Shall I or not use diesel fuel additives ?




Ivo

1981 300SD Turbocharge

Why do you think you should or shouldn't?

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1994 C280 204k miles

Most here would agree that Red Line Diesel Additive is the best and only one that works. Dump a whole bottle in the tank to clean then an ounce or two at each fill-up for maintainance. Also, when you change the fuel filter that looks like an oil filter, fill it up with the Red Line before you screw it back on and that will really give it a super cleaning. I think Red Line now refers to it as #85, it's available at Pep Boys.

Also, for once or twice a year cleaning, Diesel Purge is great too.

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Mr. BILL

91 300E 120K
90 300SE 275K (sold)
92 BMW 525iM 120K
90 BMW 525iA 175K
85 300D 175K (sold)
84 300SD 245K (sold)

Here in Canada - they have switched to low sulphur diesel at the pumps to reduce air emissions. The sulphur lubricated the injector pump and injectors. Lubricant additives are recommended here to increase the lifespan of injectors and injection pumps. I read on a VW site a few years ago that you can use ATF fluid as an additive for lubrication. I have been using it for two years with no problems so far - just put in 3 oz with every tank. Inexpensive and it seems to work.

Ivo Tyl,

I wasn't trying to be a wise guy with my question, I didn't know myself and wondered if you had heard anything negative about mixing additives with diesel fuel.

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1994 C280 204k miles

Ivo,

I would recommend the Redline DFC if you are able to find it. It did make a difference on my 82 240D and have noticed that it idles smoother and less smoke than when I don't use it.

However, I don't use the additive in my 87 300SDL because it has a catalytic converter and there is a red sticker located inside the fuel door the specifically states "diesel only/no additives." I was warned on another post that additives usually contain some metals that will clog the converter with regular use....so I don't use it but my 300SDL idles smooth anyway.

Herb
'82 240D
'87 300SDL

So, just a guess, but I assume my 1981 300sd probably doesn't have a catalytic converter?

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1994 C280 204k miles

Herb:

That warning, I believe, is for the original trap that was on your car. If you have it replaced under the recall, you should have no problem with additives.

Quite a few people I know who have that particular engine use additive regularly. My 87 300TD has (essentially) the same engine with the trap removed and I use additive regularly without problem but with some benefits.

dwcasey,

I would bet that your 81 SD does not have a converter. My '82 240D doesn't.



loubapache,

Yes, the trap oxidizer on the 300SDL was removed. However, in removal process, MB installed a catalytic converter down further down the exhaust pipe that is located next to the transmission. I looked underneath the car and counted three objects along the exhaust pipe (the catalytic converter, the mini pre muffler, and then the muffler towards the back). If you look underneath at your '87 300, you will see the converter located adjacent to the tranmission, unless your setup is different that mine. But if you have been using additives all this time and have no ill effects then maybe the Redline additives don't have those metals.

Loubapache, could you tell me what type of additive you've been using, how long you've been using it and (if it isn't too much trouble) check to see if you have a catalytic converter? I would like to use an additive but I'm afraid that I would be damaging the converter.

Also, does anybody else on the forum that has this same six cylinder engine (603) with cat. converter have any ill effects from using additives, please chime in.

Thanks

Herb
'82 240D
'87 300SDL

Herb:

Yes, I know the catalytic converter in the 87 diesel (mine has one). All gas cars have catalytic converter and additive does not hurt them. What I tried to say is that the trap did not like additives but the catalytic converter is OK with addtives.

Many diesel fuels (#1 or premium) contain the same additives we can buy.

I use Power Service additives (two different kinds). One is more for cleaning and the other for ant-gel, etc. Both have some cetane boosts.

I have only been using it since Nov when I bought the car. The previous owner started using it after the trap recall (replaced with the catalytic converter) and she told me the MB shop service person told her to use because of the poor and inconsistent diesel quality.

I tried a few times without the additive and I observe noticeable roughness.

I know Lance on this forum who also has a 87 300SDL with over 250kmi. He uses Power Serice and Amsoil cetane boots.

Yes for 3 reasons - 1- keep fuel from jelling in cold weather
2- keep injectors clean
3- keep water suspended in tank

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1995 S-350
370K + SOLD
1952 220B Cabriolet
39K kilometers + SOLD
1998 E300D
310K +
2012 E350 BlueTec
120K

Ivo - go for it. They won't hurt your car. Just make sure your additive does NOT contain alcohol. I'd recommend first Stanadyne's performance formula or Redline's diesel fuel catalyst. I've only used Stanadyne with no complaints. This morning at 16 degrees my car barely turned over before firing up. Additives claim they will help fight fuel gelling in cold weather, increase cetane, clean injectors, lubricate fuel systems, and help separate the water in the tank.

DO NOT add ATF to your fuel, thats an old truckers' myth , and its not designed to be burned in an engine. The chemicals can harm your fuel injection system, and when its burned it leaves ash deposits in the engine. To use a cliche - use the right tool for the job, ATF is made for transmissions, not combustion.

hope this helps,
Dave

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2004 Ram 2500 Cummins HO
2000 Jetta TDI
1999 E300 (sold)

loubapache is absolutely right. I have an 87 300SDL (255k mi)and a 98 VW Jetta TDI (195k miles), both of which have catalytic converters.

I bought the TDI new and put several thousand miles on the 300SDL. All along, I've used a mix of the white bottle Power Service or Howe's Conditioner and Amsoil Cetane Boost with every tank. The idle on both cars is smoother, start better, and have less smoke compared to not using the additives. If I'm on a road trip and do not have the additive, I can tell the difference by about 1/2 way through the tank without additives. Also, I see a slight increase in MPG (more noticeable in the MB than in the TDI).

BTW: If you are concerned about the fuel system, I would recommend the use of additives. Maybe not at every fill up, but often enough. My TDI has the original pump and injectors. The 300SDL has the original pump and the injectors lasted about 254k miles. I had one injector get noisy, so I went ahead and replaced the set. The owner's manual of the car specifies not to use additives due to the trap oxider catalyst. Once it is removed and a regular converter installed downstream, as long as the additive doesn't contain metals, you'll be fine.

Everyone I know locally uses either Power Service, Redline (not the diesel fuel catalyst), Howe's, or Amsoil. The reason I use Power Service is because it is widely available, inexpensive, and turns acceptable results. Amsoil is about the only company I know of that offers a commercially available Cetane Boost product. It is sometimes a hassle to have to mail order Amsoil products and they are a bit pricey. A while back I purchased several individual cans and a 5 gallon pail of the stuff! As the cans get empty, I just keep filling them up from the pail...

If you'd like any more information about diesel additives, email me at LDA4793@UDNET.NET.

Cheers!

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Lance Allison
Lance@LanceAllison.com

Current:
11 MB S550 4Matic, 55k miles, Designo Black/Black
14 Ford F150 XLT Lariat Crew, 73k miles, 5.0
Coyote V8 4x4. Black/tan.
09 GMC Envoy Denali, 5.3 V8, 4x4 SWB. 38k miles,
Jewel Red/Med Gray.

Gone:
87 MB 300SDL, 320k miles, Astral Silver/Blue.
98 VW Jetta TDI, 488k miles, Classic Green/Gray.
85 Olds 98 Brougham FWD, 4.3 DIESEL V6, 80k
miles, 3x Gray.

MBCA Member, Chicago Region