* Valve cover gaskets: These are common points of leakage, especially on older engines or those subjected to vibration. Check them carefully for cracks or gaps.
* Rear main seal: This seal is notoriously difficult to replace in some engines, but a leak here would result in oil dripping onto the underside of the engine and possibly onto the transmission.
* Oil pan gasket: A leak here will drip oil onto the bottom of the engine.
* Front main seal: Similar to the rear main seal, a leak here can be subtle but significant over time.
* Oil pressure sending unit: A faulty sending unit or its gasket can leak oil.
* Worn piston rings: While you say it doesn't smoke, *very* slow burning can occur without visible smoke, especially if the oil is burning cleanly. This is less likely given the lack of smoke, but still a possibility if the rings are worn or improperly seated.
* Cracked engine block or head: While less common, a hairline crack can slowly seep oil, particularly when the engine is hot and under pressure. This would typically require a pressure test to diagnose.
Troubleshooting Steps:
1. Visual Inspection: Thoroughly inspect the engine, especially the areas mentioned above, for any visible signs of oil leaks. Start the engine and let it run for a while to see if you can pinpoint the source. A clean engine beforehand will make this much easier.
2. Check the oil level frequently: Monitor it more closely than every 1000 miles to see if the consumption rate is consistent.
3. Pressure Test: If you can't find a visible leak, a pressure test of the engine block and heads will help identify internal leaks. This requires specialized equipment.
4. Compression Test: A compression test will help evaluate the condition of the piston rings and cylinders. Low compression in one or more cylinders could point towards worn rings, but again, the lack of smoke makes this less likely.
Important Note: A quart every 1000 miles is still significant oil consumption and shouldn't be ignored. Continued running with an oil leak could lead to engine damage due to low oil pressure. It's best to get it diagnosed and repaired promptly. A professional mechanic specializing in performance engines would be the best resource for accurate diagnosis and repair.
