1994 Honda Civic EX. A little unsure of the engine...it looks like attachment Honda pic 1 (similar VTEC markings, updated air intake, front spark plugs).

Overheated today due to radiator leak (another issue found my heat gage doesn't work). Almost ran dry. The engine did not die, but no power. Turned off. Car would turn over but not start. Turned off again. Discovered leak on overflow tank cap, but almost no fluid in radiator itself. Refilled. Car started and ran (drove about a mile home)...but whining sound on LH of engine (driver side). There is a cover that looks almost like plastic that appears to be the source on the driver side of engine (see attachment Honda pic...better example of cover). Can feel vibration along with whining sound when revving.

Not sure what this component does. I did check oil and radiator fluids for signs of blown head gasket and seems ok (no cross contamination). Any advise on how to proceed?

As a side note, is the radiator overflow on this car pressurized or no?

Thanks much,...Dean

 

Quick update now seeing my pics. First pic is just to show the component in question. Second pic looks more like my actual engine config (VTEC, air intake/ignition updates)
Thanks again,
Dean

 

Timing belt lies under the cover. Properly tension it.

 

That plastic cover is your upper timing belt cover so as you might be thinking, yes you're timing belt is directly behind it. If you're mechanically inclined enough remove the valve cover and then remove that timing cover. If there's a physical problem it should be easy to spot if the sound is truly coming from up top. If not my next idea would be more involved and require you to remove the lower timing belt cover. My hunch would be the water pump since it's directly underneath that upper cover.

The expansion tank isn't pressurized, it's literally there just to catch the coolant when it expands from heating up.

EDIT: ^Beat me to it

 

Thanks much RonJ / 24TEN...on the case!

 

If the engine actually went dry, the water pump does use the coolant as a lubricant. Without the lubricant and being driven it could have been enough to push it over the edge as was previously mentioned, especially if it was old and close to being on it's last legs already.

It's quite likely that the water pump is complaining from the abuse of being run dry. Especially if the sound wasn't there prior to your overheat and dry radiator and came about just after all that.

 

Sounds like timing belt/water pump time. One thing I've used is to take a length of 3/8" rubber hose, and use it as a stethoscope to probe for source of noise. If you've got the tools, time, and a book, it's a piece of cake to change the timing belt/water pump.