350 sdl issues - PeachParts Mercedes-Benz Forum

t walgamuth · #1 07-24-2006, 08:12 AM

so i dont have much experience with the 603 engine and i have a couple of issues i want to run by you guys with more experience than i.

1. i have a bearing popping noise at the front of the motor. we have replaced the idler bearing on the serp belt and the shock for the tensioner. i am thinking maybe it is the water pump. the car has 154k miles. is this a life expectancy for the wp on these motors?

2. i have a fuel leak around the injection pump and the shut off just slows the engine down. what should i be looking for there? appartently the shut off is different than the vac operated one on the 617.

thanks guys.

tom w

t walgamuth · #2 07-24-2006, 07:37 PM

bump

come on now i know there are guys out there with this expertise!

tom w

dieselbeagel · #3 07-24-2006, 09:03 PM

Mercedes id know for keeping alot of the components the same in many models.

As for the injection pump leaks, pin point the leaks. Most probably from the splined nuts on the injection pump. U will need a special socket to loosen the nut to replace a rubber oring underneath.

I believe the shut off valve is on top of the injection pump, but under the manifold. The manifold has to come off. I believe there r 2 torx bolts that hold the shutoff valve. Makesure the hook at the end of the shutoff valve grabs the lever in the opening for the shutoff valve or u will have a runoff engine.

t walgamuth · #4 07-24-2006, 09:34 PM

db, thanks for responding.

i dont understand your first sentance.

so does it sound like a bad shutoff valve? or is there a possibility of a loose vac connection as i would suspect on a 617 engine?

thanks for the warning about running away.

tom w

TheDon · #5 07-24-2006, 10:01 PM

how does the idle sound? compression good on all 6?

dieseldiehard · #6 07-24-2006, 10:46 PM

OK, TW, does the shut off lever go all the forward and down when you turn the "ign" off? What happens if you press the shut off arm down will it stop better? It sounds like insufficient vacuum might be involved which brings us to the possible source of bearings noise, that being the Vac pump! Is it the newer style (torx head bolts on front cover)? If not get one ASAP!
I'd suggest using or finding a mechanics stethoscope to pinpoint the area where the sound is coming from. If its behind the front cover that is a 10 hour job to remove.

t walgamuth · #7 07-25-2006, 12:15 AM

oh yeah, the vac pump. i should have thought of that! i will look tomorrow.

that sounds like a good guess.

then the fuel leak would just be a coincedence, right?

hmmmm

tom w

dieseldiehard · #8 07-25-2006, 12:38 AM

Hopefully just a coincidence, the coupling ends of the inj lines can crack if you overtorque them onto the injector nozzles and supply ports. You should be able to find the source of the leak fairly easily, dry everything off then run it a few minutes and look for wetness.

t walgamuth · #9 07-25-2006, 09:02 AM

thanks. will do.

tom w

jrgslg · #10 07-25-2006, 09:30 AM

In addition if you have a mightyvac make sure the engine shuts down using it,if it does you need to backtrack the other way and look for a possible leak.If you dont have a mechanics stethescope ,you can place a large screwdriver on the suspected area and put your ear on the handle end(kinda like the old tin can and a string) and listen to help isolate the noise ,just be careful.good luck

hughet · #11 07-25-2006, 09:40 AM

When you replace the O rings in the delivery valves replace the copper washers too. You can get the O rings and washers from Phil. Torque the delvery valves in 3 stages to facilitate sealing the O rings.

There is an O ring on the shaft of the shutoff valve that can cause leaks. It is easy to change. If you do a search you can find out how to change it. The O ring just happens to be the same size as one of the o rings that come with the fuel filter.

If you hook up your mityvac directly to the shutoff valve and pump it a couple of times it should shut the motor down. Thats how you can tell if the shutoff valve is working properly. If it is then you will have to troubleshoot the vacuum system with the mityvac.

t walgamuth · #12 07-25-2006, 05:09 PM

ok thanks guys. i wont be able to do anything today it appears.

i will keep you posted.

tom w

jshadows · #13 07-25-2006, 05:15 PM

Quote:

There is an O ring on the shaft of the shutoff valve that can cause leaks. It is easy to change. If you do a search you can find out how to change it. The O ring just happens to be the same size as one of the o rings that come with the fuel filter.

ahh..that might be exactly where my nagging leak has been coming from. I knew it wasn't the delivery valves or cracked lines. as the ALDA and surrounding seemed to be getting the bulk of the leaked fuel.

Thanks too!

t walgamuth · #14 07-25-2006, 11:10 PM

Quote:

Originally Posted by TheDon

how does the idle sound? compression good on all 6?

compression is fine. nice smooth idle.

tom w

t walgamuth · #15 07-26-2006, 08:23 PM

ok, checked it out in more detail today. leaking apparently around base of pipe to ip joint on #1 cylinder.

no apparent leaks in vac line to ip shutoff.

if i hold the emergency shutoff down just 1/8" and shut off the key it shuts right down.

the vac pump has standard bolt heads holding it on.

tom w