GT-40: Possible Head Gasket Issue

[dgfrinell]

Evening Everyone,

I hope I am posting in the correct spot, but my wife and I need some assistance with this.

2002 Air Nautique
GT-40 (5.8L)
850ish hours
Ski-32mph / wakeboard-16-18mph / surf-9-11mph

I was starting to get the girl ready to play in the water when I noticed a spot of oil I had not seen before. The possible leak is located on the left rear side of the engine, between the cylinder head and the block. Doing some investigation, I could not find any other location on the motor that the oil could have leaked from and dripped to that location. I found a few drops of oil in the bottom of the boat. I pulled her last September and she has been in a heated garage since.

The best/worst guess my wife and I can think of is a possible head gasket issue, but no way to really tell without pulling it apart. And since we live in a small rural town in NM, I am very limited in where I can go to get either advice or any service at all. My current best option is to tow 2-hours away and drop it off and wait for when they can get to it. No other shop has even ventured to offer anything else. The shop says they will run it in a tank for about an hour to gauge where everything is and if the leak gets worse. If it does, they will progress to tear it down and try and figure it out.

So here's what I'm looking for; any and all advice you guys have out there to see if this is the right way to do it? Of if I need to be thinking it is something else? Or if I need to be asking different questions.

Thank you all in advance for your time and assistance.

V/R,
-Doug

My apologies for the pictures being rotated 90-degrees left...couldn't get them to load correctly.

[charlesml3]

If it's oil it's unlikely to be a head gasket problem. If anything it might be a small leak in a valve cover. No way to know without more troubleshooting. Get it running and see if you have water in the oil. Again, with it running look around for anything that doesn't seem right.

-Charles

[kylem03]

When I bought my boat my valve covers were loose and leaked a little bit because of it. I’d find an occasional drip in a random spot. Once I tightened the bolts on the cover the problem went away.

Kyle

[dgfrinell]

Charles,

Thanks for the quick reply. With my current location, I am unable to run it...issue with living on base and doing everything late at night. So I did a compression test and found out I'm a bit low...on all cylinders, but especially the one near the leak. Yes, the test was conducted cold, but from what I can read it can be done with the expectation that it will be a bit lower. But in the 80's low, it should not be.


Kyle,

I have checked all the torque specs on all the bolts and everything is where it is supposed to be. Thank you for the advice.


When I was conducting the compression test, I found oil on the 1x plug that is located near the leak, which just so happened to have the lower compression. All other plugs were clear and dry. So we have talked with a few more shops and are going to head in and have some more advanced diagnostics done that I am not able to do. We are anticipating either head gasket or rings...that's the simple side.

I'll try and keep you all up to date on the escapades that is our life with a boat.

V/R,
-Doug

[Blamey]

I'd recommend cross posting to correctcraftfan.com.

Lots of members there have experience with working on these engines and the love to help walk someone through trouble shooting.

Also, post the results of the compression test.

I would suggest doing the compression test when warm and doing a leakdown too.