A low compression reading in one or more cylinders
If a garage found low compression, ask for the readings from every cylinder and how the test was carried out. One number is difficult to interpret without the test conditions and the specification for that engine.
What a compression test can show
The result can reveal that a cylinder is not building the expected pressure. It could be losing pressure through the valves, the head gasket or around the piston and rings. Valve timing and the conditions of the test can also affect the reading.
How further checks may narrow it down
We may need a comparable repeat test or a leak-down test to help find where air escapes. If the cylinder itself is suspected, measurements of the engine block may be needed. Wider damage can warrant an engine rebuild assessment.
What to share with us
Send the readings and tell us what the car was doing and what has been checked. See engine diagnostics for how we agree further tests.
Start by telling us about the fault
Open WhatsApp, review the suggested message and decide whether to send it.