Ed Hughes

Having owned a 911 now for about 5 years, the engineering of it amazes me in both positive and negative ways. Example-great motor, but lousy A/C.

So, on to thye 928. Obviously a masterpiece, but what's up with the belly pan and oil changes? I did my first change this afternoon, and I can't believe they couldn't have put some kind of panel or door to access the drain plug and filter. Lord knows it wasn't because they wanted to limit the number of fasteners-I counted 14 that secure the belly pan itself.

The next change, I'm seriously thinking about taking the Dremel and cutting out a panel, and figuring out a better solution.

Every oil change I've ever done was capped off by starting the motor after filling with new oil: kind of an immediate gratification. This one was delayed 15 minutes while I put the belly back together.

ROG100

Ed,
Talk to Jim M he has done that already.
Roger

Ed Hughes

Thanks Roger. I shoulda come over and rented some "lift time" at your place. This car's a bit heavier than my 911, took a little more oomph to get her up off the ground!

It was good time to bond, though. She's really pretty dry, no leaks at the pan gasket that I could see.

ErnestSw

Ed,
If you're changing your oil once a year it's no big deal. If you buy into the 3000 mile oil change bull**** it's a little more trouble. Personally, I'd rather have the belly pan there for cooling and protection.

Ed Hughes

Ernie, I'll probably be changing a couple of times a year. No question about leaving it in place, but the access panel should've been part of the design.

perrys4

Ernest, how does the belly pan aid cooling. I am missing mine and have been considering replacing it with one from 928 intl.

ROG100

Ed,
Why would you change your oil twice a year?
Providing you are using Mobil One you are good for 15K or a year which ever comes first.
Probably longer but thats what I do.
Roger

ErnestSw

The belly pan directs cool air over and hot air away from the engine and is part of the total cooling system design. Note the louvers and NACA ducts designed into the belly pan.
Speaking of oil changes, it's time for mine. I just ordered four gallons of Mobil 1 Delvac 5W 40 for $98.00 plus shipping and I'll be sending a sample of the old oil in for testing for the second year in a row.

Ed Hughes

...I may do more than 15K per year?

PorKen

Now or then, I don't see that the engineers ( ) considered the home mechanic when they designed these cars.

IcemanG17

Ed
The belly pans are a major PITA.....but they serve a purpose too.....I have so many mismatched screws on mine (some fatter 10mm some standard) thats is a total pain to put back on....it took Bill and I almost as long to put the pan back on as it did to check the thrustbearing (another good idea)!

chaadster

There are those vacuum devices that suck the oil up and out the dipstick, such as spec'd for late model Mercedes Benz cars...I expect they could be used just as well for our cars, no?

http://www.liquidvac.com/

deliriousga

One thing I did with the belly pan to make it easier to put back on was to replace all of the front screws with longer ones. The original ones were so short it was a real PITA to get them to connect with the speed nut just to get things started. With the longer ones, things go much quicker and easier. If you do it, check the length once you have them tightened down to make sure they don't hit anything.

Nicole

The 928 had one of the largest oil reservoirs of its time - to allow for 20,000km or 12k miles oil change intevals -- very important in the 958s home country, where 20 years ago the quart of oil was already $8 and is now at about $20.

We've seen lots of evidence from oil analysis reports that even 12k miles is short for modern oils, and we could safely stretch this further. In this case, removing the belly pan is a good thing - it allows you to inspect all the other components that should be inspected occasionally.

However, if you have been brainwashed by Jiffy Lube and Pennzoil (who advocate 3k mile oil changes), you have to go through the belly pan removal more often. That's probably one of multiple reasons why we see 928s being driven or offered for sale without the pan. The result is a loss in the aerodynamics department, and a lot more debris in the engine compartment. If you look closely, the louvers are designed to suck air out at speed to aid the air flow through the engine compartment, and the extra ducts direct cool air to the motor mounts.

I would like the idea of an access door for oil changes in the belly pan, but have been told this might end up being a product liability issue when the door gets damaged and flies off the pan, and damages some other vehicle, driver, or motorcycle rider.

Ron_H

I have done one oil change on my car after installing a Devek belly pan (aluminum). I devised a method of removing and reinstalling it that may help. I used a small rolling seat which was just the right height to slide under the pan and carry it when it was free of the mounting points. Then I slid it out of the way, changed the oil and filter and slid the pan on the seat back in place and screwed it back on. No problems at all . Took only a few minutes in each direction. The seat I used is a mechanic's seat made of plastic on rollers which I would use if I was working on the brakes or something else that height.

As for the pan itself, I had run the car for three years without a pan. One day in another state near California, at "adequate" speed, I encountered a section of roadway that resembled a roller coaster. The first couple of bumps put a laugh on my face; the next one put an immediate frown on that face and I immediately stood on the brakes. I had bottomed out big time as the car came down when the road was going up. I got out to check under the car. No leaks visible. I drove aways, and repeated the exercise. No visible leaks. But the interior was a little warmer all of a sudden. The AC compressor had taken the major part of the hit and it was destroyed. And I still had about 3000 miles of summer driving to do. I was in the middle of nowhereville and spent the next few days with the windows open to keep cool.
I suggest that the belly pan is for more than cooling; it is also to protect vulnerable parts on the underside, such as belts and pulleys and mounting points and AC compressors. During that trip, several birds were unfortunately smashed and luckily none of them went through the windshield or under the car to get lodged in between a pulley-belt. The pan would have prevented the latter.