What happens if you overfill engine coolant past max line?
Overfilling the coolant reservoir past the maximum line can cause the fluid to overflow and expand out when the engine gets hot. Depending on how much extra was added, it may simply vent safely or require removing some excess to prevent potential mess or pressure issues.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Use a turkey baster or large syringe to suck out the excess coolant.
- 2Use a cleaned out shampoo or conditioner pump to pump out the fluid.
- 3Use a rag to soak up and pull out some fluid.
- 4Let the excess naturally spill or leak out of the overflow bottle when the engine gets hot.
- 5Leaving the excess coolant in the reservoir to let it naturally expel through the cap if it gets too full
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Wasn’t paying attention when filling and went way over the max line. How should I proceed?”source ↗
“while the engine was off, i filled it up, now after driving while the engine is hot this is where the coolant is up to.”source ↗
“i filled the reservoir o about full will it be an issue or should i remove some?”source ↗