Ukiah!

[Jeremy5848]

Or is it Eureka?

Anyway, a great learning experience to pass along to other EGR-laden MB owners, especially the 1985 300DT 123-bodied cars. The lesson is: a broken EGR flex pipe does turbo response no good. Here's the story.

I had the right front of the engine compartment pulled apart to find and fix a coolant leak (turned out to be the bypass hose, old and failing rapidly). While looking at the engine from this new perspective, with the air filter housing and stuff removed, I discovered that the flex pipe from the trap catalyst to the EGR valve was cracked right across. Instead of one pipe, I had two, separated by a narrow gap (see pictures).

Since the EGR valve does not work (a BB got sucked into the vacuum line somehow ) some of the exhaust has just been puffing out into the engine compartment. This explains why the engine compartment has always been rather sooty (and I, innocent as the new-blown soot, thought it was a "diesel thing" ).

Since I plan to install one of Brian's kits and remove the EGR valve, and later to replace the cat with a "test pipe" (if I can ever find one), I didn't replace the flex pipe, just wrapped heavy aluminum foil around the break and put a hose clamp over the "joint." That should hold until I can make a permanent repair.

In the 1985 cars, the flex pipe is down underneath and is hard to see. In my car, it's been broken for over a year -- as long as I've had the car and more, probably. Other cars, such as the 1987 300DT W124 cars, the flex pipe is up where you could see a crack much more easily.

The final moment of enlightenment came when I put the car back on the road and discovered how much more quickly the turbo spools up. The boost gauge showed the difference, spinning up to 10 psi much faster that before. I was amazed at how much difference the loss of boost from the leaking exhaust would make. I can even get 5 psi boost on the gauge with the car parked, just by revving the engine -- could never get the gauge to flicker before. I'm now, even more than before, looking forward to getting rid of the trap cat. It will be a new car!

Jeremy