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Discussion Starter #1
I just checked compression on my 2000 GT 4.6 SOHC engine. 6 of the cylinders are 140-150 with the two inside cylinders on the passenger side about 80.

1) Since it looks like I have a small water leak, would a head gasket leak cause this same type of compression loss in both cylinders or could there be something else wrong?

2) If so, what does the Mitchell manual say in terms of time to change it.

3) Are there any special tools that are necessary?

4) Do the rocker arms have to come off?

5) Is 140-150 in each cylinder normal for a 40k mile engine with a blower? (we disconnected the blower to do the compression test).

6) Are there any special things I should know before changing the gasket?

Any help on this would be greatly appreciated. Thanks.
 

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If the engine wasn't hot when you did the tests you can get all sorts of wierd readings. It need to be as close to operating temp as possible. I'm also assuming your doing the compression tests correctly. Mainly, hot engine, all plugs removed, throttle wide open, injectors disconnected and cranking until pressure stablizes. It should take about the same number of compression strokes on each cylinder.

But even still those aren't not encouraging numbers. My car also has 39k miles, 10k of which are with a blower. The car shows 193 psi with very little varience. So far anyway! :)

Ed
 

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Discussion Starter #4
Yea, I'm pretty sure we did it correctly according to the Ford manual. I'm not as worried about the 140-150 as I expected some loss just from the way I drive the car. I don't plan on keeping the engine in there much longer anyway. I'm using this one to learn with.
 
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