M103 full maintenance recommendations - PeachParts Mercedes-Benz Forum

OM618 · #1 12-30-2008, 02:49 PM

I'm about to do a full maintenance change on my 91' 300SE and was hoping for some recommendations on some of the best parts to use.

OIL:

I've heard and seen great things about Royal Purple oil. If I do buy a synthetic this will be it. However, I'm aware that most engines don't need to run full synthetic and in many cases it's complete overkill. Yet, the M103 is a high revving engine, and I'm wondering if it would be useful to run a full synthetic oil in this engine.

Another concern would be the effect on the seals of this engine going from dino to syn. Would full syn quantifiably change the structure of the seals, possibly causing leaks?

Also, is it OK to run API grades higher than OEM recommendations for further protection against wear? I was considering running 20w-50 during the very hot Texas summers, but I'm not sure of the effect this would have on the engine besides reducing fuel efficiency.

OIL FILTER:

I've normally used FRAM but I'm hearing from many that this is a very poor quality filter. Suggestions?

AIR FILTER:

Again, I've normally used FRAM but I'm hearing that this is a poor quality brand. Is K&N a much better choice? What would be the best choice for this motor?

SPARK PLUGS:

There was just recently a post about this very topic but it quickly derailed into argument about circuitry. How about some quick suggestions on best personal experiences?

I think I've got the rest of my bases covered, but I'd enjoy hearing from you all about any other maintenance products you've had positive experiences with.

Thank You.

deanyel · #2 12-30-2008, 03:11 PM

Click on Buyparts / Fastlane at the top of the page to get some nice "German" parts. You can run synthetic if you wish but the engine doesn't require it. Try a search for lots of threads on this.

pifcat2 · #3 12-30-2008, 03:32 PM

You list a very basic maintenance list, there are many things to check to be a "full" maintenance. Start with your owners manual. There's a dealers check list too.

Why use synthetics if not necessary? It's a matter of cost, does it's higher cost buy you more longevity or better performance? I used Mobil 1 on my RENNTech modified motor but standard oil on my stock motors. Just replace on schedule.

When in questions, use factory filters, buy them from discount Benz suppliers or eBay bulk for a cost savings.

There are specific plugs for this model and several brands to chose. Don't use Platinum.

pawoSD · #4 12-30-2008, 04:20 PM

Quote:

Originally Posted by OM618

I'm about to do a full maintenance change on my 91' 300SE and was hoping for some recommendations on some of the best parts to use.

OIL:

I've heard and seen great things about Royal Purple oil. If I do buy a synthetic this will be it. However, I'm aware that most engines don't need to run full synthetic and in many cases it's complete overkill. Yet, the M103 is a high revving engine, and I'm wondering if it would be useful to run a full synthetic oil in this engine.

Another concern would be the effect on the seals of this engine going from dino to syn. Would full syn quantifiably change the structure of the seals, possibly causing leaks?

Also, is it OK to run API grades higher than OEM recommendations for further protection against wear? I was considering running 20w-50 during the very hot Texas summers, but I'm not sure of the effect this would have on the engine besides reducing fuel efficiency.

OIL FILTER:

I've normally used FRAM but I'm hearing from many that this is a very poor quality filter. Suggestions?

AIR FILTER:

Again, I've normally used FRAM but I'm hearing that this is a poor quality brand. Is K&N a much better choice? What would be the best choice for this motor?

SPARK PLUGS:

There was just recently a post about this very topic but it quickly derailed into argument about circuitry. How about some quick suggestions on best personal experiences?

I think I've got the rest of my bases covered, but I'd enjoy hearing from you all about any other maintenance products you've had positive experiences with.

Thank You.

I switched our M103 to synthetic the moment I got it. Mobil 1 0w40 synthetic is the right stuff and is recommended by MB. Also use the Mobil 1 oil filter, it has the proper anti-siphon/drainback valve in it like the factory intended. I've driven ours nearly 1500 miles on synthetic and it runs very smooth and has had no issues with it.

For air filters use a quality german brand, like Mahle or Hengst...both available from the online retailers.

Spark plugs, go to the dealer and get a set of the proper Bosch non-resistor plugs. About $20ish for a set.

Check the belt and other things for wear and any issues.

tinypanzer · #5 12-30-2008, 05:47 PM

I agree with whoever told you that Fram filters suck. If you cut one open, you will see why. There are way too many cardboard components in there. The anti-drainback valve is a joke, as is the bypass valve. These filters plug up fast and go to bypass. Although, since bypass is built into the 103, I'm not so sure if a 103 oil filter even has a bypass, but most others do.

Good brands are Purolator, NAPA, Wix, and any other brands that are ultimately manufactured by those makers. I think NAPA is a purolator, but I forget. At one point I did a bunch of research on oil filters. There are some good sites out there that have comparisons of all the brands. The consensus is that Fram filters are cheap garbage, as are all the brands made by them such as the Penzoil filters provided by SuperLube..... Yet another reason to avoid that place.

While you're doing your plugs, you will want to at least inspect if not replace the cap and rotor.

Also, pull off the air cleaner and inspect all those vacuum lines under there. There are lots of places for cracks to develop leaks. Take a nice lint-free cloth and wipe all the crud out of the air intake underneath the air meter flap. You'll find that it gets pretty oily/dirty in there especially if you have a K&N air filter. Avoid FRAM. If you use a K&N you must be religious about cleaning and oiling it or you will let dirt into your motor. Too much oil, and that runs down into the intake as well. I use a K&N, but sometimes I honestly wonder if all the effort and risk is worth it.

Take some grease in a small syringe and lubricate all of the linkages to your accelerator pedal. This can make a big difference in throttle response.

Inspect the breather hoses, especially the funky one with two 45 degree bends in right behind the big one that goes to the air cleaner. That one tends to get cracks on the underside that are otherwise invisible. When it finally opens up, the vacuum leak is huge and causes much havoc.

Snug up all your radiator hoses while you're at it.

-tp

S-Class Guru · #6 12-30-2008, 06:24 PM

OM, I have a car that is "kinda similar" to yours - '91 300SE.
It has spent it's entire life in Texas; approx 180k miles, and I have owned it since it was a baby.
(Up-front disclaimer: Just my opinion, your mileage may vary, etc, etc).

1. Oil
I tried M1 for awhile, but soon concluded that the major benefits of synthetic oils are in super-tough conditions like very cold startups, desert towing, racing, turbos, or very long oil-change intervals. I don't do any of these in the old Benz (but I definitely run M1 in my modified Vette).
For the last 8 years or so I have been running Valvolene 10w-40 Max Life.
It is supposedly formulated with the viscosity at the top of the 10-40 range, and has additional detergents and seal conditioners. May be marketing BS, but it sounds good.
I have had no oil-related issues whatsoever in 180k miles - when we redid the head gasket at 110k, the cylinder bores looked like new, and there was no sludge at all. Initial startup is still where 90% of wear occurs, so I think the 10-40 is the best compromise for even a very "experienced" Texas engine. I fully expect my motor bottom end to go 300k. No matter what you use, the front timing cover will leak every other year.

2. Filters. I use a Purolator oil filter. They have the anti-drainback feature, and Pepboys always has them in stock. I suppose there could be better filtering ones, but I have no definitive proof of that; and no problems.
Same for the air filter; I buy a name brand paper filter. Everyone argues the benefits of the K/N, but everything I have seen on the Corvette Forum indicates the K/N replacement element (not the whole cold air kit) is less restrictive, will make a tad more power (1-2%) on a high-horsepower engine, but does not filter quite as well as a good paper unit. I wouldn't notice 1.5 HP on my M103, so paper it is.

3. Spark plugs. We all agree: NON-RESISTOR PLUGS ONLY.
The OEM Bosch H9DC is still the recommended one, but pretty hard (impossible) to find. I bought up a 10-year stock awhile back. I hear there is an NGK equivalent NON-RESISTOR one available - do a search here, tons of info.

Things you didn't ask:
- plug wires are stranded copper, and last a very long time if treated well.
- Ditto for the rotor and cap.
- Use the yellow antifreeze for Daimler-Chrysler cars. Autozone carries it - Zerex I think, but can't remember.
- change your power-steering filter, and use the MB fluid.
- When changing the tranny fluid, find the torque-converter drain plug also. You can get 7/8th of the fluid drained.
- After 17 years, belt tensioners die at the worst possible time.
- PBR brake pads DO NOT DUST, and have 99% of the same pedal feel.

Lots more, just check the archives.

DG

tinypanzer · #7 12-30-2008, 07:47 PM

Good stuff, Guru.

I'd like to get 300K out of my 103 also, and you've confirmed some of my hopes and fears.

-tp

pawoSD · #8 12-30-2008, 10:52 PM

Quote:

Originally Posted by S-Class Guru

3. Spark plugs. We all agree: NON-RESISTOR PLUGS ONLY.
The OEM Bosch H9DC is still the recommended one, but pretty hard (impossible) to find. I bought up a 10-year stock awhile back. I hear there is an NGK equivalent NON-RESISTOR one available - do a search here, tons of info.

DG

Why does everyone say this? I walked into my dealer, said I needed 6 plugs for a M103, and 2 mins later they handed me a nice box of the H9DC bosch plugs for $20. The dealers have them!

OM618 · #9 12-31-2008, 01:00 AM

These are some GREAT replies!

I was trying not to saddle the forum down with a bunch of newbie questions (and yes, I have been using the search feature regularly), but it's great to be a part of a community that can really provide when there's a need!

As for the vaccuum hoses, belts, electrical components, brakes, suspension, etc. I'm pretty well versed in inspection and replacement of such things. I've gone through this "light overhaul" proceedure with 3 other used cars prior to becoming hopelessly addicted to MB's for the rest of my life.

First was a farking NIGHTMARE of a car - an '87 Cadillac DeVille w/ an '88 HT4100 4.5L V8 in it.....*pukes in mouth a bit* ahem. Second was my little Isuzu I-mark hatchback, which seems to talk to me and tells me that it will run forever no matter how much abuse I mette out to her. Thirdly was my brick; an '89 Volvo 740 GLE 16-valve, which, comapratively speaking is as fun if not more fun to zip around in than my 300SE (but not my '83 300SD, I farking <3 that car...though, I guess it dosen't really "zip" per se).

Now it's down to sprucing up anything I can on my 300SD/SE's, which, thanks to all you fine people, has been quite a pleasure so far.

Anyone heard of KEHL motors here in San Antonio? I've been curious if anyone knows him (Mr. Kehl) here on the forums. He's apparently a very well respected MB wrench.

EDIT:

P.S. I did an entire valve job and head gasket replacement on that '87 DeVille, hence my disgust...now it's become a candidate for the scrap yard, as it's currently in need for a rear main seal replacement

! We'll see if I can muster the patience for that...

S-Class Guru · #10 01-02-2009, 01:16 PM

PawOSD, you're a lucky man if your dealer has the spark plugs. The Dallas dealer said he was giving me the last set in existance about 3 years ago.
But he did come down from $4.50 to $2.50 each (such a deal).
He might have since gotten more in, but hopefully I won't have to ask.
That's when I went to Napa and bought all they (and 2 other stores) had in stock - for $1.05 apiece. Ah, love that MB dealer tax.

Hey, I had an old '82 Caddy Eldo with the infamous 4.2 engine. Finally got to trade it for the Benz when the wife began to notice every Eldo she saw had been turned into a lowrider! Sure enough, saw it about a year later - slammed and bombed.

cheers,
DG

pawoSD · #11 01-02-2009, 02:42 PM

Huh, I just find it hard to believe that Bosch would stop producing a spark plug for one of the most widely sold cars/engines out there. MB sold zillions of M103 powered cars both in Europe/USA/rest of the world.....the demand for those spark plugs is probably pretty significant.....

ps2cho · #12 01-02-2009, 06:29 PM

I contacted Zerex about their G-05 formula which I cannot find ANYWHERE local.

They responded:

Quote:

Our biggest supplier for Zerex products will be Carquest. Other options will include Napa Auto Parts and select Walmart stores. If these stores do not stock the products, please ask to order.

I'm gonna make some calls and see if they do in-fact carry it.

pawoSD · #13 01-02-2009, 06:50 PM

Napa has it, I've bought it there a few times recently.....