My 95 with 130,000 miles has oil that is being diluted by gas. This shows up in multiple oil analysis that have been done over the last 30,000 miles. The flashpoint of oil has gone from 405 to 330, to 300 over the course of 35,000 miles.

Now the question is, what is the reason. Plugs were changed 10,000 miles ago, fuel filter was changed, air filter changed.

No codes, no starting problems, no stubble no hesitation, no change in mileage.

Is is a bad injector, or bad coils. Any ideas on what to check. In spite of the oil being diluted by fuel, the oil analysis was pretty good with German Castrol 0w-30, run to about 6000 miles.

 

my guesses (in order of likelihood) are:
1)injector stuck open
2)running rich due to a bad sensor (temp, 02, etc) or thermostat
3)piston rings sticking, causing low compression and blowby

you can verify by:
a) checking you plugs for carbon soot
b) tracking your gas mileage (are you sure your MPG is normal?? - my guess is it's low - it has to be if you have big time fuel dilution)
c) checking your compression

if you are running rich on all cylinders then you likely have a bad sensor somewhere that is not throwing a code, or the thermostat is fubar. then it becomes a process of elimination (testing and/or replacing every sensor there is until you fine the bad one).

if you want a true professional's opinion consult Terry Dyson. for a modest fee he'll analyze your UOAs and tell everything you need to know.

please keep us informed as to what you find!

 

my guess would be piston rings worn causing blowby

 

The oil sample did go to Terry. His (very well informed) guess is in order: coils, operating temps (thermostat????) or injectors. He also suggests pulling the injectors and taking them to an injector specialist for testing. Good luck here in Central Wyoming.

I was hoping that someone else had the same problem and could say, "it was my coils" or "It was my thermostat" or perish the thought "it was my injectors"

I will pull some plugs and look to see if there are signs of running rich. or if one or more plugs look appreciably different from the others. That might narrow it down to an individual cylinder.

Any other ideas would be appreciated.

 

interesting - Terry thought it could be coils. I suppose if a plug isn't firing the unspent fuel could wash down the cylinder walls. but since you don't have a misfire I think you can rule that one out.

to check engine temp - go borrow a code scanner from an auto store (most have some sort of loaner program). get one that can display live data. watch your temp as the car warms up and as you drive. fully warm it should get close to 200F. if it stays way low you have a bad thermostat. this will cause your engine to run rich. of course a bad temp sensor will have the same effect, and may give you a false reading on the code scanner.

(edit - btw, you cannot tell if you're running too cold by the temp guage in your dash. anything above about 140F and it is in the mid range)

I think you have a good handle on checking your plugs for an injector problem.

I think you'll figure this out pretty quick.

 

I have had oil analysis done three times on this vehicle. To be honest I didn't think I got much out of it until now. The last time I had fuel dilution, but I thought it was due to changing the oil without a good long drive to fully warm it up.


The extra money for Terry Dyson to look at the results was worth it. My vehicle is running (seemingly) perfect. But in reality it is constantly diluting the oil.

I use Castol Syntec (the green colored stuff that is made in Germany), with the addition of Lube Control to the oil. In spite of the oil dilution, the German Castrol protected my engine and I actually had a good report from Terry, except for the oil dilution.

I am sold on Terry's service in specific, and oil analysys in general.

 

Just a long shot here so take it for what it is worth

We get drums of various oils, for gearboxes, turbines, jet engines where I work. We randomly will sample a drum when it arrives at the site. Sometimes we will find the supplier has q/c issues.

Have you ever tested unused oil out of the container? this would give you a baseline to compare with.

We have also found variablity between same samples sent as seperate samples to the same lab will give misleading results.

Good Luck

 

It could be as simple as an injector O ring that is leaking.

 

I have three oil analysis over the last (approx) 35000 miles. They show a trend of increasing gas in the oil. This is with three different brands of oil, so I don't think it is a bad batch of oil.

I have seen some virgin test with high silicon, and high iron, that could be misleading. Thanks for the shot.

 

If u have a trend of increasing gas in the oil it prolly ur rings

 

Rings are certainly a possibility, but this engine has had sythetic oil for its life time. The oil change interval was usually around 5000-6000 miles. I didn't know about oil analysis until the vehicle had about 95000 miles on it. The three analysis show chromium wear (rings) of either 1 or 2 ppm, which is low to normal.

While oil analysis is not foolproof, the engine burns no oil whatsoever and never has. It gets the same mileage it always has, and it has great power. I will do a leakdown test after I look at plugs, and after I try the run the fuel pump trick and see if one plug gets gassy.

I am hoping it is an injector or a injector o ring. I work at a High School and have borrowed the OBD-II unit for the weekend to check on the water temp and any possible codes. The check engine light is NOT ON.

Thanks for the thoughts.

 

Managed to borrow a Snap on Solus diagnostic tool. As near as I can tell this 95 does not have OBD-II but it does have a hookup near the fusebox for an adapter that allows me to use the Solus.

Now I am a rookie, but the water temp is 195 degrees at idle, and as near as I can tell when I run every screen test possible there is nothing wrong with anything.

You can cut out each cylinder, in order and when I do the car runs rough for each one. My guess is that means the coils are ok. If they were bad and I cut out a cylinder it would make no difference.

Next will be to look at each plug, but it is pretty cold out today and I am just waiting for a bit more heat in the air.

The Solus OBD meter is amazing, as it should be for about $5000 from Snap On.

So some one please tell me if I have succesfully eliminated thermostat problems, and coil problems.

 

with about 95% certainty I'd say your thermostat is fine (that is, unless you have a flakey CTS - which is unlikely or you'd probably have some whacked out reading). and your coils look to be ok too.

narrows it down to sticky rings or leaky injector IMO. maybe a flakey 02 sensor. compression test and plug check are next.

if you find low compression on one or more cylinders there is a product called auto-RX that purports to free sticky rings. I cannot vouch for its effectiveness at doing so, however.

 

Perhaps use 10W-30 Castrol GTX. You might get a better cyliner wall seal with that over a 0 weight. Do an oil analysis after one or two cycles of 10W-30 and see what the flash point does. I'm sure there is absolutely nothing wrong with your engine.

 

I did two Auto RX treatments before switching to the Castrol 0w-30. I always thought ring problems would lead to oil consumption. I have no oil consumption. With the low wear levels that the three oil analysis have shown, I don't think I have ring problems. No smoke at any time upon starting or driving.

Later today I will pull the plugs on the rear bank.

I will do a compresion and maybe a leakdown test if I can talk my high school shop teacherr into lending me the equipment and helping.

All three O2 sensors were changed a year ago, and the CPS was also changed in addition to the fuel filter.

 

The read bank spark plugs look like the front bank, PERFECT.

Now the question (if anyone is listening) is how do I check for a leaking injector o ring??

Or does any one else have any ideas short of pulling each injector and sending them out for testing, or just replacing them all.

 

Interesting post.

If you are having a leaking injector I would expect to see your fuel pressure drop. I know when the engine is shut down there is always a residual pressure in the fuel line.

I don't know if there is enough room, but could you pull the injectors without disconnecting the fuel line. I have had some cars where the fuel injectors are easily removed from the intake without disconnecting from the fuel line. You could look at each injector this way.


good luck and keep all posted.

 

AWESOME THREAD! Just to suggest something really simple, could it possible be driving style? I mean, your not doing 5k holeshots first thing in the morning are you? Forget the coolant temp, it takes a good 15-20 minutes for the block and pistons to reach their operating temp.

I would recommend a wet and dry compression test even though you don't think it's the rings, or just drive it like you stole it, I bet you'll still get 200k out of it

 

I live in rural Wyoming, work at a high school and am 54. I do run the car hard when warmed up but no hole shots!! although when I was younger.....

The car gets driven about 3 miles to work at 35-55 MPH. Usually it gets to the mid point on the temp gauge by the time I get to work.

I hate to just start replacing sensors, (that could easily be $600.00), and I will have no way of knowing it it worked until the next oil analysis. I also am reluctant to just start changing the injectors, although the front bank would be easy.

Looking back, the only thing I haven't mentioned is I did change the air filter after this oil change. It had an inch long hunk of the rubber gasket missing, so the engine was getting a good amount of unfiltered air. Can't imagin it would be something as simple as a filter.

 

post all the UOA results you have going as far back as you can (have you done this yet on bitog?). if you had unfiltered air it should've showed up in your UOAs.

also, I'd now like to see your actual fuel % numbers. 3 miles one way is not enough to heat up the oil to burn off the fuel - and you are running rich the entire time - the effect is cumulative. KRRZ may be right - this might just be as simple as "aunt-minne" short-trip driving (even if you do not hole shot it - whatever that means). and if you let your car idle for more than 60 sec on cold start it will exacerbate the whole situation.

 

I have three sets of data for this engine. I won't type them all in but I will touch on the high points:

11/15/04 105,000 total miles 5142 on this sample 5W-30 Amsoil
silicon 6
chrom 1
flashpoint 330
iron 6
lead 4
fuel 1.8%

06/15/05 112,944 total miles 8000 miles on sample 5W-30 Amsoil SERIES 3000

silicon 10
chrom 2
flashpoint 405
iron 15
lead 6
fuel <0.5%

11-29-06 130,000 total miles 6200 miles on sample 0W-30 Castrol German Green Syntec with Lube Control

Silicon 16
chrom 1
Flashpoint 300
iron 12
lead 3
fuel 1.4%

the first two samples were done by Blackstone, and the third was done by Dyson Analysis. No anti-freeze in any sample.

 

ok, the one thing that stands out immediately is that your two samples with high fuel are split by a sample with low fuel -- if the high fuel were caused by an actual malfunction there would probably not be a "good" sample in between.

that tells me this is a likely driving habit thing and not a problem with the engine. do you remember if you had any road trips or more longer-haul trips during that 8k miles w/ amsoil series 3k? (especially right before you pulled the sample?)

since you've checked everything you can (except compression) what you should do now is make a point of getting out on the highway once a week for a 20 mile high speed drive. this will help burn off the fuel in the oil. then right before your next sample do the same high speed drive and then immediately pull the sample. I'll bet your fuel will be normal.

keep in mind - those short trips twice a day are not enough to heat up your oil (even if the coolant temp gets to 200F, the oil is still cool) and it takes a good 20-30 minutes for fully hot oil to burn off excess fuel and water.

re: the air filter - yes your silicon is slightly elevated in the last sample, but not enough to cause any problems. it's a good thing you changed the air filter though.

if you want to see what a serious fuel problem looks like check this one out...
http://theoildrop.server101.com/foru...e=8#Post726672

 

The only thing for sure is that during the winter I drive twice a week 160 miles. The next time I change oil it will be after one of these 160 mile trips.

I am really begining to think that there is nothing wrong. I have owned this car from new and this morning it started up within 2-3 cranks, like it always has. When I step on the gas hard, it downshifts and accelerates like it alway has.

I have check out just about everything I can short of pulling each injector and having them cleaned or rebuilt.

I will try a round of Techron or BG 44,as soon as I can find some on the net.

I do use Fuel Power, but I am not convinced that it is as good a cleaner as Techron.

 

Another thing you have to check is the PCV system. If it's blocked then you will have extra hydrocarbons in the crankcase. Another thing that you should do is run at least a 5W-30 if not 10W-30 and see if the tests come out different. Next thing would be a dry and wet compression test. Doubt it would be a leaky injector because you don't have signs of running rich.

 

Changed out the PVC valve last summer.

I did ask Terry Dyson if he thought that I would be better off with a 5w-40 oil like Delvac 1, and he indicated that the 0W-30 Castrol was doing a good job and not to change.

 

yeah, after seeing your data and learning of your short trips I'm also inclined to say there's nothing wrong.

one word of caution with the fuel adds - don't over-do it, and try to use the techron about 500 miles before an oil change (to get it out of your oil). techron/gumout regane & the like are very strong solvents and will eat your bearings alive (this is of special concern with you since you tend to have fuel dilution). you can look at my UOAs at the following link. during the fill of Gold GC i used 20z techron followed by regane the very next tank, and then waited a bit to change the oil - and my copper spiked as result. FP60 is safe to use every fill.
http://theoildrop.server101.com/foru...e=0#Post754417
incidentally, as you'll see in my UOA thread, I was battling cold start knock with GC (both gold and green) - but after a few hundred miles of Maxlife Syn the knock has gone away. it seems my VQ doesn't like PAOs and prefers GIII oils. doesn't make a lot of sense, I know, but I have no other explanation for it -- the maxlife syn is almost as thick as GC, and I've also run thinner oils with no cold start knock. I'm just going to avoid GC from now on, even though it does protect quite well.

I understand the rationale here, but the problem with this theory is that 0W30 GC is one of thickest 30wt oils on the market at every temp down to about -20F. it even thicker than most 10W30s (although the maxlife Syn 5W30 might be a bit thicker below 20C). so I don't think his fuel dilution is tied to oil viscosity.

 

you definately have a problem with the fuel getting in the oil, so its escaping through your rings. A thicker weight oil will seal the bottom of the cylinder better, and maybe that would make your problem better. it's worth a try, you can't hurt anything by running the type of oil meant for the car.

 

the 0 weight oil is less viscous than the 5 weight oil at cold temps. if it is less viscous then it has more resistance to flow, so the 5 weight is thicker at cold temps. It has to be otherwise they were not evaluated by the SAE. So if it is thicker is will seal better. I'm not saying that the oil viscosity will fix the problem, but it's worth a shot because that excess fuel in the oil is not helping lube the engine.

 

My first guess at this would be a fuel injector leaking through. It doesn't need to be bad enough to affect engine run and performance to bleed the fuel pressure into one cylinder and subsequently having the gas finding its way by the rings. You probably would get some black smoke at startup but that won't always happen. You can check your fuel pressure at shutdown and see if it holds steady or drops off. On the other hand, stop worrying so much about it. That engine is rock solid. Mine is up over 370k miles, Castrol GTX 5w-30 every 7-8k miles, and has never had any problems even though I beat the crap out of it.

Rene

 

not true.

more viscous = more resistance to flow.

0W and 5W ratings are measured at different temps (-35C and -30C, I believe, with different cP standards for each), and an oil that meets both can be called either.

in the case of 0W30 GC, it is much thicker at 100C than all other 30wts (it is borderline 40wt) and it remains thicker until the 0W spec kicks in. it is, in fact, a 0W that is thicker than almost all 5W & 10W 30wts until you get below about -20F. you can read all about this in the GC forum at bitog.

 

Sky Jumper.

already read your report. Techron, or BG 44 or whatever (Redline?) I will use before an oil change.

Madisonmxma,

Go to Bob is the Oil Guy website and lookup the long FAQ on German Castrol, and viscosity. I couldn't begin to explain it as well as they do. Also this report is really no worse, (in fact it is better) than the report that indicated a flashpoint of 405. So even though the oil has gas in it, the German Castrol still lubricated better than average.

Zerepener,

This is still the most resonable thought, (a leaking injector after shutdown). How do I check fuel pressure at shut down to see if it drops.

Will the Solus do it. I am a novice with the Solus and it is sitting at home. Just because it was such a kick to use, I am going to hook it up again and take it out on the road for a 10 mile or so run and see what happens to the data.

 

sorry, i misspoke. more viscous=more resistance to flow