Brucie’s Diary: September 2014

Current mileage: 162,871


Jaguar X300 Exhaust system replacement – an update on work carried out between March and August 2012, and finally completed by the long awaited addition of a chrome exhaust manifold heatshield.

Brucie had been having trouble with emissions since I purchased him in November 2010, and I had always dreaded the MOT for this reason. For two years running he had been coaxed through the emissions test by thoroughly warming the engine before the MOT, but I felt it was only a matter of time before he failed completely. I suspected that it was something to do with the exhaust, as it could be heard to be blowing slightly, but not enough for an MOT failure.

Over a period of two or three months, early in 2012, most of the exhaust system was replaced. First the rear silencers, with the addition of nice new shiny chrome tail pipe trims fitted. This pushed the pressure back and the next thing to go was the downpipe and catalytic converter. These were unavailable from Jaguar at the time, so a reproduction part was sourced. It does the job, but doesn’t quite fit as well as the original, causing it to hang lower than it should, which now makes negotiating speed humps a nightmare! I am afraid that if I am forced over too many of these, I will have a hole in the bottom of the downpipe and be back to square one again!

Despite replacing all these parts, there was still the unmistakable hissing of escaping exhaust gases and Brucie did not go as well as my experience of a 4 litre AJ16 suggested it should.

Finally, while replacing the power steering pump, which necessitated removing the exhaust manifold heatshield, it was discovered that both exhaust manifolds were cracked. These were replaced, and the hissing ceased.

As I had hoped, Brucie ran better following replacement of the offending exhaust system components, and the MOT of the following year was final confirmation that the problems with the emissions had now been solved!

The only other item which is now obsolete is the heatshield which sits over the manifolds in the engine bay. For the X300 this was previously available in standard aluminium finish or special order chrome finish. I have only seen one X300 with the chrome finish, and it is the one I would like, as it looks far nicer, as it does on the XJ40 (where it was standard!)

I was hoping that I might be able to persuade a parts manufacturer to reproduce the chrome heatshield, as the aluminium one on Brucie was very tatty and let the car down.

Parts used included those listed below and shown in the diagrams provided by Jaguar Heritage Parts



Number on Diagram Description Part Number
1 Exhaust manifold (front) NBC 2903 AC
2 Exhaust manifold (rear) NBC 2902 AD
8 Heatshield (chrome) NBB 2910 AA



Downpipe and Catalyst

Number on Diagram Description Part Number
1 Exhaust downpipe (with slip joint) NBC 6711 CC
2 Manifold gasket (x2) EBC 9388
4 Catalytic converter NNA 6752 GA



Rear Silencers

Number on Diagram Description Part Number
2 Rear silencer (right hand) NNA 6784 BC
2 Rear silencer (left hand) NNA 6784 BC
3 Chrome tailpipe finisher (x2) NNE 6723 AA



Finally in June 2014 I sourced my much longed for chrome exhaust manifold heatshield (in mint condition) from Eurojag which I think completes Brucie’s engine bay and the work on the exhaust system!