If water gets in the combustion chamber, you could hydro-lock the engine. The pistons were designed to compress a somewhat gaseous fuel mixture. Coolant is a liquid; not a gaseous mixture. This puts undue pressure further down and can bend the connecting rods.
I know $$$ do not grow on trees, but the $$$ you'll need to fix the car will be much >>> if you keep driving it.
My 2 cents..
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.