Oil leak... ideas?
04-07-2006, 11:07 AM
#1
Oil leak... ideas? Okay guys, I have a bit of a quandry.
I purchased an LS1 from a totalled Camaro last year. The car was hit HARD up front (100+ mph and guardrail don't mix). The only visible damage to the car was a broken alternator mount (and a chipped mounting pad on the block for the alternator), and the crank pulley was tweaked.
I replaced the alternator/alternator bracket and installed a new crank pulley, as well as ALL of the gaskets/seals/bearings on the motor, the rear oil gallery plug was also replaced. The motor leaked oil out near the rear main seal/oil pan gasket area. There is no oil forward of the oil filter/starter area, and none above the top of the rear main seal anywhere on the motor.
I then pulled it back out, changed the entire rear cover, new rear main seal, and reassembled it. I'm quite positive the oil pan and front/rear covers are centered correctly, and there is no oil leaking from any of the obvious joints. The leak is still quite severe. At cold idle, I have approximately 40-45 psi oil pressure, with 60+ psi at 3000+ RPM. At hot idle it drops to around 25 or so, which isn't terrible as my bearing clearances are on the loose side. I'm currently losing ~1.5-2 quarts per 100 miles of driving, rather major problem, obviously.
I have a custom catch can setup for the PCV, though this problem existed with stock PCV (98 style), and with breathers on both valvecovers. The catch can pulls a normal amount of oil during driving, nothing spectacular.
In discussing with some of my mechanic friends, the best options we've come up with are as follows:
1. Crank is tweaked. The crank did take a shot during the accident, enough to tweak the factory pulley. It does NOT leak at the front of the motor at all however. A basic measurement of the crank shows it straight, but I don't have the equipment up here to measure runout completely. The bearings it rides on have good wear patterns.
2. Oil pan is cracked/tweaked. I don't have any oil leaks anywhere but the rear main area, so I'm doubting this, and I have good oil pressure, so I can't foresee it blowing out under pressure, but it's still an option.
3. Rear cover tweaked. I replaced the rear cover once, so this seems unlikely.
4. Rear main seal installed incorrectly. I've done MANY of these on different cars, and 3 on this one, same problem, I'm very confident in my installation.
5. Block is damaged. Back to the oil pressure again, pressure/volume seem to be fine, so I'm doubting this. I took a straight edge to all mating surfaces and everything checks out, so this seems unlikely as well.
I'm currently planning to pull the engine this weekend, replace the oil pan, oil pan gasket, rear cover, rear cover gasket, rear oil gallery plug (behind rear cover), rear main seal, and crank.
Anyone have any input/ideas on this? I'd really like to drive my car at some point, but this has thus far been holding me back.
I purchased an LS1 from a totalled Camaro last year. The car was hit HARD up front (100+ mph and guardrail don't mix). The only visible damage to the car was a broken alternator mount (and a chipped mounting pad on the block for the alternator), and the crank pulley was tweaked.
I replaced the alternator/alternator bracket and installed a new crank pulley, as well as ALL of the gaskets/seals/bearings on the motor, the rear oil gallery plug was also replaced. The motor leaked oil out near the rear main seal/oil pan gasket area. There is no oil forward of the oil filter/starter area, and none above the top of the rear main seal anywhere on the motor.
I then pulled it back out, changed the entire rear cover, new rear main seal, and reassembled it. I'm quite positive the oil pan and front/rear covers are centered correctly, and there is no oil leaking from any of the obvious joints. The leak is still quite severe. At cold idle, I have approximately 40-45 psi oil pressure, with 60+ psi at 3000+ RPM. At hot idle it drops to around 25 or so, which isn't terrible as my bearing clearances are on the loose side. I'm currently losing ~1.5-2 quarts per 100 miles of driving, rather major problem, obviously.
I have a custom catch can setup for the PCV, though this problem existed with stock PCV (98 style), and with breathers on both valvecovers. The catch can pulls a normal amount of oil during driving, nothing spectacular.
In discussing with some of my mechanic friends, the best options we've come up with are as follows:
1. Crank is tweaked. The crank did take a shot during the accident, enough to tweak the factory pulley. It does NOT leak at the front of the motor at all however. A basic measurement of the crank shows it straight, but I don't have the equipment up here to measure runout completely. The bearings it rides on have good wear patterns.
2. Oil pan is cracked/tweaked. I don't have any oil leaks anywhere but the rear main area, so I'm doubting this, and I have good oil pressure, so I can't foresee it blowing out under pressure, but it's still an option.
3. Rear cover tweaked. I replaced the rear cover once, so this seems unlikely.
4. Rear main seal installed incorrectly. I've done MANY of these on different cars, and 3 on this one, same problem, I'm very confident in my installation.
5. Block is damaged. Back to the oil pressure again, pressure/volume seem to be fine, so I'm doubting this. I took a straight edge to all mating surfaces and everything checks out, so this seems unlikely as well.
I'm currently planning to pull the engine this weekend, replace the oil pan, oil pan gasket, rear cover, rear cover gasket, rear oil gallery plug (behind rear cover), rear main seal, and crank.
Anyone have any input/ideas on this? I'd really like to drive my car at some point, but this has thus far been holding me back.
Last edited by digitalsolo; 04-07-2006 at 11:28 AM.
04-07-2006, 12:19 PM
#2
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it sounds like normal oil pressure, but if your burning that much oil in only 100 miles then maybe your using crappy oil, what weight is your oil, most everyone recommends on this site 5w-40 or german castrol 0w-30 as they dont thin out and give excellent lubrication for our cars.
