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Problems/Service/RepairsIf you have a problem with your HHR, want a tip on repairing or performing a particular service to you HHR here is the place to post!
question for the experts- can a 2.4 exhaust cam be removed without removing the timing chain? is there enough room to slide it out?
have kept driving the car for the past month, no change- only get the P0304 when the car is idling. a couple days when we had a warm spell and were using the A/C, just that small bump in idle was enough to keep the light off. IF i could pull the cam, i was debating pulling the exhaust valve springs to have a look if one is possibly broken or weak. my buddy has a spring pressure tester so i could check them.
If you support the timing chain sprocket, you might be able to, however the phaser doesn’t have anywhere to hood it .
there are tools available to hold it , but very expensive.
the valve springs are visible from the top with the valve cover removed.
do not turn the crankshaft counter clockwise ever!
slowly rotate the crankshaft and observe the springs, look for damage around the camshaft follower’s
Phaser holder tool A view of the valve springs and cam followers
I tried this, got the special tool. The problem is that the phaser slides over the end of the camshaft. So even though the phaser was held in place, the camshaft would not come out. So I modified the tool, hoping to have enough space for the phaser to wiggle off the end of the camshaft. Still couldn't do it, and then the phaser slipped and I had to retime the engine anyway.
Slide it out of what? Have you ever looked under a valve cover?
Have you done a compression test? Have you moved coils and injectors around? (I don't feel like scrolling back through 4 pages)
just a recap for anyone who doesn't want to go back- I've done all the tests, swapped/changed all the parts and right now all signs point to a burnt exhaust valve on #4.
the reason I was wondering if I could get to the springs was to 1- remove to see if they might be broken (yes I had the valve cover off, couldn't see anything. doesn't mean its not broken where I can't see) or 2- slipping a shim under the exhaust valves to increase spring pressure slightly.
past 2 weeks I've driven the car with the A/C on 100% of the time- no light. the light was on and actually turned off while driving.
I can sympathize with trying to avoid pulling the head. If the CEL went out then maybe the valve is sealing better? Could try compression test again. Probably futile to try to look with a borescope. Intake valve maybe. Exhaust valve not so much.
Did the P0520 go away? If the oil pressure sensing system (just a switch, I know) is not working properly an undetected low oil pressure condition is possible.
just a recap for anyone who doesn't want to go back- I've done all the tests, swapped/changed all the parts and right now all signs point to a burnt exhaust valve on #4.
the reason I was wondering if I could get to the springs was to 1- remove to see if they might be broken (yes I had the valve cover off, couldn't see anything. doesn't mean its not broken where I can't see) or 2- slipping a shim under the exhaust valves to increase spring pressure slightly.
past 2 weeks I've driven the car with the A/C on 100% of the time- no light. the light was on and actually turned off while driving.
Did you LOOK at the chain between the sprockets?
Are the codes pending, current or permanent/historic?
When the light is on are you absolutely sure the code that caused it is P0304?