Turbo knocking on 300TD?
 

Hola my PeachParters. I have another possibly odd question here. The turbo on my '85 has not worked in some time and I am trying to troubleshoot that once I get a vac gauge. (There are no obvious broken line or parts).

My question here may or maay nor be related, but it seems like there is a lot of chatter/clatter coming from the turbo itself lately. The engine is noticeably noisier at idle and almost sounds similar to a gas engine that has spark knock. Obviously that is not the case here, but wondering if anyone might have run into similar prob like this before.

As I mentioned in a previous post, the turbo has been inop for some time (no whine) but the car still runs good- albeit lacking kick and hill-climbing power.

Appreciate the input and responses here as always! Thanks.

Some turbos never whine my Garrett make will peg a boost gauge with the gate wired shut and not make any whistle. Have you checked for play in the shaft? What motor is this?

Could be bad bearings in the turbo. Not sure how a vacuum gauge will help diagnose turbo problems. Have you checked the integrity of the overboost lines?

That might make some sense based on the sound I'm hearing, although I have read that people claim they're bulletproof :\

Do you have any idea how difficult it is to replace those? I am at the mercy of my own wrenches and ability, as in this area, the dealer is the only other one that will work on it, and we all know how reasonable they are (not). No doubt they will tell me I need a new 1/2 or whole engine.

Thanks.

If you have access to a boost gauge you can temporarily bypass all that stuff and go straight from manifold to alda and see what kind off pressure that turbo is making. Thats where i would start first thing to see is if its functioning and making pressure. If there is no boost even at wide open throttle in second then you have some sort of wastegate failure or lack of fueling. Are you absolutely sure this noise is coming from the turbo? Worn injectors leaky DVs and and bad timing also make a clattery knocking noise.

Rebuilding a turbo isn't too bad its either a Garrett t3 or a KKK kits run $70-$125

As the Thrust Bearing wears the Compressor Wheel gets closer and closer to the Turbo Inlet Housing.
As the other Bearings Wear the side of the Fins get closer to either of the Housings.
As they wear the eventually make contact with the Housing. If the Wheels have rubbed at all during a rebuild they should be rebalanced.

On the Exhaust side there is a Calmp that Holds the connects the Tubo to the Expansiong Joint. I have tried to remove several Clams at the Junk Yard only to find the Nut is frozen on there.
If that happend to mine I think I would split the Nut rather than damage the clamp wich new cost a bit.

I had no issues with the other Blots that Held the Turbo in. But, I guess it is possible for them to be frozen.

It is a good time to replace the Turbo Draing 2 O-rings and Grommet as well as the Oil inlet and outlet gaskets.
If your Breather Drain is next to the Turbo Drain you need an O-ring for that also.
I think there is 2 big O-rings where the Turbo Connects to the Intake Manifold and of couse the Exhaust Manifold to Turbo Gasket.

Is very unlikely be a turbo problem more likely it's a fuel problem check the all the lines and fittings to the alda for blockage.

The knocking noise could be anything from air cleaner fitting brackets to the injectors

Agreed. I had r/r'd all of the air cleaner assembly and all of the couplers connected to the turbo. Everything should be tight. I think it is more of a mechanical noise, definitely on pass side. I thought I had a bad alternator (which I had just replaced two months ago) so I swapped that out- again- but not the problem.

I have not seen too many postings about having to replace turbo bearings, but maybe it's time. Thanks.

OK, so after more listening and evaluation, it does seem like the turbo bearing is in need of replacing.

How do I determine which turbo it is? or are the kits universal?

I also found one guy that offers modified tools for this job to do on the car, but says if you remove the whole unit, modified tools are not necessay. Any insight here?

Thank you!

Guessing that this is a Garret turbo?
 

From what I can gather, the Garret has waste gate hose coming out front, which is apparently what I have here? (sorry for crappy pic :)

http://i44.tinypic.com/k3u83b.jpg

looks like a Garrett to me but if you clean the front around the air intake it will be cast in real obvious "garrett air research" or some such thing. No special tools to get it off, a couple wrenches and sockets was all i needed last time i pulled one. Check your wastegate opening pressure and reset when its off much easier to do on the bench then in car.

Thanks.

Do I need anything more that what is shown here from this eBay listing: Garrett T3 T4 T04B T04E TB41 TA31 Turbo Rebuild Kit Dynamic Mercedes 300D | eBay

I REALLY would advise that you FIRST CONFIRM the actual Turbo is the CAUSE of your issues.
--Get someone experienced to check it out and confirm the fault IS the turbocharger.
--Otherwise--All that money you spend on it will be wasted--If it turns out to be fault-free, and You'll STILL have the fault on the car!

Turbos don't normally Knock. Its just NOT the sorta noise a faulty one makes!
--Just because you cannot Hear a whine--Doesnt mean its faulty.

I reckon your pipework and overboost-controller or maybe ALDA are either blocked or faulty, and that the Turbo is fine....

Thanks Alastair. I believe the sound I am experiencing is mechanical and does seem to be worse under acceleration. The turbo has not worked properly for quite some time, as I mentioned earlier, but it had not been making this type of noise until a week or so ago. I don't know if/how the inop and noise may be related, but guess i have to invest in some parts to start eliminating. Unfortunately no one in my area- short of the dealership- knows anything about this car. And the dealer just wants to replace all the parts until it's a new car again.

Yesterday I came off the highway and tested by putting car in neutral while going downhill. The noise lessened considerably.

Also when I first bought this car 10 yrs ago, I had the luxury of access to head mechanic at Benz dealership. The turbo used to 'whine' when it spooled up and even barked shifting into second gear. That stopped and the car has limited power now. I have adjusted the valves a few times over the years too, so i know how important that is too.

Appreciate your input.