Fuel additives - waste of money? - PeachParts Mercedes-Benz Forum

GregS · #1 12-28-2002, 11:27 AM

I'm just wondering what the general opinion is of additives like Power Service or Redline Fuel Catalist. It seems to me like these things might just be snake oil and I'm ultimately just wasting my time and money purchasing them. Has anyone ever talked to a Bosch or knowledgable diesel mechanic to get their take on these products?

Of course some products are important to prevent gelling in the winter, but my main goal is lubricating the pump. I have read that sulphur was reduced in fuel in the early 90's, and that this caused the death of many injection pumps. Is this true? Were Mercedes pumps affected by the change in sulphur? Are additives really going to protect the pump? Have any of you out there been running your diesels for years without additives? So many people say the pumps on the 617 engine never have problems that I think I should just fill it up and not bother with the bottled additives.

Thanks for your opinions,

Greg

P.S. Lets keep this thread limited to marketed diesel additives rather than the pros and cons of adding ATF or motor oil to the tank. Thanks.

tryan · #2 12-28-2002, 11:53 AM

i used to use redline in a 79 240. the injectors where worn and the additive made them quieter. eventually i just replaced all the injectors, cheaper in the long run.

the fuel you buy at the pump has its own additives. adding them is a waste of money unless you have crappy fuel ( water and or microbs )

i buy my fuel for all my cars/boats at the same station. it leaves no question of fuel quality. i try to run down to the last gallon before i fill up.

your injection pump internals are lubed by engine oil. the seals reform themselves to the new fuel ( sept 95? ), so you may get a leak from that.

we are supposed to get another formulation in 2004 according to epa mandates.

atf will destroy your injectors instantly.

Stevo · #3 12-28-2002, 12:04 PM

You don't have to worry about lubing the pump as your engine oil gets to it. Red Line or Molley purge can be very helpful cleaning injectors in conjunction with a good Italian tune up.
I personally don't add anything till theres a problem.

Diesel 924 · #4 12-28-2002, 12:50 PM

Power Service white bottle in the winter, 'Diesel-Kleen' in the summer. Every fill-up.

rwthomas1 · #5 12-28-2002, 04:57 PM

Okay, first of all I have never seen an oil feed line to an injection pump. Granted I have never done a pump on an MB but I seriously doubt the pumps are lubed by crankcase oil. Secondly these pumps were designed when fuel had sulphur in it for lubricating properties. Now maybe the barrels/plungers in your pump will be fine without it but then again maybe they won't..... Thirdly diesel fuel in the US is pure cat-pee. It is often contaminated with other fuels, water, etc. and usually has a low 40centane rating to boot. Getting your fuel from the same place is a great idea but what do you do when you are on a trip? Buying from a high-volume place is a good idea but is no guarantee either. I have always used Stanadyne Performance Formula in my diesel vehicles. I occasionally have picked up a load of fuel that caused a loss of mileage/performance but I believe the regular additive use kept it from being a real problem. I buy the Stanadyne by the case so the cost to treat 20gallons is $1.60 (price includes shipping to my door). $1.60 per fillup is a small price to pay for a little peace of mind. In the truck it has proven to be worth +0.5mpg (proveable) so it pays back for itself even if its only a little bit. I have also taken to adding 2oz of two-cycle oil to each fillup but I have not been doing this for long so I don't know if it affects mileage or anything else yet. Maybe the pump fuel is okay and maybe it provides enough lubrication and maybe the cetane is high enough and maybe there is enough anti-gel additive, etc. etc. When I put the Stanadyne in the tank I am SURE that it is taken care of. For anyone who is obsessive about their car and its maintainence to NOT be concerned about the quality of what goes in the tank is beyond me. RT

"atf will destroy your injectors instantly"-Hogwash. While atf may not be the best thing to put in your fuel system it certainly will do no damage in the short-term.

Stevo · #6 12-28-2002, 05:54 PM

rwthomas1

Hummm....... No oil feed line. My "78",and "80" have oil lines that come into the pump on the outboard side, close to the bottem. You better oil it if you dont have an oil line.

240Joe · #7 12-28-2002, 06:19 PM

Unless you are worried about the fuel gelling up, additives are not needed. I will use power service (white bottle) if it's going to be near zero, but only sparingly.

Many people are confused on the fuel lubrication issue. These injection pumps don't use the fuel for lubrication so it doesn't matter.

Most additives boost the cetane rating but again that really doesn't matter much if you above zero.

And I would definitely not put ATF in the tank. While it probably doesn't hurt much, since it is formulated to withstand extreme temperatures, ie not burn, it's not the right thing for the combusion chambers.

Only my 0.02.

Joe

BJ300SDL · #8 12-28-2002, 06:22 PM

If you have never worked on a Mb pump then by what means do you base your facts from?

The reason you don't see the oil line is because it is an oil galley part of the case bolted to the block. Not a rubber line.

Oil lubricates the cam, flywieghts, cam followers etc.

However fuel does lubricate the pumps.

Stevo · #9 12-28-2002, 06:31 PM

just to add a little fuel to the fire I have heard it said that ATF causes soot build up, ok, I know, lota folks swear by it, I was the same guy that heard excissive ideling can cause soot build up too, Maybe old wive's tails but I believe it.

240Joe · #10 12-28-2002, 06:40 PM

Stevo

I agree with both items. I've heard mercedes issued a tech bulletin many years ago telling people not to idle them longer than 5 minutes.

I think what it comes down to is that these engines are so robust that even with a little abuse, they just keep going....assuming the correct maintenance is done.

Joe

rwthomas1 · #11 12-28-2002, 06:49 PM

I base my opinion on the experience I have with other diesels. I have done pumps on VW's, GM's and some marine stuff and I had never run across a pump which was engine-oil lubed. I never said nothin' bout "facts" Mostly wrenched on Bosch VE type pumps which don't have oil lube. I just checked my service CD and I was WRONG and STAND CORRECTED, MB pumps are indeed lubed by engine oil. I still think that a lubricating additive is cheap insurance. I also don't see how you can argue that increasing the cetane is a bad idea? 40cetane is what I see on most pumps and that is crap. I have tried others but Stanadyne gives me the best results even though its not the cheapest. Reduces smoke and improves MPG=probably a good product. Its pretty simple really, if you don't want to use an additive then don't. The cost is so low it matters not. RT

Stevo · #12 12-28-2002, 06:51 PM

BJ300SDL

I think his has an actual hose to it. I thought all the W 123, 240s and 300s were like that. On your later car the oil passes in unseen then. I guess the older cars had little dip sticks to check the oil and my MB mechanic buddy claims the older pumps had "goat skin" diaphragms. wonder if it had to be goat?

Stevo · #13 12-28-2002, 07:14 PM

rwthomas1

I can understand your reasoning about the oiling of the pumps if you came from the marine side of things. I was not an engineer (mighta been easier to find a job) but thats my background and the fuel lubs the pumps on most marine engines and I also assumed it was the same with MB.

BoostnBenz · #14 12-28-2002, 08:28 PM

Well I wasn't sure if it was worth the money or not but I bought a gallon of DFC for about $43 shipped. It should last quite a while, so the price is quite minute when you figure how little you add in. Anyway when I bought the car I had to drive it back from North Carolina, I probably put around 1-2k on it before I put the first fuel additive in it. Then after driving maybe another 1k with the DFC I noticed a funky smell at idle. My fuel injector bypass hoses were spewing out fuel through the SIDEWALL! So apparently the cleaner portion of DFC works....

Another thing to note is that most gas stations sell anywhere from 40 to 45 cetane most on the lower portion, kinda like low octane gas. The big tractors and such don't mind it, but our mercedes were intended to run 45+ cetene, the fuel additive also boosts this up few points.

~jm

sublettm · #15 12-28-2002, 10:58 PM

I might be ignorant, but how did the diesel additive cause leaks through the sidewalls of the bypass lines? Curious about this because I have only had my '84 for about four months now and when I first got it, the bypass lines weren't leaking, and now they are. I have been using the Rotella additive with every fill up.

I agree with the posts that whether the additives do any good or not, the little bit of money it costs to buy the stuff is good insurance. I might be burning money, but it is better to err on the side of caution. My father bought his first 300D in '84 I believe and as far back as I can remember, he has been putting additives in his tank. His cars, he owns two 300D's, both run like champs. I own three of these cars, only two of them are road worthy though, and I will continue to run a diesel additive through them until someone can give me clear proof that doing so will cause damage to my car.

Mike