Forum menu
Our 2008 2,5tdi 130 T5 is soldiering on like an absolute trooper and just about to top 200k. It pulls like an train and after a bit of a spend to get it through its MOT today, it is driving very nicely.
Annoyingly over the last few months it has developed what I would describe as a whining whistle between about 1500 and 2000 rpm, or thereabouts. It only happens under load ie pulling the trailer and is barely noticeable if we pootle about empty. It doesn't affect the power output and as soon as you lift the throttle, it goes away. It sort of sounds a bit like a slipping belt might, but I am pretty sure it isn't that but could be wrong I guess. I'd say it has got a bit worse since the autumn.
My friendly mechanic thinks it is probably a split hose, or maybe a leak in an exhaust manifold gasket, but then there is no loss of power
Has anyone else experienced that or have a suggestion or tips of where to start looking? Its hard to locate as with the bonnet up and revving, it doesn't do it. I'm reasonably ok with basic spannering so happy to get under and start checking but at the moment its a bit of a headscratcher knowing where to begin
Leaky intercooler? Mine wasn't a problem until it eventually split in a big way!
Leaky intercooler? Mine wasn't a problem until it eventually split in a big way!
This sounds familiar (Mondeo in my case) and it was an intercooler hose.
And of course it chose to do the gentle wheeze to big split thing on a Friday evening at rush hour coming down the A34. 😬
My initial thought is split hose / intercooler. There aren’t any traditional belts to slip on the 2.5
The clutch on my aircon pump sounded pretty funky right before it self destructed.
If it’s a leaky exhaust manifold you’ll smell it when stationary through the air vents.
Ours also has this. Doing a smoke test on it should show up any leaks. I need to do one on ours. I've already found a couple of small leaks using soapy water around the EGR cooler. Need to get some new gaskets for those pipes. There's also a lot of soot on the heat shield behind the turbo so I think the turbo to manifold gasket might need doing which could definitely be causing a whistle. We've also got fumes into cab at idle.
Basically could be anything to do with the boost/intake system. The clips on the boost pipes particularly around the intercooler are notorious for being a bit iffy.
Ok this sounds like somewhere to start looking more closely, thanks all
Definitely sounds like a boost leak somewhere. Mine was the intercooler - bumper comes off pretty easy and intercooler is right there if you fancy DIY'ing it. If it is the intercooler, they tend to "banana" so if you can see the top/bottom of it is bent out of shape by looking through the grill, that might be your problem. Easy fix...
sounds like boost, agreed.
My 2.5 T5 used to whistle pleasently under boost, but i always assumed it was normal, and that the turbo mustve been located on the back of the engine.
never changed though, didnt get worse or louder.
It did eat a turbo at one point: apparently the waste gate pivot gets gummed up, so there was a notch in the pivoting action, causing a slight delay in opening the turbo wastegate, that manifest as an overboost and put the van into limp mode.
could be worth checking the wastegate is opening correctly.
Has anyone done anything that involves removing the airbox/air filter or pipework pre-turbo? If it's not smoking or down on power it might be that you're just hearing the boost/turbo build more because a cover or resonator etc. has moved or not been refitted properly?
It may also be one of the boost pipe seals, they have a rubber/Viton seal which can be replaced separately and cheaply but as suggested a smoke test to find the actual issue would be worth it before chucking money at hoses/seals etc.
Ah yes I’d forgotten that I also replaced a load of the green seals and at least one of the hoses. The metal lugs can wear out that clip the hoses in, although they’ll pop off suddenly so you’ll know about it.
As the proud owner of a 2.5L T5 with 155K on the clock I take great pleasure in hearing that yours is still trucking at 200k.
The annual services are getting a bit more expensive as there's almost always something that needs doing but other than that she's a beaut, just don't want to think too much about the fuel costs thanks to the big orange turnip.
I also have a 2.5 T5 on 175K miles. i get a whistle just as the turbo kicks in, I quite like it.... but might need to investigate further now. also fumes on tickover have returned had the manifold gaskets done and a mashed bolt replaced a year or two ago which cured it but its back, from what i've read they are prone to cracking manifolds which leads to fumes? anyone else have any clues on this?
Can someone explain the smoke test? and how this works please
Apart from bodywork (coastal location) which i'm about to start refurbing all good and hoping to get to 200K+
Happened to me too. Intercooler whine when the turbo kicks in. If you’re DIY’ing it don’t make the same mistake as me by not quite get the retaining clip past the hose notch. Any bit of pressure means the hose will pop off, and if you’ve reassembled everything it’s an absolute bastard to re sit properly.
If anyone knows anywhere in the east ish that knows these engines to work on that would be useful to know.
Smoke test basically uses a smoke machine with an expanding plug to fill the system with smoke. Then you just look for where it's coming out. In practice I don't know if it matters where you attach the machine to test certain parts. Guess the air intake would be a good start?
As for the manifolds. The 'A' series engines have stainless manifolds that can split. The 'B' series engines went to a cast manifold which won't split, but can warp and pop the manifold studs. Mine is a BNZ engine with the cast manifold and I *think* the studs are all good. I've had a look with a torch and an inspection mirror and no sign of soot so think my issue is the turbo manifold gasket which is a common issue especially with a DPF as the back pressure can cause the gasket to blow earlier.
Pain is the **** engine. But it does drive great compared to the 1.9.
Oh it's also leaking oil from unknown origin :,)
from what i've read they are prone to cracking manifolds which leads to fumes?
Mine wasn’t cracked but had warped so I got a local engineering firm to skim the mounting faces which I think cost me £50. I had to change my turbo as well at the same time.
It ran great afterwards and no more fumes in the cab.
Mine was a BNZ
I also took my DPF off but I wouldn’t recommend that these days (it’s still in y shed if anyone needs one…)
Thanks for that info, very helpful from what you’ve said it sounds like mine had warped as two of the studs had to be replaced when they did the gasket I’ll check in the morning whether it’s cast for definite but now you’ve said that I’m pretty confident it is!