# Torque wrench a necessity for DIY? (oil change& drive belts)



## Andyjoe (Apr 5, 2010)

Just bought a 2003 330ci

Going to take a stab at doing some DIY with a oil change and drive belts replacement, looking at some of the DIY online, they mention a torque wrench. Is this a necessity? 


(Note: I have little if any experience working on cars)


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## Llarry (May 17, 2002)

Particularly given your last sentence -- Yes, a torque wrench is necessary.

A finely-calibrated sense of torque in a very experienced mechanic is one thing, but for those of us who are inexperienced or mere mortals, consider the possibilities: Under-topqued fasteners that come loose or over-torqued fasteners that break in two.  Bad -- very, very bad!


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## compusatman (Apr 14, 2010)

AndyJoe, I second the last post. Learning the fine art of backyard wrenching on an M3 is...well...let's just say...a risk. To be quite honest, just jacking the M3 up in the air takes a rocket scientist. It is too low to drive up a set of ramps. So a custom ramp has to be made (I'm in the middle of that now). There are very few qualified points of structure in which to rest a jack stand...only a very few. And please don't trust a floor jack to support the car whilist you change the oil. You do have a floor jack don't you? That should have been purchased before the torque wrench. I'll leave you with one motivating reason to be a DIY Beamer owner...my son plays college football and I am no weakling and it was all he could do (and with a breaker bar) (essentially a fulcrum point) to break the lug studs loose so we could install the Michelins we bought from Tire Rack. It seems most (my experience) non BMW Dealer tire dealers regardless of tire brand employ people who think the torque spec' of a lug nut/stud is 200 ft. lbs. In reality it is about 40-50 ft. lbs. In other words, my wife could tighten them to spec' by hand and feel safe. That's why you need to be a DIY'er and that's why you need a torque wrench. I won't even get into why it is an accident waiting to happen that the BMW uses lug studs instead of lug nuts. Suffice to say if a stud were not removable it would be a nightmare. Buy yourself a floor jack, some 4 ton jack stands and a good clickable torque wrench...otherwise take it to the dealer. Tools ain't cheap.


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## JimD1 (Jun 5, 2009)

I use an inexpensive torque wrench from Harbor Freight when I change oil in my e88. They cost about $20 each on sale and I have a 1/2, a 3/8, and a 1/4 inch. The 1/2 is good for wheels (which I also do with a torque wrench on vehicles with aluminum wheels). The 3/8 is good for the drain plug, spark plugs, etc.. The HF torque wrench is not what I would call a "good one" but it is good enough IMHO. I have rebuilt engines and transmissions so I am a fairly experienced amateur but I want a little more insurance I am not under or over torquing so I use an inexpensive torque wrench. I also use a cap wrench from Bavarian for the oil filter housing - it was also around $20. The cap wrench happens to have the same 17mm size as the drain plug. 

I think the spec for the lug nuts is closer to 90 ft. lbs (86 comes to mind) than 50 but I would need to look to be sure. I agree that dummies with impact wrenchs are a menace and should not be allowed near nice cars. I have resorted to stomping on a break over bar before and even getting a section of pipe to slip over a bar when dealing with the results of an impact wrench.

Jim


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## compusatman (Apr 14, 2010)

Actually, I have changed my mind. The torque wrench should in fact, be your first tool purchase. Because even if you never buy another tool and never become a DIY'er and never intend to be anything except the fighter pilot, you still need to check the torque on your lugs after you have wheel service. My BMW (Mercedes and Porche) dealer is the only group of mechanics I have ever seen regularly use a torque wrench when reinstalling wheels. And Jim, you are correct, according to "Pinecone" it is BMW spec 88 ft. lbs.


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