OM603 Compared to the others - Page 2 - PeachParts Mercedes-Benz Forum

INSIDIOUS · #16 07-19-2021, 05:13 PM

... and ... is Diesel Purge a product?

cmac2012 · #17 07-20-2021, 01:55 AM

Quote:

Originally Posted by filp

I have om603 turbo with almost 250k miles as daily driver.
I like it, it's not fast, but it's just enough to live in a big city. It's fast compared to om617 for sure.

1. Take off valve cover and check timing, then check timing relative to injection pump. Check chain slack if any.
2. Turbo seals like to go bad and smoke, I replaced the whole turbo on the cheap and it's been fine.
3. EGR delete is a good thing to do.
4. Blowby...a little is ok. It likes to spit a bit of oil around turbo, that's normal.
5. Delivery valve seals, sooner or later, plus make sure the hard lines from IP to injectors have all their plastic holders. There's a lot of vibration and they are a must!
6. Other than that, as others mentioned, belt and belt tensioner is very common failure point.

Usually these engines are really good, I have the #14 head and no issues even when car got to 110 degrees.
Typically your transmission or axle shafts will go first rather than this engine

If you are getting this car, I highly recommend doing LiquiMoly Engine Flush right before first oil change.
Then, of course, Diesel Purge with all new filters, as you probably know

It really makes a huge difference for city drivers

The safety (of hardware) upgrade I’d like to get into is somehow giving the temperature gauge and the coolant level warning light audible alarm components. I miraculously saw the coolant idiot light flicker on back in October ‘19 when my SDL blew its radiator.

Not sure if that incident caused my crisis last Feb.when I perhaps experienced a cracked head. After a while you don’t glance at the gauges every minute. A loud audible alarm could prompt you to shut the engine off before the danger zones are reached.

87tdwagen · #18 07-20-2021, 03:01 PM

I've had 2 OM603 daily drivers for 34 years. First was a company car 300SDL that was mostly dealer maintained and I put 360K miles on it before I changed jobs. The company still has it, and last update I received it is a 420k miles. Dont know what has been done since, but in my time with it, no major engine or transmission repairs that I'm aware of.

My current 300TD has 310k mi, of which 210k are mine and I have done all the maintenance. At the 225k mi mark I had to replace the head gasket due to the front corner oil leak, no running or performance issues, just the growing black oil stains on the driveway that forced me to do the HG. I did find a micro fracture between the first and second cylinder combustion chambers on the orig #14 head. I had a #17 head on the shelf that I swapped in during the HG replacement. At 300k mi, I replaced the original front main oil seal and hub, simply due to the oil leak, I never had to top off the oil in a 5k change interval, probably lost a total of half a pint between changes due to leaks and blowby. I have an oil catch can to collect most of the blowby and that has and still is minimal, maybe a table spoons worth every 5k mi. The rear main is leaking a little, and has been for at least the past 15 years, but again, dont register a drop at the dipstick, so I will tackle that whenever the trans has to come out. So far the trans is original, has been run on Mobil1 since 50k miles and still works very well. Engaging reverse is slow, maybe 2-3 secs, has been like that for at least 200k mi.

The car gets used for carrying heavy loads alot, so the rear axle bearings were changed at 230k mi. At that time, noticed the rear axle was nearly void of gear oil had been running that way for ??? Sealed and refilled and there were no growling, grinding, noises...just like when it was nearly empty

Long story short, if you get a well maintained example and keep up with it, make sure cables, linkages are well adjusted and lubed; the engine and drivetrain should give you fairly good, reliable usage.

Compared to the V6 OM642, I would much rather work on an OM603, I think the engine components are far more robust and durable. The I6 layout makes access generally more manageable, and if you upgrade to electric cooling fans you can gain 3-4 inches of depth in font end working space, making it easy to replace a bad tensioner, or belt.

Hope you get a good one and enjoy!

filp · #19 07-20-2021, 03:24 PM

Quote:

Originally Posted by cmac2012

The safety (of hardware) upgrade I’d like to get into is somehow giving the temperature gauge and the coolant level warning light audible alarm components. I miraculously saw the coolant idiot light flicker on back in October ‘19 when my SDL blew its radiator.

Not sure if that incident caused my crisis last Feb.when I perhaps experienced a cracked head. After a while you don’t glance at the gauges every minute. A loud audible alarm could prompt you to shut the engine off before the danger zones are reached.

Yeah, coolant level light is easy, just add a buzzer to the light. With gauge you need more work.

I had a loose aux pump hose and dropped my coolant on highway, fortunately noticed it the moment the light came on, temp rose only to 115, I pulled up on the shoulder and waited for AAA. In the meantime, I found the hose, tightened it and ironically, it was 2 miles from walmart where I could've gotten some coolant or distilled water.
Then I checked the cooling system again with pressure, exhaust fume detection fluid and IR temperature gun. Replaced radiator and water pump. No issues found, although my radiator is now a bit smaller (used to have the 606 one) and city driving in 90-100F ambient results in 85-90C engine temp, which is still perfectly normal. Head measures 92-95C. I wonder if an electric fan instead of visco would quiet it down a bit and keep temps lower, for better AC efficiency. Best would be to keep the aux pump running after engine shut off for another 10min to avoid coolant temp spike. If you run city errands on a hot day, you come back to your car after a few minutes to see the engine temp at 95C and AC totally sucks.

87tdwagen: interesting point about oil catch can. I had it too for a bit. I did lose a quart every 4-5k miles, I had a light white smoke on idle, not much though. I ran LM engine flush for 10min before last oil change and for the past few months, I have zero smoke from exhaust. Did good 2k miles and oil level is approx the same.

filp · #20 07-20-2021, 03:33 PM

Quote:

Originally Posted by INSIDIOUS

Thanks for that effort. Regards 2. Would that smoke be on start up or while at operating temp, all the time?

It would be on a hot car, the oil would burn off around the turbo or go through your exhaust and provide a nice sign to everyone that the Pope has been elected.
Mine never did that, but the turbo shaft had some play so I decided to do it sooner than later. Biggest problem was getting at those bolts on exhaust manifold.

Diesel purge is a LiquiMoly product and it is a miraculous fluid that is meant to be used in a jar, with your fuel lines submerged in it in the engine bay. Run the engine at different rpms until the jar is nearly empty, dump the remainder into the fuel tank. Then replace prefilter AND main fuel filter, which collected all the gunk from injectors/injection pump. You'd be surprised how much faster your car becomes. Do it annually.

Injector balancing can also add some benefits to power response.
Also, Bowden cable and throttle linkages - lubricate and adjust, that makes all the difference. I have my Bowden quite tight since I want to get on highway quick. Makes the shifts a bit late and rougher but I'm ok with that.

Look here for complete workshop manual for 124:
https://drive.google.com/open?id=1oP2_Nl3IrneW_6xw4H9IvIgE9pLPhMI-

The password for archive: cardiagn.com

cmac2012 · #21 07-20-2021, 09:31 PM

Quote:

Originally Posted by filp

Yeah, coolant level light is easy, just add a buzzer to the light. With gauge you need more work.

That’s what I was thinking. The terminals on the coolant sensor are out there to be accessed by any and all comers. Attaching something to the inside or outside of the instrument cluster is heading towards rocket science.

Quote:

Originally Posted by filp

I had a loose aux pump hose and dropped my coolant on highway, fortunately noticed it the moment the light came on, temp rose only to 115, I pulled up on the shoulder and waited for AAA. In the meantime, I found the hose, tightened it and ironically, it was 2 miles from walmart where I could've gotten some coolant or distilled water.
Then I checked the cooling system again with pressure, exhaust fume detection fluid and IR temperature gun. Replaced radiator and water pump. No issues found, although my radiator is now a bit smaller (used to have the 606 one) and city driving in 90-100F ambient results in 85-90C engine temp, which is still perfectly normal. Head measures 92-95C. I wonder if an electric fan instead of visco would quiet it down a bit and keep temps lower, for better AC efficiency. Best would be to keep the aux pump running after engine shut off for another 10min to avoid coolant temp spike. If you run city errands on a hot day, you come back to your car after a few minutes to see the engine temp at 95C and AC totally sucks.

87tdwagen: interesting point about oil catch can. I had it too for a bit. I did lose a quart every 4-5k miles, I had a light white smoke on idle, not much though. I ran LM engine flush for 10min before last oil change and for the past few months, I have zero smoke from exhaust. Did good 2k miles and oil level is approx the same.

You used a 606 radiator? Which car are we talking about? I was under the impression that swapping a different radiator into an SDL was pretty tough. I have one of the Chinese one piece aluminum radiators. Seems like a good unit.

But I always figured that if my SDL radiator went, and I couldn’t find a unit made for the SDL that I would figure out a way to jury rig another radiator, would just need to find one as close as possible.

cmac2012 · #22 07-20-2021, 09:56 PM

Quote:

Originally Posted by filp

3. EGR delete is a good thing to do.

My old engine had a sort of amateur EGR delete done on it, at least I think that’s what happened, I never met the original owner. I bought it from Mercedes personality/broker Blue Nelson. The story I heard, the lady of the house, whose car it was, grew weary of needing to shut the engine off with the push lever under the hood, she couldn’t find someone who could fix the shut off thing, so she gave it to her sons to hot rod. My guess is they did the EGR delete.

I’ve been told that the bypass pipe they made almost certainly resulted in a loss of power owing to being non-insulated.

The new/used engine which is being put in my car at this time has the original post trap oxidizer delete EGR and pipe in question set up. Pretty sure that’s what it is anyway, here t’is:

Diseasel300 is big on the BB EGR delete method. I gather you put the right size BB in the vacuum line leading to the EGR and presto-disable-o, no EGR. I think I’m going to go that route, and appear to any and all prying eyes to be complying with the law.

Not sure what size BB is needed but my guess is one that fits pretty tight in the vacuum line.

INSIDIOUS · #23 07-21-2021, 10:29 AM

BB is a size.

INSIDIOUS · #24 07-21-2021, 12:59 PM

I'd be interested to see his posts on that BB thing.

cmac2012 · #25 07-21-2021, 02:24 PM

I’ll see if I can find them when I have more time. By the way, gotta say Sid, good thread you started here. Two of the fellows above have a lot more experience with the 603 than do I. Diseasel300 also a font of good info. I hope he’s OK, I haven’t heard from him in a while. There was a time he would’ve been all over this thread.

Maxbumpo · #26 07-21-2021, 03:20 PM

Quote:

Originally Posted by INSIDIOUS

Thinking about picking up a local TDT wagon. What should I know about this engine? Thank you valued experts!

I love this engine. Have an '87 wagon, going to move the drive train over into a '94 wagon.

Weak points, mostly already covered, are:
1) Head, original #14 prone to cracking.
2) Vacuum pump, prone to failure which dumps ball bearings into timing chain area, resulting in broken chain / engine destruction.

Ask to see the car with engine stone cold, after at least an overnight rest. First thing pop open the hood and see if the radiator hose is pressurized. If yes, then the head is cracked. Check the casting number, #14 was original, #17 and later are preferred. I think the last version is #22.

Look at cover on the vacuum pump. Original was a crimped on cover, upgrade / later version has screws holding the cover on. The upgrade version is redesigned so that it won't drop ball bearings into the timing chain upon failure.

INSIDIOUS · #27 07-21-2021, 04:12 PM

Quote:

Originally Posted by Maxbumpo

I love this engine. Have an '87 wagon, going to move the drive train over into a '94 wagon.

Weak points, mostly already covered, are:
1) Head, original #14 prone to cracking.
2) Vacuum pump, prone to failure which dumps ball bearings into timing chain area, resulting in broken chain / engine destruction.

Ask to see the car with engine stone cold, after at least an overnight rest. First thing pop open the hood and see if the radiator hose is pressurized. If yes, then the head is cracked. Check the casting number, #14 was original, #17 and later are preferred. I think the last version is #22.

Look at cover on the vacuum pump. Original was a crimped on cover, upgrade / later version has screws holding the cover on. The upgrade version is redesigned so that it won't drop ball bearings into the timing chain upon failure.

Thank you. Where is the cast# found? Any photo of the vac pump?

cmac2012 · #28 07-21-2021, 05:04 PM

Here are a couple of posts from D300 regarding covert EGR delete.

And now I’m a little worried. His last post was June 17. I didn’t get the impression he was a geezer like myself. I’d hate to see him go.

http://www.peachparts.com/shopforum/diesel-discussion/412477-anybody-recognize-electrical-fitting-top-om603-ip.html#post4171125

http://www.peachparts.com/shopforum/diesel-discussion/412477-anybody-recognize-electrical-fitting-top-om603-ip-2.html#post4171285

cmac2012 · #29 07-22-2021, 12:44 PM

Quote:

Originally Posted by INSIDIOUS

Thank you. Where is the cast# found? Any photo of the vac pump?

The cast number can be found on the side of the head facing the driver side toward the front of the car.

Usaguy · #30 07-22-2021, 03:58 PM

Quote:

Originally Posted by cmac2012

The cast number can be found on the side of the head facing the driver side toward the front of the car.

To add to this post: You read just the 7th and 8th number. Its a #14 head in the photo.

Some people might think that they have a #16 head. They all have 016