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?

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87 300SDL (115,000mi. 7/1/2008)
03 Jetta Wagon TDI (62,000mi. 7/1/2008)
75 240D(sold, sad to sell it, needed the garage for the SDL!)

Smokey

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?

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!

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87 300SDL (115,000mi. 7/1/2008)
03 Jetta Wagon TDI (62,000mi. 7/1/2008)
75 240D(sold, sad to sell it, needed the garage for the SDL!)

Smokey

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.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

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.

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.

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.

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87 300SDL (115,000mi. 7/1/2008)
03 Jetta Wagon TDI (62,000mi. 7/1/2008)
75 240D(sold, sad to sell it, needed the garage for the SDL!)

Smokey

I'd replace the vac pump and do the brakes. I prefer not to be on the side of the road 2k miles from home. You don't want to find out how bad the brakes are in the Rocky mountains.

As far as the vac pump is concerned you are rolling the dice leaving it on. The old ones have exposed bearings and when they fail they usualy take the engine with them. It may never fail during your ownership or may blow up tomarrow, like I said its a roll of the dice.

Personaly the $350 for a new pump now looks much better to me then $6,500 for a rebuilt engine +$350 for a new pump down the road.

With plastic radiators time is as much of a factor as mileage. Personaly I would replace it if it were over 10 years old and I was about to embark on a trip such as that. Remember Behr is the only company that makes radiators for SDL's, so if it blows hope you are near a MB dealer. If not expect the local shop to rape you, hmm lets see $450 from the dealer with a 20% mark up. $50 for shipping and $100 for labor.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

You've got it wrong ~ it's ' If It Ain't Broke , Fix it Untill It Is '



Grab the upper radiator outlett and wiggle it gently ~ it'll either crumble off in your hand or not .

Have a good trip , I just made a cross country trip in a junker W-123 and I made it , I'm sure your well maintained car will be fine .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

You can run brakes down to the friggen pads on rotors...it sounds like you are due for a rotor replacement anyway so just RUN EM!

No reason to get dicey and replace your brakes 20K before they will probably need it just becuase you are afriad you are going to put 20k worth of wear and tear on them

Remember there are ALWAYS cars out there with WAY more miles with WAY more problems doing much MORE than you are planning to do...

So no worries...there are plenty of us around to help you out

Just bring a cell phone

Don't replace your rad...give it a wiggle on the top of bottom hose and if it is good...run it.

If you start replacing things like a mad man just becuase you fear failure...you'll end up dropping 10k into your car before you know it

As far as the vac pump...updates are good...but with your low miles? Take your pick.

If murphy has been kickin' you lately...best not roll dice.