Are tiny bubbles in drained engine oil an indication of a coolant the oil?

Yes, tiny bubbles in drained engine oil can indicate the presence of coolant in the oil. When coolant mixes with engine oil, it can create small air bubbles that can be visible in the oil. This can be a sign of a blown head gasket, which is a serious engine problem. If you see tiny bubbles in your drained engine oil, it's important to have your engine inspected by a qualified mechanic as soon as possible.

Here are some other symptoms that may indicate a coolant leak:

- White smoke coming from the exhaust pipe

- A milky-looking substance on the oil dipstick

- Low coolant levels in the radiator or reservoir

- Overheating engine

If you experience any of these symptoms, it's important to have your engine inspected by a qualified mechanic as soon as possible. Coolant leaks can cause serious engine damage if left unrepaired.