Q about frequent parts failure underhood

Hi all,

I'm seeing what I consider abnormal parts wear, particuarly on rubber items underneath the hood of my 16v. In 5 years I have had 4 alternators, 3 belt tensioners and 4 tie rod bushings (rubber bushing under exhaust). None of these parts were purchased from benz, but all rubber was OEM. I do have Euro headlights, i'm not sure how much this might affect the alternator.

Could high temps be to blame? My 16v never overheats, but I can't help but note how close the alternator and the tie rod bushings are to the header.

Any thoughts?

cheers,
dan r.

ps. My alternators (3 are rebuilt bosch through an indy shop, one by a local repair house) have been failing JUST outside the 1-year replacement peroid. I suppose this indicates they are exceptionally well designed

[Mike Murrell]

Dan:

If I read it right, your alternators were redone locally and were not true Bosch reman units.

I've had one experience thus far with a Bosch reman alt. - installed about 2 yrs. ago - still OK.

I would wonder about the quality of the parts your local guys are using and/or just how much of a true rebuild is being done?

I got my Bosch reman from a local parts house that specializes in european parts. I pulled off the old one and took it in so that it could be matched up.

My 2 cents.

[Hatterasguy]

Their is a difference between local rebuilt and a Bosch rebuild. Another member was having problems with the local shop using crap parts to rebuild the alts.

What exactly is failing on the alternators? Are they failing to charge, or are the bearings going bad?

The Bosch rebuild on the SDL is doing fine, after about a year. (knock on wood)

Thanks for the info guys,

I am not sure what the brand/lineage of the original alternator was. The second one (to my memory, this was a few years back) was sold as a 'bosch rebuild', as in, it came back from bosch, who rebuilt it. The third was a local shop and the third I left to the discretion of the shopforman; he's a factory trained tech and agreed that they are not all made alike. I'll ask him what kind of parts he uses after I pick the car up when its done-its getting one put on as i type.

I'm not sure what the symptoms of failed bearings are; the 16v has a meter-you can watch the volts slowly drop to zero as the alternator fails.

Nobody has a problem with the rubber parts failing so damn frequently? Looks like this 'hot-underhood' theory might be a non-starter (no pun intended).

cheers,
dan r.

[oxymoron]

You're right.
It's never-ending. I have a 6.9 and the starter is right beneath the passenger side exhaust manifold. The last Bosch brand-new at 750 American dollars lasted about 15 mos.
All my vacuum lines and lots of the rubber goes crunchy after a few years.
A black car and Houston summer (11 months) doesn't help either.
Open the hood on a summer day after a drive on the freeway and it's like sticking your head into a barbecue pit. MMMMM barbecue.

My car's in the shop getting painted and I am going to have the bodyman work some kind of way to exhaust the heat that builds up with no place to go.

I have seen a 107 (the famous green AMG w/a 7.3) that has fender louvers and they don't look too bad. I really don't care what the originality police say anyway.

I think a hood louver might just dump all the hot into the ventilation intake at the bottom of the windshield so that's probably not good.

Lower underhood temps result in more power, so there's more than one reason to look for relief here. I have been thinking inner fenders exhausted to wheel wells, but keeping wet out is always part of the problem for engine vents.

Finding a cosmetically acceptable solution is difficult.

Daaaaaang! I was thinking a radical solution might be to wrap the exhaust manifold, and you're talking louvers! I'm impressed. I understand the passenger engine mount on the 300/320E tends to fry because of the exhaust manifold heat as well. The hood-pad on mine is certainly cooked as well.


cheers,
dan r.

Even if it is hot, i bet that black looks nice on the 6.9

[oxymoron]

header wraps or jet hot ($$$$$) is a good idea to improve efficiency, but exhaust is only part of my issue. idling in summer, the air being drawn through the radiator (right in front of the air cleaner snorkel!) is so hot, you can't hold your hand in it.

I re-routed that pretty early on.

I have some pics, I'll put up a gallery later.

[mctwin2kman]

Take off the Clutch type cooling fan and put in an electric that kicks on a hair earlier. Wrap the exhaust manifold or Jet Hot Coat it. Also make sure your sound deadining panels under the engine are on. They help air flow past the engine while at speed to cool it. Instead of the air going down and under the car they force the air to exit by the tranny tunnel and thus keep it flowing directly past the engine.

[oxymoron]

starter location proximity to exhaust manifold

[oxymoron]

[Hatterasguy]

Oh my! Talk about no clearance! I'd Jet Hot coat those manifolds for starters. Then maybe look into making some sort of heat sheild?

[simmo300e]

i know all about that barbecue pit feeling - in my 300E if I open the door I can feel the heat coming out from under the car. As for the heat affecting rubber parts, I replaced the belt tensioner when I bought the car about two years ago, it needed replacing again after 18 months because it was all out of adjustment. Not sure how long the new one will last but it stills seems OK.

In Singapore - equally hot - I have seen 124 model taxis with front fender louvres, these are Mk II models (post 92) but I don't know if they are diesels, special models, tropical spec or whatever. I have a vague recollection that they might be a special model but the louvres look kind of cool and if they are factory spec, there must be a reason for them.

[G-Benz]

Originally Posted by Dan Rotigel

In 5 years I have had 4 alternators, 3 belt tensioners...

...Any thoughts?

I condensed your quote specifically to address the alternator and belt tensioner replacements.

While it may be true that some remans are better than others, the belt tensioner replacement intervals seems a bit odd...have you considered the possibility that the belt tension might be overly tight? Perhaps causing premature bearing/pulley failure on both the alternator and tensioners?

[haasman]

dan r

Do you park your car in a garage? Are there appliances in there such as an old freezer or refrigerator?

Haasman