Hey everyone!

I've been eyeing up these boards for a while but finally made an account to ask a question about my 2003 GS500.
It was bought used with 47000km's and during the test ride ran great (didn't ride it for all that long)

However now I notice that after 20-30min of varied riding, my bike's oil light slowly comes on at a standstill (flickering at first) then stays on until you give it some revs or just start riding.
I just got it serviced & they said it was fixed (oil level was too low according to them?) & the carbs needed tuning; however once home and on my driveway the light came on again.

Things like the spark plugs, air filter, oil filter, have all been replaced and I'm not sure what I need to do.
I called them up again and they mentioned major engine damage due to neglect (maintenance history is unknown), I read some posts about the oil sensor being dirty and that *possibly* causing it but he is not willing to change that part & kept telling me it's not fixable without giving much more reason. (Other mechanic probably will but I could break even on the bike if I just traded it in for a new one.. so spending more money is a hard pill to swallow  )

TL;DR

• Oil light comes on when idling
• Bike just got serviced mainly to fix this issue

All answers are greatly appreciated! 

I can give a general response.

When the oil light comes on there are two typical courses of action.

The preferred action is to install an oil pressure gauge (temporarily for testing) and check the oil pressure.
- If it's ok, then you have a faulty oil pressure switch or (uncommon) the wire to the switch is shorting to ground at some point.
- If the oil pressure is not ok, then you have to troubleshoot the engine/oil system.

The second course of action is to just replace the oil pressure switch and see if the light stays off. ( oil pressure switches do fail)
If it does... all set. If not, back to action one.

Is the oil level ok?

First off, I'm assuming that the oil level check is the same on the 500 as on my older '82 450, and that it has the dipstick in the oil filler cap. If someone could confirm that it would be awesome 

The correct way to check the oil level is with the filler cap sitting on top of the threads, not screwed in. If the oil level is read after screwing the oil filler cap in, the oil level will be too low, and you will definitely see that oil light flicker at idle. I made this mistake myself when I first got my 450 back in '98.

The fact your shop have not taken seriously and fully investigated an indication of low oil pressure and mislead you over the nature of the cause is concerning and leads me to doubt their competence............. I would be giving them a swerve in future.

The fact you have also recently bought the bike suggests the previous owner may have already known about the potential issue and decided to sell it on........along with the problem!!!  The lesson here (and always has been) is to be careful when buying high mileage bikes with no service history.

Generally if the oil level is becoming low you will see the light flicker as you corner before it starts to flicker when vertical at tickover.

The engine needs an oil pressure test, its a simple as that. If the test proves satisfactory you can look elsewhere and investigate the sender and wiring. If the test proves unsatisfactory you have to assume there is an internal issue relating to a bearing or journal or the oil-pump itself, the engine will have to be dismantled and carefully inspected to locate the cause and you will have to consider the cost implications. There are no oversize bearings available for the GS5 so any wear on the crank and balance shaft journals will mean they will have to be replaced with new or serviceable items. 

The pressure test itself is not difficult to carry out but it does require special equipment. The procedure is covered in the Haynes manual. I suggest you find another more competent shop and ask them to carry out the test. A mobile car mechanic may also be able to carry out the test assuming he carries a good quality, for that I mean accurate, oil pressure test set.  I am looking at the manual now, the quoted tolerances are 2 to 5 bar at 3000rpm with a warm engine.

A replacement sender (part no3782033D10) is around £45 here in the UK, not cheap , you can convert this figure to your own currency to give you an idea of the likely cost to you. 

Personally I would put the money towards the pressure test rather than taking a stab at the sender and possibly wasting the cash........ but it is your call 

Quote from: sledge on August 13, 2020, 03:44:24 AM
The fact your shop have not taken seriously and fully investigated an indication of low oil pressure and mislead you over the nature of the cause is concerning and leads me to doubt their competence............. I would be giving them a swerve in future.

The fact you have also recently bought the bike suggests the previous owner may have already known about the potential issue and decided to sell it on........along with the problem!!!  The lesson here (and always has been) is to be careful when buying high mileage bikes with no service history.

Generally if the oil level is becoming low you will see the light flicker as you corner before it starts to flicker when vertical at tickover.

The engine needs an oil pressure test, its a simple as that. If the test proves satisfactory you can look elsewhere and investigate the sender and wiring. If the test proves unsatisfactory you have to assume there is an internal issue relating to a bearing or journal or the oil-pump itself, the engine will have to be dismantled and carefully inspected to locate the cause and you will have to consider the cost implications. There are no oversize bearings available for the GS5 so any wear on the crank and balance shaft journals will mean they will have to be replaced with new or serviceable items. 

The pressure test itself is not difficult to carry out but it does require special equipment. The procedure is covered in the Haynes manual. I suggest you find another more competent shop and ask them to carry out the test. A mobile car mechanic may also be able to carry out the test assuming he carries a good quality, for that I mean accurate, oil pressure test set.  I am looking at the manual now, the quoted tolerances are 2 to 5 bar at 3000rpm with a warm engine.

A replacement sender (part no3782033D10) is around £45 here in the UK, not cheap , you can convert this figure to your own currency to give you an idea of the likely cost to you. 

Personally I would put the money towards the pressure test rather than taking a stab at the sender and possibly wasting the cash........ but it is your call 

Thank you so much for the reply!
I knew the high mileage along with no service history was a bit of a gamble, but I didn't expect to fall in love with the bike the way I did so immediately throwing her out isn't an option.

The shop acted as if the oil level was extremely low and gave that as a reason.
I played dumb (I'm no mechanic but I can check the oil and I did before taking it in), so it was suspicious.


I heard great things about that shop but will definitely take it some place else where they're willing to do an oil pressure test this Saturday.
As it only occurs once the engine is fully warmed up I might be looking at something more serious here, I did keep an eye on the light the last while and it didn't once come on during driving and I didn't see it in my FOV while cornering or on the GoPro footage.

If that turns out satisfactory I'll get the sender looked after or the wiring, if not I'm not sure how much taking the engine apart for the oil pump or other parts to be looked at would cost but I'm assuming that's not going to come cheap? (Any estimates are welcome, obviously they'll vary from country->country & shop->shop)

Anyways thanks a ton again for the information, I feel more confident going in now that I can explain what needs to be checked in some more detail instead of the "Oil light is on when not moving & engine is hot" I could give before!

I'll update once I know more, for future GS owners

As a quick update, I went in this morning for a second opinion at a different shop.
I felt a lot more comfortable & it seemed like the mechanic actually listened, he also reckons its the oil pressure sensor and if it wasn't my engine should've blown up long ago.
He ordered the part as to test the pressure he'd have to open the engine regardless, € 50 for the part + labor sounded good.

Next week Thursday I'll bring her in and cross my fingers!
With some luck I'll get to keep riding the lovely GS for many more km's.

Quote from: peteGS on August 12, 2020, 08:10:21 PM
Is the oil level ok?

First off, I'm assuming that the oil level check is the same on the 500 as on my older '82 450, and that it has the dipstick in the oil filler cap. If someone could confirm that it would be awesome 

The correct way to check the oil level is with the filler cap sitting on top of the threads, not screwed in. If the oil level is read after screwing the oil filler cap in, the oil level will be too low, and you will definitely see that oil light flicker at idle. I made this mistake myself when I first got my 450 back in '98.

I totally forgot to reply to this, my bad!

Did a check after riding 500km's (and not holding back on the throttle) and it didn't consume a drip of oil; so that's a good sign.
No smoke can be seen either, had someone ride behind me to make sure that it didn't blow blue smoke.


Short version :
Went to a different mechanic.
Oil pressure switch/sensor really could be the issue & went ahead with letting him order the part & plan the installation.

No oil was consumed during a long ride, no smoke is produced either.
Engine still runs smooth & revs happily, crossing my fingers (and toes  )

Couple of things. You DONT need to open engine to test oil pressure. That mechanic also seems dodgy. It's a 30 minute job!

Was the sump dropped recently (installing a later sump gasket in a Pre oil cooler bike will give low oil pressure) there are a few threads on here about that.

Good luck!

Unlikely the engine will ever `blow up`.....not until the light comes on at speeds above tickover.

He simply doesn't have enough information to say with 100% certainty that the sender is a fault.

He has taken a guess......lets hope it pays off 

I looked at the service manual and at the bike.  Suzuki made it real easy to check oil pressure.

This is ten minute job at most. Pull in to the shop with the engine warmed up. (Should be measured warm/hot)

Unscrew the chrome plug, screw in the oil pressure gauge.
Start the bike and check at idle and up through 3000 RPM range... or at least until the pressure levels out.
Shut the bike off, unscrew the gauge, screw the plug back in.

Oil pressure switches shut off with 3-5 PSI pressure. You want to know if it's higher than that.

The manual states oil pressure should be between 28 and 71 PSI (2.0 to 5.0 kg/cm2) at 3000 RPM

I'd say that these "mechanics" either don't own an oil pressure gauge (with adapters) and a service manual... or they want to make a job and replace something, rather than test it.



Illustration from the service manual





The chrome plug (rusty) on my bike.


free photo hosting

@Sledge, hey good to see you around here. Wise words as usual.

I just got it serviced

When I saw that it's already a worry with these bike, it's like shops don't care about them any more and just give it to the noob to work on.

I'd never buy a high milage bike without a full service history, in fact normally I'd never buy a high milage bike in any circumstances, but I've changed my mind since. I just sold my GS yesterday with 76,000 on the clock, and I had the full service history that I'd done. Put in semi synthetic oil with extra zinc. Still has the original factory shims and well within spec, the worst one is .05mm. She runs better than when I got her at 15k kms. A joy to ride. This is what the GS is capable of. FFIW.

Sorry that you have found out the hard, way, hopefully not too serious. But I'd check the shims, not just the clearance, see what size they are up to.

Therefore that's what you can expect from a GS that has not been abused, so I suppose checking the shims is always a good idea to give you an idea. There was a thread recently where someone needed less than a 215 shim. I'm still at 365, mainly riding between 4 and 6k, never redlining, and only occasionally doing a hi rev shift, by high I mean 7k.

Quote from: herennow on August 16, 2020, 02:16:56 PM
Couple of things. You DONT need to open engine to test oil pressure. That mechanic also seems dodgy. It's a 30 minute job!

Was the sump dropped recently (installing a later sump gasket in a Pre oil cooler bike will give low oil pressure) there are a few threads on here about that.

Good luck!

I was told it's about a 30-45min job to replace the sensor anyways, he however indeed looked up a manual & was looking to check the oil pressure from somewhere else (not sure if he was mistaken, he supposedly owned multiple GS's himself)

It wasn't done recently that I'm aware of, it's been handed over today for the new sensor to be put in so we'll know soon enough.

Quote from: sledge on August 17, 2020, 11:24:54 AM
Unlikely the engine will ever `blow up`.....not until the light comes on at speeds above tickover.

He simply doesn't have enough information to say with 100% certainty that the sender is a fault.

He has taken a guess......lets hope it pays off 

He doesn't know with 100% certainty & was upfront about that as well, he did talk to the other mechanics there which all agree it's about a 95% chance that this is causing the oil light flicker.
Let's hope it doesn't blow up & lock up the rear tire, that wouldn't end all that well! 

Quote from: Sporty on August 17, 2020, 03:39:40 PM
I looked at the service manual and at the bike.  Suzuki made it real easy to check oil pressure.

This is ten minute job at most. Pull in to the shop with the engine warmed up. (Should be measured warm/hot)

Unscrew the chrome plug, screw in the oil pressure gauge.
Start the bike and check at idle and up through 3000 RPM range... or at least until the pressure levels out.
Shut the bike off, unscrew the gauge, screw the plug back in.

Oil pressure switches shut off with 3-5 PSI pressure. You want to know if it's higher than that.

The manual states oil pressure should be between 28 and 71 PSI (2.0 to 5.0 kg/cm2) at 3000 RPM

I'd say that these "mechanics" either don't own an oil pressure gauge (with adapters) and a service manual... or they want to make a job and replace something, rather than test it.



Illustration from the service manual





The chrome plug (rusty) on my bike.


free photo hosting

I probably should've looked up how to test it & put some more pressure on them to test it; he was however going to check the engine while it's in. (Including oil pressure after replacing the sensor).

Quote from: user11235813 on August 18, 2020, 02:16:56 AM
@Sledge, hey good to see you around here. Wise words as usual.

I just got it serviced

When I saw that it's already a worry with these bike, it's like shops don't care about them any more and just give it to the noob to work on.

I'd never buy a high milage bike without a full service history, in fact normally I'd never buy a high milage bike in any circumstances, but I've changed my mind since. I just sold my GS yesterday with 76,000 on the clock, and I had the full service history that I'd done. Put in semi synthetic oil with extra zinc. Still has the original factory shims and well within spec, the worst one is .05mm. She runs better than when I got her at 15k kms. A joy to ride. This is what the GS is capable of. FFIW.

Sorry that you have found out the hard, way, hopefully not too serious. But I'd check the shims, not just the clearance, see what size they are up to.

Therefore that's what you can expect from a GS that has not been abused, so I suppose checking the shims is always a good idea to give you an idea. There was a thread recently where someone needed less than a 215 shim. I'm still at 365, mainly riding between 4 and 6k, never redlining, and only occasionally doing a hi rev shift, by high I mean 7k.

The first shop I went to clearly didn't give a damn, I realized I'm missing 2 bolts (both heel-plates are now loose) which were there before; I checked pictures I have and up until the first service they were there.
If I brought it in all dilapidated I'd understand some type of carelessness but it was freshly cleaned/waxed with a clean/lubed chain & some fresh tires.
The high mileage really is/was a gamble, same goes for knowing how it's been ridden.

I still have better hopes for the shop it's with now, at least here they didn't push me to buy a Vespa or GSXR-250 & get a loan..

Anyways thanks for all the replies!
I should have it back by tomorrow or Saturday, if the gamble-marathon pays off the light will stay off; I'll post an update regardless!

If it doesn't fix the problem I would use it to your advantage and ask for a `free` oil pressure test 

I've got some great news, after changing the oil sensor & re-syncing the carbs/setting the idle a little higher the light finally doesn't come on anymore! 

Next week Friday she'll (hopefully) be getting me my permanent A2 license as well, fingers crossed because now it just depends on my riding abilities.

I'd like to thank everyone for helping out & giving such useful advice, I'll get to enjoy Suzy for at least two more years & seriously consider keeping her after as a fun around town machine 

Because pictures never hurt anyone :

Quote

If anyone happens to be looking for a fun luke-warm hatch, I can recommend the new Nissan Micra 0.9T; underrated & a lot of fun!

Hi everyone.
I also had an issue with the oil light coming on after a 20 or 30 minute ride. Also the oil cooler was cold to touch .Figured out that it was the wrong sump gasket . That was after replacing the oil pressure regulator ,oil pump .🥴 Just took it for a 45 minute ride with no issues at all. Hope this helps.
Regards
John Sydney Australia

  great!  Glad my advice above helped! I also spent some money on other things before confirming this stupid gasket problem. It's especially problematic on 2003s as they are an in between year and many sites show the incorrect part.

I have a 2004 and also had this problem after ordering the wrong gasket. I think some websites just don't know that there are two part numbers for that gasket and send the older gasket for bikes with the oil cooler. I had to ride like 5 miles home with the oil pressure light on at idle. I never noticed anything with the bike that could be 100% attributed to running with low oil pressure so hopefully all I lost was the cost of the gasket.