Alternator and fan drive belts off car: can I start the engine? - PeachParts Mercedes-Benz Forum

HuskyMan · #1 08-17-2016, 02:59 PM

I turned the drive pulleys on the alternator after removing it from the car to check it. It drags quite a bit in two different places, no doubt the alternator bearings are toast. I then turned the cooling fan on the engine by hand and it appears to turn freely. I'm wondering if I can start the car and let it run for only a few seconds to listen for any unusual sounds? I'm 99% sure the previous squeal/smoking drive belts were due to frozen alternator bearings.

leathermang · #2 08-17-2016, 03:22 PM

A few seconds will not hurt it.

Mxfrank · #3 08-17-2016, 03:25 PM

That's my first step in diagnosing odd noises. The engine doesn't care about the alternator, AC, or power steering. And it takes a few minutes to overheat even without the engine fan and water pump. So go right ahead.

DeliveryValve · #4 08-17-2016, 05:00 PM

Sure. I've driven 10 plus miles without an alternator and with a shoe lace acting as a belt to spin the water pump from the main pulley. Had to do this because the alternator seized up.

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leathermang · #5 08-17-2016, 06:54 PM

I think cars should be designed to where the water pump is run by belts not running anything else.....and two should be used so the side pressure on the water pump shaft can be minimized ... but I am old and increasingly interested in not getting caught out on the road... here in Texas that can be life threatening in and of itself in the summer...

jay_bob · #6 08-17-2016, 08:16 PM

The OM60x have a serpentine belt (so you lose everything at once if something breaks) but at least they dual loaded the water pump pulley. And they put it close enough to the crank pulley that you could "run it on a shoestring" if you had to.

Pretty much every modern engine has gone to serpentine belts.

leathermang · #7 08-17-2016, 08:32 PM

Has anyone tried.... or carry ... Linkbelts to use for an emergency like running the water pump..... I don't have shoe strings handy all the time....Have heard of a woman's nylon being used... but don't have those in an emergency either...

Skippy · #8 08-18-2016, 07:36 AM

I've seen linkbelts in the military. They're better than nothing, but I don't know how long they hold up.

For the OP, yes you can start the engine and let it run at idle briefly without any belts. I wouldn't do it for more than a minute or two.

DeliveryValve · #9 08-18-2016, 03:25 PM

Quote:

Originally Posted by leathermang

Has anyone tried.... or carry ... Linkbelts to use for an emergency like running the water pump..... I don't have shoe strings handy all the time....Have heard of a woman's nylon being used... but don't have those in an emergency either...

Come on Greg. Just go to your local Walmart/Target/etc, buy a pack of 99 cent shoelaces and throw them in your glove compartment. Forget about them until they are needed. The pack is small so you don't even notice them in the compartment.

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leathermang · #10 08-19-2016, 02:52 AM

Quote:

Originally Posted by DeliveryValve

Come on Greg. Just go to your local Walmart/Target/etc, buy a pack of 99 cent shoelaces and throw them in your glove compartment. Forget about them until they are needed. The pack is small so you don't even notice them in the compartment. ....

I hate to say this for fear of offending someone.... but I really do not trust the shoestring fix for getting me home without overheating the engine... But in thinking about it... I would trust these.... But I have AAA and have trouble bending over now....

Springfield Leather Latigo Indian Alum Tan Boot Lace 1 8" x 108" | eBay

Charlie Foxtrot · #11 08-19-2016, 08:22 AM

I have a friend & client in his late 80's who drives 70k+ miles per year in his 85 300SD's (he has several). He is somewhat ambivalent about critical maintenance. I packed a Rubbermaid tub w/belts, filters, fluids, chocks, jack, flares, jumper cables, charger, extension cord, tool kit & a six pack of water.(He would prefer Red Bull.) I shoved this tub in his truck along with two full size spares. Over the years the most common failures (in order) have been alternator/water pump belts, plugged fuel filters, dead batteries & flat tires (punctures). The most predictable failures have been belts. Every time he is in town, I pop the hood & check the belts. The pair that drive the alternator & water pump take a beating. My guess is the uneven tension from running a pair of v-belts causes early failures. I don't seem to be able to get matched pairs easily. My advice would be to replace the belts every 20-25k miles. I get good results with Gates, Dayco Top Cogs, and Conti.

In answer to Husky's question: Yes, you can run the engine for a short time (a few minutes) w/o belts. My high mileage friend drove his 85 300SD into the shop w/busted belts last week (about 10 miles at 50+mph, 90F ambient). He didn't want me to tow it. I wouldn't have done that, but he got away with it.

DeliveryValve · #12 08-19-2016, 11:51 AM

Quote:

Originally Posted by FromTheLongLongAgo

I just keep an extra set of belts in the spare tire tub.

Lance, that works too. But I have to say it's useless if you froze your alternator.

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DeliveryValve · #13 08-19-2016, 12:05 PM

Quote:

Originally Posted by leathermang

I hate to say this for fear of offending someone.... but I really do not trust the shoestring fix for getting me home without overheating the engine... But in thinking about it... I would trust these.... But I have AAA and have trouble bending over now....

Springfield Leather Latigo Indian Alum Tan Boot Lace 1 8" x 108" | eBay

Point of reference for you Greg. I had to resort to this trick twice in my driving experience.
Once in the 1990's in my Volkswagen driving across the US, in which I threw a belt that operated also the alternator and water pump. I too had AAA, but was in the middle of nowhere and didn't want to wait a long time for a tow. I resorted to the shoe string and drove approximately 50 miles to the next repair station where the tech threw on a belt for me with little downtime.
Then most recent was in 2007 when the alternator on my 300D froze. Drove home when it was getting dark. Headlights operated with the battery and all was good making it home. Here are some pics from a past thread.

Based on my experience on driving 60 plus trouble free total miles on shoes laces. I sure do believe and have trust in this method.

Now eBay link you provided with the leather shoe lace, yes it would be stronger. But it does not have the stretch and recoil, if you will, that a nylon shoe lace has. This action would make the shoe lace very tight on the pulley and I would be concern about tying a knot tight on a leather lace.

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