Discovery 2 Noises - Not Serious, But Would Like To Identify - Please

[rjsdavis]

Dear all

I have two noises and another separate quirk that I am trying to identify in my Discovery 2 TD5 (1999) with an auto box;

1 - When moving off from the stationary, there is a distinct "hiss" which is related to the throttle and throttle use. If moving off from stationary, it will last about 1-1.5 seconds and then disappear. It won't come back unless I idle and lose speed, and then use the throttle again - when it will briefly (less than a second) re-appear, or if I go back to a full stop and start off again. Should it do this? My 300 Tdi never made this turbo hiss type noise!

2 - When moving at low speed and higher torque, i.e. moving up a hill slowly, there is a rattle coming from underneath the car. It only happens between 1750 & 2500 revs, and only at low speeds. It does happen in the same rev range on the flat, but is less noisy. It dissipates largely when the car is very warm, and has been running for 30 minutes or longer. Any ideas?

3 - Just a niggle - she can sometimes be slow to change up properly to 4th gear. She should move upto 4th at about 55mph, and will should drop down to about 2,000 revs. However, whilst she is cold, she will change up, but the revs only drop down to just below 3,000 revs. It can take anything between 10 - 25 minutes before she is warm enough to fully drop down in revs at 55-60mph. Any ideas?

Thanks so much in advance to anyone kind enough to reply.

Richard

[BogMonster]

Not sure about 1 - possibly a split turbo or intake hose somewhere? but I would expect the hiss to continue... another possibility (less likely) is a leak in the intercooler somewhere.

2 - possibly something loose in the exhaust system, I have seen Td5s making this type of noise and it has been something loose inside one of the silencers. Can you reproduce it by revving the engine with the vehicle stationary?

3- it sounds like the in built delay in the torque converter locking up, my V8 does the same. I think the electronic auto box is programmed to hold on to gears slightly longer and not to allow the torque convertor lock-up to operate until the gear oil has had a chance to warm up. My V8 does this but it only lasts for a few minutes (usually until about the time the engine reaches full operating temperature) and then it behaves normally, though it does "go better" after 10 or 15 minutes once the auto gear oil is right up to temperature.

[mcw]

I would like to comment on the second problem item with the rattle, you are suffering with identical rattle to our newly purchased td5 ser 2 2001, we have just recently taken our l/r in for diags on the rattle.

The garage have told us that, where the down pipe(manifold) meets the the first box section there is a coublin device that allows for movement in the exhast, this is beginning to break down and two metal components are rubbing together.

The cheapest price for the front box section is £87.00 + vat online from britpart +gaskets are for joints are 0.20p each approx

We are off to watch the world offsore power raceing in isle of weight this weekend, so i hope it should not give us grief as this is the first time since having the car that a large distance will be done.

best of luck

mcw bridgwater

[rjsdavis]

I would like to comment on the second problem item with the rattle, you are suffering with identical rattle to our newly purchased td5 ser 2 2001, we have just recently taken our l/r in for diags on the rattle.

The garage have told us that, where the down pipe(manifold) meets the the first box section there is a coublin device that allows for movement in the exhast, this is beginning to break down and two metal components are rubbing together.

The cheapest price for the front box section is £87.00 + vat online from britpart +gaskets are for joints are 0.20p each approx

We are off to watch the world offsore power raceing in isle of weight this weekend, so i hope it should not give us grief as this is the first time since having the car that a large distance will be done.

best of luck

mcw bridgwater

For those that read this thread - all three problems have been identified and resolved (well sort of!)

1 - Hiss was caused by a leak / crack in the flexi-joint on the old exhaust downpipe. Hiss has gone completely with the new pipe that has just been fitted.

2 - Rattle has been identified as also being the downpipe as I suspected. However, I got a replacement from a salvage specialist, and whislt it cured No. 1 - it still rattles (which you couldn't tell until fitted), therefore still have the torque rattle. At least I know what it is now though.

3 - Completely cured by filter a new transmission filter kit and new gearbox fluid. It will happily change up to final lock-out at 55mph, when still only a quarter of the way on the temp guage on the dashboard clocks - which is excellent news.

Anyone got a good downpipe for a non-cat TD5?

[gotto]

Hi, newbie to this forum but am wondering if my problem can be related to this... I have a 2003 TD5 Disco II and lately noticed a booming noise coming from the exhaust pipe when accelerating. It only occurs at ± 100-1100rpm and then disappears. My local LR agent recons it is a common problem but I have yet to hear of any other Disco’s with the same issue. Apparently this is caused by sound waves at a resonant frequency and is cured by replacing the down-pipe. Could it be a similar problem to the one described and do you concur with the fix? Why would it be only noticable after 115,000 km's? Your advice will be appreciated.