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MNBoxster · 01-12-2006, 10:23 PM

Hi,

To expand a little on John's (deliriousga) post about the Sparkplug Wells, traditionally, most engines had a single row of Valves, covered by the Valve Cover and the tapped hole for the Sparkplugs was offset. But with many Dual Overhead Cam Engines, a Camshaft runs on either side of the Sparkplug Hole. Rather than produce two separate Valve Covers, several manufacturers incorporate the use of a single Valve Cover covering the entire Head, now referred to as the Head Cover.

This being the case, some provision must be made to allow the Sparkplugs to screw into the Head. Simply punching holes in the Valve (Head) Cover wouldn't contain the Oil runnning through the Head. So, a Tube (or Well in Porsche Parlance) is inserted into the Head Cover, and the Plugs are installed through these. These Tubes (or Wells), usually made from Hi-Temp Nylon or sometimes Delrin, have an 'O' ring on either end to Seal them from the Oil in the Head. Over time, these 'O' rings fail and so must be replaced.

The procedure is quite simple: Remove the Coil and Electrical Harness connection, pull the Sparkplugs, using an Expandable Pliers (or in the case of a truly stuck Tube, an Internal Puller) you remove the Tubes (or Wells). Remove the old 'O' Rings, clean-up the Tubes and install new 'O' rings. Add a light coating of Oil to lube the 'O' Rings and then reinsert the Tube by hand until it seats on the Head. Reinstall Plugs (torque to spec), then replace the Coil and Electrical Connector.

The 'O' Rings are cheap and I would recommend changing them with a Plug Change (you're 90% there anyway). This way, they're not likely to fail which can result in Oil Leaks and/or misfires due to the Oil shorting out the Plug or worse. Frying the $$$$ ECU (DME in Porsche Parlance). You could simply inspect the old Plugs for signs of Oil as an indication, but even if they are OK when you change the Plugs, they could easily fail within the Service Life of the new Plugs and, as Luck usually has it, leave you stranded on the Roadside, late at night and in the Rain.

I haven't done this repair to my Boxster yet, but the 3.2L V6 DOC Engine on my Honda Passport uses the exact same arrangement and I have changed these 'O' rings a couple times - as I said, Cheap, Easy. I first became aware of them when one cylinder leaked OIL badly, shorting out the Plug resulting in VERY poor running. The Dealer wanted $350 to change them, so I did it myself for $12 in Parts and about 2 Hrs. of my time. Hope this helps...

Happy Motoring!... Jim'99

01-12-2006, 10:23 PM	#30
MNBoxster Registered User Join Date: Sep 2005 Location: Minneapolis/St. Paul, Minnesota, USA Posts: 3,308	Hi, To expand a little on John's (deliriousga) post about the Sparkplug Wells, traditionally, most engines had a single row of Valves, covered by the Valve Cover and the tapped hole for the Sparkplugs was offset. But with many Dual Overhead Cam Engines, a Camshaft runs on either side of the Sparkplug Hole. Rather than produce two separate Valve Covers, several manufacturers incorporate the use of a single Valve Cover covering the entire Head, now referred to as the Head Cover. This being the case, some provision must be made to allow the Sparkplugs to screw into the Head. Simply punching holes in the Valve (Head) Cover wouldn't contain the Oil runnning through the Head. So, a Tube (or Well in Porsche Parlance) is inserted into the Head Cover, and the Plugs are installed through these. These Tubes (or Wells), usually made from Hi-Temp Nylon or sometimes Delrin, have an 'O' ring on either end to Seal them from the Oil in the Head. Over time, these 'O' rings fail and so must be replaced. The procedure is quite simple: Remove the Coil and Electrical Harness connection, pull the Sparkplugs, using an Expandable Pliers (or in the case of a truly stuck Tube, an Internal Puller) you remove the Tubes (or Wells). Remove the old 'O' Rings, clean-up the Tubes and install new 'O' rings. Add a light coating of Oil to lube the 'O' Rings and then reinsert the Tube by hand until it seats on the Head. Reinstall Plugs (torque to spec), then replace the Coil and Electrical Connector. The 'O' Rings are cheap and I would recommend changing them with a Plug Change (you're 90% there anyway). This way, they're not likely to fail which can result in Oil Leaks and/or misfires due to the Oil shorting out the Plug or worse. Frying the $$$$ ECU (DME in Porsche Parlance). You could simply inspect the old Plugs for signs of Oil as an indication, but even if they are OK when you change the Plugs, they could easily fail within the Service Life of the new Plugs and, as Luck usually has it, leave you stranded on the Roadside, late at night and in the Rain. I haven't done this repair to my Boxster yet, but the 3.2L V6 DOC Engine on my Honda Passport uses the exact same arrangement and I have changed these 'O' rings a couple times - as I said, Cheap, Easy. I first became aware of them when one cylinder leaked OIL badly, shorting out the Plug resulting in VERY poor running. The Dealer wanted $350 to change them, so I did it myself for $12 in Parts and about 2 Hrs. of my time. Hope this helps... Happy Motoring!... Jim'99 Last edited by MNBoxster; 01-13-2006 at 08:03 AM.