Quote:
Originally Posted by tan man
I sprayed carb cleaner in that area where the manifold meets the head and the engine surges.
I replaced the vacuum hose that is in that area (both the small tubing vacuum hose and the shaped rubber hose that goes from under the manifold to the Throttle body). Therefor I am pretty sure the leak is coming from where the intake manifold meets the head.
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The hands down best way to find a vacuum leak is with a smoke machine. See if your local MB indy mechanic has one.
You must replace ALL ALL ALL the rubber vacuum parts in the engine compartment. There are a bunch of tees, Y's, and short pieces of tubing all over the motor. Track them down and replace them all. The vacuum systems diagram on EPC shows where the vast majority of them are. All the vacuum parts can be ordered new from MB.
Quote:
Originally Posted by tan man
My question is how do I tighten the manifold bolts (Allen head). First, it seems there is only one bolt between every other cylinder (spaced quite far apart - how does it manage to keep a tight seal). Second, it seems to be impossible to get to. I couldn't manage with any of the flex attachements I have.
If I manage to tighten the manifold bolts and it doesn't cure the leak, Any advice would be welcome.
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Huh. This is a tough one, sho 'nuff. I did mine on the bench when I had the head off the motor and even then it was gnarly. Don't do this job around women and children - causes lots of blue air in the garage. You can use a ball-end Allen wrench or ball-end Allen socket bit on those bolts. What I did was got disgusted and threw out those dang Allen screws and replaced them with regular Murrican 8.8 hex head bolts because with those you can use a socket and universal and no more Allen bolt foolishness. A shop-originated engineering change order, if you will. Another trick is to take a ball-end Allen wrench of the right size, cut the ball end off with about 1" of hex using a Dremel tool, then use a 1/4" drive 6-pt socket on the cut-off Allen wrench and then drive that using universals, extensions, and your torque wrench. So visualize a 1" long straight Allen wrench without the hook end and with a ball end. Make sure you buy the best quality Allen wrench you can. This is no time for a Harbor Freight 99-cent special.
Make sure you lube the bolts slightly when assembling and use a torque wrench that is within the correct range, i.e. within 20% to 80% of the wrench's scale for a clicker-type. (This isn't an issue for the beam pointer type of torque wrench.) Hope this helps - let us know what you find.