Codes after new headgasket. Water pump.

Since they're all historic faults I would clear them and see if they come back.

 

As you Google historic or permanent codes you will find out there are processes to drive them out of the system It is quite a chore for most people as you have to pay attention and do certain things most people just drive and forget about it because the codes aren't on their screen in their car and when something does come on and a light comes on again like the check engine light you will not be looking at the word historic on your code reader You will see that it's active or pending those are the buzzwords you're looking for It do make a difference on how things are written apparently historic is not something you want to worry about unless you're a historian are you studying your car or driving it exactly forget the history enjoy the drive You've done a bunch of work better use that work up before the next problem arises It's time to start thinking about a new or real car

 

Right, those will go away on their own one by one as soon as the car convinces itself each problem has been fixed.

If you are in some kind of a hurry—say, if an inspection date is coming up and they will care about those historic codes—then you can look in the repair manual and each code will have its own "confirmation driving pattern" that you can follow to make sure the car detects it is fixed. But if you're not in that sort of hurry, it's easier to just live your life and let those codes go away when they do.

If you are in a hurry and want to follow the confirmation patterns, you should know that those patterns generally start with doing a code clear, and any time you do that, all of the car's continuous monitors reset to 'incomplete'—not just the ones you are interested in. And if you're in a hurry because of an upcoming inspection, be aware that you'll need to wait for all of those monitors to show 'complete' again (or drive all of the associated confirmation patterns).

 

A more complete description of how the car acts in various scenarios would help.

Does it clear up when you give it gas?

Small rumble on startup makes me think the head gasket job didn't take. Is that different than the death rattle? Did you get a chance to examine the old spark plugs?

Did you do the head gasket job yourself?

 

Engine rattling on startup and misfires while the coolant gets 'burned off'. Best bet might be to buy a borescope to look in the cylinders assuming you've double checked everything else involved in the head gasket job like gaskets, vacuum lines, etc.

 

If it’s not a severe death rattle this time the most common problem is timing chain off by one tooth.

 

Here is one of many threads about timing after hg. 2010 timing chain, can you get it to skip a tooth? | PriusChat

 

I think you only need to remove the valve cover to be able to check timing. You can see the crank shaft timing mark through the timing chain cover.

With a small head gasket leak you probably wouldn't notice low coolant for a while so I wouldn't completely rule that out. You might consider re-checking with the borescope after you take the spark plugs out if/when you remove the valve cover.

 

When checking the timing chain marks, it's been mentioned by ChapmanF here that it can take up to 9 revolutions of the chain before the marks line up again.

If it comes to reinstall of chain: IIRC crankshaft normal rotation is clockwise, and when you've armed and installed the timing chain tensioner, you need to rotate crankshaft counterclockwise some, say 20 degrees (??), and maybe you can hear the tensioner release.

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