Suggest a ring scanner with minimal offset.
If you are “lucky”, coolant will flow freely.
But if, as tends to be the case, the block is full of sediment, it may only be a trickle – or, worse still no flow at all.
In either of the latter cases, poking about with a wire or drill bit (not easy on a narrow bodied car) may increase the flow but is a sure sign of likely cooling problems.
The sediment tends to set like concrete around the base of the liners which means the engine will almost certainly need to be opened up to allow the block to be thoroughly cleaned out. It’s a fairly major operation.
Hope this is not so in your case.
B……
Dudley Forsyth
Bernie