what can zero compression, my timing belt is tight, does not appear to have jumped, timing chain is correct. car was running and lost all power
Zero compression usually points to a timing belt issue and bent valves on an interference engine.
Some more info about mileage, if zero compression exists on all cylinders, whether the timing belt covers have actually been removed, etc. might aid in offering advice.
And your car does not have both a timing belt and timing chain. Maybe a tensioner or water pump seized and teeth on the timing belt stripped. This could cause the same damage as a broken belt.
shop told me car had no compression but the timing belt was intact, I being a non believer took off the timing belt cover and found that is was still intact and all the lugs were still in place, no slack in the belt I took off the valve cover checked the timing chain that connects the two oh cams and it was intact and tight I ran the belt around to tdc and checked the timing marks on the chain, they were correct compression check showed zero on all 4 cyl 245K on engine, driving along and sudden loss of power followed by overheating no water in oil how can all 4 cyl have zero compression?
This is just speculation, as to the sequence of events, but how about this scenario?
Engine was overheating for an extended period of time
Severe overheating caused the cylinder head to warp
Warped cylinder head led to multiple breaches in the head gasket
Multiple breaches in the head gasket=zero compression
It is possible to have a bad head gasket without any coolant appearing in the engine’s oil supply.
Have you actually turned the crank shaft and watched the belt turn the cam shaft and inspected the entire length of the timing belt?
yes that was one of the first things I did, it was completely intact no lugs missing, cracked, ect. belt was almost as new
The only way to determine why there’s no compression is to do a cylinder leak down test.
Remove the spark plugs. Bring a cylinder to top-dead-center. Connect a tool like this http://www.harborfreight.com/cylinder-leak-down-tester-94190.html and apply compressed air to the cylinder. Listen for air escaping the engine. Tail pipe means burnt/ bent exhaust valves. Throttle body means burnt/bent intake valves. Dip stick tube means broken piston rings/holes in pistons. Bubbles in coolant or air escaping into an adjacent cylinder means a blown head gasket.
From your post you may have this backwards. You state a “sudden loss of power followed by overheating”. Maybe this is reversed with the unnoticed overheating preceding this loss of power.
Zero compression on all cylinders generally means a bent valves/valves out of time problem.
This could be verified by checking for excessively loose intake valve adjusters or by applying air to a cylinder which is at the top of its compression stroke and then listening for any air that may be hissing out of the throttle body. There should be no air hissing back through the throttle body.
It would be very unusual for a piston ring and head gasket fault to cause zero compression on all cylinders but it’s possible. If this is the case then you must have had this puppy glowing red from the overheating.
You could pick a cylinder, give it a small squirt of motor oil, and then retest the compression. If it take a big jump up then the rings are beyond bad; they’re barbecued and the engine is not likely even worth rebuilding.
My bad, but here’s something else to keep in mind. It’s possible to have a faulty compression tester and whenever there’s a compression problem I always run the test twice; the second time around with a different gauge.
If the Schrader valve in the tester is faulty or sticking open due to a tiny piece of debris that has been huffed into the compression tester and ends up stuck in the Schrader valve the tester can read zero. The piston rising will huff air into the gauge and then suck it right back out when the piston goes down.
Something to keep in mind anyway.
I had no idication that the engine was running hot, temp gauge was midrange when engine lost power after about 3-5 min temp gauge increased to hot… I found it hard to believe that all 4 cyl would show zero compression will continue to trouble shooting, don’t want to pull the head unless it really needs to come off. thanks
I also find it hard to believe that an engine has zero compression on all cylinders and there is no evidence of a broken/peeled timing belt or jumped cam chain.
Who performed this compression test? Just wondering.
I agree OK. If the compression gauge is accurate and properly used, and there are no incidental issues left out I would look very closely at the cam timing situation.