Background info: Had a blown head gasket and a mechanic used a sealant on it to patch it up. Car went from not turning on to running ok
Problem: at idle the engine creaks. It isn’t a ticking or knocking but definitely more of a creaking sound. Can’t figure out if this is safe for the car to be driven and what could be causing it.
I have a video of the sound if anyone feels confident they might be able to guess what’s going wrong. Potentially a head gasket that was partially fixed maybe??
You don’t seal up a leaking head gasket. You replace them.
There are “magic in a can” type sealers but these are temporary fixes to keep an old junker running a few more months, not a repair for a car you plan to drive for years. It is sodium silicate, the same stuff they used to destroy perfectly good engines during cash for clunkers. Maybe some of this leaked into the cylinders and scored something which is now making an odd sound.
Odds are an engine replacement isn’t far off.
If you blew a head gasket, I would have to believe the engine has been overheated. To what extent? I don’t know, but it sounds like things were once seized up and now you’re hearing a bearing on its way south. So with that in mind I would have to agree with CW. Engine replacement isn’t far off.
This part does not make sense if it had a blown head gasket.
If the mechanic was able to fix the head gasket with an additive…the engine would have been running while the additive did it’s thing.
I think you had some other starting problem and the mechanic said that you also had a leaking head gasket.
I’m wondering if you are just hearing a chirping, which could be bearing failing on any of the pulleys that run off the serpentine belt.
I’d like to hear the video if you can post it.
Yosemite
Here’s the link!
As you can hear… it’s way less of a tick sound and a strange creak and almost always only at idle.
It was def. a blown head gasket 100%, leaking coolant, rough idle, milky oil, cylinder misfire.
It would not turn on but was turning over… then with the sealant, it now runs just with this sound.
Was the sealant the recommended repair by the mechanic? If so, what were his reason for recommending it over a head gasket replacement that would have bought him a much nicer boat? 
Is this a car you’re just trying to get a few more months out of before you bite the bullet and get a new one, or are you hoping to keep driving it for a long time?
The mechanic is a close friend and did this to save cost and to let the car run enough to take me to work and back. We are currently saving for a new vehicle, as we know to get any more life out of it we will probably have to replace the gasket completely. I just don’t want to damage the engine by driving it with this creak.
The engine sounds like it is hammering/knocking as you accelerate. The engine was probably ruined when the coolant contaminated the engine oil. I didn’t hear the idle noise, you will need to get closer to the engine to record that but it sounds like there is nothing salvageable.
At the time of the head gasket issue, only water was in the coolant resevoir… coolant was disappearing very quick and we put water in to test how quickly. Thus, coolant wouldn’t be the culprit there… unless water is just as bad and deadly. 
Water in your engine oil, “milky oil” will destroy the engine bearings.
In addition to @Nevada_545’s point, you put in water to find out why the coolant was disappearing. That coolant went the same place as the water did, so if the water got into the oil, so did the original coolant.
Would changing the oil immediately help give it a little more life? The creaking has disappeared since I posted but still want to be cautious and keep it running for as long as we can.
I am inclined to less catostrphic noises. Heat sheild, motor mount, muffler clamp etc. It would help to be able to pinpoint the noise. At idle with proper safety measure in place if it has to be in drive would be where I would start.
Yes, DEFINITELY change the oil if you have not. The mechanic should have insisted on it after the sealant had done its job. If I was a mechanic I would have included that in the price of the job without the option of opting out.
You might go up a grade in viscosity when you change the oil as well. If the car calls for 5W30, I might try 10W40. This engine sounds like it has a knock and odds are it won’t hold together all that long anyway. Be prepared for a loud bang and having it roll to a stop on the side of the road.
Okay I will do that ASAP. Sad to hear the engine will probably give out soon. Head gasket busted ironically while driving to rescue a friend’s car that overheated. Thank you guys for sharing your knowledge and perspectives.
Update: the creaking was a piece of wood that the person who was looking at the car left at the top of the hood! Once removed, no strange noises.
That settles it!!!
No Christmas gift for that friend. Or just wrap up the peice of wood and give that to him./
Yosemite