How to fix a Td5 warped exhaust

Has the Td5 engine in your Discovery 2 or Defender developed a high-pitched whistle or squeal from the engine bay? If it has, the chances are that your exhaust manifold has become warped and will have broken a stud or two – or pulled the studs from the cylinder head. The squeal that one hears is the exhaust gases being expelled under high pressure through the tiny gap that has opened up between the manifold and the cylinder head.

The temperatures generated within the Td5 exhaust manifold can be quite extreme. When the engine is driven very hard or if it’s highly tuned or perhaps doing a lot of heavy towing, the temperatures become so great that the tendency for the manifold to warp is stronger than the studs holding it in place. It is most common for a stud at the front or rear of the engine to break first. A tell-tale sign will be sooty deposits around the manifold and cylinder head. There might also be a drop in performance, lower power and reduced fuel economy.

Removing the manifold 

As with virtually any job on a Land Rover, if a methodical approach is used, the removal of all the old parts should be a fairly straight forward task. There are ten nuts on the studs holding the manifold to the engine, and some of these are really quite inaccessible. But with patience, and perhaps making some stubby spanners by cutting them down to size (as shown later), the manifold will eventually come off.

Fitting the new manifold

There is no need to buy a brand new exhaust manifold for your engine, when carrying out this repair. Your local Land Rover parts specialist will probably have in stock a second hand exhaust manifold which has been machined. They will require your old manifold on an exchange basis. If not, you can take the original warped manifold to a good engineering works where they will machine the mating surface of the manifold flat again. There is a theory that once a Td5 exhaust manifold has warped and been machined flat again, it will not warp further, but I can’t confirm this. 

Time: 4 hoursCost: parts £168

Tools

General workshop tools, drill, M10 tap, welder

Cost

Exchange exhaust manifold £99; uprated manifold stud kit £60; manifold gasket £9

Contact

• BLRC www.blrcvehiclespecialist.co.uk • Alive Tuning www.alivetuning.com 

Health and safety 

• Wear protective gloves and appropriate mask when welding, drilling and grinding• Keep fire protection equipment readily available at all times • Use protective eye wear as appropriate, particularly when drilling and grinding • Keep on your toes safety-wise by seeing if you can spot our deliberate safety mistake. If you miss it, you’ll find the answer at the end of the feature• Always wear gloves on both hands when welding, to protect from sparks and radiated heat

Click on the gallery below for our handy step-by-step guide…