Low compression on cylinder three

2010 CHEVROLET SPARK
110,000 MILES • 1.2L • 4 CYL • MANUAL
Avatar
PHUMZILE2
  • MEMBER
  • 3 POSTS
Hi,
I took my car to a mechanic to check why the car is getting tired. He did a diagnostic and found P0303 cylinder three misfire. So he stripped the car to find what causing the misfire. He just told me that the cylinder head is faulty because the compression test is low on cylinder three, so I will have to take the whole cylinder head for engineering. I need to know if that possible? I have been Googling and I have not seen anywhere that the head must be engineered as a solution.
Your feed back will be greatly appreciated!

Kind regards, Phumzile
Feb 14, 2018 at 5:03 PM
Advertisement
Avatar
ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good morning.

Yes, the cylinder head will have to be removed and the valves inspected for failure. the valves may be burned, head could be warped or piston rings worn out. The failure can be determined once the head is removed.

Roy
Feb 14, 2018 at 5:24 PM
Avatar
PHUMZILE2
  • MEMBER
  • 3 POSTS
Thank you asemaster6371.
Feb 14, 2018 at 5:28 PM
Avatar
ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
you are welcome.

Roy
Feb 14, 2018 at 5:32 PM
Avatar
CARADIODOC
  • ✓Experienced Mechanic
  • 34,366 POSTS
Rebuilding a cylinder head is a standard procedure but it is normally done at an engine machine shop, then the mechanic reinstalls it on the engine. There is another, more time-consuming test that could have been done. A compression test just tells you the compression is low. A cylinder leakage test will tell you why it is low. Burned intake and exhaust valves are the most common causes, but there can also be leaking piston rings and a leaking cylinder head gasket.

If the mechanic did a cylinder leakage test and found the head gasket to be leaking, as long as the head has to removed anyway for the repair, a mechanic who has your best interest a heart will want to have the head gone through at the engine specialty shop to take care of any worn valves or guides rather than wait for other problems to develop in the near future. The machinist will also check the head for flatness. That can be corrected if it not too bad, to insure the new head gasket will seal properly.
Feb 14, 2018 at 5:32 PM
Avatar
PHUMZILE2
  • MEMBER
  • 3 POSTS
Thank you for your replies they are very helpful.
Feb 14, 2018 at 5:36 PM
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.