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Failed compression test


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Okay so my girlfriend bought a 2002 Jeep liberty from a dealership back in March. Last week it wouldn't start. ...

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Old 06-18-2015, 11:40 AM   #1 (permalink)
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Default Failed compression test

Okay so my girlfriend bought a 2002 Jeep liberty from a dealership back in March. Last week it wouldn't start. After I replaced the spark plugs it started but was idling poorly. I decided to have it towed to a shop. They did a compression test and cylinder 2 has 0 compression. They pretty much told me I was probably going to need a new motor. I'm gonna have it towed back here so I can work on it myself. Is there any chance of saving it? I already have a $300 shop bill for the little bit of testing that they did.
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Old 06-18-2015, 11:45 AM   #2 (permalink)
 
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Dropped a valve seat probably??
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Old 06-18-2015, 12:01 PM   #3 (permalink)
 
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Isnt there some kind of lemon clause on that you bought this thing from a dealership less than 4months ago
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Old 06-18-2015, 12:06 PM   #4 (permalink)
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Originally Posted by dude1116 View Post
Dropped a valve seat probably??
Seal or seat? I know what the valve seal is. Do you have a diagram of what where exactly the valve seat sits?
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Old 06-18-2015, 12:11 PM   #5 (permalink)
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Originally Posted by Jbergun View Post
Isnt there some kind of lemon clause on that you bought this thing from a dealership less than 4months ago
She bought it as is with no warranty so I really don't know
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Old 06-18-2015, 02:00 PM   #6 (permalink)
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dropped a valve it happens on them eventually ... just like the rad leak ... and the saggy front suspension .... you either need a new motor or get the whole top end done.
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Old 06-18-2015, 02:05 PM   #7 (permalink)
 
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Originally Posted by dude1116 View Post
Dropped a valve seat probably??
That was my first thought too. In layman's terms, the seat is a hardened ring pressed into the head that the valve sits down to. They have a tendency to work loose and "drop", which could wedge the valve open. A stuck open valve will give you zero compression. Even a terribly worn engine has some sort of compression, unless the cylinder wall is blown out. Ask them if they have a scope where they can go in through the spark plug hole for an exploratory. I think they're jumping the gun trying to tell you you need a whole new engine.
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Old 06-18-2015, 02:32 PM   #8 (permalink)
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Originally Posted by CactusJacked View Post
That was my first thought too. In layman's terms, the seat is a hardened ring pressed into the head that the valve sits down to. They have a tendency to work loose and "drop", which could wedge the valve open. A stuck open valve will give you zero compression. Even a terribly worn engine has some sort of compression, unless the cylinder wall is blown out. Ask them if they have a scope where they can go in through the spark plug hole for an exploratory. I think they're jumping the gun trying to tell you you need a whole new engine.
agreed on the whole new engine.. but at least while in there may as well do the whole top end ... if funds are an issue a new to him motor may be in order .
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Old 06-18-2015, 06:34 PM   #9 (permalink)
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Originally Posted by CactusJacked View Post
That was my first thought too. In layman's terms, the seat is a hardened ring pressed into the head that the valve sits down to. They have a tendency to work loose and "drop", which could wedge the valve open. A stuck open valve will give you zero compression. Even a terribly worn engine has some sort of compression, unless the cylinder wall is blown out. Ask them if they have a scope where they can go in through the spark plug hole for an exploratory. I think they're jumping the gun trying to tell you you need a whole new engine.
I got the jeep back from the shop. I'm going to pull the heads off myself and check out the damage. Trying to cut down on the cost of fixing it since we just got it. It the heads are bad I will the them machined. I got the time so I'm hoping I can do this myself. Any tips are greatly appreciated.
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Old 06-18-2015, 08:20 PM   #10 (permalink)
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Originally Posted by Dannyboy745 View Post
I got the jeep back from the shop. I'm going to pull the heads off myself and check out the damage. Trying to cut down on the cost of fixing it since we just got it. It the heads are bad I will the them machined. I got the time so I'm hoping I can do this myself. Any tips are greatly appreciated.
its not the heads its the sleve that the valves sit in ... heads will be fine. its the valve train you will need to replace. they have a habbit on some to come loose drop down and cause the valve to be stuck open giving no compression the other thing could be a lifter off under the rocker cover you will need a lash adjuster to fix that the plastic rockers can come loose. ..... thats the minor problem they normally fall off because of the dropped valve and thats the sleeve ..
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Last edited by ftaa; 06-18-2015 at 08:22 PM.
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