Front seal leak or oil pan leak

[GoToGuy]

A precision machined item mounted on another precision rotating assembly capable of Five thousand RPM or more. And some of you believe it's ok to use it as a jacking / lifting point. Imagine a small bit of metal moving at the speed of a bullet. When a damaged balancer fractures and comes apart. At 2500 RPM the broken piece would be moving at 883 inches per second. If it self destructed at 5000 RPM parts would leave the engine bay at 147 feet per second. Anything struck by bits of broken balancer will look like shrapnel damage from a grenade or bomb. This has happened before. And as long as shortcuts exist, well you know what...

 

[Hipster]

This has happened before.

I especially like it when they exit the vehicle via the hole they create in the hood. lol

 

[Erik the Awful]

Look at the back side of the balancer. If it's coated with oil, your crank seal is leaking. If not, your seal is good.

I reused the plastic cover on the motor in my Suburban by putting a dab of RTV in the corners where the molded-in seal ends.

Put a dab of RTV where the oil pan gasket has sharp corners on either side of the crankshaft, front and rear.

 

[GMTJunky]

. Also, use a lot of RTV to seal the cover bottom lip against the pan because the gap is pretty pronounced there so you need a substantial bead. By a lot I mean practically the whole tube.

Even if I'm using a gasket? I used the felpro one piece gasket for replacement.

 

[GMTJunky]

Leaks while running. What's also operating/ running? Oil pump, constant leak around crank snout Harmonic balancer? Seal worn, wear grooves where seal rides. Did you identify where leak is coming from or " kinda looks like the pan gasket"? Who told you to jack the engine by the balancer?

It leaks when I start the engine. It leaks enough that I wouldn't drive it. Its more than a leak though. I would say it could leak a quart in 30 minutes to an hour. I am going to try and get a better look at it tonight and identify exactly where. As far as who "told me" to jack it up by the balancer, it was my friend the internet lol. It seemed like a good alternative to removing the differential.

 

[GMTJunky]

Look at the back side of the balancer. If it's coated with oil, your crank seal is leaking. If not, your seal is good.

I reused the plastic cover on the motor in my Suburban by putting a dab of RTV in the corners where the molded-in seal ends.

Put a dab of RTV where the oil pan gasket has sharp corners on either side of the crankshaft, front and rear.

Thanks Erik..Im going to try and et a better look tonight and will check out the balancer

 

[JeremyNH]

Even if I'm using a gasket? I used the felpro one piece gasket for replacement.

I don't know about the oil pan gasket. When I pulled the timing cover from my motor it was GM original and whether it was gasket maker or a gasket it stuck to the cover not the oil pan and came off with it. In any event the cover has a U shaped channel that fits over the oil pan but since it is below everything that rotates and has a natural drip lip you shouldn't get any leakage there when running. On stopping when the oil sloshes forward it would come out but just idling at rest it shouldn't even if there is a gap. The timing cover, new or replacement has a rubber gasket permanently inserted into it which sits against the raised lip on the block around the timing chain but it stops just short of the cover bottom where it meets the drip lip for the oil pan. The timing chain is half inserted into the block channel for it and half exposed so the timing cover gasket absorbs the oil spray coming of the chain and cam/crank sprockets. When the engine is running it is effectively under pressure. Because it is inverted tear drop shaped all of the oil captured from above will follow the gasket line into the oil pan. But if the lower part of the cover to block is not sealed, due to the gasket gap I mentioned or because it was pulled away from the block when you were reinserting the oil pan (which would be mu guess), the oil will leak out there. As mentioned the oil from the timing chain and sprockets when spinning effectively puts the timing cover to block flange seal under pressure so you can get a lot of oil coming out when running but none when off. I wouldn't expect leakage from the crank seal because the spinning crank would be flicking it off inside the timing cover.

 

[GoToGuy]

Thats not quite correct. PCV positive crankcase ventilation case blowby routed back into intake system. The timing cover balancer seals function is to prevent oil from leaking, seeping from internal side of block to outside. So you have a spinning shaft through a fixed panel. That rubber round flexible seal prevents lube oil from exciting around the spinning balancer hub. Sure the oil inside the block is sprayed and flung everywhere inside the block. If the oil just from spraying inside the block causes leaks you got bad seals and or gaskets and or your seallibg surfaces are damaged not flat straight. If it's coming out around the balancer hub when it's running the seals is worn out and or damaged and or the hub could have a wear groove. A worn out engine or defective pcv system can cause high internal blowby pressure resulting in forced oil leaks.
You may have induced your own problem by using the balancer as Jack point. And somehow damaged the cover seal. Did it leak before your non standard repair action?

 

[GMTJunky]

I crawled back under the truck lasnight and used my phone to doe some videos in places I cant see. I found a gap in the timing cover in the area the oil was coming from. I attached a screenshot below. Its kind of blurry where the gap is on the top right, but you can see its there. I either separated it when I jacked it up, or, it was already separated some and I pulled the sealant/gasket off when cleaning the pan to expose the gap and make it leak worse.

Either way, Im going to be ripping into the front. I'm going to replace the harmonic balancer, water pump, timing chain cover and timing chain set while I'm in there. Any suggestions or gotchyas that process? It all seems pretty straight forward and for the timing chain I know I have to align the timing marks at 12 oclock before removing and then put the new back on the same way.

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[JeremyNH]

For the timing chain I recommend the Cloyes true roller:

Cloyes Gear 9-3157X1 Cloyes Original Race True Roller Timing Sets | Summit Racing

Free Shipping - Cloyes Original Race True Roller Timing Sets with qualifying orders of $109. Shop Timing Chain and Gear Sets at Summit Racing.

www.summitracing.com

I think the plastic Dorman cover is fine. You can get it off Amazon for about $20 free ship but probably want to add it to your Summit order to get over the free ship mark if you get the timing chain from them. You'll need a gear puller to get the 4x reluctor wheel and crank sprocket off and a hollow tube for tapping them back on (I used a 1.5"x6" iron pipe nipple from Lowes which worked well). 1A Auto has a good video for timing chain replacement that will go through everything you'll face. Three issues with the video though: (1) they call the 4x reluctor wheel the "oil flinger" which is annoying, (2) they line up dot-to-dot and say this is #1 TDC compression which is both wrong - it's #6 TDC compression, #1 TDC exhaust - and very annoying and (3) they WAY overtorque the cover bolts. IIRC they say 18 ft-lbs in the video which is a good way to break the bolts. Correct is something like 100in-lbs max. The hardest part is getting the crank pulley off. Everything else is pretty easy. Why are you replacing the harmonic balancer?