Possible turbo issue? Engine much louder under acceleration & less go at speed

[Upex]

Morning all,

Just done our first big journey in the wife's 3.0d and I'm impressed, glad we ventured into this bmw world. However, after about 500-600 miles, the engine suddenly got quiet a bit louder when accelerating and when holding higher speeds. Not sure, but appears to have less go when at speeds to, ie when trying to floor it from 70 to overtake, it appeared to lack the rush it used to. Acceleration off the line appears unaffected though, still shot off lights like a rocket versus what I expected from the car, even when fully ladder and likely 4ton lol.

Can't say that I've noticed any smoke out the back, and I checked the oil level of course, was fine, and it made the other 1100 miles and didn't use much oil (about 1/8th or 6th of litre across whole trip maybe, need to check again today).

Any ideas on what I need to check please folks, or possible causes, as the extra noise was not fun for such a long time and kind of spoiled the nice comfy journey otherwise.

I'm not overly familiar with these motors yet, so any additional support would be great, ie location of the things to check.

Cheers all

[ianst0028]

Check the exhaust manifold.... Turbos seem to be pretty strong on the BMW's (unlike Peugeot/Citroën) but the actual manifold seems to be a weak point

[Upex]

Cheers Ianst0028, would this cause the symptoms? I assume this is just a visual check, ie looking for cracks etc, or is this a manifold off job to check for warpage or such? Not sure what I'm looking for.

Cheers for the heads up, fingers crossed eh

[lezmtaylor]

Look and listen!!

Lez

[X5Sport]

If it is the manifold then replace it with a cast iron one.  OEM fitted pressed steel and it is a known weak spot.

[Upex]

Cheers all, assume the money on the manifold then? I'll be happy with that, although having seen some other posts, it's a pita to get to, with injectors, rocker cover and inlet manifold to get off, joy. Changing the airfilter was a pita with those stupid bolts at the back, but this sounds like I may shove it in the garage lol.

Cheers all

[Alan Gunn]

What car is it.
When i first got my 52 plate 3.0d i thought it went ok but when i floored it i didn't get what i expected.
Ha a good look round the engine bay and found a vacuum pipe had perished at the end and come off.
I cut the said pipe back a bit and refitted it and what a diferance it made.

[X5Sport]

Worth checking every vacuum hose, and especially those fitted to what looks like a small plastic cage sitting on the front of offside wing under the bonnet.  If the little pipes on that come adrift you lose some vacuum control of the engine.  It's a common occurrence at servicing time when they got forgotten and not put back.

[Upex]

Alan, it's a 3.0d sport built August 05.

Was shifting along lovely (better than I expected when purchased the car given its weight) and had lots of pull from a start or when already moving. This was lovely for about 5 weeks since buying and for first 500 miles or so of this long journey, only then did it get noticeably louder and lack the grunt when already shifting along, I.e. overtaking. Pulls ok under light throtal (just noisy) and still fires off the line great etc, but, alas something isn't right at the upper end.

I'll check out the vac lines and hopefully it's one of them.

Cheers.

X5sport,

Thanks for heads up, will check them out. I've not disturbed them during service, as ran great for 2 to 3 weeks since I serviced her before we had this long trip, however guess 1 could have persisted or popped during the long drive, especially as car was brimmed with 3 people and associated stuff, so likely weighed shed loads and had some cracking mountains to climb up, so would have been worked harderror than it has in long time/ever lol.

Can I get a pic of vac lines anywhere, so can make sure I do find and check them all? If I miss one, it'll be that sucker thats split, sods law! But will definately check those which you've called out.

Thanks.

[Upex]

Going to try and get hands to all the vac lines and replace those I can reach. Hopefully will resolve.

I believe all the vac lines are 3.5 mm id, sound about right?

I only have some silicone vac tube, assume this will be OK or should I be looking to stick to the rubber with cotton over braid? If the latter, only some hoses are cotton wrapped, do I need to match like for like, or can all be cotton? Keen to not have 2 seperate orders for short lengths as is just plain wasteful in money terms due to double postage.

Checked the vacuum boost converter canister cage thing, or whatever it is, and hoses there seem fine, just hope I can find the other hoses, as struggling to find a complete diagrammatic (but did get 6 seperate ones from realom so hopefully they will cover all between them lol.

[Upex]

Well, found a real crusty vac pipe, one that goes from the 4 vac sources from the hard plastic vac pipe, to a vac controller type thing below the inlet manifold at rear of engine (right side looking from front). Number 2 on:

http://www.realoem.com/bmw/enUS/showpar ... Id=11_3877

Was a real pita to reach and cut old rubber hose off, but did it by mooving the Webasto thingy on the right of engine bay. The hose was in very bad shape, lots of cracks and perishing badly (both ends broke off and stuck on vac connections). I've replaced with some silicone vac hose, as that's all I had, but I don't think it's resolved it (hadn't drove car for over a week, so need the Mrs to drive and see if different), still seems to lack the kick that she did and still sounds louder under acceleration. All other lines look in pretty good shape, no cracks or perishing at all, that I can see at least.

Did find that one of the bolts holding the big metal guard plate was loose though, and having tightened them all up, a knock from steering/suspension has disappeared though, so at least I've managed to achieve something.

Used a cheapo code reader (so not best answer) and it found no stored or live codes before or after chaning the crapy hose. Can't see any signs of exhaust manifold being cracked or anything either, so any ideas what I can check next? Fear that shoving her into garage with only symptoms being louder and less poke will only lead to £££ worth of wasted diagnostic with them saying it's fine, especially as drives well and idels perfectly. Either that or they just want to replace turbo - call me sceptical but want to try and narrow it down more before going there.

Cheers all, Upex

[henrym3]

Not familiar with X5 diesels but symptoms sound very like a loose intercooler hose, in or outlet perhaps loose pipe or split hose or worse case, intercooler holed. Would explain noise and lack of upper end power.

[Upex]

[quote="henrym3"]
Not familiar with X5 diesels but symptoms sound very like a loose intercooler hose, in or outlet perhaps loose pipe or split hose or worse case, intercooler holed. Would explain noise and lack of upper end power.
[/quote]

Thanks for input, obviously I can look at pipes etc, but how can I check for smaller leaks and duff cooler? Not done much with coolers, other than flush the slks one out once when it had AA bit of oil in lol.

Thanks henrym3

[henrym3]

I would suggest you familiarise yourself with the run of the pipes, ie from the turbo to the intercooler inlet and from the intercooler outlet to inlet manifold, some will be metal/alloy the rest rubber, visually check for loose connections and splits in the pipe work, listen with engine running for sound of escaping air, hissing, get someone to give bursts of revs, I know engine noise makes this difficult but mostly you can distinguish between the two. You can disconnect the pipework at inlet manifold and hold your hand over the pipe to create pressure between turbo and your hand to see if any air escapes elsewhere. Of course if you don't feel comfortable doing this stuff you maybe can get someone to help you out. Good Luck

[Upex]

[quote="henrym3"]
I would suggest you familiarise yourself with the run of the pipes, ie from the turbo to the intercooler inlet and from the intercooler outlet to inlet manifold, some will be metal/alloy the rest rubber, visually check for loose connections and splits in the pipe work, listen with engine running for sound of escaping air, hissing, get someone to give bursts of revs, I know engine noise makes this difficult but mostly you can distinguish between the two. You can disconnect the pipework at inlet manifold and hold your hand over the pipe to create pressure between turbo and your hand to see if any air escapes elsewhere. Of course if you don't feel comfortable doing this stuff you maybe can get someone to help you out. Good Luck
[/quote]

Nice one, thanks henrym3, will check this out when dry and have time lol. Thanks