What does no compression in 2 cylinders mean?

CASE 1: No compression in 2 or more cylinders. This test result tells you that the engine has serious internal problems. The most common issues would be: Broken timing chain. Or a blown head gasket. Or the engine threw a rod. To test for a blown head gasket, see this tutorial: How To Test A Blown Head Gasket (GM 3.1L, 3.4L).

Can you do a compression test on a GMC 4.8L?

Testing the engine compression on your Chevrolet or GMC 4.8L, 5.0L, or 6.0L engine is not hard to do. A compression test will help you to determine the health of your engine by measuring the pressure of the air that gets compressed by the piston rings against the cylinder head valves.

How to test engine compression in GM 3.1L mini van?

Testing the engine compression of the 3 cylinders that face the firewall of your 3.1L or 3.4L GM car or mini-van (Chevrolet, Buick, Oldsmobile, or Pontiac) can be quite a challenge, since removing those spark plugs is not the easiest thing in the world. In most cases the alternator has to be removed to gain access to them.

What can cause compression in a car engine?

When these valves fail, the head can come apart from the stem. The head of the valve, will drop into the cylinder. This will allow compression to leak from the cylinder; while causing extreme damage to the piston and cylinder head. The piston may fail due to, excessive heat in the combustion chamber.

How to test engine compression in GM 3.1L?

This tutorial will walk you thru’ the engine compression tests as it pertains to troubleshooting a misfire condition that is lighting up the check engine light (and storing any of the misfire codes: P0300, P0301, P0302, P0303, P0304, P0305, P0306). You’ll also be able to find out if a compression problem is causing an engine no-start problem.

Why are the compression rings worn out on my GM 4.3L?

This tells you that the piston compression rings are worn out and thus the problem is in the bottom end (block) of the engine in your GM 4.3L, 5.0L, or 5.7L equipped vehicle. Here’s why: The engine oil helped the piston rings seal better, thus bringing up the compression value almost back to normal.

What causes low compression at the top of the engine?

The head gasket connects to the cylinder head at the top of the engine. If there is a problem, you’ll notice a gap between the cylinder and the head, and gas will escape the cylinder, leading to low compression. The problem could also be something going wrong with your pistons, which power your car’s movement.