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  #1  
Old 10-24-2006, 12:50 AM
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Default 123 Alternators Always a Problem

I've just been reading some of the latest posts and many have to do with poor charging, engine overheating and loose alternator belts -- all related. The 123 chassis cars have had this alternator belt loosening problem for as long as I can remember. I had a 1977 240D that actually puked the lower alternator bolt and lower spacer while I was driving 70 MPH on the highway. Fun times.

It may sound like overkill, but I check the alternator belt tension *every* time I change the oil, and it usually needs a smidge of tightening. Over this past summer I actually removed the factory fan shroud and metal fan and replaced them with a radiator-mounted electric fan with an automatic thermo. Less drag on the engine means a bit more horsepower (which means a lot when you only start out with 67) plus now it's dead simple to access all of my belt driven components, including my alternator which still needs minor tightening about every 3K miles.

BTW, I also only use Conti V-belts which seems to help tremendously versus the cheapo belts like Drive-Rite, etc.
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  #2  
Old 10-24-2006, 05:34 AM
 
Join Date: Apr 2006
Posts: 31
Default RE: 123 Alternators Always a Problem

Solid advice. After my recent troubles I know I'll be checking my belt at least that frequently too. It's just not worth the engine melting itself into 1 peice.

Could you elaborate on the electric fan coversion you've done? That sounds like an excellent idea, but I'd have no idea where to start even. What'd the parts end up costing you? I can picture that being really pretty inexpensive.
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  #3  
Old 10-24-2006, 10:17 PM
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Default RE: 123 Alternators Always a Problem

Yeah, it was pretty easy and relatively inexpensive. I bought a 15" "puller" fan on eBay for about $100. Then, I removed the OEM fan shroud, 4-blade fan and aluminum fan spacer. I replaced the 4 long fan bolts with shorter ones in order to re-attach the water pump pulley to the pump shaft. Then I attached the electric fan assy to the radiator (some minor fab required) and hooked up the thermostat and a Bosch relay that only allows the fan to run when the engine is running.

Works great. Fuel economy increased a bit and it definitely feels like I have more power without the engine-driven fan robbing me of some horsepower. Plus now there's much more room to work around the front of the engine.
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  #4  
Old 11-05-2006, 02:37 PM
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Default RE: 123 Alternators Always a Problem

Do a search for Ford Taurus two speed fans or 3 wire fans. There many writeups on these as they can be found in a junkyard for $15. The high speed pulls a lot of air. I have one I am going to put in several of my vehicles.

K2
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  #5  
Old 11-06-2006, 11:50 PM
 
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Default RE: 123 Alternators Always a Problem

So do you mean that the MB fan is still mounted in front of the radiator? If it is, why couldn't you use that one? Anybody have input or an idea? As far as Hp increase, your right on that as a 600hp engine needs about 40kw of power for cooling.
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  #6  
Old 11-07-2006, 01:08 PM
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Default RE: 123 Alternators Always a Problem

The electric fan mounted in front of the radiator is a "pusher" fan for the A/C only. The OEM solution for cooling the engine is a regular metal fan attached to the water pump shaft that is driven by the alternator v-belt. It is the v-belt fan that we are talking about replacing with an electric "puller" fan for this upgrade.
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  #7  
Old 10-11-2009, 05:02 PM
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I have had problems with losing charge, especially driving at night, with multiple loads on the system. My belt did slip some, I've tightened it, but there's still alot of slack, and the alternator bolts are as far as they can go on the slotted mounting track. The belt shows no signs of wear, do they just stretch out? I'd rather not replace the whole alternator if it's a just a belt issue. I've probably got 3/4" slack, maybe even an inch. shouldn't it be more like a quarter inch? I saw your post that Conti v belts are superior, so I may try that before replacing the alternator.

Cheers!
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  #8  
Old 10-11-2009, 06:39 PM
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Quote:
Originally Posted by markcool View Post
I have had problems with losing charge, especially driving at night, with multiple loads on the system. My belt did slip some, I've tightened it, but there's still alot of slack, and the alternator bolts are as far as they can go on the slotted mounting track. The belt shows no signs of wear, do they just stretch out? I'd rather not replace the whole alternator if it's a just a belt issue. I've probably got 3/4" slack, maybe even an inch. shouldn't it be more like a quarter inch? I saw your post that Conti v belts are superior, so I may try that before replacing the alternator.

Cheers!
Sounds like you need shorter belt/s to begin with.
Question: Mine has 2 belts on the Alternator; does yours?

I have read of folks haveing problems with the belt that the pars store say is the correct one not fitting. It may be that some cars of the same chassie and model do not use the same belts.
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Last edited by Diesel9112; 10-11-2009 at 06:42 PM.
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  #9  
Old 10-12-2009, 02:57 PM
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I have just one alternator belt. 1983 240d, manual transmission.
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  #10  
Old 10-17-2009, 05:19 PM
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1980 Mercedes-Benz 240-Class
 
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I need to get the alternator out of my 240D, but I don't know where the bolt is to loosen the auto-tightener. How do you get the belt off?
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Old 10-17-2009, 05:19 PM
 
 
 
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Tags
190e, 1983, 240d, 300cd, 83, alternator, belt, change, lower, mercedes, mount, problems, replace, replacing, tighting, wearing


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