1984 190D - belt tensioner spring?

Hello all - I'm a new owner of a tough old 190D (223k mi. and counting) and while she seems to be running pretty stable given her age, I've noticed the alternator/voltage lite glowing faintly at idle, and found
that the main serp. belt is very loose. I tracked that down to the tensioner pully sitting fully slack, and after staring at the drawing in the service manual, said "hey, there should be a spring there." I don't know if it wasn't there when I bought it, or it sprung off to other places recently, but it's gone. The pulley looks fine, otherwise. I can move it with a pliers and tension the belt, which also looks in good shape.
Not wanting to engage the services of the local Euro auto shop to the tune of $500 or so, I've since rigged up a field repair involving some wire and the nearest bolt, but I owe it to the car to do better than that. I know the full tensioner assembly is available on ebay or the parts sites, but since that appears fine (and replacing it would require me to remove the radiator and refit the belt, a task I don't think I'm up for,) is it possible to buy just the spring? Or perhaps the better question is, what size/tension/strength spring is needed, and does anyone know of a source for one?
Thanks much, and keep on rollin' to 500k!
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Si.7k

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I doubt how the tensioner can link without the spring. Note that the spring is encolsed inside a black cover.
If you do need a new spring, either get one from junkyard or dealer. I would prefer junkyard, because you will be able to see how it goes. It is not very obivious if you have never seen it before. However, this model was not produced in large quantity and is quite hard to find. If you are lucky, find other MB diesel between 84 until late 80s. OM601 (4 cyl, used in 84, 85 190D), OM602 (5 cyl, 190D 2.5) and OM603 (6 cyl, in E300 diesel and 300SDL) all use the same tensioner.
Find an official MB manual. It does describe how to remove it. If you need any more help, drop me an email. I can send a picture or the instruction.
Silent700 wrote:

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There is no spring. The tension is SUPPOSED to be provided by the elastomer (ie a grommet) the is between the central hob and the outer portion of the tensioner. You rubber grommet has failed and the tensioner has spun on it's axis...
I bought this part from the wrecking yard here in Seattle for $75, versus $275 at the dealer (US dollars).
So far so good...
Good Luck, Marty
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Wrong... 190D has different setup from 190E.
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Tiger wrote: > Wrong... 190D has different setup from 190E. > > I guess it does, yeah. Here's the pic in the manual I'm using:
http://joybus.net/images/190d_belt.jpg
In my case the wheel (#6) swings freely left and down, resting against the coolant pump pulley (#3) and letting the belt go slack.
I think part #380 is all I need, or at least a suitable replacement. Yes, I could probably go to the dealer, but I'm looking for a $5 hardware-store option here.
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Silent700 wrote:

Wanning Tan was right. My '87 250D (OM602 engine) looks just like this drawing and has the same spring, it's covered in a rubber casing, though.
Ximinez
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$29 for the spring online... $38 at dealer... It is a very strong spring... you are not going to find anything similar at hardware store.
You probably will need the upper tensioner... the black plastic thing on the top that holds onto the spring.
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Tiger wrote:

Ah great, thanks. Do you have a source for the spring?
I believe the upper tensioner is still there - I'm using it to anchor the guy wire :)
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If you are going to order just the spring, you might as well just run over to the dealer because of shipping cost. If you buy lots of parts, then online is the way to go.
bimmerparts.com has those springs... but some other with same worldpac supplier will also have them at different prices.
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Sorry! My bad, I didn't even notice your car was a D.
I like the spring setup much better personally...
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There should be a spring there... Go to dealer and they will pull out a picture of what you should have.
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