P38 Muffler & Tailpipe/Resonator Replacement


Introduction
Parts Needed
Tools Needed
Removal of Old Muffler and Tailpipe
Replacement with New Parts
Exhaust Upgrades
More Information


Introduction
The p38 models have the main muffler/silencer (called the center muffler) just inside the left hand chassis rail under the "B" pillar. (This muffler has a heat shield on it which is liable to rattle; see cat and muffler repair page for tips on how to stop it). Early models have a single tailpipe leading across to the right hand rear of the vehicle with a resonator at the rear end. Most but not all later models have two tailpipes and resonators, one on each side of the vehicle.

I found my tailpe burnt out at the front of the rear resonator at about 130,000 miles, but made hardly any difference to the sound of the engine. Indeed, in some aftermarket exhaust suystems for the RR 4.0/4.6, this component is omitted altogether. I left the old one on for another 20,000 miles, but at about 150,000 miles the center muffler started to leak on its rear end with a noticeable sound change. I  thought I would replace both of the leaking exhaust components at once in order to avoid the possibility of an ignominious failure on an upcoming sog emission test. Replacement was fairly straightforward -- replacing both the muffler and tailpipe/resonator took me about 2 hours of unhurried work. The procedure is illustrated on the remainder of this page.  (Photo above shows early model muffler and tailpipe components courtesy of Atlantic British).

Parts Needed
Center muffler: ESR 3195 (1996-97), WCE103880 (98), WCE 104310 (99-02)
Resonator and tailpipe: ESR 3538 (1995-96), ESR4126 (1997-98 single), ESR4124 & 25 (1997-8 LH & RH dual), WDV 100250 (1999 & up single), WDV100260 & 270 (1999 & up LH & RH dual).
Rubber exhaust hangers ESR 3172 (2 for muffler, 2 for tailpipe/resonator)
Nuts 13mm (two for joint between cats and muffler and two for the joint between the muffler and tailpipe).

When looking for replacement parts for my exhaust, I called Midas to compare their prices to suppliers of OEM Rover systems. I found their parts were actually no bargain -- $317 for just the center muffler (parts only), which is available at any dealer for much less than that. Into the bargain, I doubt if parts from the generic exhaust repair facilities would be designed for maximum ground clearance.

Tools Needed
13 mm socket and extensions (a deep socket is best)
13 mm box wrench (ring spanner) optional

Removal of Old Muffler and Tailpipe
The muffler and tailipe system is connected together by donuts which come already mounted to the pipes. They are bolted together with 13mm bolts which come already permanently affixed to the donuts to prevent them turning. The nuts may be rusted and seized fairly well, especially on the joint between the cats and the muffler which gets more heat cycling. A bit of liquid wrench on the threads helps free them up, but one of mine broke off during the disassembly process. I found the other nuts fairly easy to get to except for one on the tailpipe joint that was positioned above the pipe, but could not be seen. I think it was probably put in that way from above during assembly of he bare chassis. Anyhow this nut can be loosened by adding an extension on the socket. Due to the protruding bolts, all the nuts were marginal for my shallow socket so I had to resort to a box wrench for one or two. A deep socket would have been much better.

Although either the muffler or the tailpipe can be removed or replaced independently, if you are doing both at once I found it easier to remove the tailpipe first. Once all the nuts are removed you can pull the tailpipe sideways to remove it from the rubber hangers, then extract it rearwards from the vehicle, manoevering it past the items like the rear axle that might get in the way. The same can be done with the center muffler. This is a fairly heavy item and I found it easier to remove the rear of it from the rubber hanger first, let it rest o the axle, then remove the front hanger.

Replacement with New Parts
While you are at it you might as well replace the rubber hangers and the nuts that secure the system together. These are inexpensive parts and are just as critical as the main components -- if any one of them fails you are in trouble.

If you are replacing both muffler and tailpipe, it is easier to instal the new muffler first, followed by the tailpipe. In either case, just attach the brackets on the component to the rubber hangers. Once in place you can bring the donuts together and put the nuts on, trying to get them roughly evenly tightened on each side of the joint. During the tightening process you can also rotate the donuts to the easiest position for future access to the nuts.  I put some anti-sieze compound on the threads before putting the nuts on.

Job Done!!

Exhaust System Upgrades
If you would prefer never to have to crawl under the vehicle to do this operation again, you might consider replacement with one of the stainless steel systems that are now available for the 4.0/4.6. Alternatively, if you are looking for a louder exhaust sound and a slight horsepower gain, you might try a performance exhaust system such as the Borla one shown below.

More Information
Catalytic Converter and Muffler Repair Page
Exhaust Parts section of 4.0/4.6 Parts Sources page