There are 2 timing chains.

One is the ignition timing chain. This is the one that causes pistons and valves to contact if it breaks or slips a few teeth.

The other is the balance shaft timing chain. It turns the balance shafts and the water pump. Someone correct me if I'm wrong, not nearly as critical. If you slip a few teeth on it, no big deal, your engine shakes badly, makes a terrible WAH-WAH sound. Then it will have to be retimed correctly, but the engine isn't damaged.

 

How many times do we have to say "the tool holds the chain"? If you only change the pump there is NO need to mess with the chain. The tool just needs you to tighten a couple of screws. I don't know what you are seeing that makes you think "messing with the timing". Touching the front cover?

The whole reason for the tool is to NOT mess with the chain. However, My guess is that your chain and guides are close to gone.

I am not calling any names, just saying don't buy 15 year old cars if you can't afford to fix them, they will break. The best way to save on repairs is to DIY.

 

I suggested to replace the timing and balance shaft chains along with the water pump, because of the age and condition of the HHR .
There are tools to hold the water pump sprocket, while you change the water pump. Then no touching the timing chain

 

With the water pump and timing potentially being off replies this is what I'll have done then just so I don't end up replacing the pump then having chain done shortly after. I'll probably drive it to Tucson and have it done there could be a LOT cheaper than here in Phoenix.

Before that though I'll keep burping it since I only did that once. Thank you !

 

That sounds like a good plan. Yes, like Oldblue said, it can take several times.

 

Kokomo, I have had two 2.2 HHR’s and neither did what yours does.

Running hot under load and promptly cooling down at low speed and idle is what happens when there is a restriction in the exhaust system, causing high back pressure only under load, so you need to eliminate that. The 2.2 exhaust is was a bit restrictive in the first place. You should prove the exhaust is escaping freely.

Are the any codes?

What’s the state of the exhaust system? There could be a kink in the pipes. Scale may have clumped up inside a bend. Do you have the original muffler? The OEM mufflers hold together very well on the outside but eventually crumble on the inside and the loose scale can clog things up. You could temporarily disconnect the flange between the downpipe and the resonator and see if it runs cooler under load.

The cat could be clogged.

 

I haven't thought about a clogged exhaust system that's a good idea to have the pressure tested before/after cat. Everything in this car I've worked on has been original so I think it's safe to say it's the original cat/muffler/piping. Although the CarFax said it spent 2006-2015 in Kokomo, IN (username idea haha) before it came to AZ so it may have rusted out at one point but I've been under there and it looks original and did not see any kinks.

No codes, pending or historical, it got a lobotomy almost 2 months ago. Could a clogged cat also be why this car is an absolute snail even at WOT until like 3000rpms? Then it takes off like a rocket. Sorry this is probably something I should've added to the OP. I've read this can also be intentional by GM using torque management to prevent wear on the trans. Internet says the 2.4 is supposed to have 174hp at the crank but man until about 3000 rpms it feels like it has 30hp lol

Also I've tried to burp it twice more now even with the nose high and as soon as take the cap off I can't add anymore coolant it's already full. Do I start it and let it run so it burps itself or will that just puke coolant everywhere. I've just been letting it cool down then opening the cap with the car off.

 

I always do what you've been doing, letting it cool down to top off coolant and it works out just fine. If you want to test to see if there is a restriction in the exhaust you can also remove the O2 sensor and take it for a spin. It will probably throw a code but you'll already know why but with the extra vent it should be enough to see if you gain any HP.

 

Don’t run the engine with the rad cap off, as you suspect it’ll just spew coolant.

if it is the cat , I recommend this one, it’s mandrel bent and very good quality, I installed one of these in my 2.2 LS .

https://mufflerexpress.ca/products/c...rter-2005-2007

 

Well that’s the exact opposite of what I’d expect with a partially clogged exhaust so IDK, but I’d still want to confirm that the exhaust system is unrestricted.

Is it noisy or quiet as new?