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Old 05-06-2003, 01:02 PM
JHZR2's Avatar
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Location: New Jersey
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my diesel purge experience


I did a can of diesel purge for the first time ever in my car, as a 200k 'treat'. I have never used it, and I really doubt the previous owner ever did either.

Ill usually put a splash of rotella DFA into my tank every few tanks int he warm weather and nearly every tank in the winter, to keep water and gel in check. However, on a trip to TN a few weeks ago, I got a bad tank of fuel, and my mileage dropped from a rock steady 28.6-28.9 for the last 10 tanks, to 23 for that one. After I drove and refilled, I was back to the the 28 range. It seemed OK, but I figured it was a good time to do the purge.

It went through (I had someone watch it for me as I couldnt be around due to work), and now that I have run again on diesel Ive found that:
-the idle sounds faster, although the tach registers the same numbers as usual
-the idle sounds clearer
-there is less diesel knocking
-After everything was reconnected and I restarted on diesel, I let it sit. The first cold start, the car really smelled like strong diesel exhaust
-the car shakes slightly less at idle when hot (It didnt always do it anyway)
-the car doesnt feel like it has any more power
-throttle response is unchanged
-turbo lag/pickup is the same

All in all, I was neither impressed or unimpressed. It definitely seems a little different at idle, but thats the only thing I have noticed. Will I use it again? maybe. Ill keep using the rotella DFA from time to time, because it is pretty cheap by the gallon with rebate at wal-mart. I might do diesel purge in another 50k, but not until then... I can see how it would do a really good job in a car that is used around town or with a poorly maintained engine (mine always is used on highways).

So those are my observations, in case anyone is considering doing the lubro-moly diesel purge for the first time...


Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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Old 05-06-2003, 01:41 PM
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Location: Reno/Sparks, NV
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Thanks for the input. I'm considering doing Diesel Purge too, but first I'll probably wait until I refuel because I suspect I got a bad tank of fuel last time as my car misses during cold idle. If the new fuel doesn't fix it, I think I'll want to try the purge. Where can I get it and how do I use it?
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL
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Old 05-06-2003, 04:20 PM
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What is "rotella DFA"?
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Old 05-06-2003, 06:03 PM
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Location: Houston
Posts: 131
Rotella branded Diesel Fuel Additive. Claimed benefits includes cleaning, anti gel, and cetane improvement. Don't know how effective it is since I have not used it myself.

16 GLC300
12 C250
98 E300D
89 300SE
84 300SD sold
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Old 05-06-2003, 06:25 PM
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Join Date: Aug 1999
Location: Cincinnati, Ohio
Posts: 1,937
I personally don't care much for any of Lubro Moly's products. Rather, I prefer Red Line.

A long time ago I had a 240D with a bad injector ping and Diesel Purge didn't do a thing for it. The first bottle of Red Line took care of it right away. I've been faithful ever since.
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Old 05-07-2003, 12:16 AM
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lubro molly

this place has the best price onthe purge 4.50 a can... they also have mb coolant for 10 bux a gallon..

I run a can of purge thru all three of my 124 turbo diesels twice a year.. its cheap enough and it does help .. they say its the strong medicne for sick diesels!
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Old 05-07-2003, 12:20 AM
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site.. :>
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Old 05-07-2003, 04:36 PM
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run it pure, not through the fuel tank!

JHRZ2, To get the true benefits of using diesel purge you need to run it DIRECTLY (at full strengh) through the engine for about 20 minutes. There are some posts here how to it. To put diesel purge in the fuel tank is a waste of money and the results are nill!

1982 240D 313,000 (4 speed)
1984 300CD 172,483
1985 German Shepherd Dog -Lacey- R.I.P.11/04/05

Hood Stars, Wrist Crowns and Obsession Dobs
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Old 05-07-2003, 05:11 PM
JHZR2's Avatar
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Maybe I didnt specify... Thats what I did... It ran straight through.
Current Diesels:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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Old 06-15-2005, 03:52 PM
Join Date: May 2005
Location: CALIF
Posts: 508
Diesel Purge

Remove Large Fuel Filter At Left Side Engine And Fill With Can Of
Diesel Purge Install And Drive
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Old 06-15-2005, 04:27 PM
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Location: Deltona, Florida
Posts: 2,360
Putting it in the filter is also a waste as the unused purge goes back to the fuel tank.
The proper way to do it is here:
Click Here

When I did it I didn't notice much of a difference. It ran great while it was on the purge but as soon as it got diesel fuel it was the same as it always was.

1984 300SD Turbo Diesel 150,000 miles

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Old 06-15-2005, 08:19 PM
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Location: Alpine, AZ / Green Valley, AZ
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Remember - Diesel Purge will only help you if the injectors were somewhat dirty to start with. I run Redline on a regular basis (3 oz at fill-up, with an occasional half bottle instead of the 3 oz) and my injectors are clean enough that running a can of Diesel Purge through it doesn't provide any noticeable improvement. I still keep a can of DP around in case of an emergency, though.

It would probably be a little cheaper to not use the Redline and to use DP every six months or so, but I've been running Redline for so long that really don't want to change. Besides, it is also an algaecide,

just my $.02.
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Old 06-15-2005, 09:11 PM
WANT '71 280SEL's Avatar
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Do you guys run the Redline directly like the DP or just add the specified amount to the tank?


2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Old 06-15-2005, 10:08 PM
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Join Date: Feb 2000
Location: Powder Springs, Georgia, USA
Posts: 207
the bma website quoted above seems to have a few glitches. I can't get to where the Lubro Moly is.
David McDonald
1981 240D
1985 300D (wrecked)
1985 300TD 365,000 miles
1969 Mustang Fastback
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Old 06-16-2005, 02:19 AM
lrg lrg is offline
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Location: San Francisco
Posts: 1,163
I use Redline additive too. I put a couple of ounces in with every fill up. I'll also use it to fill the secondary fuel filter when I do a filter change. I've done a Diesel Purge on both my cars and felt little or no difference. I tend to agree with Wes that my injectors weren't dirty enough to feel the effects of the cleaning.

1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold
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