Crankcase Backpressure

[-EJ]

I'm looking for some input where ever I can find it...

I recently changed the oil on my 2013 Chevy Sonic 1.4L Turbo automatic.

It's my daughters car.

She brings it home after driving it after the oil change. She says the car is acting funny... then asks what the red oil lite and eng lite means... (that's a seperate parenting issue)

I look under the hood and there is oil everywhere. I think I forgot the oil cap or I did not secure the oil cap. I check to see that the oil cap locks and it feels like it does. I put in 2 quarts which brings the oil to the bottom of the dipstick. I start the car and it is running smooth but there is white smoke coming out of the tail pipe. It then dumps all the oil on the ground when the engine is shut down.

I figure she fried the engine. I have it picked up and taken to the dealer. (mistake nbr 2)

They say the engine is fried... cost... $7900 to replace and there are no engines available until after the 1st.

I consult a friend who has a body shop (Dallas Collision... Dallas,GA fantastic place)... he thinks it's the turbocharger.

The dealer has the car apart already... no written agreement... charges me $150 to put it back together so I can have it shipped to a mechanic I can trust.

The dealer tells me the oil cap was loose to the point of being held by one thread... I know it was secured the second time. I did not check it after running it the second time. This made me think if there was any way the crankcase could be over pressured.

My friend that I had the car taken to... cleaned up the engine and serviced it with oil to see where the oil was leaking. He tells me the oil is being blown out the oil dipstick past the o-rings. If there was that much pressure... it would now be unrealistic to think the oil cap being worked free with the pressure and normal enging vibration.

Sorry for the long post but can anyone offer any input.

Thanks much.

Ed

 

[Sonic]

Welcome to the forum. Sorry your first post has to be something like this. I don't know about the cause, but if you do need to replace the engine or any individual components at your expense, they can be found for much cheaper on Ebay or other sites. Don't pay dealer prices.

 

[Preloader]

So, it has been determined time after time that if the crankcase isn't sealed, as in the oil cap is loose or the dipstick isn't seated fully, that the engine will run ragged.

This is directly related to the PCV system, which circulates crankcase vapors back into the inlet side of the turbo. The compressor is essentially sucking on the PCV. So when the oil cap is loose, the suction from the turbo will pull a much larger charge of air though the crankcase...... grabbing tons of oil with it.

2 problems. Oil being ran through the compressor wheel can be fatal to the turbo. And, since the air from the PCV is returning into the intake AFTER the airflow sensor, the ECM is unaware of how much air in coming in, causing rough running.

Now that the cap is secured.... If it runs fine, but smokes like hell..... Then it's just burning the large amount of oil that has entered the charged air piping and intercooler.

If it however is running bad and way down on power..... I'd guess that your turbo is toast.

 

[-EJ]

I do know better but it was a momentary rash decision. The car is only about 4 months old. Things are looking better. Thanks.

Welcome to the forum. Sorry your first post has to be something like this. I don't know about the cause, but if you do need to replace the engine or any individual components at your expense, they can be found for much cheaper on Ebay or other sites. Don't pay dealer prices.

 

[-EJ]

Everything is/was sealed but what you said makes me think. Before I changed the oil it was idling very rough. I was going to take it to the dealer to get it checked out.

I'll have that checked out but I've been told that the turbo is good.

Can you think of any way the crankcase could be over pressured?

So, it has been determined time after time that if the crankcase isn't sealed, as in the oil cap is loose or the dipstick isn't seated fully, that the engine will run ragged.

This is directly related to the PCV system, which circulates crankcase vapors back into the inlet side of the turbo. The compressor is essentially sucking on the PCV. So when the oil cap is loose, the suction from the turbo will pull a much larger charge of air though the crankcase...... grabbing tons of oil with it.

2 problems. Oil being ran through the compressor wheel can be fatal to the turbo. And, since the air from the PCV is returning into the intake AFTER the airflow sensor, the ECM is unaware of how much air in coming in, causing rough running.

Now that the cap is secured.... If it runs fine, but smokes like hell..... Then it's just burning the large amount of oil that has entered the charged air piping and intercooler.

If it however is running bad and way down on power..... I'd guess that your turbo is toast.

 

[Stew]

Can you think of any way the crankcase could be over pressured?

The crankcase can have excessive pressure from badly worn rings, which would be consistent with running the engine with no oil pressure.

 

[-EJ]

Hey Preloader... I wanted to thank you for an excellent post on the operation of the PCV system in another post. I might not have explained myself clearly but this is exactly what seems to have happened in my case. I've found that this is an up and comming common problem with this engine that dealers don't want to seem to acknowledge. I'm going to look into it further and bring it up to the dealers attention.

When I first asked them the question... 2 dealers said they did not see who the crankcase could get pressurized. This really makes me wonder. A friend of mine had the same thing happen with a turbocharged Volvo. Their T/S manual immediately pointed to the PCV valve.

Anyway thanks for a very clear explaination.

Oh... took it to a second dealer... they found the camshaft timing sensor bad. Replaced it... has been running great ever since. I did mention that the car was idling very rough long before I changed the oil. I'm convinced that it was not my fk up.

So, it has been determined time after time that if the crankcase isn't sealed, as in the oil cap is loose or the dipstick isn't seated fully, that the engine will run ragged.

This is directly related to the PCV system, which circulates crankcase vapors back into the inlet side of the turbo. The compressor is essentially sucking on the PCV. So when the oil cap is loose, the suction from the turbo will pull a much larger charge of air though the crankcase...... grabbing tons of oil with it.

2 problems. Oil being ran through the compressor wheel can be fatal to the turbo. And, since the air from the PCV is returning into the intake AFTER the airflow sensor, the ECM is unaware of how much air in coming in, causing rough running.

Now that the cap is secured.... If it runs fine, but smokes like hell..... Then it's just burning the large amount of oil that has entered the charged air piping and intercooler.

If it however is running bad and way down on power..... I'd guess that your turbo is toast.

 

[ss2000slp]

Funny you mentioned the Volvo. We've had 4 or 5 of them (some turbo, some not) in the last year that had PCV issues, one so bad it literally blew out the front crank seal. A few weeks ago we had a 2.5 Jetta that had part of the vent system go and was burning oil like crazy. Then, most recently, a BMW that had part of a valve freeze, and within 5 minutes of running, sucked 4.5 qts of oil into the cylinders and actually hydrolock the engine with oil.

My point being, PCV issues can cause all kinds of crazy sh** to happen, I don't see a reason for you to eat the bill. Now, the asking what the yellow and red lights mean...

 

[-EJ]

The issue of the meaning of the yellow and red lights has hopefully been resolved.

Thanks for the added input.

Funny you mentioned the Volvo. We've had 4 or 5 of them (some turbo, some not) in the last year that had PCV issues, one so bad it literally blew out the front crank seal. A few weeks ago we had a 2.5 Jetta that had part of the vent system go and was burning oil like crazy. Then, most recently, a BMW that had part of a valve freeze, and within 5 minutes of running, sucked 4.5 qts of oil into the cylinders and actually hydrolock the engine with oil.

My point being, PCV issues can cause all kinds of crazy sh** to happen, I don't see a reason for you to eat the bill. Now, the asking what the yellow and red lights mean...