Mattyb123 wrote:

Your a landrover god Valhalla

My rubber sealer was missing.

All fixed now.

Thanks again

Matt

Valhalla wrote:

As one of many things to check, it is easy to view and fix a problem that many TDV6's had with their intake trunking around 2006-2007. The symptoms of the problem are that the customer complains of poor low-speed turbo pickup, also poor performance below 2250rpm, and hesitation after changing-up a gear (especially manual Tx cars). Together with these complaints, there is a characteristic absence of smoke during any manouevres, and the car may even be cleaner than normal. They are all typical of a MAF meter reading lower airflows than true. Sometimes the car will have had several replacement MAF meters fitted to "cure" the problem - sometimes genuinely so, but for the wrong reason as I'll explain;

The MAF meter reads the airflow at the aircleaner box, so if a "hole" of some description appears between this and the engine, the airflow will read low at the meter, but actually be correct at the engine. This leads to the symtoms above. A common "hole" that is part of the design of the TDV6 is the junction between the upper and lower clean-air ducts to the LH side (as viewed from the driver's seat) of the fan cowl. This cowl is often removed to service the front of the TDV6 engine, which contributes to issues "down the road". The two parts of the duct should be jointed with a rubber fir-tree section seal, as shown in the following photo (upper duct removed);



The arrowed joint is made of a female section in the upper duct, a male section in the lower duct, and the soft rubber seal sandwiched inbetween. Problems arise from any of the following;
a) The upper and lower radiator fan cowl parts move apart (unclip) so pulling the clean air duct apart with them
b) The upper clean air duct is not secured down to the upper fan cowl with the two Pozi screws, so the upper duct can "float" upwards in free air
c) The lower clean air duct becomes insecure from the lower fan cowl (most likely) and therefore is unable to react securely when the upper duct is pushed down over it after your local friendly garage mechanic has finished his/her service
d) The rubber fir-tree seal is dislocated/missing from the male/female duct joint

The fixing problem mentioned at point c) is due to their only being a single fixing to secure the duct (arrowed in the following photo);



This has to secure the duct to the lower fan cowling, and the opposite side of the duct is only located by a peg that slides back into a channel - often as not this is not anywhere near the channel as shown here;



The solution is to secure the lower duct with a second self-tapping screw, and also to smear silicon grease on the rubber fir-tree section seal. This ensures that the joint between the upper and lower clean-air ducts can be made correctly, and without dislocating the rubber seal on assembly. As a belt-and-braces, the two halves of the duct can be secured with a screw through the male/female joint - this is difficult to access, and extra, extra, care has to be made that nothing can drop into the duct (nothing to stop debris hitting the compressor wheel from here!!!).

Some cars suffered a very bad problem, where the MAF meter was correct in the workshop, but was poor on the road. This was the effect of the duct joint opening-up on the move, partly due to vibration and dislocation of the radiator cowls whilst driving, but also due to the engine lateral rocking under load (during acceleration / deceleration) dragging the lower duct up and down to loosen the joint.

So why does changing the MAF meter help to "cure" this problem (temporarily)? What happens is that the upper duct has to be disturbed to fit the new meter. If the mechanic does not notice that the upper/lower duct joint is poor, it will go unfixed, but the action of pushing the duct back down to the radiator top cowl will "fix" the joint for a few miles.