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Hey everybody. I’ve got a 2000 ford ranger with a v6. It has 195,000 miles if that helps. The problem is the engine runs awful! I had the compression checked and the back 2 cylinders (one on each side of the engine) have NO compression. I checked the oil and the oil looks clean. No antifreeze in the oil. What would cause this to happen? Head gasket? Do I need new heads? Maybe the valves. I have no idea what to expect. I guess what I’m looking for is what could the cause be and if I would need a whole new engine or if I’m just going to be looking at a top end rebuild. The engine seems to be pretty good except for the missing. Thanks
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No compression at all, huh? Doesn’t bode well…
Okay.. I’d ask the mechanic if he put a shot of oil down the back two cylinders… see if that helps it seal anything up. If it does, then rings.. otherwise, valves.
You might want to ask the mechanic to use a ‘scope on it.. see if he can find anything unfortunate on those back two cylinders. Otherwise, really, the next step would be to pull the heads off. In a no compression situation like that, it’s pretty much a fact of life that the heads have to come off.
Hopefully when you have them pulled, what you find underneath is repairable. Could be a head gasket, could be a bunch of things… won’t know until you have a look.
-Hinoki
Thanks! I don’t know what all he did to check the compression. I will try to do a compression check with oil in the cylinders. I just shoot it down the spark plug hole? How much? Hopefully it’s the head gasket or the valves. They’d be the easiest to replace/ repair.
Yep. From an oilcan, a single shot or two of oil down the spark plug hole into the cylinder itself. That allows it to form a wet-seal around worn rings (and other problems). Don’t want to put too much in there, though.. that causes -other- issues.
If you’re going to do it yourself, don’t forget to pull the fuel pump relay so the engine doesn’t flood too.
Good luck!
-Hinoki
No compression can be caused by bad/broken rings, valve failure, head gasket failure, block failure, etc…
The best way to find out what it is before you tear into it is to do a leak down test or apply compressed air directly to the cylinder.. This will let you know where the air leaking from… Crankcase noise is rings, exhaust noise is exhaust valves (generally the ones to get burned), bubbles in cooling system is head gasket…
Depending on what you find, will dictate what course of action you can take… If it is bad valves, a simple head rebuild may fix it. If a head gasket is blown, then the head may need re-surfaced…
If you have a broken ring, much deeper work is required…
Eric has a video about this…
Good luck…
-Karl
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