Rear Camshaft Plugs/Seals

This page originated when i discovered a plastic part wedged down in the head of my engine, located in the left (front of car looking aft)section of the the aft cam tower. The part was stuck just over one of the oil channels. Well, after a few responses from RENNLISTers I discoverd what the part is and where it goes.

Below is a little history of my discovery and pictures of what it all looked like as i proceeded to fix it. During this repair you will see that it is an excellent time to consider replacing the rear cam shaft seals, as they become fully exposed.

The original question I had was.....ANY IDEA OF WHAT THIS IS....AND WHERE IT CAME FROM???

The answer i got was a camshaft plug, it is a hard plastic piece that has a steel retaining pin that passes through it and sits in the hole that used to be occupied by the end of the camshaft. My car is an 87S4 and the camshaft doesnt run the entire length of the head and this part was/is apparently used to plug the hole were the LONGER camshafts would normally sit. Also, from a few replys, i was told that when this plug fails it may be responsible for a low oil pressure indication at idle ( i guess there was a TSB on this at some time???). Im thinking now that this may also be a partial cause to an occaisional sticky lifter i have.


This is a good close up of the part that was wedged down in the location you see above. It is apprx. the size of a quarter in diameter. The part is plastic and has a steal retaining pin that passes through its entire length.


After receiving answers to this question i went out to investigate further and snapped a few they are and what i found....

As you can see there are 2 areas on each aft cam tower where the plugs go.

The cap i found came from this area. You can see the hole from the pin and the ring where the plug sets. Also you can see there is another plug in there as well, farther back. Looks like 2 plugs in this hole you will see later there is only 1 in the upper half.. Look closely you can see that the plug/cap that is still there is warpped and damaged and that the bottom of the retaining pin has actually "popped" out of its hole!!

This is a picture of the aft tower on the other side. Both plugs and pins were intact and they looked in great shape!!

Thanks to Fred Clark, Sterling Gee and Jim at 928Intl for responding to my questions!! And again thanx to all of the RENNLISTer's that post. We are our own best source of information on this car!!!

Now for the FIX................

I used a 6mm hex socket and a cheater bar on my rachet to make the unseating of the bolts easier. All the bolts were tight but they all definitely broke loose at about the same point/amount of torque. A nice, easy, firm push on the rachet is all it took. Also, i had to remove a bolt that held a wiring harness bracket, it made access easier to one of the hex bolts.

After all the bolts were out, i found a perfect slot to place a wide head screw driver in. A very gentle twist and the upper half of the cam tower came loose. It was pretty well stuck on there though. Dont worry, parts and springs arent going to go flying when you remove this!!! : )

This is the top half once removed. As far as i could tell, there was NO gasket on here, just a smooth surface mating with the lower half. As i said, it was still well stuck together!

heres a shot of "the big picture" i guess. Upper plug...two lower plugs out...shorter cam shaft....and aft cam seals.

A good shot of the upper plug and a aft cam seal that appeared to be in good shape.

This shows the area occupied by the 2 lower plugs. Aft cam seal is shown also.

This is the culprit!!! A close up of the other lower plug that was found to be warped. The problem i see is that the retaining pin, although it is long, doesnt protrude from the top. This means the plug is anchored by only one pin and when it warps over time, enough clearance is created so it can come free (this is what happend to the other one)

At this point i dont have it all back together yet but, im sure the bolts that were removed are TORQUED to SPECS!

Hope this helped......................