Poor performance on Euro 300D? - PeachParts Mercedes-Benz Forum

Zerohour3k · #1 09-21-2006, 12:32 PM

Here's a question for you guys. I drive around in an 84 300D Euro, with a turbo (someone slapped it on while still in germany, along with a "turbo diesel" trunk plate). Yes, it's a euro, and not just a US model that's been modified (I checked the VIN number.. plus, all the seats are cloth.. hello stains!).

The car runs great, very little to no blowby, and the only big oil leak, comes from the filter housing (very common, and not really worth fixing. Drains about a quart every 1000 miles). I used to own a US 300D, which was relatively quiet on the highway, in comparison. So here's the issues I have.. maybe someone can clarify if it's a real problem, something small, or just all in my mind.

* Car runs loud. I attribute this to the fact that (I'm guessing) the Euro's had less sound insulating material behind the dash.
* Car runs REALLY loud when at 65+mph
* Car seems to have a hard time going past 85mph. It probably can go faster, I'm just afraid to push it, since it sounds like the RPM's are near-redline. Car has a clock, instead of a tach.. so I can't tell if it's just the car being loud.
* Not as fast as my US model was, both in terms of off-the-line (WOT), and highway driving. And my US model was in pretty poor shape, with a good deal of blowby (the thing kept blowing the turbo line off the engine), oil leakage, and a mushy transmission. That's what you get for $850, though.

Are these things normal for euros, or is my car in need of major tune-ups? Is it safe to run the vehicle at high RPMs? Thanks!

greasybenz · #2 09-21-2006, 12:40 PM

Hmm, well the same goes for my dads 78 300D. US model though and a non-turbo. Its loud on the freeway at 70mph, just as you described it sounds like its at red-line but weve gotten used to it and just push it more if the need be. My 300SD with a 617 turbo is quiet at those speeds, only time it makes a loud "red-line" noise is when im going up a grade to get onto the freeway. But soon after im on the freeway on flat surface it shifts and shuts up.

Cant say for sure. But if the US model does it as well it either must be normal or something is wrong that neither i or you know

Johnhef · #3 09-21-2006, 08:10 PM

for one, check what boost pressure they have it set at and two, if they just bolted it on with no internal modification, that engine's life has been severly shortened.

did they swap injection pumps too?

t walgamuth · #4 09-21-2006, 10:54 PM

also if it is a non turbo car to begin with it will be running a 346 rear end. this will make the engine run at a higher rpm at highway speeds and will be more noisy than a us spec car with a 307 rear end.

the other problems cannot be diagnosed without more information.

imho.

tom w

Motorhead · #5 09-22-2006, 02:41 AM

I agree with tom w on the gearing. Does it have a solid mounted radiator fan or a fan clutch?

Zerohour3k · #6 09-22-2006, 09:40 AM

Quote:

Originally Posted by Johnhef

for one, check what boost pressure they have it set at and two, if they just bolted it on with no internal modification, that engine's life has been severly shortened.

did they swap injection pumps too?

I'm at work right now, so I can't really check the fan clutch. I know it has a radiator without an expansion tank (rad fills from the top), and a large metal fan.

The boost pressure, I have no idea. I'm guessing they set it pretty low, as to not damage the engine. Valves are set for a turbo engine, and the turbo is either a garret or KKK. What sort of internal modification do they require, aside from proper valve settings? Whoever did it seems to have done a professional job (it was installed in 1984, right after the car was bought, for import to the US.)

Injection pump is original, AFAIK. It's the blocky euro-style, with the very small "stop" lever (not the US-style with the hexagonal shaped one, this one is a very small rectangle). Who knows, maybe they did do a messed up job installing the turbo, and ended up disabling it as to not cause damage to the car. I know whenever I accelerate from a stop, there's a non-stop hissing sound, as if the wastegate was stuck open.

piccolovic · #7 09-23-2006, 06:28 PM

I think before checking all the "esoteric" possiblities that would normally be further down the diagnosing protocol, check the obvious . . . . the manifold gasket and muffler system. After that is ruled out, you can think gear ratios, etc. Get out the old spray bottle with soap water and see if revving it spits the soap back in your face, or on the inside of the tires. Only after you rule that out, look for the esoteric potentials. Next i would check all your mounts . . . motor and tranny mounts to see if there is a transferrance of noise that would normally be dampended by rubber.

Good luck.

--Torie

t walgamuth · #8 09-23-2006, 07:31 PM

picco is right on.

tom w