Using an oil stop leak in a TDI?

Nellie

Veteran Member
Joined
Jun 24, 2005
Location
Los Angeles, California
TDI
Jetta Wagon GLS, '05
Please forgive me if this has been mentioned previously in a thread, but my search skills are, to be honest, less than skillful.
I have an oil leak that seems to be coming from the main seal, or at least so I'm told by a reputable mechanic. My question is, would it be advisable to use a stop leak additive in a TDI? This was recommended by a friend, but I'm skeptical as most advice from non-TDI owning people is spotty at best.
I've been living with this for the past 35,000 miles since I had a new clutch put in the car and although it's not a bad leak, quart every 6,000 miles or so, it's made a real mess of my driveway. I'd hate to pull everything apart just to fix the leak properly, so wonder if an additive might be safe to try. Any advice, as always, would be much appreciated.
thanks,
 

Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
IMHO, just fix the problem. There are tons of snake oil "additives" parts houses sell that their only function is to make your wallet lighter and could damage your engine. Be very careful about free advice. When talking to woman, some men may not have a clue about anything mechanical and just make stuff up to "gain favor" with you.

Being a TDI doesn't make a difference. On any engine, an oil leak is still just an oil leak.

Was the rear main seal checked for leaks when the clutch was changed?

Almost forgot. Are you sure it's not transmission oil?
 
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jmodge

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Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Ditto on the stop leak opinion, it's like using a bandaid when you really need stitches. As most owners can contend, oil leaks can be difficult to locate and can be coming from multiple locations. I would suggest confirming the location or locations. Clean and start at the top with your search, as oil running down can collect and appear to come from somewhere other than the source. Crankcase vent, ASV, boost hoses or clamps. valve cover, cam seal, turbo oil feed and drain lines, oil pan will all make their way down. Most will end up collecting at the rear of the pan and run on to the dogbone and deteriorate the rubber in the mount. Trans of could also be a source.
If you start at the top, in that order, clean and repair all you find, eventually you will have a relatively leak free engine. I did not mention main seals because they are the most difficult to deal with and therefore EVERY other source should be eliminated first.
Good luck and watch your language while you are working on it, kids and women could be within earshot.
 

hughesjasonk

Veteran Member
Joined
Nov 8, 2013
Location
New York
TDI
2002 Jetta MK4;
You can put in a thicker oil to get you by until you can get it into the shop. but you definitely need to replace the seal. I would not put any of those stop leak stuff in your crankcase unless this is a temporary car that you're going to send to scrap very soon or your engine is on the verge of blowing up and it's cheaper/easier to replace it anyway

To be honest with you I'm a little skeptical that your rear main is leaking. it's more probable that your vacuum pump or your valve cover are the culprits.

Sent from my SM-G930V using Tapatalk
 

mohawk69

Veteran Member
Joined
Apr 27, 2005
Location
Richmond Hill, GA (Savannah)
TDI
1996 B4, 1996 B4V, 2000 Beetle TDI
Clean the engine so you can confirm the location. Also, changing your oil brand may help. I once had a car that leaked but the leak stopped when I changed the oil brand. After a while, I tried the old oil and the leak returned. There's no downside for trying it.
 

jmodge

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Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
i missed the vacuum pump for a source of oil leak, good catch. Oil can make a difference in crankcase pressures. Some vaporize or steam off at a lower temp. It's called the"Noack Volatility", the lower the percentage the better. 5% is a very good rating. Oil running through a turbo gets quite hot. The material data sheet on the oil you use will tell the story.
 

Lightflyer1

Top Post Dawg
Joined
Sep 13, 2005
Location
Round Rock, Texas
TDI
2015 Beetle tdi dsg
Even if you use some stop leak you still have to fix the issue. The stop leak if it works at all, won't keep working forever. Find the leak and fix it now.
 

turbobrick240

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Joined
Nov 18, 2014
Location
maine
TDI
2011 vw golf tdi(gone to greener pastures), 2001 ford f250 powerstroke
I wouldn't use the stuff. Anything thick enough to stop leaks is going to gum up and sludge the oil galleries too.
 

Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
On the PD engines, which I believe yours is develop leaks from the valve cover over time and need the valve cover snugged down occasionally.

A very easy thing to check. Remove the engine cover and check for oil on the backside of the head just below the valve cover.

If evidence of oil is found, it is a very easy fix. The valve cover is secured by 8 or so Torx screws. Snug those screws with a Torx screwdriver and it should stop the valve cover leak if you have one. Use the correct size Torx screwdriver and do not overtighten as that could snap screws. Until the screw bottoms out and then just a little bit more is enough.

I recommend a Torx screwdriver over a Torx bit because a Torx bit could get knocked loose from the tool and be extremely hard to find in the nether world behind the engine.
 
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Nellie

Veteran Member
Joined
Jun 24, 2005
Location
Los Angeles, California
TDI
Jetta Wagon GLS, '05
Thanks everyone for the replies. I will further investigate other sources such as the valve cover before tackling the main seal. The advice about the torx bit is also very helpful. Stuff can easily disappear down there. I don't post a lot, but I never fail to learn new things about these cars when I log on. Thank you,
 

Fahrvegnugen

Veteran Member
Joined
Jan 21, 2017
Location
Burlington Vt
TDI
01 golf 1.9 alh gls silver
I put oil stop leak in My 79 td and it killed the vehicle. It was thick enough to make for compression so low it wouldn’t start. That’s what they mean when they say stop leak. It’s worth it to Torque measure the valve cover bolts.
A flexible magnetic tool retriever is good because it’s terrible to drop things down there. Taking off the skid plate every time is even worse.
This then causes the dropped objects to fly out on the highway.
 
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vanbcguy

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Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
A main seal leak will never be solved with a stop leak type product. At best that goop will slow a leak between two stationary surfaces, but it will never do much for a seal sliding along a spinning shaft.

Sent from my LG-H873 using Tapatalk
 

Ol'Rattler

Top Post Dawg
Joined
Jul 3, 2007
Location
PNA
TDI
2006 BRM Jetta
We don't really know if the RMS is actually leaking. I think that the diagnosis the OP got may have been an armchair diagnosis from someone that may not even know these cars.
 
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