* Blocked or malfunctioning PCV (Positive Crankcase Ventilation) system: This is the most common cause. The PCV valve regulates crankcase pressure. If it's clogged, stuck closed, or the hoses are restricted or disconnected, pressure builds up. Check all hoses and the valve itself – a simple test is to remove the valve and see if it's freely moving.
* Worn or damaged piston rings: While you passed emissions, slightly worn rings can allow excessive blow-by (pressure from the combustion chamber leaking past the rings into the crankcase). This isn't necessarily dramatic enough to show up as significant blue smoke, but it can increase crankcase pressure significantly.
* Clogged or restricted breather: The breather allows air to enter the crankcase, helping to equalize pressure. If it's blocked with sludge or debris, pressure can build.
* Valve cover gasket leak: Although it seems counterintuitive, a leak *could* contribute. If the leak is pressurized, it could force oil upwards, particularly at higher RPM when crankcase pressure is higher. However, this is less likely to cause squirting directly from the dipstick tube.
* Oil pump issues (less likely): An excessively high-pressure oil pump is possible, though less likely to be the sole culprit. This would usually manifest as other symptoms.
Troubleshooting Steps:
1. Inspect the PCV system: This is the first and easiest step. Check the valve, hoses, and the connection points. Replace any damaged or suspect parts.
2. Check the breather: Make sure it's clean and not restricted.
3. Inspect the valve cover gasket: Look for any obvious signs of leakage or damage.
4. Consider a compression test: This will help assess the condition of your piston rings and rule out significant blow-by. Low compression in one or more cylinders suggests ring wear.
5. If all else fails, a leak-down test: A leak-down test is more precise than a compression test and can pinpoint the source of pressure leaks better.
Important Note: Continuing to drive the car with this problem could lead to more serious damage. The excessive pressure can push oil into places it shouldn't be, potentially leading to engine damage. Address this issue promptly.
