No compression in cylinder number six

1992 MERCURY MARQUIS
160 MILES • 4.6L • V8 • AUTOMATIC
Avatar
WESTRUCK
  • MEMBER
  • 55 POSTS
check compression in cylinder number 6 no compression reading. I did the wet test no reading. What might be the problem?
Oct 3, 2019 at 11:09 AM
Advertisement
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.
Avatar
KASEKENNY
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 18,907 POSTS
Hi,

Here is a guide that lays this out. However, there are a number of reasons which are the intake valve, exhaust valve, compression rings on piston, and then a head gasket issue.

You will want to do a cylinder leakage test. This is where you put the piston on TDC, put about 50 PSI of compressed air in the cylinder and then check the intake, exhaust, cooling system, and crankcase (oil fill cap) for air escaping. This will tell you where the air is coming out which means this is where your compression is escaping. This will tell you what component you will need to go in an replace:

https://www.2carpros.com/articles/the-reasons-for-low-compression

Let me know if you have questions. Thanks
Oct 3, 2019 at 6:18 PM