Oil analysis - gasoline present?
11-21-2012, 11:58 AM
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Oil analysis - gasoline present?
My GF's 02' Boxster with automatic had an oil analysis with oil change at 64,800 miles. Although metals are extremely low, there was a note regarding the presence of gasoline...
"Fuel dilution above 4% by volume in oil. Oil viscosity in 30W range. Moderate amount of fuel dilution detected. Consider sampling at half the normal interval to monitor. More sample history needed to establish a wear trend."
I've been changing the oil and filter on this car at every 5000 miles with 10W-40 Mobile 1. This analysis was done at a friends workplace that has an extensive fleet which is monitored. One source of such contamination would be clogged injectors. I plan on running some Seafoam through the fuel system to see if that helps but any other informed comments regarding this condition are appreciated.
"Fuel dilution above 4% by volume in oil. Oil viscosity in 30W range. Moderate amount of fuel dilution detected. Consider sampling at half the normal interval to monitor. More sample history needed to establish a wear trend."
I've been changing the oil and filter on this car at every 5000 miles with 10W-40 Mobile 1. This analysis was done at a friends workplace that has an extensive fleet which is monitored. One source of such contamination would be clogged injectors. I plan on running some Seafoam through the fuel system to see if that helps but any other informed comments regarding this condition are appreciated.
11-21-2012, 01:14 PM
#2
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My GF's 02' Boxster with automatic had an oil analysis with oil change at 64,800 miles. Although metals are extremely low, there was a note regarding the presence of gasoline...
"Fuel dilution above 4% by volume in oil. Oil viscosity in 30W range. Moderate amount of fuel dilution detected. Consider sampling at half the normal interval to monitor. More sample history needed to establish a wear trend."
I've been changing the oil and filter on this car at every 5000 miles with 10W-40 Mobile 1. This analysis was done at a friends workplace that has an extensive fleet which is monitored. One source of such contamination would be clogged injectors. I plan on running some Seafoam through the fuel system to see if that helps but any other informed comments regarding this condition are appreciated.
"Fuel dilution above 4% by volume in oil. Oil viscosity in 30W range. Moderate amount of fuel dilution detected. Consider sampling at half the normal interval to monitor. More sample history needed to establish a wear trend."
I've been changing the oil and filter on this car at every 5000 miles with 10W-40 Mobile 1. This analysis was done at a friends workplace that has an extensive fleet which is monitored. One source of such contamination would be clogged injectors. I plan on running some Seafoam through the fuel system to see if that helps but any other informed comments regarding this condition are appreciated.
But the absence of water build up which would go along with this suggests there might be a leaking injector.
Before I go on I have to say I'm not a fan of using Seafoam.
Anyhow, if one or more injectors were leaking short and long term fuel trims can sometimes show one bank's fuel trims quite a bit leaner than the other bank's as the DME reduces the injectors' open time -- to compensate for the leaking injector.
The leaking injector can't be leaking that bad or there would be an adaptation error (threshold reached) or misfires from the other cylinders will normally functioning injectors.
If you want to use something use Techron a bottle or two as per directions. Afterwards change the oil/filter.
But chances are the best solution would be to id which bank was undergoing the enleanment due to one (or more) leaking injectors and replace all injectors on that side, unless you have the shop do a spark plug job and from the conditions of the plugs the shop can pinpoint the cylinders with the leaking injectors and then replace just those injectors along with all new plugs of course.
11-21-2012, 09:14 PM
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But chances are the best solution would be to id which bank was undergoing the enleanment due to one (or more) leaking injectors and replace all injectors on that side, unless you have the shop do a spark plug job and from the conditions of the plugs the shop can pinpoint the cylinders with the leaking injectors and then replace just those injectors along with all new plugs of course.
11-21-2012, 11:08 PM
#4
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Probably not.
There is no reading obtainable from the injectors. They can be individually turned off to see which cylinder is weak. This works because the weakest cylinder contributes less to the engine at say idle and when deactivated by turning off the injector the rpms drop the least.
However, this is not often used since the DME constantly measures each cylinder's contribution to the engine's output by measuring the speed imparted to the flywheel during the combustion of each cylinder.
If a weak (or overly strong) cylinder is found a misfire code is logged and the CEL turned on.
As I recall though the CEL is not on.
So the suspected leaking injector is not causing a weak cylinder and the DME in attempting to compensate for the assumed leaking injector has not yet gone far enough (lean enough) to cause misfires in the cylinders with properly operating injectors.
The above of course assumes there is a leaking injector. There may not be. The accumulation of fuel may be normal based on the type of driving.
To recap: Lots of cold engine starts, short trips, the engine not getting very hot, can have fuel build up.
BTW, what is the amount of water build up in the oil? With a viscosity of around 30 I suspect there's a good amount of water. Water and unburned gasoline both work to lower the oil's viscosity.
You can have the injectors removed/tested. Some shops have a special setup in which all injectors are hooked up and feed high pressure (cleaning) fluid. The spray patterns are observed and compared along with the flow rate. A leaking injector can also be id'd.
If the cleaning improves the pattern and brings the flow rate back into line then fine. If not one or more injectors will have to be replaced.
I'm not sure what I would advise. There may not be anything wrong other than the engine needs to be run more and given a chance to get hotter. I would though consider using Techron as I mentioned before.
But I would still like to observe the short term fuel trims for both banks. Durametric IIRC can be used for this.
Of course you change the oil now and then after the Techron is burned up. I'd also give up that 10w-40 oil but I don't to get into another oil thread.
There is no reading obtainable from the injectors. They can be individually turned off to see which cylinder is weak. This works because the weakest cylinder contributes less to the engine at say idle and when deactivated by turning off the injector the rpms drop the least.
However, this is not often used since the DME constantly measures each cylinder's contribution to the engine's output by measuring the speed imparted to the flywheel during the combustion of each cylinder.
If a weak (or overly strong) cylinder is found a misfire code is logged and the CEL turned on.
As I recall though the CEL is not on.
So the suspected leaking injector is not causing a weak cylinder and the DME in attempting to compensate for the assumed leaking injector has not yet gone far enough (lean enough) to cause misfires in the cylinders with properly operating injectors.
The above of course assumes there is a leaking injector. There may not be. The accumulation of fuel may be normal based on the type of driving.
To recap: Lots of cold engine starts, short trips, the engine not getting very hot, can have fuel build up.
BTW, what is the amount of water build up in the oil? With a viscosity of around 30 I suspect there's a good amount of water. Water and unburned gasoline both work to lower the oil's viscosity.
You can have the injectors removed/tested. Some shops have a special setup in which all injectors are hooked up and feed high pressure (cleaning) fluid. The spray patterns are observed and compared along with the flow rate. A leaking injector can also be id'd.
If the cleaning improves the pattern and brings the flow rate back into line then fine. If not one or more injectors will have to be replaced.
I'm not sure what I would advise. There may not be anything wrong other than the engine needs to be run more and given a chance to get hotter. I would though consider using Techron as I mentioned before.
But I would still like to observe the short term fuel trims for both banks. Durametric IIRC can be used for this.
Of course you change the oil now and then after the Techron is burned up. I'd also give up that 10w-40 oil but I don't to get into another oil thread.
11-22-2012, 01:07 AM
#5
PCV check may be in order.
Could you post the UOA for reference?
Using some 2cycle oil in the gas at 500:1 is always a good idea. A little bit extra the first time, after that you'll be sold on using it all the time.
Could you post the UOA for reference?
Using some 2cycle oil in the gas at 500:1 is always a good idea. A little bit extra the first time, after that you'll be sold on using it all the time.
11-22-2012, 11:07 AM
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To recap: Lots of cold engine starts, short trips, the engine not getting very hot, can have fuel build up.
BTW, what is the amount of water build up in the oil? With a viscosity of around 30 I suspect there's a good amount of water. Water and unburned gasoline both work to lower the oil's viscosity.
You can have the injectors removed/tested. Some shops have a special setup in which all injectors are hooked up and feed high pressure (cleaning) fluid. The spray patterns are observed and compared along with the flow rate. A leaking injector can also be id'd.
If the cleaning improves the pattern and brings the flow rate back into line then fine. If not one or more injectors will have to be replaced.
I'm not sure what I would advise. There may not be anything wrong other than the engine needs to be run more and given a chance to get hotter. I would though consider using Techron as I mentioned before.
But I would still like to observe the short term fuel trims for both banks. Durametric IIRC can be used for this.
Of course you change the oil now and then after the Techron is burned up. I'd also give up that 10w-40 oil but I don't to get into another oil thread.
Don't worry about the motor oil discourse - I don't have time for that either.
Thanks for your help on this issue Mac. I'm going to take some Durametric readings this weekend and see if I can see anything obviously amiss.
11-22-2012, 01:19 PM
#7
Try this. Go and drive the car for over an hour on the freeway to make sure its really warm and all gas in the oil has burned off. Take off the oil filter and use the oil in the canister for another UOA. If it comes back clean, the problem is driving style.
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11-25-2012, 09:17 PM
#8
Before doing anything else I would
Establish the type of driving done, and if possible, modify it. Macster's first point was the highly likely one. Dilution is totally normal if a car does not regularly get up to > 200F for a sustained period. Fuel always enters the crankcase when the engine is started and while cold - its only a question of whether you boil it out.
A weekly 30 minutes run should do it. But if you perform the test on the 6th day, of after moving the car into the garage; then out, then stop, then go to the garage 2 miles away and take the sample.......
I hope you get the idea.
Worrying about leaky injectors is premature. Plus a leaky injector would normally affect drive ability to some degree, since it would impact mixture, thus emissions, thus fuel delivery as the feedback look operates around the mixture.
Grant
A weekly 30 minutes run should do it. But if you perform the test on the 6th day, of after moving the car into the garage; then out, then stop, then go to the garage 2 miles away and take the sample.......
I hope you get the idea.
Worrying about leaky injectors is premature. Plus a leaky injector would normally affect drive ability to some degree, since it would impact mixture, thus emissions, thus fuel delivery as the feedback look operates around the mixture.
Grant
The explanation of the presence of fuel could be from the type of driving the car gets. Short trips. The engine never really gets hot.
But the absence of water build up which would go along with this suggests there might be a leaking injector.
Before I go on I have to say I'm not a fan of using Seafoam.
Anyhow, if one or more injectors were leaking short and long term fuel trims can sometimes show one bank's fuel trims quite a bit leaner than the other bank's as the DME reduces the injectors' open time -- to compensate for the leaking injector.
The leaking injector can't be leaking that bad or there would be an adaptation error (threshold reached) or misfires from the other cylinders will normally functioning injectors.
If you want to use something use Techron a bottle or two as per directions. Afterwards change the oil/filter.
But chances are the best solution would be to id which bank was undergoing the enleanment due to one (or more) leaking injectors and replace all injectors on that side, unless you have the shop do a spark plug job and from the conditions of the plugs the shop can pinpoint the cylinders with the leaking injectors and then replace just those injectors along with all new plugs of course.
But the absence of water build up which would go along with this suggests there might be a leaking injector.
Before I go on I have to say I'm not a fan of using Seafoam.
Anyhow, if one or more injectors were leaking short and long term fuel trims can sometimes show one bank's fuel trims quite a bit leaner than the other bank's as the DME reduces the injectors' open time -- to compensate for the leaking injector.
The leaking injector can't be leaking that bad or there would be an adaptation error (threshold reached) or misfires from the other cylinders will normally functioning injectors.
If you want to use something use Techron a bottle or two as per directions. Afterwards change the oil/filter.
But chances are the best solution would be to id which bank was undergoing the enleanment due to one (or more) leaking injectors and replace all injectors on that side, unless you have the shop do a spark plug job and from the conditions of the plugs the shop can pinpoint the cylinders with the leaking injectors and then replace just those injectors along with all new plugs of course.
