Driving home yesterday some douche bag put a boulder on the road. I came up over a hill and at the top were three big rocks across the road that were not visable until you came up over the hill. I couldn’t stop or serve it in time and ran over a big rock/boulder head on destroying my oil pan. I drove about a quarter mile after the initial hit and the low oil/engine off light came on. I pulled over and shut off my ignition immediately, I called triple A and had the car flat bedded to my house. I haven’t had the chance to look into the damages, just to get an idea what are some of the possible damages? Does the low/oil light engage after the damage to the engine has taken place or when it the oil pressure gets dangerously low? I hope its only an oil pan that I have to replace.

 

I don't think you went far enough to damage anything other than the impact damage.

 

thanks Jury,

I sure hope I havent damaged anything else, good to hear that I havent gone far enough to cause major damage

 

The low oil pressure light is triggered off a sensor that simply checks oil pressure. If the light just flashed on, and you turned the engine off, then I would agree with the Jury that your chances of damage are slim.

"Possible" damages? Feel free to ignore the ensuing horror story. I'm bored at work, and besides, (hopefully) it doesn't apply - I used to rebuild Porsche engines and can tell you the first thing to go are bearings. Rod bearings specifically, although the mains aren't far behind. I don't know how long the engines I've rebuilt were run with little or no oil pressure. The owners usually said something along the line of "but I only drove it long enough to pull over". However, "just long enough to pull over" must have been Swahili for "drive it three exits to the nearest all night gas station", because I've seen engines that needed a complete bottom end rebuild. Because you turned yours off immediately, you won't have the "joyful experience" of arguing with the service writer about the long distance phone charges that are part of the bill. The phone charges from having to call some machine shop in Germany to track down the only oversized bearing set in existence (going by the price of those bearings, I'm assuming they’re the only ones in existence). You're safe. However, those that continue to drive with the "no oil in the sump" light on get to witness a hellacious knocking noise that they will never forget. The rumor in the Porsche community is that noise spells out "we'll need $15K to make this run again" in Morse Code.

In all seriousness, if you turned it off promptly, you're safe. If not, and it's not too late to report it stolen . . . . . . . .

 

Porsche guy eh? Do you know if only the 98 Boxsters were the one's dropping engines from the sleeve slipping? (or did that spill over into 99?)

 

Ex-Porsche guy. Way ex. I've never worked on a water cooler, but the short answer to your question is "yes". 1998 and 1999. IMO, the sleeves aren't the worst of it. You know about the rear mail seal, right? Do you know "why" the rear main seal leaks?

I can't see there being many 200K mile 986's.

 

Jury, you seem very knowledgable. What is the proper way to seal and bolt an oil pan. I left a piece of card board under neath the oil pan last night and checked this morning it's leaking. How much of the sealant do I apply and where?

 

I’m still bored at work, so I’ll post why I don’t think there will be very many 200,000 mile Boxsters. As I understand it, the problem with the Boxster started with leaky cases (cases are Porsche engine blocks). This particular leak is aside from the engineering defect that resulted in the leaking rear main seal (I’ll get to that shortly). This is the one where the cases themselves leaked . This was discovered in 1997 and a lot of cases were rejected. To add to the problem, the company that supplied the cases had a "manufacturing problem" (code word for one of a pair of expensive pieces of manufacturing equipment having been damaged. Rumor has it that the busted one was “dropped”.). Between the supplier only being able to produce cases at half the expected rate, and the number of cases that ended up being rejected due to porosity (there was air in the die at the time of manufacturing), Porsche didn't have enough engines to keep up with demand. Running short on engines, Porsche came up with a solution. They decided to bore the cylinders and insert cylinder sleeves in the cases that had been originally rejected. As you already know, the lip on the sleeve that was supposed to hold it in place, was known to "occasionally" fail. That resulted in (1) part of the lip breaking and falling into the combustion chamber, (2) the piston pushing that broken lip into the head, (3) the sleeve slipping down a bit, and (4) the catastrophic ending: the piston ring extending past the slipped sleeve, grabbing it, and pulling the sleeve down into the crankcase. The 97, 98, and 99 model years suffered from this problem. The good news is, those cars usually blew an engine very early on. No worries about the quality of those rebuilds. The damage was usually so bad that nothing was worth salvaging.

The bad news is, the engineering defect that I mentioned earlier. Here’s the story on that. In the bottom end of BOTH the 996 and the 986, the crank is mounted in a cradle. The cradle is bolted in the middle of the two case halves. This is opposed to the way it was done in the old days, where the crank simply sat between the case halves. The tail (flywheel side) of the crank isn’t held in place by anything. Ordinarily there would be a bearing, but a sprocket sits where the bearing would be. The sprocket is required to drive a chain which drives the intermediate shaft. Over time, this free standing tail has a tendency to move downward. When it does, the rear main seal leaks and has to be replaced. Eventually, the crank hangs down so far that no seal will work and the engine has to be disassembled to the point where the cradle can be repositioned (might as well just rebuild the bottom end). I’ve been told the problem is due to the weight of the dual mass flywheel and clutch assembly, but the problem occurs in tiptronic cars as well. The most permanent (temporary) fix I’ve heard of is to use the rear main seal from a Cayenne V8. The absolute permanent fix is to redesign the engine and put a bearing where the gear sits.

Recognize the photo?

 

opps my bad, i meant marcus f, you seem very knowledgable

 

I am ill qualified to tell you how to do the pan on a Mercedes-Benz. I've never done one on a Benz. The big question that I don't know is whether to use silicone or not. Some cars use it, others don't. I can explain both methods, but you may want to ask someone who’s actually done it on a Mercedes which is the correct method.

You're starting with a new pan, so you won't have to worry about cleaning all the old gasket sealer off and making sure the pan is straight. Once the pan is clean and dry, place a 1/4 inch wide bead around the entire pan and each bolt hole with the Ultra-Black silicone. Place the pan in position and finger tighten all the bolts in a star pattern. Then, using the manual to determine the correct torque, tighten the pan to that torque in a star pattern. Let the car sit for 24hrs (this allows the silicone to cure), add oil, and you're done. If the Mercedes doesn't use silicone (just a gasket), then the procedure is the same except (naturally) don't use silicone and you don't have to wait 24 hours.

If you've never done any mechanical work, and/or everything I just wrote seems confusing, I'd recommend taking the car to a dealer or an indy.

I hope this helps.