"if it ain't broke don't fix it" ?

[Smokey]

I have an 87 300sdl, just turned 100k and I'm planning a trip say 2000-3000 miles. I have my original behr radiator, vaccum pump, as far as I can tell wheel bearings have never been repacked, original disk rotors.

What I've been pondering over is at what point should I be proactive and replace radiator etc. I have never had a cooling problem, at 85 mph T gauge reads about 87-88, never been over 95 F, EVER !

And what about wheel bearings? I still have 20k+ left on my pads, rotor thickness getting close to minimum spec (maybe slightly below), should I go ahead and repack bearings as a precaution? I was planning to wait until I needed new pads and then do rotors and repack bearings at the same time.

I wish statistics were available so that one could make a judgement as to when things are likely to fail but as everyone knows no two cars, drivers or conditions are the same so failure predictions are very difficult. As far as I know only things like timing belt change intervals are prescribed since I assume their failure based on wear is more predictible.

If someone would tell me that since my radiator is almost 19 years old and made of plastic it's about to distegrate because of it's age I might be more concerned, it looks fine from the outside and it doesn't appear clogged at all based on running temp readings.

Advise anyone?

I don't understand why you're worrying about this at 100k miles. My 82 has over 300k on the original radiator, etc. and I routinely drive it across the country. I expect to drive from Denver to Jersey (round trip) three times during January and February. I replace/repair parts at the first sign of failure, but I don't believe it is possible to predict the next failure prior to having any symptoms. What's the worst thing that can happen?

[Smokey]

Craig,

Good point, hearing that you have an 82 with over 300k miles gives me some piece of mind, I've just heard all the horror stories of how brittle these radiators can get with age giving me the impression that they spontaneouly fail at some point.

Have you repacked wheel bearings? I would assume so, if so when?


As far as the worst thing that can happen, I wasn't thinking of risk from a safety standpoint but from being stranded far from a MB parts shop!

[Hit Man X]

I'd not worry about the radiator (until you see it starting to leak) as the SDL ones are near $500. My SD's just sprung a leak here last week so I'm going to patch it here until I get a new one installed. Not sure if I'd go used unless it's $25 or something.

The vac pump is a different issue on the 603. I need to become unlazy and install my updated one. I understand the early ones like to break for some reason but mine still has the original one.

Brake wise, I'd drive on them without thinking twice.

Be smart and always keep some fluids with you... motor oil, ATF, power steering, etc.

[barry123400]

The only thing I can really think to comment on is the vaccum pump. When something like that is known to produce catastrophic engine failure it seems to be unwise to leave it on a car. Even salvaging the newer style off a junk car is probably better than keeping the original design unless say there are no known cases of failure at under 150k for example on the original style pump. Tragically it might remain in service till it fails. Far too late to change it then. Other failures of course could cause engine problems but at least you have a chance to catch most of them while they are occuring. Merceded dealer might give indication of expected lifespan of original part over phone. That assembley perhaps should have been a recall as the problem was serious enough for mercedes to change the design. If you plan to own the car for years why not change it out now. Will never be cheaper to do. Peace of mind kind of thing as well. Have a pleasant trip.

[Smokey]

Thanks for the feedback Barry. If I get a response from the Dealership regarding the original vac pum failure rate I'll post their comments.

I understand the concern of getting stuck in the middle of no-place, and it can cost you time and $$$ if it happens. There is an issue with the plastic radiator necks becoming brittle and failing. I have not done anything with mine, but I understand that there is a metal sleeve available to reenforce it. I've looked at mine and it seems OK, but I am careful not to over-tighten the clamps. I assume I will just end up replacing mine when it no longer cools adequately.

My wheel bearings end up getting repacked only when the brake rotors are replaced. I did have a rear wheel bearing seize and ruin the hub a few months ago, but it didn't get me stuck. I do bring my car to a good indy mechanic for most significant work and he does a good job of looking for any problems.