OM603 VS. OM606 - PeachParts Mercedes-Benz Forum

benzguy300 · #1 07-25-2009, 01:31 AM

I'm looking to buy a W124 with a OM606 my daily driver is a W124 300TD with a 603 and I love the way it drives. Any issues with the OM606 like the head on the 603 any thing to look for on the 606 is the 606 a better engine then the 603?

pawoSD · #2 07-25-2009, 01:37 AM

The 606 is an awesome engine, better than the 603 in many ways....no head issues, much more power, better economy....etc. An all around more modern and robust engine. The main issues that it seems to have are fuel system/seals/o-rings related. The delivery valves on the Injection Pump leak eventually, and there are a lot of little o-rings in the fuel system that can get brittle and leak air/cause running issues. The motor itself is good. It also has the risk of stuck glow plugs in the head.....that is one of the other biggest issues.

Jeremy5848 · #3 07-25-2009, 02:16 AM

Quote:

Originally Posted by pawoSD

The 606 is an awesome engine, better than the 603 in many ways....no head issues, much more power, better economy....etc. An all around more modern and robust engine. The main issues that it seems to have are fuel system/seals/o-rings related. The delivery valves on the Injection Pump leak eventually, and there are a lot of little o-rings in the fuel system that can get brittle and leak air/cause running issues. The motor itself is good. It also has the risk of stuck glow plugs in the head.....that is one of the other biggest issues.

If I could be picky here, the TURBO 606 is more powerful than the 603 but the NA version in the '95 W124 and the '96-97 W210 has less power and feels like it has much less power. You have to let the 606NA engine wind up before you get any power out of it, it lacks the low-end oomph of the 603. I own both, I know.

Otherwise, the 606 has no significant problems, especially no head problems. In both NA and turbo versions it is more economical than the 603. As PawoSD says, there can be o-ring and fuel line problems (I have had some) but these are things you can fix yourself. I have not had any stuck glow plugs (have replaced only two so far) but others have and it can be a problem.

Jeremy

W124E300TD · #4 07-25-2009, 04:54 AM

Quote:

Originally Posted by Jeremy5848

If I could be picky here, the TURBO 606 is more powerful than the 603 but the NA version in the '95 W124 and the '96-97 W210 has less power and feels like it has much less power. You have to let the 606NA engine wind up before you get any power out of it, it lacks the low-end oomph of the 603. I own both, I know.

Otherwise, the 606 has no significant problems, especially no head problems. In both NA and turbo versions it is more economical than the 603. As PawoSD says, there can be o-ring and fuel line problems (I have had some) but these are things you can fix yourself. I have not had any stuck glow plugs (have replaced only two so far) but others have and it can be a problem.

Jeremy

The 300 TD has the NA 603?

Haven't heard of any 603 engines with engine wiring harness-issues - but the 606s harness can be troublesome.
The wiring insulation were supposed to be degradable and easy to recycle - and degrade it does...

cessna5354 · #5 07-25-2009, 06:16 AM

I would not steer clear of the 606 due to fuel leaking prob's. After 200k I replaced all hoses, DV Orings & washers, and shut off valve Oring. Holy Crap, This engine ran like new(actually 50K when I purchased).
The only head problem I know of is if you break off a GP. I am not a great mech, certainly within this arena, but I have done these items in several hours for $300. Spread over the miles, I can take that, and I am looking for another instead of a replacement 603.
Wiring harness, trans wiring harness, spring perches all things I have not encountered on my '99.

Good Luck,

DslBnz · #6 07-25-2009, 09:29 AM

If you want something that will offer the least amount of risk, mechanically. Go with any OM606.

Power and fuel economy is a wash, if you're good with your tools, facts and figures.

Jeremy5848 · #7 07-25-2009, 11:32 AM

Quote:

Originally Posted by W124E300TD

The 300 TD has the NA 603? . . .

All 603s imported into the USA were turbocharged. Don't know if Europe got an NA version, don't know if an NA version was built.

Number_Cruncher · #8 07-25-2009, 12:39 PM

All UK 603s were NA - apparently there was too much difficulty in fitting a turbo to a RHD car, as the exhaust and steering box wanted to share the same space! We had to wait until the later W210s to get 3 litre turbo diesels here.

In the rest of LHD Europe, turbo 603s were available, but, I'm not sure about NA 603s.

I would very much like to update my 95 W124 E300D to turbo form, but, it will take some good fortune to find the parts (and more understanding from SWMBO than I'm entitled to expect!). I'll need the engine from a W210 E300TD, and probably the injector pump from one the turbo 603s, which would need a bit of tweaking, because there's no way I would install the electronic nonsense from the W210.

matthias08 · #9 07-25-2009, 01:14 PM

I absolutely love my OM606NA. its gotten better fuel econ than anything I've owned... and no engine related problems yet, I'm just doing some catch up maint. from the previous owner

Jeremy5848 · #10 07-25-2009, 01:35 PM

Quote:

Originally Posted by Number_Cruncher

All UK 603s were NA - apparently there was too much difficulty in fitting a turbo to a RHD car, as the exhaust and steering box wanted to share the same space! . . .

Interesting, thanks for the explanation.

W124E300TD · #11 07-25-2009, 02:19 PM

Quote:

Originally Posted by Number_Cruncher

In the rest of LHD Europe, turbo 603s were available, but, I'm not sure about NA 603s.

Overall there were built 3 times as many 124s with NA 603 than Turbos.

Quote:

Originally Posted by Number_Cruncher

I would very much like to update my 95 W124 E300D to turbo form, but, it will take some good fortune to find the parts (and more understanding from SWMBO than I'm entitled to expect!). I'll need the engine from a W210 E300TD, and probably the injector pump from one the turbo 603s, which would need a bit of tweaking, because there's no way I would install the electronic nonsense from the W210.

Interesting!
Have you given any thought to the transmission/rear end?
I don't think the 722.435 will love much more power...

babymog · #12 07-25-2009, 04:00 PM

The E320 (M104) had something like 230hp, not sure on torque, in the 124 body.

I'm pretty sure the transmission is the same as the turbodiesel 124s other than ratios, shift points, and stall speed.

Quote:

Originally Posted by W124E300TD

Have you given any thought to the transmission/rear end?
I don't think the 722.435 will love much more power...

W124E300TD · #13 07-25-2009, 06:40 PM

Quote:

Originally Posted by babymog

The E320 (M104) had something like 230hp, not sure on torque, in the 124 body.

I'm pretty sure the transmission is the same as the turbodiesel 124s other than ratios, shift points, and stall speed.

The big gasoline-engines and the TDT uses 722.3xx transmissions - much more heavy duty.
Mercedes-Benz never connected the 722.3xx to the OM606 Turbo or NA, they used the more modern electronically controlled 5 speed 722.6xx.

Jeremy5848 · #14 07-25-2009, 07:18 PM

Quote:

Originally Posted by W124E300TD

The big gasoline-engines and the TDT uses 722.3xx transmissions - much more heavy duty.
Mercedes-Benz never connected the 722.3xx to the OM606 Turbo or NA, they used the more modern electronically controlled 5 speed 722.6xx.

The 1995 (W124) and 1996 (W210) E300D both used the 4-speed 722.4 mechanical/vacuum transmission. The E300D (W210) in 1997 and later got the electronic 5-speed.

My 1987 300D Turbo (W124, OM603) has a 722.357 transmission -- at least that's the number stamped into the body. I don't know if it is original or not, the poor car was abused as a child. EPC says it is supposed to have a 722.317.

Jeremy

babymog · #15 07-25-2009, 10:47 PM

... which is in line with what was stated above, that the 3L and larger gas 124s and the 3L turbodiesel 124s got the 722.3xx where the 2.5turbodiesel, 606NA, and 2.6/2.8 gassers have the 722.4xx transmission. I was not aware of this, had to look it up, haven't had any of the .4xx equipped cars.

I wonder also if 'cruncher's car is a stickshift, being a UK car.