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Kountry 2SUM · 08-20-2017, 05:34 AM

This is always my first stop when facing yet another RV "challenge on the road. I'm a fix-it guy so I love these things because "the list" never ends.

2004 Newmar Mountain Aire 3778 W22 8.1L WH chassis

Our current "challenge"- We just launched out on a 5 week tour of the southern states from Albuquerque. Had a good service check before leaving, lube, oil, brakes, all systems A-ok. We get to Childress, TX. on our way to see the DW's sister in Burleson, TX and spend the night at Walmart. Yesterday morning I wrapped it all up and started the engine and do my normal walk around visual inspection, but when I get to the right front wheel I hear an exhaust leak. We pulled out of the Walmart parking lot and eased onto the highway but I couldn't hear the leak inside the RV. So the first bridge we hit I had the DW open her window and sure enough it was loud and clear. I can't determine if it's the manifold or the donut on the exhaust pipe flange but suspect the manifold as the sound is coming from one cylinder and not all cylinders. . So we are here in Burleson TX visiting now.

We planned to pull out tomorrow (Monday) for Destin Florida, however I would like to get this fixed before we leave. Here's my questions:
1. Does anyone know of a reputable mechanic in the south Ft. Worth area? (I've browsed the service center thread and didn't find anything)
2. Has anyone attempted this repair themselves and if so what challenges besides rusty bolts and 100 degree weather am I facing. If it's the donut that shouldn't be a major deal but the exhaust manifold is a different puppy.
3. Does the stock manifold take a gasket or am I looking at a new exhaust manifold?
4. Worse case scenario is we have to drive it in this condition. Is it safe to drive the engine like this for another 4500 miles?

Thanks for any help you can give us.

70ChevelleSS · 08-20-2017, 06:49 AM

Most likely as you suspect it's the manifold. The manifold does use a gasket, metal. It's also most likely not a gasket failure per say. The manifold studs have stretched or even broken and/or the manifold itself is cracked. I installed a set of headers on ours so I know what is involved. It's not something you want to tackle yourself on the road. You need to remove the dipstick tube from the oil pan as it runs through the manifold. You need to remove the plug wires and plugs so you don't damage them while man handling the manifold and it's possible to ruin a plug wire while trying to remove it. Then the real fun starts, you have remove all the studs and hope none snap off or are already snapped. If everything comes apart with no broken studs you can slide a new gasket in and install new studs. Any broken studs and the manifold needs to be removed from the exhaust pipe so you can access the broken stud. If it's not broken off below the surface of the head you can weld a nut on the end of it. The heat from welding will usually break it free and it should come right out. If it's broken off below the surface of the head, well that's more fun. If it's close to the surface you may be able to weld a smaller bolt to the end of it or you'll have to drill it out. Anyway it's not a lot fun and access on our MH wasn't the best. Driving as is? The hot exhaust will continue to burn away the gasket where ever it's leaking. Probably won't hurt the head as it's cast iron just try not to push it too hard, like accelerating quickly as that increases exhaust pressure and causes it to leak more.

what next · 08-20-2017, 09:02 AM

Holt Cat service on 549 West Loop took care of my DP when I had an emergency. I called after hours they returned the call in a short time. I got there at lunch next day, by 3 I was fixed and on my way. Yes it is heavy equipment repair but they had several motorhomes in. Rush truck had worked on it to the day before $ 700. Holt $350 found the electric problem and fixed. Good luck

Duner · 08-21-2017, 05:42 AM

I would get under there in the fender well and make sure it isn't just the exhaust donut leaking. Mine cracked and a chunk was missing.

Good luck,
Bill

TexasTom · 08-21-2017, 02:35 PM

I may be a little late to the party, but Lynn Smith Chevrolet in Burleson has a good reputation as being a good Workhorse service center.

boatman10 · 08-23-2017, 06:27 AM

even if its just a donut, I needed a breaker bar AND a cheater and all I could get on it, and I'm in pretty good shape.

should not hurt to drive it, accelerate slowly.

eddndee · 08-28-2017, 02:22 PM

Probably information everyone already knows but here in the northwest we have lots of mountains. If we stop after a long run, we never turn off the engine immediately because the cool mountain air against the hot manifold will frequently cause a brittle fracture to occur.
EdD
1998 Safari 2620 Class C