Ok so, new opti in my 96 lt4. Car runs beautifully, gets to redline beautifully. Pop the hood, to check for leaks.

And of course, I see quite the leak under the harmonic balancer. I wiped it, thinking it was coolant from when I drained the coolant.

Drove it again, and voila: the leak said, "hi, i am here"

I did change the seal that goes behind the opti. Perhaps I installed it wrong?

No idea. Any idea(s)

 

Did you double check the bolts that fasten the water pump? Also were the gasket surfaces on the block totally clean? Did you also double check all the hose clamps? Might be something simple..

 

There are no coolant leaks. I took my precious time cleaning the surfaces. Checking tightness of hose clamps

Every bolt I took off, has been tightened to what the fsm says to.

 

Your posts aren't very clear. You say there was liquid under the balancer. You didn't say what the liquid was. You thought it was "coolant". You wiped up the leak and it came back. But you say "no coolant leaks. So I guess the liquid is oil?

The seal behind the opti seals oil. So does the one behind the water pump in the cover. This water pump drive seal absolutely WILL LEAK if it is installed without an installation tool. If you didn't use an installer 'cone thingy' for this seal, I'd suspect this is your oil leak. Another possibility for oil leaks are the bolts that hold the opti. The only thing that blocks the leak path from the timing chain area to the bolt hole is the timing cover gasket. These gaskets become compressed over time and when the opti is exchanged by removing the bolts that also hold the cover down, the gasket may looses its seal, and not re-compress to seal the bolt again. I've learned to put a bit of RTV on the opti bolts if I'm not also replacing the front cover gasket.

I had a thread/rant regarding front oil leaks after 10,000 miles. No one responded, but I ended up resealing everything on the engine except the rear main seal. Everything. It is still dry, for now, but I'm not holding my breath. LT1/4 leak oil.

EDIT/ADD: In another thread you are leaking oil at the dipstick after WOT runs. The engine is developing high internal pressures which if they can blow oil out of the dipsitck, the same pressures exist at all the seals. Particularly the front hub seal and oil pan corners. I didn't comment in that thread, but the PCV valve doesn't do squat during WOT because there is no manifold vacuum, it closes at low vacuum. The crankcase evacuates through the air tube on the passenger side valve cover into the throttle body. The PCV valve functions at idle and part throttle conditions, not at WOT. You're not going to notice any reduction in blow-by with a new PVC valve.

 

Check that thread for my latest response. No more dipstick popping out at wot runs, nor any new leaks.

I noticed this leak under balancer the day I noticed the oil leak from the dipstick. But again, I thought it was coolant spill that I forgot to clean. I noticed it again, the leak under the balancer. So, that is why I started this thread.

 

Did you do the crank seal also? Might be that now that youve cleaned it all up the oil has an unobstructed path and has become more evident? Might need to put a speedy sleeve on the crank hub... Im about to do mine and Im going to order everything I can to be sure there are no leaks whan Im done... HOPEFULLY!

 

I'm thinking it is the crank seal. Crazy, this is my 4th or 5th opti job, and I have never had this issue before. I'll clean it again. Drive it. And run my fingers under the hub as best as possible to see if the leak re-appears from there after cleaning under the hub.

 

I subscribed expecting to learn something helpful. I'm glad I did. I'm expecting to reseal an engine soon, and this post showed me things to watch for.
Thanks for the post and the answers.

 

Unfortunately it would have been the right time to fully pull the cover to replace all seals, including the crank seal. The crank position sensor could also be leaking, or the timing cover gasket/RTV itself. Best to pull the cover, clean all surfaces, replace all seals (including crank pos. sensor) and reinstall with new gasket/RTV.

 

I agree, but I never knew about the crank seal till now. Also, to do the front crank seal, I don't think the opti or waterpump has to come off.

 

I recently got my LT4 back together after doing all front seals (water pump/optispark/crank). As I removed the timing cover, I knew I was going to have to then proceed to replace the oil pan gasket, too. I had a major antifreeze leak from the middle driver side water pump bolt - I had done a water pump over 20 years ago. The gasket and RTV had failed, now, and it was a mess. I had had an oil leak almost since I bought the car in 2001 (sadly it only has 17k miles now). Taking the timing cover out it was easy to see that at least the crank seal was the primary cultprit of the oil leak with oil caked all around it, but not really around either of the other two seals. I replaced them all, not hard when they're out. Make sure to replace the crankshaft position sensor o-ring if it's never been done. It's right there at the bottom of the timing cover - easy to get to if the timing cover is out. If the crank pully is in place, though, it's a bear to get to it. I replaced that o-ring in the car many years ago and no change, but easy to see the crank seal was the main issue. I should have done this job many years ago! I have run the car for a few hours since getting it back together, but it's only been driven a couple miles.
If you can maneuver in there to replace the crank seal without taking the optispark or water pump off, you are a better man than I I spent many hours contorting myself in there to get the timing cover off as it was, even having removed the water pump and optispark - the crank hub and pully were fun but I bought the correct Kent Moore puller which made that part very easy! They can be found fairly often on eBay.

Mike

 

Is this the puller I need for the balancer and hub?https://www.ebay.com/itm/256706532268

 

that kit appears to be for some of the timing cover seals and the water pump gear puller. That metal puller part is designed to attach to the water pump gear and pull it out of the block. The tool on the right side is to install that same gear. I was able to use a HF puller to get the hub off. It’s finicky but worked. Here are the only pictures I took of the puller installed.