Pope

So I went to Midas today to get my oil changed. The lady tells me that they found gas in my oil when they drained it. I asked her what the reasoning behind gas in my oil would be and she couldnt tell me squat. Any ideas as to how gas can get into my oil?

phister

Some of the causes is that your car is running too rich and the gas is getting past the piston rings into the crankcase or that your fuel pump is defective.

Pope

I think my coolant temperature sensor may be bad, because my fan is running constantly. Can that be the cause of it running rich? I just ordered the new CTS today.

pcy

Coolant Temp Sensor has nothing to do with engine running too rich.

Defective CTS may be causing the fan running constantly.

LILBENZ230

Midas? Oh dear. I would have the oil analyzed by professionals (Midas does not qualify) and take what Midas says with a grain of salt.

contact148

google blackstone labs they will send you a kit you put some of your oil in it send it to them and you get a lab report

worth the $25.00ish it cost

Glyn M Ruck

Gas can get in the oil - too many short trips etc. or a dribbling injector. The whole question is how much gas?

Is the car warming up correctly - do you ever get a P0128 which would indicate your thermostat has failed.

Do a 1000 miles then send an oil sample to Blackstone.

Boom vang

sounds a bit odd

I am thinking that Gas would work as a solvent and thin out the oil as opposed to coolant which is water and glycol and the two don't really mix and give you a milky mixture, not sure if you could see the two of them as separate components as Midas has discovered

C230 Sport Coup

Midas BS. Say no more, Say no more.

Pope

Ya I will probably wait till next oil change, take it to someone different and ask them if they notice it at all. They didnt seem like the brightest crayons in the box. But it was close to school and not much time or many choices. Better than going to wal-mart down the street though. Ill have to send a sample to that Blackstone company to really get an answer.

Thanks guys!

Glyn M Ruck

https://mbworld.org/forums/c-class-w...ning-c240.html

LILBENZ230

BTW are you making Midas use the appropriate oil and filter on your car? I can just imagine them dumping in generic dino oil 10W-40 blindly in.

Pope

No codes or anything. I asked them to put synthetic in and asked them which filter they were using. They told me it was direct oem fit to my car, so i didnt think anything else of it.

cpbeasley

lets hope they used the correct synthetic oil. telling them to just use "synthetic", I would imagine, would prompt them to use up whichever type they were looking to move.

and it may be a direct OEM fit, but it still needs to be the correct type

oh well. too late. one round like surely won't be the death of it. I cant imagine how many of these are improperly maintained.

C230 Sport Coup

Midas= Run Away!

LILBENZ230

Sounds like you've got the wrong oil and filter. I'd change it again immediately.

Glyn M Ruck

Please only use 229.5 approved oils & fleece filter

RobertG

If the fans are running all the time then your engine may not get up to operating temperature or it will take longer to get there.
If your engine doesnt get up to operating temperature, your pistons will not fully expand , causing oil dilution and engine wear.

Glyn M Ruck

It's not due to piston expansion. It's due to incomplete combustion of the fuel. Pistons do expand very slightly in some engines dependent on metalurgy but ring pressures remain pretty constant.

RobertG

If the piston doesnt expand fully then the ring lands will allow for blowby, unburned fuel will dilute the oil over time.

Glyn M Ruck

Yes agreed it can exacerbate the problem - but if you have complete combustion it will not be an issue - the issue is complete combustion. A well tuned car does not have unburned fuel sloshing about the ring belt. If it did the wear would be horrendous due to washing oil off the bore. You could achieve such washing with old manual chokes on twin side-draught Weber’s on vehicles like Alfa's - & you were running aluminium pistons in an iron sleeve. In the FI age things are far more controlled & you have no crude throttle pumps either.

Benz piston to bore clearance remains remarkably consistent with temperature - iron particle sprayed aluminium pistons in aluminium "Alusil" bore.

RobertG

As in aluminum and silicone?
Hypereutectic is what I'm familiar with

Glyn M Ruck

Indeed - "Hypereutectic"

C230 Sport Coup

Why is anyone bothering with this thread?
Midas says there's gas in the oil?
And they did this without analysis?
Please,
people, don't go to Midas.
They will always tell you some crap to get more money,
sell you brake jobs when you don't need them,
replace parts that don't need replacing.
How many people I've heard who ended up with thousand dollar brakes jobs,
and not on an import, but on an American car and that was 20 years ago.
Probably 2000 dollar brakes jobs now.

Are there still people who don't know that every single
Midas place is just a rip off?
Hell they wanted $600 + tax, ~$650 for a Cat that I ended up buying
for $140 and got welded on for $50.
I just asked for sheets and giggles, and the response was expected, the highest
price in town.

If they told you, you have gas in your oil, they are lying,
unless they sent out the oil for analysis, and we already know they didn't.

End of story. Next time you change your oil, pay $25 and send a sample to
Blackstone if you are so concerned.
Then post the results.

Pope

Thanks for all the replies guys. I got my coolant temp sensor this morning, going out now to replace it, Hope my fan stops going haywire, its on turbo speed it seems like. I will change my oil asap. I requested an oil sample kit from Blackstone and will send it off as soon as it gets to me, which they said a week or two.

Now i was just looking at this CTS and it looks like there are no threads on it to be screwed in, is it just held in place by the o-ring above the sensor?