petrol in oil after coilpack failure advice

[Lucase483]

Hello,

Last night i suddenly had a coilpack failure, my bmw m50 suddenly went 5 cylinder.

Because I couldn't directly pull over, i had to continue for 2 minutes/ 2km.
When I found the coilpack that was bad and pulled it out, i saw the petrol was flooded that much that i went over the spark plug.

I off course pulled the plug to clean and dry it, and the fuel drained down the cylinder....
Afterwards replaced the coilpack as i always carry a spare. And fired up, and all was fine and I drove home.

I just changed the oil 2 months ago with helix ultra 5w40.
But well what now? Too much fuel dilution? New oil change? Or just forget it and count on helix to be able to handle it?

 

[Boomer]

Change it. Your car is worth too much to gamble on this. Could result in scored bearings, etc. Better to fork over the money for an oil and filter than a new engine.

 

[mightymousetech]

We always change the oil after an event like that. The car will run really rich when it warms up until you do. The newer DI engines will shut down the injector on that cylinder to prevent fuel dilution.

 

[Astro14]

I would change the oil.

I’m surprised the injector kept firing when the coil wasn’t.

On my nearly 20 year old Volvos, the ECM will shut off the injector in a cylinder with a coil failure, preventing just this kind of dilution.

 

[BigCahuna]

A few years back my wife's Kia, had a similar problem, but the spark plug well was filled with motor oil. Apparently the valve cover gasket leaked oil into the well, and grounded out the plug wire. Once I had the leak fixed, the plug fired and worked as it should. We didn't have to replace any coils. I wouldn't throw your old coil pak out just yet, it might still be good.,,

 

[Lucase483]

A few years back my wife's Kia, had a similar problem, but the spark plug well was filled with motor oil. Apparently the valve cover gasket leaked oil into the well, and grounded out the plug wire. Once I had the leak fixed, the plug fired and worked as it should. We didn't have to replace any coils. I wouldn't throw your old coil pak out just yet, it might still be good.,,

This was not the case, the older m50 engines do occasinally have that problem too.
Mine is a 1992 M50 OBD1.
Often in Cylinder 6 near the firewall, the sparkplug overfills with oil due to valve cover failure and refuses to ignite.

But this time it wasnt the case, the coilpack was just not firing right, it was also making a strange tick noise.
The replacement coilpack is silent as it should be and everything is fine now, i just checked the others and they are good and dry no oil seepage or anything.

So hmm too much fuel in the oil, too bad of the recent change but it doesnt sit right with me either.
I was hoping since i did drive after that... the heat with just evaporate the petrol.
But it probably washed a cylinder clean and its piston ring, hope that didnt do any damage further.

 

[Jetronic]

Hello,

Last night i suddenly had a coilpack failure, my bmw m50 suddenly went 5 cylinder.

Because I couldn't directly pull over, i had to continue for 2 minutes/ 2km.
When I found the coilpack that was bad and pulled it out, i saw the petrol was flooded that much that i went over the spark plug.

I off course pulled the plug to clean and dry it, and the fuel drained down the cylinder....
Afterwards replaced the coilpack as i always carry a spare. And fired up, and all was fine and I drove home.

I just changed the oil 2 months ago with helix ultra 5w40.
But well what now? Too much fuel dilution? New oil change? Or just forget it and count on helix to be able to handle it?

2km, how much fuel are we talking about really. Some of that fuel has evaporated and went out the exhaust. Can you see ANY oil level increase?

Drive for 10 minutes with a hot engine and the fuel dilution will be a lot less again.

 

[Jetronic]

I was hoping since i did drive after that... the heat with just evaporate the petrol.
But it probably washed a cylinder clean and its piston ring, hope that didnt do any damage further.

There we have it, any damage has already been done. Save your money now.

 

[Chris142]

How much fuel does 1 injector squirt in 2km? A couple of ounces at the most? Much of the fuel got sent out the exhaust valve and out the exhaust. The rest did go into the oil. A ounce maybe? An ounce in 5+ quarts of oil.

 

[Zaedock]

2 minutes? It's fine. If you already drove after the repair, it likely would show trace in a UOA.

 

[Lucase483]

There we have it, any damage has already been done. Save your money now.

This engine has already got close to 400.000 km on it.
I dont think it could have done bearing damage, would be ridiculious if engines would suffer catastrofic failure when a coul/spark plug fails or everytime it gets flooded.
I was more worried if i should continue on this oil.

 

[Jetronic]

Not bearing damage, like you said it would have cylinder scoring if there would have been damage, and you took away the possible cause of that.

Save your money, it doesn't need new oil unless you see that the oil level has risen due to fuel contamination.