OM603 turbo woes - PeachParts Mercedes-Benz Forum

deanot442 · #1 05-24-2004, 02:38 PM

Well I am hooked! I just bought my 2nd 87 300 td. I love it! My woes are with the wagon. After hearing my wife complain that her 87 300 TDT felt like it had been castrated, and taking it for a test ride. It seemed like the turbo was not functioning (properly). I had taken it out to renew the oil seals to fix a leak in the drain tube several weeks ago, but when re-assembled, it worked well. This time upon removal and inspection i did find that there was some play in the unit, and it didnt seem to stay spinning for very long (almost binding). So I did read about one person in this group that got a replacement cartridge and installed that. I did not see any markings To identify my turbo by when it was out. Ive been told that there are 2 brands of turbo used in these cars (1 KKK, 2 Garrett) does anyone have a list to cross this with and who has anyone delt with for parts and possibly rebuilding their turbo.

Dean

md21722 · #2 05-24-2004, 02:51 PM

Garrett turbos have a rubber hose to the wastegate, KKK's have no rubber hose, but a metal line and the wastegate is nearer the firewall.

www.turbocity.com might have some info about cartridges.

Regards,

deanot442 · #3 05-24-2004, 02:57 PM

This is the garrett then, do you know what model they typically used in the 87 300 TDT?

gsxr · #4 05-24-2004, 07:55 PM

Have you checked the simple things first, like boost pressure, and the ALDA line? Maybe fuel filters too? Why is the turbo suspect...?

deanot442 · #5 05-24-2004, 08:22 PM

I did not check the ALDA, but was thinking about that today. the turbo is suspect because there is a ton of play in the spindle and it was most recently messed with (drain tube oil leak) (honestly I was "Easter Egging") what about checking the over pressure sensor on this eng? any tips on that?

gsxr · #6 05-24-2004, 08:30 PM

I'd insert a "T" fitting at the ALDA and run a length of tube out the hood seam, to a boost gauge in the car. Take it for a drive and see what the reading is. 10-12psi is normal under load at high RPM - say, 4000rpm, floored in 3rd gear. Anything under 10psi and you've got issues. If the overprotection switch is engaging you'll feel the power switch on & off, or if it's off all the time, you'll see zero PSI at the ALDA.

deanot442 · #7 05-25-2004, 03:40 PM

Thanks gsxr, I'll try that this evening. Thanks to all who replied. youv'e been very helpful

dieseldiehard · #8 05-25-2004, 07:16 PM

another reason for very low boost is if the wastegate is stuck open. Mine was found to be open, a super let down after rebuilding the top end. The car lacked any power (it felt ALMOST like a NA 300D). It turned out the flapper was gunked up so bad with exhaust carbon that it became stuck partially open, just enough to lose pressure. Driving with the remote indicator gsxr described showed a max 0.25 to 0.3 mBar at 2500 - 3000 RPM. I was looking for 0.8 mB minimum (11.75 psi)
After some exercise and flooding it with WD40 it was freed up and works to this day.
DDH

deanot442 · #9 05-25-2004, 10:41 PM

I had checked the waste gate and it shuts very tight, I even thought that the actuator was malfunctioning, but after thinking about it, I realized that sticking shut would definitely not cause the lack of power. I did pick up a vac/pressure gauge this evening and a bunch of hose to try to check out the amount of boost I am seeing. I also checked the over pressure valve which seemed ok.
Dave, Does the car need to be driven to accurately check the boost pressure or can it be throttled from under the hood?
Should I be able to hear the turbo spin up (whine like on the larger commercial diesels) while throttling from under the hood? Because I do not (this concerns me)
When we first started driving the car the whine was noticeable, then we got the TO changed out and the whine was gone but the car still had some giddy up. Now it is 5 months later and the giddy is gone.

dieseldiehard · #10 05-25-2004, 11:23 PM

...with a bad turbo a turbodiesel becomes a flat out slug, a turtle, or something close to it.
You need to drive the car to get boost. Uphill is even better than flat out if you want sustained boost.
Sounds like you already checked the flapper, so it must be the bearings that are causing the turbine not to spin up. A new cartridge seems in order, because you said yours has lots of play. There should be VERY little side play (radially) and only a little end play (axially).
I had a OM617 turbo rebuilt by Majestic turbo in Waco, TX http://www.majesticturbo.com
DIY'ers like you may also be rewarded by cost savings if you can get the right cartridge and install it yourself. I chose to leave the job to someone that has the experience and could balance the turbo also (whether or not they actually have to balance them is a question I wish I knew the answer to).
DDH

gsxr · #11 05-25-2004, 11:48 PM

Revving the engine in park, with no load, will show zero boost pressure. As DDH said, you need to drive the car - uphill helps. With a fully functional setup you will see full boost at even partial load, but the proper factory test is 3rd gear, WOT, 4000rpm, under as much load as you can give it...