pressure gauge & proper adapter to check oil pressure. As I stated it is a metric machine thread and not a NPT thread.

 

OK, dumb question. I have only an owner's manual. Where is the oil pressure switch? I see a Y fitting with three hoses in front between the cylindars- that is all I can see.

[jrt]

Thanks for all the help. I find it interesting that the light would go on at such low pressure that there would be a problem with dammage to the motor form riding home easy. Never have raced anything with an oil pressure light or guage, never had any oil pressure probs with my other Guzzi's (one is 30 years old and the motor has never been open!)- I just change the oil and filter, get the valves checked every couple years, and go. Have owned a slew of Kawis since 1976, and they always recomend getting to a shop as quick as you can ( riding it) if an idiot light goes on- never had any trouble with dammaging a motor. Hopefully I'm not too much of an idiot. So now I will show my idiocy- can someone pos a pic of where the switch/sending unit is? Don't really want to take off the fairings etc... if it is easily accessable.

 

The oil sending switch is a screw-in thingy between the cylinders, kind of toward the front...on the left side. It's screwed in at maybe 20-30 degrees off vertical. It is very close to the oil delivery lines to the heads. Look on your old bike first, if that one doesn't have a fairing. Guzzi hasn't changed the location of the sensor since the V700.

I don't think the oil pump is any less robust on modern Guzzis, but there has been at least one failure that I recall. That was quite rare, and unfortunate. With the older Guzzi's...they have been around long enough that any problems have been addressed or the bike is parts. I have a couple of older models that require very little maintenance. Change the oil, set the valves, go.

BTW, the advice about a loose oil filter is good- I forgot that one....

[motodoc43]

Well, I changed the oil and filter, cleaned the screen filter. No metal peices in the pan or oil.

I found the pressure switch and removed it, went all over town looking for a guage that had an adapter that would fit, no luck. So I grounded the switch and put an air pump to it. It seems to be going off at about 50 PSI. So my guess is, the switch. In doing that however, I ran the battery down, and CANNOT GET THE SEAT OFF!!! The owners manual says the helmet lock will unlatch the seat but no such luck, it is just a stand alone helmet lock with no cable attached. So how in the world do you get the seat off to get to the battery?