Good day everyone,

I have a click type torque wrench that I've been trying to figure out how it works for quite some time now.

I understand how to set the torque, but i'm stuck trying to figure out how it tells me when the desire torque has been reached.

I set it to 15 nm , turned the locking nut on the bottom, and started wrenching on the gasket cover bolts. Eventually it got to the point where it was insanely tight. I loosened the whole thing and started over. Same problem.

I don't want to warp my valve cover, yet I feel like this thing isn't telling me when i've reached my desired torque.

What type of event should I expect when I get to 15 nm? I'm waiting for a "click" but it never comes

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-Typos courtesy of my mobile phone.

Is it broken? Go slow, it should feel like a notch, but it still keeps going. What model wrench is it? Set it as low as possible and try to do it by hand with an extension or something. Is it set in lb. ft, by chance? Because 15nm is like, 11lb ft. I don't think I have one that goes that low.

It could be that your wrench is not accurate in that range. Smaller wrenchs are made that measure in NM; you may need to get one of those.

Your wrench may be really subtle. On some torque wrenches the head of the wrench clicks slightly to one side when the torque is reached. Sometimes torque is reached sooner than you expect and you may not even notice the slight tilt of the head...

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1984 300D, 228k, Light Ivory, Java MB-Tex

Mine makes a slight clicking and the handle moves about 15 degrees without the head turning. You might need to take your torque wrench in and get it checked. I took one of mine in, and found it was 45% out in the low range, and 70% out in the high end... Said torque wrench is now a breaker bar. The other one was about 5-7% out through the whole range of 30-250 ft lb.

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All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

I ruined the original intake manifold on my first 87 300D by using a clicker torque wrench from Northern Tool - any setting below 20 ft/lbs would torque to double what you set it for.

My advice - for low torque settings, get a simple Craftsman balance beam torque wrench. If the clicker is a reputable brand, and not a cheap piece of Chinese junk, save it for stuff 50 ft/lbs and over.

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Just say "NO" to Ethanol - Drive Diesel

Mitchell Oates
Mooresville, NC
'87 300D 212K miles
'87 300D 151K miles - R.I.P. 12/08
'05 Jeep Liberty CRD 67K miles
Grumpy Old Diesel Owners Club

Try checking on a non critical bolt... like your license plate mounting bolts or screw. Many local parts houses have free loaners if you need a lower capacity wrench.

PS ... NO stupid questions.. only stupid answers.

If you have the huevo's to ask.. no doubt many others do too !

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

15Nm is a probably way overtorqued. Most Benz valve cover bolts are specified at 3Nm.

Concur with the beam wrench comments. Your best bet for low torque values is the beam wrench. In fact, I use a 1/4" drive beam wrench on valve cover bolts to ensure the reading is near the center of the range. All types are m,ost accurate in the center range.

I always check mine by griping the drive in the bench vise with the handle horizontal. Then I apply an appropriate weight and make sure the wrench clicks. Remember the clicks at low torque settings are often very subtle.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

Is it really only 3nm? I was pretty sure in said 15 nm in the FSM for w123s.

I ended up discovering the "notch" while playing around with it. Interesting device to say the least. It's a cheap chinese knock off so I deserve the problems I am having.

I ended up tightening the bolt just barely to the point where it wouldn't tighten any more. So far so good, no leaks and there's pressure in the case when I blow into the pcv pipe with the engine off of course.

I'll steal my dads dial wrench and take a look at the correct values.

I need a better torque wrench.

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-Typos courtesy of my mobile phone.

A good snap on torque wrench is worth the price. Check ebay and get it recalibrated after you get it...

__________________
All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

You are correct in regard to your 15Nm torque value for the W123 valve cover. I guess I was projecting the M117 engine with aluminum head that has a torque value of 3Nm. Sorry.

I think however my advice to select your torque wrench to ensure the desired torque is near the center of the range is still good regardless of whether it is a clicker or beam.

Happy Wrenching!

That is very good advice.