AHU TDI Metallic Clacking Sound - Video

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
~160,000 miles. DLC1019 injectors, timing belt, tensioner, replaced maybe 30k miles ago. No A/C or Power Steering. Transaxle was out a few months ago.

Runs well, just finished a few 2000+ mile road trips without any major issues. Has two codes that are always there (P1441 and P0380) but no new codes. I noticed this sound a few days ago and thought it was just something rattling like the exhaust, but after crawling under it with the engine running today, that doesn't seem to be the case.

It sounds like it's coming from the turbo, or near the crankshaft pulley. I also seem to notice it from the top of the engine, near the injectors.

I'm going to have it towed to a shop tomorrow. Thought I'd post here to see if anyone has any ideas and then will follow up after the issue is diagnosed (hopefully soon).

Sound in the video below. It seems to get louder when the microphone is near the turbo, but it's hard to tell. Sorry about the vertical video...

https://vimeo.com/358691580

Thanks in advance for any help!
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Sounds external, like you said like the exhaust.
I've heard clicky injectors and bad IPs. This does not sound like that, nore does it sound like internal conrod or valve nock. I'd look at all the pullies. It really sounds like the idle pulley rattling around.
Pop the serpentine belt off and feel all the pullies. Also kinda sounds like a throw out bearing too. I'd check the clutch for for play by pulling of the clutch slave. Does it change with the clutch in? Or is it an automatic?
 

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
Ph1osopher,
Agreed on the stethoscope though I'm going to try the screwdriver trick when I go back out there.

Mongler98,
Manual transmission. The sound does not change when the clutch is pressed. TOB was a good suggestion though.

Here's a second video:
https://vimeo.com/358929760

The sound seems to go away with just a bit of throttle though I can vaguely still hear it at low boost.

I didn't take the serp belt off because I figured the noise would increase with RPM and it seems to do the opposite. I did take the timing cover off and nothing seemed out of place. I found three different things that could have been rattling and sprayed some lube on the idler pulley on the serp belt, but no luck.

Then I took the intake pipe off to check for play, and sure enough, there's quite a bit of play. I'm 90% sure this is the noise, but need to get a screwdriver / scope on it to confirm.
At least 1/8" play in and out, and at least 1/16" play side to side.

https://vimeo.com/358936928


So if I'm assuming it's turbo time - any turbo upgrades recommended for a Vanagon? Not looking to get crazy with hp/torque because the transaxle is the weak link here, but a little more power wouldn't hurt.


K03/K04 hybrid seems like the easiest bolt on option to get a bit more power. Like I said, it has DLC1019 nozzles and a tune from Kerma. Also have a rocket chip for it but didn't notice any difference between the two. Some guys have put GT2052s in their vanagon TDIs. And then there's the VNT route but it seems very involved, and while VNT is cool, with this vanagon I tend to want to K.I.S.S. if you know what I mean.

Down the road the only other thing I've been considering is one of the euro PD150 manifolds.

A couple of turbo diesel newbie questions:
1. It's no problem to drive 5 miles to the shop on wednesday with turbo play like this, right?
2. Why is there oil on the intake side of the turbo? I'm assuming the seals are compromised.
3. If those fins have been scraping the inside of the turbo (I forgot to feel for that when I had the intake boot off) does it mean there's metal dust downstream somewhere - in the intercooler(?)
4. What's the normal lifespan of a stock K03 turbo?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
My AHU turbo after I melted TF out of it from my 764,s had this much play in the shaft front to back, that’s shot, kind of. It could be that but sounds too slow to be the turbo IMO

The side to side is typical and all of them do that. Its normal, oil fills the void when it’s spinning and it runs true, but the forward to rear play is a sign of a turbo on its last legs.
DO NOT go with the 2052 unless you’re willing to sacrifice the low end power. I’m running a gt2052 with 764's a bunch of other stuff , IP work head ... so on with a stage 6 smoke out the hippies tune from Malone. I love the turbo, but it lacks down low. But it’s a BEAST up high. I rev from 2500-2600 rpm at fool boost to nearly 6 grand at what feels like FULL heart in your throat power!!!
VTN,s are great but you have to convert the entire system to vacuum over boost, there is a way to convert the waste gate actuator but I have never seen a version that is suitable for the road let alone works as well as the conversion.

your nozzles are not HUGE, but they could be enough for high EGT's you should install a EGT gauge to figure that out. up your QA just to be safe until you do. the AHU turbo is TINY AF on the exhaust side and its very easy to make high egts's well into the 1600 to 2200F range, probably not that high on your nozzles but on the 2nd pull i put down 2,230 F on the stock turbo on my 764's at 3.5 QA, i know i should have been at 6.5 or more but eh, i was going to replace it anyways, young and dumb!!!!

Answers to your questions.
#1: I drove my turbo like that, your risking a run away, be prepared to slam it into 5th if you have one, you can send brass though the engine if the journal bearing fails too
#2: there is no seal on the turbo, oil pressure goes around the journal bearing, that’s it, a little leaks past, no big deal, all AHU and ALH engines have the same deal, a little oil mist that eventually makes it into the engine's intake, hence the caked up intake and soot issue with the EGR
#3: yes, if its scraping, I don’t think it is though, if it starts scraping, it will be minutes or seconds left on its life, if by chance that sound is coming from the turbo, it’s probably from the journal bearing wearing down on its forward face and the back of the impeller is rattling against the rear housing plate or core of the turbo body. These turbos need oil, the oil pressure keeps them pushed outwards to the intake flange, when idle they sit inward, this is one of the reasons we suggest not idling an AHU TDI for long extended times during "warm up" or just sitting in an AC cooled car!
#4: anywhere from 100K to 600K. it depends on the heat put down to the turbo, larger injectors don’t help, hotter turbo core when the car shuts down, heat soaks the oil, usually not an issue but when you go up in power, you usually need a cool off time, a few seconds at idle does the trick. High altitude will kill turbos faster, same with more power, working harder.
Improper use of non-rated oils, or other contaminates from other wear, aka pixy dust metal that flows through an old oil filter that has its bypass open from neglectful oil changes, really anything can because life span decreased. In a properly maintained AHU, typical life is between 280K to 350K. Usually by the time the actuator fails, the turbo is not far behind or so it may see. Surging is also a bad day for a turbo, aka no bleed off of the exhaust waste gate at high rpm or full boost then a rapid let off the throttle will cause the pressure to build up and slam the turbo in the opposite direction. Not typical but a failing waste gate actuator can cause a version of this.

Pd150 intake is great. Love mine!
ko3/ko4 hybrids are nice, but not much of a performance increase; there are better upgrades that do more for the same price!
 
Last edited:

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
Thanks Mongler98 for the detailed answers.


I put a screwdriver on it and the sound doesn't seem to be coming from the turbo.


I ordered the PD150 intake last night and am leaning toward the KO3 hybrid because it's straight bolt on. Perfect time to tap for the EGT sender which has been on my list for a while. Gauge and sender will be ordered.


I've got an appointment to take it over to the shop tomorrow morning. Might pull the serp belt this afternoon just to eliminate that area.



Again, thanks for the help!
 

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
This afternoon I pulled the serpentine belt and the sound did not go away.


It sounds most noticeable near the valve cover by the breather. I put the screwdriver on each injector, both manifolds, piping, cat, and couldn't locate it.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
have you looked at the cam and lifters? rotate the crank so you can see each lifter too, don't rotate it from the cam sprocket.

may i suggest that you look into Auber gauges
https://www.auberins.com/index.php?main_page=index&cPath=5
its what i run and you can much more with them then a gauge that you don't have time to look at!
food for though. oil PSI is also cheep insurance.

dont get me wrong, the k03/k04 can put down 165 hp with a tune and the right nozzles and maybe a cam, very respectable and right at the 170hp reliability line. while you have it out, i would do a port job on the exhaust manifold, this will help a bit with EGT's same with cam and larger inter cooler.
make sure to clean the heads intake ports when you have the intake manifold off. you cant get it 100% but its better than leaving chunks to fly off and total the engine!
 

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
I haven't looked at cam and lifters yet, but that seems to be the next step.


K03/K04 hybrid is in the mail along with the VDO EGT gauge and pyrometer. I have a road trip up to Squamish BC planned on the 24th and the hybrid turbo was the easiest to just bolt on and go. Also have a revised chip from Kerma on order, which is a really nice surprise because it was only $25 as I'd paid for the original$$$ tune already.


Oil PSI gauge is half installed, sender and everything is ready, just need to run wires up to the gauge. Now I can run them all at the same time for EGT too.


Good tips on porting the exhaust manifold and cleaning. Thank you!
 
Last edited:

TDIDaveNH

Left Lane Coal Roller at Large
Joined
Feb 17, 2009
Location
North Conway, NH
TDI
1997 Passat TDI x2 1984 Buick Century 4.3 diesel
I had this same noise on my B4 a while back...rattles at idle then goes away with any throttle input. Turned out it was the small heat shield on the exhaust manifold making the noise. It's held on by two nuts and held captive in a folded channel at the bottom. The shield rusts away around the nuts then it can pivot fore/aft at the channel, producing the noise at the rusted out holes. I'd put money on it that's what it is.
 

brokensf

Member
Joined
Dec 5, 2006
Location
san francisco
TDI
1982 AHU TDI Vanagon
Turned out it was the small heat shield on the exhaust manifold making the noise....I'd put money on it that's what it is.
https://vimeo.com/359614606

You're exactly right! I figured this out yesterday and haven't posted an update yet.


I poked all around the turbo, downpipe, cat, wastegate, and yesterday I finally noticed that heat shield, it's tucked way up in there. Sure enough, one of the nuts had backed off 1/8". Pretty amazing considering how rusty those nuts and studs were.


The good thing to come out of all of this is that I realized the turbo was on its way out. K03/K04 hybrid will be installed on Tuesday along with the EGT probe. I also ordered a K04 blanket and some exhaust wrap from PTP. The PD150 intake is here and the new silicone couplers for it will be here tomorrow. Not in a rush to install that because I want to fab a heatshield for it first. Also ordered a spar puller fan for the intercooler.

Really trying to do everything I can to keep this new turbo healthy for as long as possible. Intake temp cruising on the freeway on a 80F day is usually 190F or so. I've seen it as high as 230-235F. These IATs seem way higher than what you all with a front engine passenger car have to deal with.

Any input on keeping IATs down is appreciated!


Thanks again for the help :)
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Those goofy rattles can drive you batty. Glad you found closure.

The metal tube that comes out of the air box, was rattling against a mounting stud on the frame horn, on my B4. I spent countless hours disassembling the dash and doors on numerous occasions, trying to track it down. I don’t remember how I found it...

-Todd
 
Top