Can a radiator leak oil but not coolant?
Yes, oil can leak into the cooling system but that does not mean coolant will necessarily simultaneously leak into the oil. For example, if you have an oil cooler inside your radiator and that starts to leak, you will find oil in coolant but not necessarily any coolant in oil. This happened to me recently on my ’94 Suburban.
Why is there no coolant in the oil?
When the engine is restarted the cylinder heads and intake manifold expand faster than the cooling system pressurises so no coolant leaks into the oil. If neglected long enough it will either leak coolant into the oil or will leak externally.
How is oil drawn into the cooling system?
When the engine cools and the cooling system goes into a vacuum, small amounts of oil are drawn into the cooling system from around the gaskets. When the engine is restarted the cylinder heads and intake manifold expand faster than the cooling system pressurises so no coolant leaks into the oil.
When the engine is restarted the cylinder heads and intake manifold expand faster than the cooling system pressurises so no coolant leaks into the oil. If neglected long enough it will either leak coolant into the oil or will leak externally.
Yes, oil can leak into the cooling system but that does not mean coolant will necessarily simultaneously leak into the oil. For example, if you have an oil cooler inside your radiator and that starts to leak, you will find oil in coolant but not necessarily any coolant in oil. This happened to me recently on my ’94 Suburban.
When does coolant start leaking from an engine?
The cracks are small and oil in this area of the engine is not under pressure. Oil will NOT force its way into the coolant, but the pressurized coolant will flow into the oil. Cylinder head cracking and coolant loss often begins around 130,000 miles, but could be much sooner. We have seen the problem as low as 60,000 miles and as high as 200,000.
What happens to the coolant in a radiator when it runs?
Coolant is forced past the piston rings and enters the oil crankcase. The coolant mixes with the oil into a brown or cream-colored frothy consistency. The radiator coolant level will drop perceptibly, while the oil level in the crankcase will rise.