Here's why:
* Blue smoke: This is a classic indicator of burning oil. The blue color comes from the unburnt hydrocarbons in the oil.
* Valve tapping: Worn valve stem seals allow oil to seep past the valves and into the combustion chamber. This can lead to increased engine noise (tapping) as the valves don't seat properly, and the oil can also affect lubrication.
* No coolant in oil: This rules out a head gasket failure, a common cause of both smoke and engine noise, which would typically mix coolant and oil.
What to do:
1. Check the oil level: While you mentioned the oil level is correct, double-check. If it's low, you're losing oil at a faster rate than you think.
2. Consider a compression test: A compression test will help determine the overall condition of your engine's cylinders. Low compression in one or more cylinders could exacerbate the valve tapping and smoke issues, even if valve stem seals are the primary culprit.
3. Leakdown test: This test can pinpoint exactly where compression is leaking in each cylinder. It will often help confirm worn valve seals.
4. Repair: If the diagnosis confirms worn valve stem seals, the repair involves removing the valve cover, replacing the seals, and potentially cleaning or lapping the valves. This is a moderately involved repair, usually best handled by a mechanic experienced with the KL-ZE engine in the Probe GT.
Less likely but possible causes (though the symptoms point strongly to valve stem seals):
* Worn piston rings: While less likely given the lack of significant oil consumption or other symptoms, worn piston rings could also contribute to oil burning.
* Oil control ring issue: Similar to piston rings, but specifically focusing on oil control within the piston.
It's crucial to get a proper diagnosis before undertaking any repairs. Taking your car to a qualified mechanic is highly recommended. They can perform the necessary tests (compression and leakdown) to pinpoint the problem accurately and provide a cost-effective solution. Ignoring the issue could lead to more significant engine damage.
