Fill cap for engine coolant missing

[Normf943]

2019 C28 missing coolant fill cap which has been ordered. Have owned the boat since June. Has run fine for over thirty hours with no problem. Engine temp stayed at 185. But recently got a low coolant warning on my chart plotter when i ran the engine at the dock. I checked and found the coolant fill cap missing. Waiting for a new cap from marine parts source. My question can I run the engine with some heavy tape over the coolant fill port?

 

[glider4]

No. Wait to run the engine until your new cap is installed. You may need to check the fill level again after you have installed the new cap and run the engine for a few minutes.

 

[Rocky]

Frankly, I would not run it without a cap.
If the cap had always been there, I would be looking under the engine in the bilge. Get a mirror or a cheap endoscope.

Unless you have a reason to think it is not in the bilge.... I don't know how it would go anywhere but the bilge.

Rocky