Hello all, I installed a K&N intake to the turbo, and added a breather filter to the valve cover (need an oil separator for oil is leaking out of my breather). Since then, my turbo whines loud after 2500 RPM and blows off loud when I let off the gas. I didn't hear this with the stock air box. I have a boost gauge on the way, but I don't know if the previous owner increased boost if it's possible . . . I'm just scared that he increased the boost and didn't measure the pressure. Dude was shady, and I think he jumped the car before it got to my hands.

After all's said and done, the 300d is quick, drives smooth at 70 - 75 but operates at 95*C while cruising down a flat stretch of highway. Is this normal?

"blows off"?
You mean spools down?

Search the site regarding the K and N filters...

Not unusual, in my opinion, to see that this time of year during the day 98dF+ running hard.

I suspect the noise you are hearing is going to be the noise that you can expect running the system you currently have in place. If you can't run with it I would suggest going back with the oem unit. Keep an eye on your oil level if you do continue to run it the way you have it set up.

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Jim

the above posts. it also could be leaks between the filter and the intake. an opening will not only let in dirty air but will let out more sound. people install the k & n hoping to increase hp or mpg. if i thought it would i would do it too. the benefit of a low restriction filter is only there if the stock setup is restrictive, which it is on many cars. i doubt that it is on a benz. you are experiencing the trade offs.

it is hard to beat a correct factory setup. good luck.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The garrett WILL make a loud woosh like a "blow-off" valve when the pedal is let off at mid-high boost. The KKK won't do this so I believe it's a design "flaw" of the garrett. My view is the compressor hitting a stall when the flow difference between the intake flow and the exhaust flow change suddenly. You are just now hearing it because of the K&N removing all the sound damping the stock intake had.

Mine T-3 Goes "whiiiiiiirrr"
sounds very little like a blowoff valve when I let off.
Still probably be a good idea to check for leaks, etc in your intake/exhaust manifold...that stuff can make some weird sounds sometimes

I put a larger compressor on mine and the turbo noise is now slightly auidable when under boost with the stock are cleaner setup.
I had to do a bunch of custom fabbing but it sure works good ...A little more air never hurt anyone

A MB tech service bulletin about defective turbo replacment guidelines: Silent turbocharger operation over 100,000RPM is not possible.

It would be best to scan through the online FSM, alot of information can be found there, even if the pictures are not the best...

Thanks for the replies everyone . . . I wasn't sure it was blow off, but just named it that out of ignorance. I kinda like the sound of it, and will keep the filter setup there for now until it drives me nuts . . .

I just got the car 3 months ago and it needed an air filter. Considered getting a stock filter element, but they go for ~$50 for the calif. cylindrical type, so I opted for the K&N type and installed a oil breather (no separator) to the 90deg elbow out of the valve cover. After a while, the breather spits (more like drools) oil out of it and am planning on whipping up an oil separator with the breather attachment out of some cheap PVC or PP.