SHOCKED when I removed the valve (camshaft) cover!
Thread Starter
Joined: 01-07-2013
Posts: 8
From: South Texas
SHOCKED when I removed the valve (camshaft) cover!
OK, HHR owners; I just learned some very surprising info about my wife's 2006 HHR LT with the 2.4 engine. It currently has 109,000 miles. Most of our driving here in South Texas is at freeway speeds of 50-75 MPH. The ambient temperature on the highway sitting at a red light can easily be 100+ degrees, and often the sensor registers 110-115 degrees while sitting at a redlight. My wife is a very easy driver, demonstrated by the average MPG.
First a little background: I just went through the problem many owners have faced with the MIL and TRAC light coming on. My scanner showed the failure of all three cam sensors (one on the right side under the valve cover, the other two on top of the cylinder head on the left). While replacing the exhaust sensor, the BRAND NEW BOLT that comes with the sensor broke off in the head. The far right spark plug already showed some oil around the base of the plug when I replaced it a few weeks ago, so I thought "hey, I know the gasket is starting to leak a little near the spark plugs; go ahead and pull the valve cover off to make getting the bolt out a little easier. That way, I can go ahead and replace the gasket now."
When I removed the cover off the top of the engine, I was shocked at the burnt oil deposits inside the cover. There was a lot more oil deposits on the cover than I expected to see on that engine. I bought the car with 25,000 miles on it, and have used synthetic oil in it ever since. The primary deposits were at each end, the high end that covers the chain and the other end that is over the cam bearings. I've seen engines taken apart with 200,000 miles that had run on synthetic oil and there were NO deposits or sludge anywhere. I expected that cover to look like new, not show significant deposits.
While shopping for a gasket (BTW, Fel Pro VS50719R is NOT the right gasket for the 2.4!) I took the cover into a Chevy dealer to match the special order gasket with the cover. While there, I asked a mechanic that had worked on other HHRs if he had seen that level of oil deposits inside the cover. He said that was typical because the engines run hotter and at higher revs than many other GM engines.
So, bottom line is, DON'T stretch out oil change intervals, no matter what the DIC is telling you! I have flushed my engine, cleaned the valve cover gasket, and will now be going 5,000 miles or LESS on oil changes using Mobil 1 synthetic oil. I want to get to 200,000 miles on this car, so the oil changes will now be considered CRITICAL maintenance items, with no sliding on the intervals.
First a little background: I just went through the problem many owners have faced with the MIL and TRAC light coming on. My scanner showed the failure of all three cam sensors (one on the right side under the valve cover, the other two on top of the cylinder head on the left). While replacing the exhaust sensor, the BRAND NEW BOLT that comes with the sensor broke off in the head. The far right spark plug already showed some oil around the base of the plug when I replaced it a few weeks ago, so I thought "hey, I know the gasket is starting to leak a little near the spark plugs; go ahead and pull the valve cover off to make getting the bolt out a little easier. That way, I can go ahead and replace the gasket now."
When I removed the cover off the top of the engine, I was shocked at the burnt oil deposits inside the cover. There was a lot more oil deposits on the cover than I expected to see on that engine. I bought the car with 25,000 miles on it, and have used synthetic oil in it ever since. The primary deposits were at each end, the high end that covers the chain and the other end that is over the cam bearings. I've seen engines taken apart with 200,000 miles that had run on synthetic oil and there were NO deposits or sludge anywhere. I expected that cover to look like new, not show significant deposits.
While shopping for a gasket (BTW, Fel Pro VS50719R is NOT the right gasket for the 2.4!) I took the cover into a Chevy dealer to match the special order gasket with the cover. While there, I asked a mechanic that had worked on other HHRs if he had seen that level of oil deposits inside the cover. He said that was typical because the engines run hotter and at higher revs than many other GM engines.
So, bottom line is, DON'T stretch out oil change intervals, no matter what the DIC is telling you! I have flushed my engine, cleaned the valve cover gasket, and will now be going 5,000 miles or LESS on oil changes using Mobil 1 synthetic oil. I want to get to 200,000 miles on this car, so the oil changes will now be considered CRITICAL maintenance items, with no sliding on the intervals.
Senior Member
Joined: 07-17-2006
Posts: 6,053
From: Dallas, GA
Interesting first post. But I know several that are well past 100K and at least one past 300K and used the DIC. Unless you can provide some details this "mechanic" is telling you, I'll stick with my current routing.
Thread Starter
Joined: 01-07-2013
Posts: 8
From: South Texas
SOLMAN,
I'm simply stating that the deposits inside that engine were very high, especially for a car not used in extensive stop-and-go driving, and has been on synthetic oil most of its' life. If those deposits I saw were consistent with the rest of the engine, then that tells me the engine (as the Chevy mechanic confirmed to me) tends to have 'hot spots' where the oil is more likely to coke onto the surface, and build up a deposit there. And, as any engine rebuilder will tell you, oil coking is a great way to block oil circulation and lubrication.
If you are comfortable with your routine, please continue. But knowing what I know now, my oil change intervals will be shorter than they would have been otherwise. If you want to check yours, it only takes about 20-40 minutes to remove the valve cover, depending on your level of expertise. If you have a 2.4 and want the part number for the valve cover, let me know. I have the GM package at home and will post the part number tonight.
As the guy used to say in the oil change ad...."you can pay me now or pay me later."
I'm simply stating that the deposits inside that engine were very high, especially for a car not used in extensive stop-and-go driving, and has been on synthetic oil most of its' life. If those deposits I saw were consistent with the rest of the engine, then that tells me the engine (as the Chevy mechanic confirmed to me) tends to have 'hot spots' where the oil is more likely to coke onto the surface, and build up a deposit there. And, as any engine rebuilder will tell you, oil coking is a great way to block oil circulation and lubrication.
If you are comfortable with your routine, please continue. But knowing what I know now, my oil change intervals will be shorter than they would have been otherwise. If you want to check yours, it only takes about 20-40 minutes to remove the valve cover, depending on your level of expertise. If you have a 2.4 and want the part number for the valve cover, let me know. I have the GM package at home and will post the part number tonight.
As the guy used to say in the oil change ad...."you can pay me now or pay me later."
Senior Member
Joined: 01-13-2008
Posts: 4,708
From: Washington State, where it rains
Who does your oil changes? Syn shouldnt be leaving anything but a stain..my truck at 280k was just stained and it ran syn for 3/4 of those miles and reg dino the rest..one of the main points about syn is it doesnt coke up unless temps get way over, what 450deg?
If your getting that hot..maybe..theres another problem
If your getting that hot..maybe..theres another problem
Senior Member
Joined: 07-17-2006
Posts: 6,053
From: Dallas, GA
Who does your oil changes? Syn shouldnt be leaving anything but a stain..my truck at 280k was just stained and it ran syn for 3/4 of those miles and reg dino the rest..one of the main points about syn is it doesnt coke up unless temps get way over, what 450deg?
If your getting that hot..maybe..theres another problem
If your getting that hot..maybe..theres another problem
Platinum Member
Joined: 05-09-2006
Posts: 6,805
From: "Upland" Mesa, Arizona
sleeper and woody hit on my specific question......
You appear to have some knowledge of auto engines so, is it the "coking" that they speak of, is it a staining of the aluminum material, is it a sludge type material.
But I also agree with their statements on oil changes. I PERSONALLY do not change before about 25% (mileage varies because of use on that particular oil change). .....and I just this past week end removed my valve cover for the purpose of looking for "sludge" and for a thorough detailing of the removed parts. It was imaculate....to the point of being shiny new.
You have a "deeper" problem.
You appear to have some knowledge of auto engines so, is it the "coking" that they speak of, is it a staining of the aluminum material, is it a sludge type material.
But I also agree with their statements on oil changes. I PERSONALLY do not change before about 25% (mileage varies because of use on that particular oil change). .....and I just this past week end removed my valve cover for the purpose of looking for "sludge" and for a thorough detailing of the removed parts. It was imaculate....to the point of being shiny new.
You have a "deeper" problem.
Thread Starter
Joined: 01-07-2013
Posts: 8
From: South Texas
This was hard carbon...
The aluminum was stained, as I expected, but there was coking (hard carbon) on each end. It wasn't thick; most of it I could clean off with a brush in the parts washer, but in several places I had to break it lose with a screwdriver and steel wool.
When I changed the right sensor, there was coking on the bottom of the senson, where oil would drain down and drip off the bottom. Absolutely no sludge or coking on the visible part of the head, so I don't think the cylinder head overheated.
As for oil changes, I do 99% of them myself; use major brand synthetic (usually Quaker State) and just about any oil filter (AC, Purolator) other than Fram. I'm wondering if the first owner (almost 2 years) neglected oil changes? I don't think so, since he owned a truck specialty and customization shop so I think he knew the value of maintenance. I have to admit since it is my wife's car, I have relied on the DIC to signal oil changes. And trust me, SHE LETS ME KNOW when it comes on....
I agree that synthetic shouldn't coke up, so the only thing I can assume would cause it would be the excess heat under the hood after driving on the freeway and then parking the car on a hot day.
Maybe I have an unusual engine, but it never overheats or seems to have any other problems (after dealing with the MIL and TRAC lights....) For whatever the reason, I think from now on it will be Mobil 1 every 5-6,000 miles, just to be extra careful.
When I changed the right sensor, there was coking on the bottom of the senson, where oil would drain down and drip off the bottom. Absolutely no sludge or coking on the visible part of the head, so I don't think the cylinder head overheated.
As for oil changes, I do 99% of them myself; use major brand synthetic (usually Quaker State) and just about any oil filter (AC, Purolator) other than Fram. I'm wondering if the first owner (almost 2 years) neglected oil changes? I don't think so, since he owned a truck specialty and customization shop so I think he knew the value of maintenance. I have to admit since it is my wife's car, I have relied on the DIC to signal oil changes. And trust me, SHE LETS ME KNOW when it comes on....
I agree that synthetic shouldn't coke up, so the only thing I can assume would cause it would be the excess heat under the hood after driving on the freeway and then parking the car on a hot day.
Maybe I have an unusual engine, but it never overheats or seems to have any other problems (after dealing with the MIL and TRAC lights....) For whatever the reason, I think from now on it will be Mobil 1 every 5-6,000 miles, just to be extra careful.
Senior Member
Joined: 06-26-2006
Posts: 1,876
From: San Bernardino, California
I too use Mobil 1 5W30. I change it according to the DIC when it gets anywhere between 10-5%. I had the cover off about 1500 miles ago and ours also looked 'like new' as Snoopy stated. If you go with a shorter interval, you're not getting one of the benefits of using synthetic oil.