Back compression judgement by air blowing out from dipstick well

2007 CHEVROLET OPTRA
90,000 MILES • 1.6L • 4 CYL • 2WD • MANUAL
Avatar
OPTRALOVER
  • MEMBER
  • 2 POSTS
I have a chevy optra 1.6 LS (Petrol) having 90k kms on odo. Recently I got it serviced from a different mechanic than from the one I usually service my car. The mechanic told me that there is some compression loss in the engine and he concluded this by the air coming out of the dipstick well.

But the car is running just fine without any noticeable power loss. I took it to a different mechanic and he told me that air coming out of the dipstick well is because optras have a lower positioned oil chamber as compared to other cars and hence its normal.

I am a little confused now. Kindly assist.
Feb 11, 2015 at 10:35 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
First, any engine will have a bit of compressed air in the crankcase. It is normal from compression bypassing the piston rings. Excessive compressed air could be a problem. However, in your case the engine is running fine.

Therefore, I feel that there is a different issue. On the engine is a valve called a PCV valve. PCV stands for positive crankcase ventelation. The purpose of the valve is to vacuum excessive air from the crankcase and reburn it in the engine. If the valve is plugged or damaged, it will not do that; thus, it will cause excessive air build up in the crank case which will escape via anywhere it can (dipstick tube, for example).

Check that first and let me know what you find. Also, remember it is normal to an extent to have air / compressed air in the crankcase. Excessive air can be a sign of worn engine valves or cylinders.

Feb 11, 2015 at 10:50 AM
Avatar
OPTRALOVER
  • MEMBER
  • 2 POSTS
Where do I find PCV valve in chevrolet optra?
Feb 11, 2015 at 10:53 AM
Avatar
JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
This vehicle is not sold in N. America, so I am not too familiar with it. However, most all cars have the PCV on the engine valve cover.
Feb 11, 2015 at 11:04 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.