From: Jason Kiplinger [jkiplinger@keyvoice.com] Sent: Thursday, January 27, 2000 10:02 AM To: 928 Subject: [928] 87 S4 LOW OIL PRESSURE Cause, symptoms, PN#, and fix Hello, Several have asked what the fix, pn etc. for this problem was. After seeing the part that caused the problem it comes as no surprise that others may be seeing the same thing. My car is a 87 S4 AT with 96k miles that I purchased about 3 months ago. Description of problem symptoms: Noticed one day at idle that there was a rattle coming from engine bay. Popped the hood and noticed a light "rattle" sound coming from left side of engine. Originally suspected bad valve. Mechanic checked it and said it was the cam chain rattling. He then checked the oil pressure and found it was at 1.2 on the guage when at idle, way too low. Made appointment that day. Since rattle would go away at higher r.p.m. mechanic diagnosed it as hydraulic cam chain tensioner not getting enough oil pressure to do it's job at idle. The fix: First mechanic changed the oil and filter but did not help. Next he pulled the cam cover and immediately noticed that all three cylinder head oil plugs had popped out and were just hanging around doing nothing. Oil would freely pump out of the three holes that were left (about 1/16 inch diameter). I suspect I lost the last one recently which finally caused enough of a oil pressure loss that the tensioner was starved at idle and the cam chain then rattled. Mechanic ordered new part and discovered that they have gone to a different part since. Porsche evidently came to the conclusion that the plastic parts maybe weren't such a hot idea after all. They now use metal pins in the oil galley to do the job. Mechanic showed me the warped plugs and they looked in bad shape. Kind of like you put them in a microwave for a few minutes until they started to melt. The result: Pressure now sits right at 3.5 on the guage at idle (it's so nice) and the rattle is completely gone. The PN# is 928 105 262 00 and costs a wopping $2.13 each. Repair manual calls for 5 so there must only be 2 on the right side of the engine. Porsche would not give me the TSB # for this problem. I discussed it with Porsche and their mechanic seems to have seen it several times before. He commented that there are many cars out there which still have the plastic part. I sensed that he seemed to have a small amount of pity for the cars and their owners. Maybe this problem can be potentially more severe then what I encountered. Best of luck to all who are going to check into this. Jason 87 S4 AT Indischrot Rattleless, RMB From: Fred Clark [fred_clark@jdedwards.com] Sent: Monday, March 20, 2000 8:00 PM To: 928 Subject: [928] 87 S4 LOW OIL PRESSURE Cause, symptoms, PN#, and fix There had been a thread several months ago about low oil pressure at idle on an '87S4 and that this is a potential problem that can easily be fixed although no one seemed to know how, there was just a part # that wasn't referenced in the shop manual (at least not in mine that covers up to MY '88). I finally found out where the pins go and how to replace them. Since many of us are pulling off our cam covers to refinish and reseal this is a good time to perform this fix. Apparently earlier 928s had longer cams that went all the way to the back cam cover bridge (firewall end). You'll notice looking at the cams on your '87 that on the back cylinders (4 and 8)the cam ends at the cam lobe for those cylinders rather than being supported all the way to the back bearing(hope this makes sense, take a look at yours). The cam cover bridge in the back has some plastic oil seals that you should replace while you're in there. They plug the oil journal to what used to lube the end of the cam. Since the cam doesn't come all the way to the end but there is still an oil journal, if the pin isn't in place oil just squirts out the holes (approx 1/16 to 1/8" diameter). The fix is to take the back bridge off and replace the old seal with either part #928.105.261.02 (see TSB #GRP 1 8711 which specified this part #), which is a round rubber seal the same diameter as the cam with a metal pin sticking out that goes into the oil journal, or a pin (no rubber seal), part # 928.105.262.00 (I believe this was used in later year cars). I'm going to use the one with the rubber seal, it plugs the hole where the cam would ride as well as the oil journal. I hope that it will keep oil from getting to the back seals where it may leak. The parts are dirt cheap and the repair pretty simple. From: Jim Bailey [mailto:jim@928intl.com] Sent: Monday, April 15, 2002 5:14 PM To: 928 Subject: [928] RE: QUESTION: Oil Pressure/Sending Unit The 928 oil pump high pressure bleed - off is set at 9 bar so cold the engine and sending unit could see as much as 9 bar of pressure . Once warm , pressure depends on several things such as the type of oil , weight of the oil , idle speed of the engine , and how hot it really is. The brown , very brown 1980 after 30 minutes " racing " in 90 degree weather with the water temp on the last white line (hot)at idle at 900 rpm only has about 1.5 bar pressure but at 5,000 rpm is back at 5 bar . At normal temperature , normal driving it holds the 3-5 bar range which most people should see . Jim Bailey Jim@928intl.com