Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Benjegen on January 29, 2006, 13:27:14
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Hi all,
I have a potential problem with my 250SL.
I have brought it for an oil change end of november to store it away for the winter. I just drove it home approximately 7 miles. Now I was working on the car and checked the oil at the dipstick (cold engine). It is approximately 1 cm above maximum and there is a gas smell. I unscrewed the oil cap and there is the gas smell as well. I had a comression test done last november and the values were 175 - 175 - 170 - 165 - 155 - 165. Does anyone know what these symptoms means ? The car was running absolutely fine without any obvious problems. Since the oil is probably diluted is it OK to drive the car at all since the lubrication is not as good ?
Thanks in advance
Thomas
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Hello Thomas,
Naturally you should run the car as little as possible with fuel contamination in the oil. Over filling even with oil or fuel will cause poor lubrication. The crankshaft churns the oil into a foam of oil and air when severely overfilled. Lubrication suffers.
Make sure they did not overfill the engine at the last oil change. You need to find the source of the problem. If the engine is allowed idle during the entire warm up period, this is the most common cause of fuel contamination.
Joe Alexander
Blacklick, Ohio
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quote:
Originally posted by ja17
If the engine is allowed idle during the entire warm up period, this is the most common cause of fuel contamination.
Joe,
Hi. Can you elaborate as to why?
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420
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Hey Joe....I would like the hear the answer too. I think it is probably very common for vintage car owners to run their cars at idle if they don't want to drive them in foul weather; time constrants; etc. Thanks for your expertise!
Best Regards,
J. P. Mose
1968 250SL
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Hello,
It is always beter to warm up these fuel injected engines, and possibly most other engines by driving the car at moderate rpms until warm up is complete. Factory literature mentions that driving off at moderate speeds is best for the warm up cycle.
I can only guess at the exact physics of this reasoning.
I suspect that the enriched cold fuel mixture has much more tendancy to load up on the cold spark plugs. In addition these injection systems tend to "wear rich" as they age. The increased rpms and load from driving the car would tend to make combustion chamber temperatures higher sooner during warm up. The injection system will cylcle through a wider range with the inputs of load and rpms during a driving warm up. The "warm up device" will also be able to cycle through its normal range of movement.
Another added bonus is the other moving parts on the car , wheel seals, differential, transnmission, steering are lubricated if the car is driven off. Mechanisms stick, corrode and seals and gaskets like to dry out, shrink and crack from lack of use. Another major bonus is the benefits to the brake system by driving the car. Rotors are rubbed clean, the brake fluid is heated, dispelling moisture, the calipers are excersized and seals and cylinders are lubricated. The same is true for the hydraulic clutch system if standard transmission.
Driving the car on a nice dry winter day will burn off some moisture and contaminants collected in the engine oil during cold starts!
Storing the car with fresh oil will prevent sludge from settling in the oil pan during storage. This will also remove moisture and combustion contamination which otherwise would be eating away at your engine during winter storage!
The saying "garages kill" makes a lot of sense.
Joe Alexander
Blacklick, Ohio
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I had the seals in my IP fail and fill the oil pan with a liter of gas in less than 10 miles. The engine was smoking a lot and oil was coming out every crack it could find. The front of the engine was covered in oil that was pouring out of the front main seal.
After I had the pump rebuilt ( twice I might add , but not by the same place ) and changed the oil it stopped leaking right away. I know there's limit as to fuel how much fuel can be in the oil, maybe 2%? Not sure though.
Dan Caron's
SL Barn
benzbarn@ebtech.net
slbarn.mbz.org
1 877 661 6061