Celtic Safari: Engine - Exhaust Tailpipe Replacement

New tailpipe in place for 1996 Safari Sahara motorhome.

Fortunately, most parts for my 1996 Safari Sahara motorhome are standard RV or medium duty truck components. Every once in a while a custom part has to be replaced, and that is when you are reminded that Safaris are no longer in production. The 5" tailpipe for my Caterpillar 3126 diesel engine is one of those parts.

Old tailpipe and stainless exhaust tip.

From the muffler, the motorhome's exhaust pipe takes a 90-degree bend toward the side of the vehicle. Fabrication would seem pretty straightforward with a 90-degree elbow welded to a length of straight pipe. Complicating matters is the position of the Onan generator's muffler. As a result, the elbow needs to accommodate a 3" drop in order to provide clearance for the generator's muffler.

The elbow and the straight section make it a custom part.

The photo below shows the corrosion that led to the replacement of the tailpipe. A hole had developed where the tailpipe mated with the exhaust tip, and the bottom section of the tip was being eaten away.

Old tailpipe and exhaust tip showing corrosion.

Once the muffler clamp was removed, I used a rubber mallet and the leverage created by the 90-degree design of the tailpipe to ease it out of the muffler.

Tailpipe removed.

In case you're wondering, the Caterpiller 3126 isn't new, only the paint is. A practice I developed working in the engine compartments of yachts is to keep everything clean and painted so you can notice and track down leaks more easily. Because the motorhome's engine is exposed to road grime, unlike a yacht, I pressure wash the engine once a year and touch up the paint.

Fabrication

I took measurements of everything from the length of each section, to how much drop (3" in my case) the elbow provided. In the end, I decided it was best to hand the old tailpipe over to a muffler shop with an order to replicate it. I removed the stainless steel exhaust tip before delivery.

New tailpipe.

The muffler shop did a great job. When it came time to reassemble the system, everything fit and the clearances were spot on.

New tailpipe showing 3" drop.

In an effort to extend the life of the tailpipe, I primed it with 2000 degree Rust-Oleum and painted it with 2000 degree Rust-Oleum.

Installation

I installed the tailpipe first. My method involved inserting the tailpipe into the outlet of the muffler and then using a rubber mallet to slowly ram the tailpipe in until it seated against the stops in the muffler. Progress would stop if I got the tailpipe and the muffler too far out of alignment, so my mallet strikes tended to go around the tailpipe. Once the tailpipe was seated, I installed the muffler clamp.

Evidence of rubber mallet blows on the elbow.

The stainless exhaust tip was placed onto the tailpipe using the rubber mallet. Care had to be taken not to deform the tip. The exhaust tip is held in place with a stainless steel clamp.

New tailpipe and exhaust tip installed.

Cost Summary

Custom fabricated tailpipe by Hazel Dell Muffler & Brake $214
5" Heavy Duty Saddle Style U-Bolt Muffler Clamp with Anti-Rust Coating $13
AP Products CTD-5000 Stainless Steel 5" Turn Down Exhaust Tip $89
Rust-Oleum High Heat Primer, $7
Rust-Oleum High Heat Paint, $7

An alternative installation would have skipped the exhaust tip, and just focused on having the straight portion of the tailpipe cut longer. Here's another Safari owner's exhaust system project that shows the tailpipe without an exhaust tip:

http://kareninthewoods-kareninthewoods.blogspot.com/2018/02/motorhome-modifications-m-is-for.html