Car Wants to Stall When Pulling Dipstick

[66chevelle300]

The strangest thing happened last night, I was leaving work last night and when I drove down to check one of my buildings and I got out and thought the car sounded different so I popped my hood and went to check my oil and when I pulled the dip stick the car started to sputter and sounded like it was going to stall!!? I have worked on plenty of other cars before and never experienced this. My car also seems like it idles a little rough sometimes when sitting at a light like its missing I saw other people had this problem too but the dipstick thing just was strange. Let me know what you think!

1.4l turbo six speed manual, No mods

 

[dvn]

You don't check the oil with the car running!

 

[theenico]

Because of the way the crankcase ventilation system works, it creates a vacuum leak if you pull the dipstick and/or remove the oil fill cap. Having it sputter like that is normal.

 

[rdss]

Yeah, I don't understand what checking the oil with the engine running would have accomplished. You should let the car set for a bit after running to get a good reading on your engine oil.

 

[seanp1]

This is the same thing as running the car with the Gas cap off.

The Dipstick takes a reading from the oil pan. Having the car running will give you a false reading. I hope you didnt add oil after it registered low.

 

[66chevelle300]

The reason I pulled it was to make sure there was oil because it sounded like a lifter was knocking. I would never add oil it after it ran. Was checking to make sure it wasn't burnt have done it before on older cars with no problems just was strange.

Thanks for the input

 

[SSpeckerwood]

there is heavy equipment with dipsticks made to check the oil when running, however our sonic's and most cars are not built this way.

i remember when a buddy thought he could check his oil in his harley with it running. Bad idea, the oil bag is somewhat pressurized and it covered him and the bike in oil. funny as heck though!!!

 

[SuperFudd]

Interesting.
The crankcase must be air tight to run properly?
How many models of cars are like this?
For how long?
The seal around the dip stick in my '96 Regal has gone away. Could that be why she runs poorly above 4000 RPM? Actually I doubt it since the stick has been that way for a couple of years and the rough runing, misfiring, started a couple of months ago.
Still...
:blankface:

 

[SuperFudd]

Nope.
I removed the dip stick on the Buick and pluged the hole with a paper towel. It made no difference. I placed my finger over the hole at idle and felt no preasure.

 

[Smartdave]

I know my 2000 vw Jetta is like this. Pull the dipstick out while it's running and it starts stumbling at idle. That's a 12 year old car

 

[omniman]

If left out long enough it will set a code for a lean condition.

 

[Chevrolet Customer Care]

The strangest thing happened last night, I was leaving work last night and when I drove down to check one of my buildings and I got out and thought the car sounded different so I popped my hood and went to check my oil and when I pulled the dip stick the car started to sputter and sounded like it was going to stall!!? I have worked on plenty of other cars before and never experienced this. My car also seems like it idles a little rough sometimes when sitting at a light like its missing I saw other people had this problem too but the dipstick thing just was strange. Let me know what you think!

1.4l turbo six speed manual, No mods

After checking the Owner's Manual on pg. 10-10 it mentions, if the engine has been running recently, turn off the engine and allow several minutes for the oil to drain back into the oil pan. Checking the oil level too soon after engine shutoff will not provide an accurate oil level. Not sure if pulling the dipstick had something to do with the sputtering.

Because I am not a technician, I'm unable to diagnose but have documented this issue you experienced. If you continue to hear strange noises, sputtering, and rough idle, I would suggest taking your vehicle in to be serviced by the dealer. Please keep me posted on what happens.

Vanessa,
GM Customer Service

 

[beaslbob]

Interesting.
The crankcase must be air tight to run properly?
How many models of cars are like this?
For how long?
The seal around the dip stick in my '96 Regal has gone away. Could that be why she runs poorly above 4000 RPM? Actually I doubt it since the stick has been that way for a couple of years and the rough runing, misfiring, started a couple of months ago.
Still...
:blankface:

Can't say for sure.

But my 1965 corvair has positive crancase ventilation which as I undersand it was introduced by car manufacturere back in '61 or so.

In order to work correctly the case is supposed to be sealed.

but then the dipstick in the old car was not sealed.
my .02

 

[jim_de_hunter]

i remember when a buddy thought he could check his oil in his harley with it running. Bad idea, the oil bag is somewhat pressurized and it covered him and the bike in oil. funny as heck though!!!

Harley V-Twins are dry-sump. That's why you see Junior Teutul adding oil tank just under the seat. Oil get pumped to the tank so if you uncap it while running, you get splattered.

 

[jim_de_hunter]

Positive Crankcase Ventilation (PVC) is necessary because pistons within a cylinder don't create a perfect seal. This allows pressure blow-by from the cylinder into the crankcase. On the 350 cubic inch GM's, the pressure is vented though the head to one of the valve banks. On the valve cover to this bank is the PCV valve. It lets the pressure back into the air cleaning on the dirty air side. On my Kawasaki ZG1000 PCV is provided above the transmission. The transmission and engine share the same oil sump and it was more convenient on the motorcycle to vent here.

All internal combustion engine have some type of PVC. Otherwise the crankcases would pressurize until the motor stopped because the pressure on either side of the piston is the same or crankcase ruptured from the pressure.

Now, my guess is that with these finely tuned engines, the engineers found some reason to monitor and use the feedback from the pressure in the crankcase. When the dipstick was no longer sealed, it changed the pressure in the crankcase and the computer tried to run the engine to bring the it back into run parameters.

 

[Alan]

I know my 2000 vw Jetta is like this. Pull the dipstick out while it's running and it starts stumbling at idle. That's a 12 year old car

Same with my '89 8v Jetta. Trashed dipstick o-rings are a pretty common vacuum leak spot with those cars.

 

[Ab09]

On my moms '98 Pontiac Transport Mini Van.. 3.6, With a Tech 2 hooked up you can see the air fuel mixture change when you pull the dip stick. It had to run richer to keep things running right... So that being said... Keep the dipstick in you'll get better gas mileage. :banana: