Fuel additives - waste of money? - Page 2 - PeachParts Mercedes-Benz Forum

TimFreeh · #16 12-29-2002, 08:52 AM

I can't give you any proof that fuel treatments will damage your car but I can say that I have owned at least one Diesel powered vehicle for the last twenty years with maybe a half million miles of operation over the same period.

I have never used fuel additives and have, to date, have not had any fuel pump or injector failures. Use additives if they make you feel better but they are NOT required for normal operation. A quick look at the owners manual will confirm this.

Tim

#17 12-29-2002, 09:25 AM

The injection pumps on Mercedes do use engine oil... On the older 240 up to about 76 you have to check and add oil ot the pump.. and be sure to change it from time to time.. On the newer ones its fed from the engine saving the checking and changing..

I have put as much as 700000 miles on the old type pump where you have to change the oil.. the only real problem was the leather diaphram that controled the throttle under load.. They would get hard and need to be replaced or softened ...

On the newer pumps I have never had a wear problem but have only put 500000 on one pump.. The others had less miles when I got rid of them..

Additives are some thing I can not say work.. Most of my experience with them is when people come by my shop and complain their car is running bad.. Most of the time some one has talked them into putting lots of additive in the fuel.. and it has broken stuff loose and is fouling the injector..Odds are the stuff came from dirty filters.. I usaly just pull the injector apart and clean it.. Works most of the time.. However I have never seen that those cars using additives have less or more problems with injectors than those that do not use additives.. We do live in the high country.. We do buy fresh fuel at a truck stop that get several truck loads of diesel a day.. and we often run for miles climbing the hills with the throttle flat on the floor.. My 300TDT often has to be shifted down to 3rd and still ran on the floor on some grades.. That means that our injectors are opening all the way..

In pulling diesel injectors and working on them for the last 50 years the only real thing I see inside them is when they have damage from water.. that is far more common than you may think... The fuel filter on the Mercedes will absorb some water.. And changing them at least once a year is a good idea..

Most good Diesel injector and pump shops have a good system for checking injectors.. If you find a good shop around talk to them about checking and cleaning your injectors... They set them up and run cleaner thru them and see at what pressure they open.. They can look at the spray pattern and tell if its good and if the darn thing drips.. Often just pulling them every 4 or 5 years and having them checked is a good idea.. The shop I use will do 5 for 50 bucks.. And then you know.. Some times they will rebuild one but it will be rebuilt to open at the same pressure as the others so it will idle nice.. However like all shops you need one that is honest or you will get took..

Ken

#18 12-29-2002, 09:41 AM

Stanadyne, good stuff. I'm always on the ready to ID another snake oil. So, I did my homework on this additive business. It's really amazing how many of us throw our opinions on the forum and state them as facts. This is a really simple issue, because it is basic chemistry. Opinions have no bearing. Diesel is a sulfur rich (less so, these days) fuel. It is massed produced and piped and shipped and stored in huge quantities. It gets crap in it, it ages, it varies in quality from place to place and from day to day. A good additive helps reduce the soot build-up that results from the combustion of the sulfur. It breaks up the water and other garbage that gets in the fuel. The additive can help lubricate the IP. Mileage improves. An engine runs quieter and smoother with a good additive. Higher cetane rating, better IP lubrication, cleaner fuel. Most of our cars surpass 1/4 million miles; a little fuel quality improvement can only help. I once ran about a half gallon of Stanadyne through at one time to clean the injectors and nozzles. Totally eliminated a bad nailing problem.

So, if your car made it 300K miles or 600K miles, it would have made it there with less fuel, less damage to fuel lubricated parts, less varnishing of injectors and nozzles and it probably would have lasted even longer with an additive that improved the quality of the fuel/lubricant.

I drive a 1979 300SD with well over 300K miles. It runs quicker (very quick diesel - can grab a screech hitting 2nd), quieter and smoother with a few ounces of additive in each tankfull of fuel.

GregS · #19 12-30-2002, 12:45 PM

Thanks for the replies everyone. I started this thread, and one of the reasons I used the additives is that they claim to "disperse water." Since Mercedes do not come equipped with water seperators (VWs do!), I thought water dispersion was a valuable thing. But I recently installed a stanadyne fuel fitler/water seperator, so I began to wonder about the merits of additives. Besides, I never noticed any increase in fuel mileage with the additives, and the only time I ever notice a reduction in smoke is when I take a long trip and the car sees extended periods of high speeds. Otherwise, the car gets a lot of city driving, which will probably result in soot buildup with or without an additive.

So maybe the jury is still out.... Personally, I'd rather just not be bothered with the added expense and hastle of additing additives, so now that I have the water seperator, I don't think I will.

Thanks,

Greg
'84 300D, 172k

tryan · #20 12-30-2002, 03:59 PM

fuel contamination is a two fold problem.

#1. water.

#2. the alge that will grow in water contaminated fuel.

water can be resolved by a filter/separator.

alge must either be killed with an algeside , which might clog your filters/screens ect.

or alge may be dispersed in to the fuel , which will make your engine run at less than optimal.

#21 12-30-2002, 05:04 PM

I always use some additives on every fill up, just because it makes me feel better, and my 300CD seems to run better. In colder weather additives seem to help my car start better.

ricali · #22 12-31-2002, 07:27 PM

I bought my first 240D in 75 and has had many of them since. More hundreds of thousand of miles than I can count I have used them with and without additives. During this time I have burned every additive and every type of fuel. ATF, used motor oil, paint thinner (mineral spirits, home heating oil, kerosene, Canola oil, Scented lamp oil and biodiesel. All with no adverse effects. I have never had a pump, injector or any mechnical failure due to engine or fuel. I did have normal diesel gell solid and was unable to start the car for three days, till the tank warmed up. I just drove non stop on my homemade mixture of used french fry oil and power service 885 miles to North carolina averaging 32/34 mpg. On the return with straight diesel 32/34. The difference was my mixture always runs much quiter with NO smoke.
So I will continue to burn all mixtures, it makes me feel better.
Sorry to be so long winded.

#23 11-10-2003, 02:47 AM

I've had very good results using Howes Diesel Conditioner every fill-up, Diesel Purge four times a year and an Itlaian tune-up once in a while.

My 84 300DT will run to 100 kph in 12.50 seconds.

redbaronph123 · #24 11-10-2003, 03:52 AM

i've tried ATF, motor oil (sae40) and biodiesel.. so far i'm happy with biodiesel... so i'm sticking to using it.

rickjordan · #25 11-10-2003, 02:07 PM

I use Power Service, summer and winter formulas. The cetane levels in our diesel is garbage. Any booster will be a plus. As for the "expense". A bottle of PS at Walmart cost about $3.50 and will treat 100 gallons of fuel. For most of us that is easily 5 tank's worth. So $3.50 divided by 5 equals a mere 70 cents per fill up. Expensive?

Gurkha · #26 11-10-2003, 11:24 PM

I live in a country where dirty diesel is a norm, you should see my sedimenter after one month, it is full of crud. I have been using DALF from ELF for quite sometime and my IP goes without a rebuild for almost 100,000 miles, my injectors need recallibrating after 50,000 miles. All this I attribute to the DALF, now gas stations have launched diesel with additives and cetane boosters, they are pricey but well worth it as you engine sounds way better, runs better and smokes way less.

Yes additives are a must for both gasoline and diesel enignes but more so in diesels due to the inherent nature of diesel fuel.

If additives save me from a trip to the injector service station then it is worth every cents.

william rogers · #27 11-11-2003, 01:41 AM

My 74 240 D has a red cap on top the IP for adding oil, but my 81 SD dose not and oils from the engine oil. I have the origional owners manuals for all three of ny MB's ,will wonders never cease.......
William Rogers.........

Hawk180 · #28 11-11-2003, 04:05 PM

OK here's my $.02 worth. I grew up around big trucks, back when additives were few and expensive. We used ATF quite a bit. But you must be careful as some of the atf's have some solid grit in them and some don't. I think Type F has grit, Dextron does not. (Could be the other way around as it has been a long time since I used atf in the diesel tanks). Of course, that was in Mack trucks with LARGE diesel engines. Recently, we have been using Power Service in the silver bottle, (2 litres for 300 gallons) and it has been working great. As far as my Mercedes Diesel, when I start it in the mornings, it smokes quite a bit without the power service, hardly any with it. not to mention it runs much smoother. I use about 4 ounces per tank full. I knoe I will be changing the injectors soon as these have over 200 K on them. #2 is starting to nail when cold. I guess 200K+ is enough on those springs.

whunter · #29 05-09-2007, 11:53 AM

good reading for all diesel owners.

csp97 · #30 05-10-2007, 11:09 AM

Quote:

Originally Posted by BoostnBenz

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

Just a comment. I work in an oil refinery, and the minimum cetane spec in the US is 45. I'd be suprised if there's anything lower out there.