Well, I was finally able to juggle my work schedule enough this week to get Son's 300SD to and from the alignment shop. I figured it shouldn't be too hard for them to do, since he replaced both tie rods at school--no rusty, balky tie rod ends to fight. The alignment was a success, I was told, though the before and after chart shows that the car started with correct camber and ended with incorrect camber in the front. On the plus side, toe-in was notably off, and that, at least, is well within specs now. I figured we would drive the car a bit and then take the car back to a different NTB to have the alignment checked again. (And yes, I know I took this car to a chain shop, but Son's auto tech teacher, a former MB dealership tech, said that with the new laser alignment racks, no special expertise was needed to do a proper alignment for this car.)
Anyway, the car now has new tires, some new front end components, fresh fuel (liberally dosed with Startron and Biocor biocides), a new and fully functional driver's seat, fresh wipers and a new tank/washer pump, and we also fixed the broken window regulator in the rear left door, so it's more or less water-resistant. Note what's missing: we haven't started doing anything under the hood, other than making sure that checking fluid levels and starting to polish the fuse block, which is heavily tarnished; the fuel filters are screaming out for replacement, the glow plugs are still DOA, and there's oil/grease leaking from numerous orifices. I have some engine degreaser, some nice nylon brushes, and a new set of Bosch plugs waiting for the next non-rainy, non-work day when we can do some work in relative comfort....
Anyway, Son and I put about 75 miles on the car today doing a highway run in support of a few not-entirely-necessary errands. I did half the driving, and it was interesting, to say the least.
1. This car is slow. I really don't think the turbocharger is doing much, but I'm hoping that a few oil changes (and changing to synthetic oil) and cleaning out the banjo bolt may help a little bit. However, part of the problem is also perception. This car feels like it's not going fast, even when it is. You can tell when my 300D is pushing. The car is louder, there's more wind noise, there's a bit of vibration, and there is more feedback in general. Son's 300SD is about as quiet at 70 mph as it is a 30 mph (with one exception, see below). There's no vibration, thanks to the new tires, fairly recent Bilstein comfort shocks, and solid motor mounts. It feels like you're just sitting there, even as you motor down the road.
2. This car is haunted by a banshee. Starting around 20 mph and increasing as the car picks up speed, this car has a low-pitched but very noticeable grumble/groan/moan. To me, this sounds a lot like it could be a worn/dry rear transaxle, but the sound really seems to be coming from the right front. We will try to check the transaxle as part of our next Benz work day to see if that might be the source of the problem. There's a bit of wetness at one of the axleshaft seals into the differential, so a low oil level there is plausible. Anyone have other suggestions? They did look at the wheel bearings at the school as part of the pre-sale inspection and claimed they're all looking good. The front wheels are nice and tight, now that the tie rods have been replaced.
3. The 300SD handles like a Crown Vic. I never thought that my 300D was a small car. Or that it handled like a sports car. However, the 300SD feels... bigger... all the way around. More hood. Wider body. It really feels noticeably bigger. This car also has more body roll than I expected when I'm going around curves at speed. I wasn't expecting Ferrari handling, but I'm still surprised how boat-like the car feels compared to my 300D. (Then again, maybe this is telling me that it's time to do some serious suspension work on my 300D so it feels less firm and, well, worn.)
4. The 300SD's motor has excellent oil pressure for a car with 418,000 miles. According to the gauge, this car has a hot idle oil pressure of over 2 bar, which I find amazing, compared to the 1.75 bar at hot idle in my much younger (mileage-wise) 300D (a mere 268k miles). Of course, I have a suspicion that this car is running 15w-40 dino oil, if not 20-50, and I've run Rotella T6 5w-40 synthetic in mine for the past nine years. It will be interesting to see if this changes at all after the next oil change, when the current oil goes out and Rotella goes in.
5. The Becker Grand Prix radio is completely dead, even though the dial backlight is still tied to the headlight switch and lights up appropriately. Does anyone have one with a working radio (working cassette tape not necessarily required) that they might be willing to part with for a reasonable price? I would rather not hack up the elegant wiring harness to put in an aftermarket radio until it's really necessary. Auction site prices are stupidly expensive ($120 for an untested, no-warranty unit that looks like it was left in the rain for a few months? No thank you.), and the radios and dash gauges appear to be the first thing pillaged at the u-pull-it lot that has supplied the new seats and a fair number of useful bits.
I'm sure I'll remember other interesting tidbits as soon as I send this, but this should be a start. As always, feedback is welcome.
--Conrad J.
