Easy Lubro Moly Diesel Purge How-To - with pics!!

Thanks for the write up. Unfortunately, there is no noticeable difference on my 205,000KM 2002 Jetta. I had hoped, as others have reported, that this would alleviate some smoke on startup.

I will, however, try some Opti-lube as you suggest, tongsli. Are you running it straight or as a fuel additive?

I did this procedure about a year and a half ago as well.

It felt like I was in the driveway idling the car (running it on purge) for a long time. Next time I hope to set it up so that It's good for moving the car during the procedure. Go pickup some milk or something while running diesel purge.

Deadend said:

I did this procedure about a year and a half ago as well.

It felt like I was in the driveway idling the car (running it on purge) for a long time. Next time I hope to set it up so that It's good for moving the car during the procedure. Go pickup some milk or something while running diesel purge.

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Yeah, makes you aware that these things really do "sip" fuel

I didn't have an issue with my car, but when I changed the fuel filter (first time servicing one of these things) I filled the canister up with Diesel Purge.

UhOh said:

Yeah, makes you aware that these things really do "sip" fuel

I didn't have an issue with my car, but when I changed the fuel filter (first time servicing one of these things) I filled the canister up with Diesel Purge.

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You guys are supposed run the purge through the various RPM range and hold it for a few seconds at a time, not just let it idle. From idle all the way to 4500 RPMs..

Found Lubro-Moly DIESEL PURGE today at NAPA for $9.29 (500ml)

How cool is that?

I agree you should vary the RPM during this procedure... I set up a fan to blow at the radiator while it was going on.

I didn't want to read thru 39 pages on this thread but what is the recommended mileage interval we should do DIESEL PURGE?

100-200K miles depending on how smokey you run.

Hey guys, I just bought a 2002 Jetta and am in the process of changing all the fluids and filters etc...before seeing this thread I changed the fuel filter and oil (Rotella T6). Want to try purging the car before a 3000km roadtrip at the end of August, but it obviously won't be due for another oil and fuel filter change before then. Questions are:

- Just how necessary is it to change the oil after purging? I've seen people say in this thread that it causes degradation of the oil quality but is there any evidence/testing to back that up? I could change the oil again before the trip but there will only be around 4000km on it by that point and T6 is $50/jug up here.

- Why may be the fuel filter affected by the purge if it's a closed process outside the fuel filter?

First diesel so please excuse the newbie questions, thanks.

speedmachine said:

Hey guys, I just bought a 2002 Jetta and am in the process of changing all the fluids and filters etc...before seeing this thread I changed the fuel filter and oil (Rotella T6). Want to try purging the car before a 3000km roadtrip at the end of August, but it obviously won't be due for another oil and fuel filter change before then. Questions are:

- Just how necessary is it to change the oil after purging? I've seen people say in this thread that it causes degradation of the oil quality but is there any evidence/testing to back that up? I could change the oil again before the trip but there will only be around 4000km on it by that point and T6 is $50/jug up here.

- Why may be the fuel filter affected by the purge if it's a closed process
outside the fuel filter?

First diesel so please excuse the newbie questions, thanks.

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1. Given the comparatively minuscule amount of DP that could possibly get in the oil, don't worry about it.

2. You answered your own question. Since the filter is bypassed, there's no need to change it.

Drive more, worry less...

1854sailor said:

1. Given the comparatively minuscule amount of DP that could possibly get in the oil, don't worry about it.

2. You answered your own question. Since the filter is bypassed, there's no need to change it.

Drive more, worry less...

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Thanks...being a vehicle hypochondriac has its pros and cons.

Did the purge today with no issues, the car seems a bit smoother through the rev range and maybe idling a bit quieter, but there was no smoke and the LiquiMoly looked the same after doing it. So may not have been that beneficial but couldn't have hurt I guess. Here's a couple pics of the setup, I used the same parts as mrrhtuner earlier in the thread. #3011 filter from NAPA and hose and fittings from Home Depot, along with a Jim Beam Black Cherry (ugh gross) bottle that someone had left behind at a party we had.



VANCOUVER people: LiquiMoly Diesel Purge is available at NAPA in Burnaby off Beta ave, I saw some there when buying the fuel filter. It's $15/can though and I got mine from Roseland Technical for $8/can when buying some other parts. Would rather support independent part dealers than pay almost double at NAPA.

Also if anyone in the Vancouver area wants my purge setup (hoses, filter, fittings, JB bottle) and a can of LiquiMoly shoot me a message and you can have it all for free, I don't have much storage space and moving soon.

Deadend said:

I did this procedure about a year and a half ago as well.

It felt like I was in the driveway idling the car (running it on purge) for a long time. Next time I hope to set it up so that It's good for moving the car during the procedure. Go pickup some milk or something while running diesel purge.

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I did this...once. There's a big difference in how fast 500ml burns when you're idling vs. driving it (aka putting the engine under load). I ran out within a mile from the house; had a second can with me (thankfully) but ran out a second time before making it home because my "auxiliary tank" (the glass jar seen in the write-up of this thread) isn't quite 500ml. With air in the system, I wasn't sure it was going to start after either time it happened. I should have taken the tools with me to swap it back over to the tank on the side of the road, but I just wasn't that smart.

So if you're going to do drive on the purge you'll need more than 1 can, something large enough to hold that much and still fit safely under the hood, and be prepared to switch the lines back to your filter BEFORE your return home. I like the bourbon bottle idea.

That said, it is likely to work better if driven since engine temps will be at normal operating speed and your injectors will be working with full pressure.

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To those just adding a can to your filter - this marginally (at best) better than just pouring it into your fuel tank because within seconds of start-up it's already been mixed into your tank via the return line from the filter.

did mine today.....

changed filter and ran 1/2 bottle of DP. should have ran full bottle but the DP was getting so hot recirculating back and forth and i was getting bored. 1/2 took 20 mins as it was. seems like it starts faster but wasn't a problem before.

I just did this for the first time on my 300K mile 2005 TDI wagon using Liqui Moly 2005 Diesel Purge. I basically had the same setup as the thread originator (same filter, but used a glass mason jar). I dumped all of the contents into the jar to start.

The stuff starts out looking and smelling like Diesel Kleen (amber clear).

After running it for about 10 minutes with varying the RPM, the fluid had gradually turned dark blueish. At 10 minutes I stopped and dumped the remaining contents back into the Diesel Purge bottle (maybe 1/4 of the bottle was consumed, so 3/4 is back in the bottle).

1. Should I just pour it back into the jar and resume, letting the Fram filter do it's thing to filter out the junk that's causing the discoloration?

2. Regardless of #1, should I get another bottle (or more) and repeat until I can cycle through a whole bottle without discoloration or will that damage something?

After noting an increase to cranking time when hot to bring our 425,000km BEW to life I gave this thread a skim. One safety note that I probably missed (have never been particularly observant....) is the fact that owners with lift pumps should be pulling the lift pump fuse or relay ? Or am I wrong?

IDP, offers this thread, and they mention pulling the fuse:

http://post.idparts.com/newest/81-t...diesel-purge?gclid=CKj0gOvNjdQCFUWBfgodHikOmQ

I'm not a real big believer in "snake oil motor cures" but figure this can't do any damage so at the next oil change I will give it a try, very curious if I will see any changes in start time.

Martin

It's not snake oil, though if the cranking time is caused by deposites on the nozzles, then this can help.

This has been a great how-to for over a decade now. What amazes me though, is how many of you still have your engine covers! again, and as always, ty arby for this. it's been a great resource for many of us.

Just did the purge today. I used the same setup that ARBY used in his original post. I've read most of the posts (40 pages!!) on this thread and I know I saw this before but the search command isn't finding it now:
It only took perhaps 10-12 minutes to run through the single 500ml can of diesel purge. I had poured the entire contents of the can into a clear plastic bottle so I could easily watch how much was left. I ran the RPMs at varying levels and all the way up to redline several times.
I see that most users here state it took 30-45 minutes to go through the 500ml can. Anyone know why I might have gone through it so quickly? Fuel leak somewhere (I don't see one)? Fluid returning to the bottle remained the same yellow-ish color as what was being sucked into the IP. I believe the injectors themselves are still all original, though I did upgrade the nozzles to the next size up about 80k ago.

On my 217k ALH Jetta, I have never purged before. It does seem to run a bit smoother/quieter.

UPDATE: After a couple days of driving, the noticeable change is remarkable. It is significantly quieter/smoother, seems to have a bit more pep and smoking is less. I am not getting any smoke on start-up, but I do still get some white-blue smoke (even after a 20-minute warm-up in 30F temps) coming down our driveway in 1st gear at around 3500RPM. I had plenty of black sooty exhaust during the purge. I have the EGR turned off and had have for several years now, so I know that will add some smoke. The exhaust at idle before (even on a warm engine) used to smell just horrific, like your stereotypical diesel exhaust, but since the purge the odor is milder. Verdict is this was totally worth doing. I will probably do it again just before my next oil change since the purge had never been done before. I had *just* changed the oil last month, but after reading the concerned about Diesel Purge contaminating the engine oil, I figure it's better safe than sorry to just change the oil again now. BTW, I have no affiliation with the company, but I have been ordering some parts, filters and oil from AutohausAZ.com for several years now and appreciate their accurate orders, fair prices and free shipping option on orders $49+. They also have Diesel Purge for about $8.

benIV said:

What amazes me though, is how many of you still have your engine covers!

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I did the "PD mod" to my engine cover. Otherwise, I probably would have tossed it.

One thing I noticed about the Diesel Purge process: the can starts to get pretty hot, from the recirculating liquid. Near the end, it got so hot I had to grab some gloves to handle the can.

Here's another way to perform the "diesel purge".


What you will need:

~6ft of 1/4" ID (inside diameter) translucent PEX plastic tubing
1/4" diameter in-line fuel filter (I found a pack of 10 online through Amazon)

Diesel purge
*side note: I ended up using Royal Purple Maxtane Diesel Additive, hence the colour* I was really impressed with the results. I varied the speed and noticed that near the end the engine was idling much better.

This particular tube can fit directly inside the vehicle's fuel lines (and in some cases can be used in place of damaged vacuum hose).

If you know your vehicle uses a lift-pump, use another 2 ft or more loop from the inlet lines fed from the tank.

I've searched and not come up with an answer so I will post it. I saw a sight that said when doing a purge for a TDI after 2004 the relay for the fuel pump should be disconnected or the engine compartment will be flooded with diesel. I haven't seen this on any other video or post. Is this true?

SalinaEd said:

I've searched and not come up with an answer so I will post it. I saw a sight that said when doing a purge for a TDI after 2004 the relay for the fuel pump should be disconnected or the engine compartment will be flooded with diesel. I haven't seen this on any other video or post. Is this true?

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Yes that is correct because it has an in tank pump.

Currently stuck trying figure out how to do this on a 2014 touareg tdi. Any ideas? I have vt, rm, and vm lines on my filter housing.

I believe that is a common rail engine. You can't do a purge like this. You'll just have to put it in the tank, or prefill the filter with it.

Damn. Pretty sure I got some ****ty diesel. Was hoping to clean the injectors at full strength.

is the effect of the diesel purge noticeable if you just add it to the tank rather than running on it?

Depends on how dirty your injectors/pumps are, and how full your tank is befor adding it. To shock treat it a lazy way, put a can of diesel purge in your tank when you're at 1/8th of a tank.

Nero Morg said:

Depends on how dirty your injectors/pumps are, and how full your tank is befor adding it. To shock treat it a lazy way, put a can of diesel purge in your tank when you're at 1/8th of a tank.

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might have to do that. i heard that the diesel purge is harder on the BEW engine. Not having trouble with sluggishness, just want to keep the old girl running as happily as possible

Andrew Dale said:

might have to do that. i heard that the diesel purge is harder on the BEW engine. Not having trouble with sluggishness, just want to keep the old girl running as happily as possible

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No different, the fuel filter placement is the same, you just need to disable the in take fuel pump.

Was it actual smoke? Or was it just diesel purge starting to vaporize?

What did you use to connect the can of diesel purge to the fuel system? The fuel gets really hot on PDs during this procedure and could melt plastic hoses. Or it could just have been hot enough to steam.

I did this in my B4 Passat weekend before last, and although the lines got warm, nothing got hot enough to cause any trouble.


It also smoothed out the engine considerably.