Q: Failed compression test
Failed a compression test and was told 2 valves needed to be replaced, not sure 2 but was told it would be easier to replace entire engine. If so how do i go about to getting a new engine? Or if its easier to replace valves then how do i do so?
My car has a manual transmission.
Hi there. First, a compression test will only check the cylinder for pressure build up during cranking and test the rings. To verify that the valves are really leaking, hook up a leak down tester to the engine and pressurize the engine to see if it is sealed. To do this, the engine must be on TDC (top dead center) for each cylinder that you test. If you hear a leak, check the intake and exhaust (for valves), remove the oil cap to hear air (for rings), and open the radiator cap and check for bubbles (head gasket). These are the 4 locations that a leak down tester checks. A leak down tester has 0 to 100%. What this means is that, if the cylinder is at 20% (normal conditions) that is 20% of the air leaking out of the engine. If the gauge reads 60% - 100% (something bent, burnt, or broken) then there is a mass leak coming out of the engine. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from YourMechanic, to come to your location and guide you through any services needed.
Get an instant quote for your car
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing