Front oil leak AGAIN! WTF?

[swharris]

Original owner '97 310,000 OG motor/trans:

Running great but can not get this thing to stop leaking. I'v had the cooler lines leak and fixed those, but the oil still seems to be coming from the lower timing cover/crank seal area. I've replaced the cover/seal with new QUALITY timing covers 3 times now. Every time I put in a new QUALITY oil pan gasket and put the proper sealant at the factory repair manual specified sites. Still, after a bit of time this B I T C H starts leaking again(hard to say exactly where as by the time I find it the residue is sprayed all over)

By the 3rd time "fixing" this I have become extremely anal about cleaning the surfaces and correct torquing of the cover/pan. I've even put some sealant around the o-ring on the crank sensor just in case that was not sealing. I lube the crank seal before putting on the balancer and all seems right with the world...till it starts leaking again.

At this point, all I can think of is that the HB sealing surface is out of round and deforming the crank seal allowing oil to leak past it. Frankly I can't believe that is the case, but it is the only part of the assembly that I have not changed out, well, the oil pan is still the old one but I checked it with a straight edge and it was fine.

Any ideas?? I just don't want to get back down there and change that **** again, but I know I'll have to
WHY DON'T I SELL THIS STUPID THING? Seriously I have no idea why I keep it. Ha.

[chevymaher]

Does the harmonic balance have a groove where the seal sits? Is the seal for it in the timing cover the right one for that particular harmonic balance.
Hey I do this all the time and I seen it all.

[Corsemoto]

I was going to ask the same thing as chevymaher...

When I recently replaced my oil pan gasket and timing cover, the harmonic balancer had a slight groove in it from the crank seal so I installed an $8 repair sleeve on the shaft. The repair sleeve should come with a cap for installation.

I also used a factory GM timing cover kit from GM Parts East after reading many bad reviews about the Dorman kit.

Don't forget a dab of sealant on the keyway/slot to seal that area too.

[dvil]

Is your crankcase ventilation functioning? Overpressure in the crankcase sure doesn't help.

[RECox286]

Randy beat us all to it...Crank shaft grooving. And Corsemoto has the cure.

Dvil mentioned another possibility of too much pressure in the crankcase due

to a malfunctioning PCV. I myself would, at 300k, be looking at the c/s and

seeing if Felpro has a double lipped oil seal for the application as well as the

sleeve kit.

Uncle Bob

[swharris]

Both great suggestions gentlemen. The crankcase pressure never occurred to me. I'm not sure about the groove, but I'd of thought I would have noticed it when putting it back on. If I get really motivated I'll get in there and fix it while I'm replacing the (rebuilt) whining PS pump I put in about a year ago. This time I will not go with the "rebuilt" unit. I always learn the hard way. LOL.

[RECox286]

Some of us always seem to learn the hard way, don't you know.

I've bent over while holding the jar too many times...too.

Uncle Bob

[RECox286]

The give away is that it works for a while. At my dinner table that means; it works until the score in the

c/s destroys the new seal, then it starts leaking again. If it were over pressure in the crank case, it would

blow the seal almost immediately. Logic ! (I'll take bets on this one. Dollars, Pesos, Escudos, Euros, Yen....)

Uncle Bob

[swharris]

Uncle,

I think you're right. It was dry for a week and then it started leaking again. When I was buying the last replacement timing cover(with the seal already installed in it) I don't remember any choices as to what type of CS to order.

All it said was "timing cover" and different mfg.'s of them. Does anyone have pictures of the different HB and respective CS's? Or maybe PN's for the correct combos of crank seals and harmonic balancers??

Thanks again for the insight. I'm dreading pulling the damn oil pan, filter, and adapter for the 4th time just to change the timing cover. I'd like the kill the engineer that came up with that design !

As I remember this is like the last one I put in. It was a Timken

Maybe I should use this HD version with PTFE surface

As I remember this is what my OEM original HB looks like. Where is the groove?

[Corsemoto]

I agree, it is a terrible design.

The groove wears into the machined surface of the harmonic balancer shaft, where it sits on the crank seal and spins. Maybe consider an OE crank seal?

I used a National 88176 repair sleeve from Advance Auto.

[Mmusicman]

Is your crankcase ventilation functioning? Overpressure in the crankcase sure doesn't help.

Yes.. very important that your PCV valve is working properly and that the crankcase has negative pressure. It is also possible that you have excessive "blow-by" getting past the rings, causing crank-case pressure.

The fact that it didn't leak right away tells me it was probably sealed correctly, and pressure may be possibly blowing it out?

Just a thought..

[swharris]

The motor does not burn much oil...if any. If the rings were bad, wouldn't I be burning oil with diminished compression and loss of power? Truck runs really strong with no issues.

[RECox286]

Correct me, but IIRC, you can just pull the HB, replace the CS seal, and reload the HB. (That is, If the seal comes as a

separate part.) I know the book calls for a brandy-new timing cover, but yours is still fresh... Well, that would be the

route I would travel. BTW: that HB, in the pic, looks to have a repair sleeve on it already. Whaaasup ???

Uncle Bob

[Corsemoto]

I see what you mean about the HB photo above but I think that is just the beveled edge on the shaft making it look like it has a repair sleeve.

If your HB is suspect and you don't want to use a repair sleeve, a new Dorman is only $30-$40 (Rock Auto, Amazon).

The crank seal is available separately, my timing cover kit came with part #10128316.

[swharris]

Correct me, but IIRC, you can just pull the HB, replace the CS seal, and reload the HB. (That is, If the seal comes as a

separate part.) I know the book calls for a brandy-new timing cover, but yours is still fresh... Well, that would be the

route I would travel. BTW: that HB, in the pic, looks to have a repair sleeve on it already. Whaaasup ???

Uncle Bob

<slaps forehead> You are right. No need to pull the timing cover. Can you tell I'm a pessimist at heart? Haha. I just pulled those pics from the RockAuto site, so I don't know anything about them specifically. I think a new seal and the sleeve kit are in order. Finally something relatively simple.

Thanks as always.

[RECox286]

Fugetaboutit !

UB

[swharris]

Just an update for anyone who finds this thread. I'm the OP of the question.

I finally got around to replacing the HB with a new GM unit and the leak is 99.9% gone. Good enough!

[WoodButcher]

Any ideas?? I just don't want to get back down there and change that **** again, but I know I'll have to
WHY DON'T I SELL THIS STUPID THING? Seriously I have no idea why I keep it. Ha.

Because it makes you feel like a real mechanic?
over, and over and over again?
gotta love these vans, glad you got it finally.

[swharris]

"
Because it makes you feel like a real mechanic?
over, and over and over again?"

You forgot to put SLOW between real and mechanic.

[Corsemoto]

Here's a pic of my harmonic balancer with the repair sleeve installed.



Even though the crank seal comes with grease applied, I also apply a decent amount of grease to the balancer before install to try and help prevent any damage to seal when pressing on.



Something that may help when replacing timing cover is before fully tightening the cover down, install the harmonic to try and help best align the cover/seal/balancer.