Front crankshaft seal leak... Additive?

zaid3ssaf

Well-Known Member
My 02 bravada was leaking oil from different spots, about a quart a month. Replaced the valve cover gasket and the oil pressure switch which brought the leak down to about 3 drops a night. I have no visible leak spots except for the front of the engine. The spot goes from the harmonic balancer all the way up to the water pump, so I'm suspecting the front crank seal to defective.
Without pulling the radiator and the balancer out, does anyone know of an additive that rejuvenate the seal without damaging the I6 engines? Amazon has AT-205 or Lucas stop leak with good reviews but I just want to be on the safe side.
 

Redbeard

Well-Known Member
zaid3ssaf, can I ask what brand of oil you are using?
The reason I ask some years ago I changed from mobile 1 oil to castrol synthetic (it probably was on sale) on both my truck and the mrs's trailblazer. Guess what...they both started a very small "oozying" out of the main seals. Not enough to show a difference on the dipstick, but enough to allow dirt and grit to stick to the engine. As for me I hate leaks or any oil usage of any kind. On the next oil change I returned back to mobile one and take a guess what happened. No more oil trying to pass the main seals :smile: I don't have any experience to any oil additives to help with the seals, so we'll have to wait for another to chime in on that matter.
just my 2¢
 

BrianF

Well-Known Member
You can try a couple indexes with a high mileage oil. Sometimes the seal conditioners may work and help the leak. Also could try moving up to a thicker 30 or 40 weight.
 

MRRSM

Lifetime VIP Supporter
The Front and Rear Crankshaft Seals are made of PTFE (Poly-Tetra-Fluoro-Ethylene)...Literally... Teflon. Unfortunately, unlike the Black Natural Latex Rubber Seals of Old that would often "Plump Up" after being soaked in Used Motor Oil as rightly suggested by @BrianF... there are very few if any Oils or Grease that can actually 'stick tight' enough to its Ultra-Slick, Microscopic Brown or Blue Teflon Surfaces to actually work to close up any Lost Sealing Gaps or leaking areas. The Failure Modes of Teflon Seals take the following paths:

(1) Cuts to the PTFE Sealing Material or Impact Damage to the Outer Seal Housing.

(2) Improper Installation from Excessive Pounding Impacts that will cause the Coil Spring Expander to become completely dislodged from inside of its casement. This unfortunate event completely removes every bit of the necessary "Squeeze" required to maintain enough pressure on the Teflon Material to keep it in constant contact with the rotational surface around the smooth OD of the Crankshaft,

(3) Direct Damage to the Outside Diameter of the Crankshaft that presents with nicks or sharps in contact with the Seal as the Crank spins around.

(4) Gravity. Yes... As strange as this might sound... ALL PTFE Seals will begin to stretch and "sag" enough merely from Gravity over time' enough in fact to leave a substantial gap forming around the bottom areas of these Teflon Seals. This usually happens at around 185,000 Miles of use and wear (According to the White Paper on the use of Teflon in Seals). So the very act of simply sitting there... unused will also take its toll on these seals over time.

(5) Direct Exposure to Extremely Powerful Solvents and Gases that involve highly corrosive compounds containing exotic combinations of Hydrogen and Fluorine.

The only real help for this situation is to R&R the Harmonic Balancer, Pry Out the Old Seal ...and using a Small Block of Wood in between...Lightly Tap a Brand New Seal right back into the Front Timing Cover until the Casement is flush with the front face of the area.

No Oils or Sealants need to be applied, lest they get trapped within the Sealing Groove and Spring areas of the New Teflon Seal. These lubricants may actually shorten the life of Teflon Seals by attracting and holding Abrasive Sand, Dirt and Grit inside of those narrow areas and eat into the OD of the Rotating Metal Surfaces.

The Front Crankshaft Fastener is a Large, "Use Once and Throw it Away..." TTY Bolt. So replacing-installing a New One after restricting the movement of the Flex-Plate at one of the Torque Convert Bolts is required. This can be done by using 15mm Impact Socket and a 1/2" Breaker Bar underneath the Engine to Transmission areas. Access to any One of the Three Torque Converter Bolt is made through a small passageway covered by a Small, Black Plastic Plug located in the underside of the Back Plane of the Crankcase-Oil Pan.

The Brand New $10.00 TTY Crankshaft Bolt required here is threaded into the Nose of the Crankshaft after a New Harmonic Balancer Special Friction Washer is fitted to the Inner Snout of the HB Bore. During the First Turning Pass... That Bolt gets Tightened to 110 Foot Pounds. Then, after making a Visible Mark in White using a Permanent Oil Ink Pen... A Vertical Line gets drawn across the TTY Bolt Face and onto the Timing Chain Cover.

Then using that White Line as a ready reference, that TTY Bolt gets slowly turned another 180 Degrees, starting at the 12:00 Position... and ending up at the 6;00 Position. The Harmonic Balancer(s) of all GM Atlas 4,5 & 6 Cylinder In-Line Engines Do NOT have Woodruff Keys necessary to prevent the HBs from rotating separately from the ODs of the Crankshafts while being Tightened. So the Crankshaft MUST be restricted from turning during these TTY Torque Procedures, or you'll run the risk a having failure with the Harmonic Balancer Friction Washer Seals during these efforts to firmly fasten everything together.

Depending upon which year GM Atlas Engine is being worked on for this Repair (2002-2003 Require a Special Puller) the Later Model Years can use the OEM Brand Model #6667 Puller to remove the updated Harmonic Balancers available on Amazon. For around $15.00- $20.00... There is a Special Hardened Threaded Rod with a Nut and several Special Washers in a Kit also offered on Amazon that can be used in combination to properly re-install ALL versions of these Harmonic Balancer(s). Just remember to wipe the Bolt Threads down with some High Pressure Grease to make this part of the job a LOT EZR.
 

Mooseman

Moderator
You can try a couple indexes with a high mileage oil. Sometimes the seal conditioners may work and help the leak. Also could try moving up to a thicker 30 or 40 weight.

Agreed. Have heard that Valvoline High Mileage might help the seals but I would think this would just delay the inevitable. It would likely come back.
 

Reprise

Lifetime VIP Supporter
I use the Valvoline Maxlife HM in the Envoy; besides the seal swellers, it has a good additive package.

If the leak is bad enough, it won't stop it. Although it would be worth a try, given the limited leakage (as described). But if it doesn't stop by the end of the OCI, it's not going to. Get a new seal and change it out. It's a bit of work, but I'm generally not one to to put band-aid chemicals in an engine crankcase. YMMV
 

Mektek

Well-Known Member
I used various type of synthetic oil in an old gm engine that lost/leaked a quart between oil changes. Once I changed to Mobil 1 high mileage and for the entire interval it stayed close to full. Then I went back to some other oils and it again lost a quart between oil changes.
So I'll go back to the Mobil 1 HM so I don't have the oil loss - maybe you'd have the same good results?
 

Mektek

Well-Known Member
One additive that worked for me was "Marvel Engine Oil Stop Leak" in a red bottle.
I had an old tempo that leaked/lost almost quart of oil after a highway run to Orlando. I had the bottle with me so I figured I might as well try it - at least it would be good as a top up. After returning home I checked again and the level did not fall. I was impressed - it actually worked:2thumbsup:
I bought a few bottles on clearance, but have never seen it for sale again.
 

CajunWon

Well-Known Member
No Oils or Sealants need to be applied, lest they get trapped within the Sealing Groove and Spring areas of the New Teflon Seal. These lubricants may actually shorten the life of Teflon Seals by attracting and holding Abrasive Sand, Dirt and Grit inside of those narrow areas and eat into the OD of the Rotating Metal Surfaces.
Saw a video on this (Kilmer?) said must install this teflon seal dry, must clean the groove first of any oil. fwiw
 

cornchip

Well-Known Member
Saw a video on this (Kilmer?) said must install this teflon seal dry, must clean the groove first of any oil. fwiw

Install these seals without a tiny dab of grease (or motor oil) on the seal lip edge and you risk burning them up on your first start. Some seals have machine applied grease right out of the package while others rely on the installer. This also applies to any other lip seal you will encounter on the TB like axle,slip yoke and the like.
 
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Mooseman

Moderator
I wouldn't trust anything that whack job Kilmer says anyway!
 

MRRSM

Lifetime VIP Supporter
@cornchip ...10-4 on the Motor Oil... I could live with that. Just wondering what the OP has been up to recently while trying to sort out the Persistent Leak...
 
OP
zaid3ssaf

zaid3ssaf

Well-Known Member
@cornchip.10-4 on the Motor Oil... I could live with that. Just wondering what the OP has been up to recently while trying to sort out the Persistent Leak...
I have switched to Mobil 1 5w-30 High mileage because I was due for an oil change anyway. It is still leaking about 4 drops a night but I haven't driven it a lot for the oil to 'work'. I was quoted $300 for replacing the crank seal and $1000 to replace the gasket on the timing cover.... Ridiculous. Its not more than a 3 hour job if you have the right tools but whatever.

So, currently I'm going to let it leak for the winter and I'm contemplating about buying the pullers, the flex plate holder, and an impact for less than what it would cost at a shop. I also gotta figure out if my HB is the first design or the second design.
 

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