Exhaust Manifold Leak? 460
 

Just Wondering?

We are traveling in the family motor home on 1500 mile trip to the west.
We have discovered an exhaust leak midway in trip. Leak is for sure in exhaust manifold. Mechanic before trip replaced broken bolt on manifold. 500 miles into trip manifold begins leaking again... What possible engine damage could occur? Do we need to fix ASAP or can we limp her home????
Thanks,
Skiing in Streamboat, Co.

I don't think it will hurt anything, as long as the exhaust isn't blowing on somthing flamable. Just might be a little louder though.

always happens with the 460s just make sure all the manifold bolts are tight and try not to let the sound drive you nuts

I think everybody is right. The darn 460’s leak a lot. The old school used to think cold air could rush up the leak and warp the valve, but if you have ever ported on of these heads you would realize that it is probably a bunch of bunk. That cold air has got to get past a lot of hot metal before it can reach that valve and that air is probably going to be pretty hot when it gets there. Dirt racer is probably right to just make sure the exhaust isn’t getting near any combustibles. The only other problem that could arise is the leaking hot gasses could etch out the head or manifold surfaces requiring the surfaces to be milled. But it would take a lot of miles for this to happen. Just put up with the noise and get it fixed when you get home and good luck on your trip.

When you do get it home the best way to fix the problem is to remove manifold and gasket, clean bolts and holes, make sure manifold sealing surface is flat, Reinstall with NO gasket and use Permatex ultra copper for the gasket. The problem is that the gaskets leak and burn out. The Ultra Copper has cured my leak.

OR, better yet, get a set of pre-cut copper exhaust gaskets that wont deterate while the M/H is sitting for long spells like the old fiber & tin gaskets do.

Those exhaust manifold bolts realy should have been checked for tightness after the first good hot run time.
Neil

I got tired of breaking off manifold bolts and having to blow the broken bolts out so I use the copper anti-seize on my bolts. The only problem is that the have to be retorqued every month or so to keep the darn things from coming loose and falling out. I tried a lock washer on a couple of bolts the last time I re-torqued them. I am going to keep a close watch on them and see if it helps. My truck doesn’t have factory air so re-torquing them is an easy task. I imagine it would be a real bitch to do on a motorhome.

I used stainless bolts and nickel based anti-seize.
Hardened washers under the heads and smashed the threads a little to keep them from loosening.
At the very least there should be enough left of the head to put a wrench on if I ever have to remove them again.

may be a little late and no help with the immediate situation. my MH has had the leak in the rear bolt passenger side since I bought it "new" in 2000. It is a '94 with 80k so far so good. Small leak that quiets once warm. hope the trip went well planning same trip as kids spring break is in March next year.