m a x i m u s

OK, here goes. I've changed my oil on the C63 many times, but this afternoon when I went to replace the filter housing cap with my torque wrench set to the usual 18.4 ft-lbs, I ended up going too far and breaking off the little lip on the filter cap that touches the engine. WTH? Unless my torque wrench decided to take a dump since a couple weeks ago when I used it on my brakes without incident, I can't understand how this can happen. I bought the filter from the dealership for the first time, and am wondering if they somehow gave me the wrong one and so the whole thing wasn't sitting properly depth-wise which led to over tightening (I'm going back to the parts Department tomorrow, since I now need a new filter housing cap). Besides the usual flaming that I know we are all great at here (myself included), does anyone have any helpful insights? Thanks.

JimmyR

Trying to recall if there is a rubber O-ring as part of the kit? Could you have left the old one in the cap and tried to tighten down the filter cap on the new O-ring?

Merc63

^ that would make sense, or it was fitted in there properly and sticking up too high. You don't need a torque wrench for that, just tighten it by hand till she is nice and snug.

Mr. Lin

there is an o-ring with the new filter, but with the effort it takes to slide the new ring into place, you'd have to really space out not to see that it wasn't seated properly. stranger things have happened i'm sure, so it's not outside the realm of possible

m a x i m u s

No, I replaced the old O ring with the new one (in the top most thread of the cap). I use torque wrenches bc I have a bad habit of overtightening things. So much for that fail safe plan.

m a x i m u s

Thanks, guys. I'm gonna swing by parts in the morning and verify it's the correct filter element, and pick up a new cap. Fingers crossed that it's in stock. And I'll be hand tightening this thing going forward. Never had any issues with my handy torque wrench in the past, though. Ho-hum.

Diabolis

Even with two o-rings you still wouldn't break the housing if your torque wrench was set at the right torque. I suspect something wasn't sitting properly, or maybe the plastic just got too brittle over time.

Be careful with hand-tightening... I've been known to overtighten things by hand a LOT more than needed and break things or strip threads. 25 N m (or 18.4 ft lb) on a torque wrench is still the safer way for me.

jmueller

Could it just be the engine heat degrading the cap? It is made of plastic or some sort of resin if I recall correctly.

layzie12g

If you over tighten things, just quit doing it. Its that simple. Learn to get a feel for what you are doing, and you won't have to worry about it. Relying on a toque wrench for everything will leave you in these situations. When people rely on a torque wrench for doing stuff that does not need to be torqued you never get the feel for what you are really doing. Then you will never have the "feel" when something is not right, and you keep going till the wrench clicks and by then its too late.

otakki

Torque wrench can also be the problem. I stick with a couple of old-fashioned Craftsman beam type torque wrenches because I know for sure there is nothing to break or malfunction.

Diabolis

Gents - I completley agreee that one should get a feel of how tight a particular screw fitting may be... what I meant was that the "hand feel" method is quite unscientific at best, and can lead to problems down the line. Among other things, how tight a particualr screw, fitting or cap feels depends on how greasy and tired your hands are, or how wide it is as you're applying a lot more leverage over a larger radius like the oil filter housing cap (and thus torquing it down more) vs. a narrower fitting. All I am saying is - if the application calls for a specific torque spec, if you have the tools, do it properly - whether it's wheel bolts or the oil filter housing. Yes, the idea is to get it "almost there" by hand and make sure that it goes on smoothly and that nothing is cross-threaded, but I would discourage you from cranking it down by hand.

Evileight

I would say engine bay temps could be hurting the plastics over time. This was a big problem in my FD3S RX7. Had to replace everything rubber and plastic in the engine bay over time. I can check and calibrate your torque wrench if you are worried about it.

layzie12g

On wheels and engine assembling a torque wrench is a must. Putting spark plugs in a direct injected Benz engine is a must. An oil filter is not one of those times.... I'm going to have to agree to disagree with you on this one.