Exhaust leak

[Bill1947]

We are traveling from Florida to Reno and back in a 40ft Monaco Diplomat. Currently we are in Las Vegas. Coming into Vegas I heard an intermittent noise like shuffling of cards. I called a mobile mechanic and he said it is an exhaust manifold gasket leak. He said it would need to go to a shop for repair but I would be ok to finish our trip.
First, is it correct I am ok to finish my trip without repairs? And second I have a 2006 400hp ISL cummins. The mechanic said the studs would probably break when the manifold was removed. Does anyone have a range of cost for this repair?

[jacwjames]

I've read recent posts of having a manifold change costing anywhere from $2400 to $4000 but that includes the manifold, which is probably ~$1000.

Once you get home it would help if you start spraying each stud with PB Blaster, this will help them break free.

If a technician does break off a stud they will charge you for the time to extract. They will have to drill a hole in it and use and easyout extractor (or some other method).

FWIW, I changed my own manifold back in 2015, cost of the manifold was $650. Took me about 8 hours but with practice I could get that down to 4.

[jelag]

In previous repairs of exhaust manifolds on other Cummins engines we have found that heat has caused the manifold to warp... and stretch the bolt... in each case the bolt has been weakened from the hot exhaust exiting around the bolt and in most cases the bolt breaks upon removal... if it breaks off and leave a short length of bolt, we have used a pair of vice grips and have grabbed and turned the bolt loose...

There is no tension on the threads and usually a good lubricant will coat the threads and allow the bolt to be removed... if the bolt fractures off at the head... in each case we have been able to use a left hand twist drill.... and sometimes the drill actually backs off the bolt and in other cases a small easy out will back off the bolt...
We have never had an issue where the broken bolt was frozen in the head and needed excessive work to remove it... as an example we have never had to weld a nut to the bolt.... or excessively drill and easy out the bolt..
In our cases the new exhaust manifold provided by an outside vendor (aftermarket) was manufactured in such a way as to provide extra ribbing and strength to prevent warping from hot exhaust.... and the aftermarket exhaust manifold weighed 8 to 10 lbs more... Hopefully you will find a re-vised part number from Cummins, which usually means they have discovered and solved the problem

[yasbush]

A pushed out gasket on my exhaust manifold was discoved during a 21 point service by Rush Trucks. Had it replaced. $1200.00. Cat 3126E. They said it was a good catch because it could potentially cause a problem for the turbo charger. I'd get it taken care first before any trip.