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screeching/ whinning noise!!

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hi all,

having looked through and through the excellent tech archive reading carefully the posts by both les and white 90 but i cant quite put an end to it,

i have a 300tdi 90 with 160000 miles, i have 35" tyres and struggle to get 60 on the A9 on the flat is this normal with tyres like this? my old 300tdi would do 85 with 265/75s!!!. When excellerating hardish through every gear from half way up the rev range to full it screeches like crazy somewhere from the front! i have checked ujs/ props/ transfer box/ diffs/ its not a belt noise i dont think.

i have stripped all the pipework of from turbo to intercooler to inlet manifold and cant find any splits, the intercoolers fins are corroded and flakey but the main frame looks good, the only thing i can think of is the wastegate seems very hard to move by hand and seems rusty squeeky when moving with a small pry bar, if it is not moving would this create this noise? other than that the boost pressure pipe that runs from the actuator to the turbo looks good but doesnt seem right the clamps either end dont seem over tight and dont want to be tightened any more.

any help would be great

thanks jack :)

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Waste gate pipe perished on mine allowing all the boost to not be limited

the opposite to the effect you describe as it was getting to nearly 2bar

Disconnect the waste gate and try a drive, ensuring the W/G is closed(to discount this item)

you may need to turn the fuel pump up a bit (also in tech section) to increase power a tad.

Screeching when I had it was a connection on the hose on the turbo

the pressurised air was escaping when the jubilee clip failed

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right ok,

so i disconnect the small clip that holds the bar on then do i need to tie the W/G shut with wire or something similliar to keep it closed? closed is towards the front right?

the silly little metal grips that hold either end of the short hard plastic pipe (not rubber should it be?) dont seem fanatasticly good ive tryed the washing up liquid trick but cant see the engine end as the inlet airbox pipe is in the way!. lol but still dont see any thing wrong, though i geuss its happening at pressure, ile try the W/G thing now.


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yep thats those clips, the pipe is a hard plastic and im wondering if it should be rubber, i cant see how it would get as good as seal to the 'brass' turbo pipe one end and the actuator at the other as it would if rubber.

i cant seem to get the wee clippy of the rod to test the W/G any pointers? theres no doubting its a pig of a place!!!!

the noise as you say is most odd! it is a screech almost like a bearing is guna give up, or air screaming through a hole, very loud and only when you have a load with power. would i be better to try to get hold of a new pipe in rubber for the turbo and fasten it good, then if nothing try the rod? just im sure if i get the clip of ile never get it back on.

thanks jack.

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Jack look at the intercooler pipe on the bottom connection of the intercooler itself this is where my clip failed

it wasn't easy to see and only happened under load

the clip on the waste gate is a sprung steel C clip that can:

break when you remove it

Fly off and disappear

a small screwdriver from underneath the car when the engine is cold is the best way I can suggest.

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aha aha, white 90 you beauty, were getting somewhere. lol

right i got the c clip of and tied the wastgate back to the bulkhead so its closed, (not as i put above ^^ to the front) took it for a blap up the road and no noise, just a lovely turbo whistle and the tyres roaring,

now what do i do?? new actuator?

many thanks tony.


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a test of the wastegate first

you need to get 15-20psi into the tube going into the wastegate

to see if it is operating or allowing air to escape

I'd suggest the tube you have is leaking or split or just not sealing properly

far cheaper to get a new pipe/clips to try

a wastegate is spendy and not a lot in them to go wrong.

can you rig a new pipe of any suitable material and jubilee clips as temp fix to try?

as for testing the wastegate I just my tyre compressor to see if it was ok briefly so as not to damage anything.

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i am on the case as i write following up some piping, but when you want something it never appears.

being so close to the turbo itl hae to be sturdy stuff.

i will get a new pipe and fit it and then try another test,

possibly thinking of fitting a boost gauge to monitor things from now on.

you think i should put a tyre gauge compressor on one end of the pipe

and see if the actuator moves the rod as to open the W/G? though carefull as not to damage.


ive seen that thread where you had that problem and, have checked the inlet manifold gasket yep and its not that, ive had it off and checked the gasket and no failure, retightened the bolts to 25nm.

think the problem is with the wastegate, as above ^^ taken the actuator rod off and it no longer squeels, so the problem is somewhere turbo related

thanks jack

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had a wee bit of time on the landy this aft and ive got the actuator pipe of and its basically useless,

it is a hard plastic type and its swollen at the turbo end, im guesing, got hot turned mallauble then soon as the presure got up expanded the pipe and it was loose from then on, prob from first fitment, possibly somebody put this pipe on rather than a LR fitment. tried the actuator on a pump and it works fine.

on the phone to D44 got a new pipe a silicone hose set and a boost pressure gauge on its way up to me, should have by the wknd.

cheers jack. :)

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  • 3 weeks later...


still not fixed :angry:

all new intercooler hoses

new pipe from turbo to actuator and clips,

boost gauge fitted and plumbed into the above pipe, only reading just 12 psi when full throttle on a slight climb in forth.

this should be 15 i think is this correct?

the noise is still occuring with all this done!

and yet if i take the wastegate arm off an drive there is no noise, is this the wastegate buggered?

hope i can get this fixed this weekend as got the landys first shakedown next weekend.


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would it be safe to wire the wastegate open and go for a short drive? ive done it closed and the noise dissappears, to see if its this thats causing it? the wastegate arm seems looseish, the wind would blow it in any direction is this right i cant find any info on it.

im now getting 14.5 psi on full throttle from shortening the rod a wee bit and going for a drive.

please someone help

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would it be safe to wire the wastegate open and go for a short drive?

Yes, you'll just get nearly zero boost.

But we're down into weirdness now! Take the exhaust elbow off the turbo and check out the actual wastegate flap - the only thing I can think of is that the flap is dodgy (corroded etc.), making it vibrate in the exhuast gas flow. This would fit with the lower boost, as the flap would effectively be part open all the time?

the wastegate arm seems looseish

Is this so even with the actuator connected? If it is then the actuator is gone.

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the actuator seems fine, extends when a foot pump is connected and doesnt loose pressure. the wastegate arm is only loose when the actuator rod is disconnected.

i do believe your right in thinking that the flap is the problem i.e corroded.

the three exhaust bolts are rusted in that heat way and im sure itl be a grinder or a snap to take them off. with a event next weekend ile not take the exhaust of til next weekend.

if it is the flap can this alone be changed? or a new second turbo?

many thanks errol209

cheers jack.

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if it is the flap can this alone be changed? or a new second turbo?

I'd guess you'd need to take it to one of those nice turbo refurb specialists, but good S/H ones should be plentiful as 2.5TDs get removed? Try a "wanted".

It might just clean up <_< , as jbs suggests below - VVV above - ^^^ (spatial disorientation holds a particular horror at this time of the morning)

many thanks errol209

Anytime, its what the forum is here for!

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This next weekend i will take the exhaust elbow off and have a look inside to see whats happening. it could well be bunged up with soot and the like, or the flap is burnt out/holey.

a mates got a couple of 300tdi engines lying about, he would take £50 for turbo and manifold but would it fit?

cheers. :)

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