2003 Boxster S with random misfires in cylinder-1

[JuncoJones]

Hi there folks,

I’m having some random misfires in my ’03 Boxster. I’ve disassembled the intake manifold to get a better understanding of the problem, and as per the picture below, there is clearly something going on with cylinder-1.

• a week ago, CEL came on for random misfires in cylinder-1 (P0301)
• Engine runs well, has high millage (320km) and no noticeable degradation in performance
• Checked the coolant, and was below the minimum mark (which was flushed a couple of months ago)
• On the exhaust side, there are dripping marks, probably coolant leaking through the exhaust manifold gasket (!)

All this makes me think that it’s leaking coolant through the head gasket into cylinder-1. I already know this is not a four-hour repair to be completed during a weekend, and that one way or another, the engine will have to come down for surgery. . so I'll definitively appreciate any inputs!

 

Thanks,

Jones.

[JFP in PA]

If your head gasket was bad, it would be the first one I have ever heard of failing.  The multi layer steel head gaskets used in these cars is stronger than either the cylinder head or the engine case alloys, so they simply do not fail.  On the other hand, these cylinder heads are known to crack around or near the valve seats:

 

So before pulling anything apart, I would pressure test the cooling system.

[JuncoJones]

Thanks for your reply, JFP. I've already ordered a cooling system pressure tester, and will post the results once I get  that done.

 

Also very interesting your comment about the head gaskets...I'll certainly keep that in mind.

 

Jones

[JuncoJones]

Found what the problem was...an aged AOS. With the replacement part, works like a brand new car, same as before...

 

Jones