Impala Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
I have changed both intake and exhaust actuators cleared codes started car and every thing was clear until I restarted car next morning, engine light came back. Took it to a service station he replaced the intake actuator and same thing happened. He said he done some research on 2.5 and others have had the same problem, changing timing chains, with the same result . Told me I should go to dealership and have them do a diagnostic check on it, where they told me they would have to do an engine tear down to further investigate, and if timing chain is ok they would have to replace engine. My mechanic doesn't believe its the timing chain because there isn't any noise from it. Here is where I have the problem the only time I notice anything wrong with the car is on starting engine, sometimes it will stall, when restarted it runs smoothly. Help!!!
 

·
Registered
Joined
·
1,363 Posts
Are you using the proper engine oil SAE weight of Dexos rated oil?
The VVT actuators will get upset when you run too heavy or too light motor oil. Nasty dirty motor oil will make trouble as well.

I've read that using aftermarket oil filters caused VVT actuator problems but I take that with a grain of salt. Til I see an actual TSB from GM stating those exact words I reserve judgement.
 
  • Like
Reactions: sheila

·
Registered
Joined
·
1,363 Posts
GM has no reason to make the engine last longer than they can get away with. I don't use the oil monitor to time my oil changes.
As finicky as the VVT engines are about oil I generally just change my 3.6L and 6.0L at 5,000 miles or a little less. The AFM in the LS4 is fairly persnickety as well but less than the VVT engines. Honda, Lexus, Nissan, ... VVT engines are equally finicky.

Is the VVT actuator a GM part or aftermarket.
The aftermarket parts chain has been poisoned with substandard Asian parts in recent years.
I've turned into a parts snob. VVT actuators and other sensors that are difficult to access get OEM parts. I don't feel like spending the time to replace parts over and over to finally get one that works for 6 months then ride the carousel again.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #5 ·
GM dealership said there is nothing wrong with actuators they working as they should they want to do engine tear down to determine if its a timing chain issue. If it isn't a chain issue they say I will have to replace engine. If there was a blockage in an oil port to actuator would there be some kind of oil Additive that could dislodge possible blockage. Engine seems to run nice just some starts are rough
 

·
Registered
Joined
·
1,363 Posts
In the 1970's & 1980's when I was a youngster and couldn't afford well maintained used vehicles I used to run a quart of ATF and some Marvel Mystery Oil for a 10 mile toot in the old oil of my new prizes befor changing the oil and did it again just before each of the first four oil changes. It seemed to rinse out a lot of filth. Afterward the oil would usually just start to get dark by the 3,000 mile interval I used to run.
The main problem with dislodging crud is where it goes after you knock it loose. The old saw about sleeping dogs applies here in spades.
I wouldn't reccomend that method in vehicles manufactured after 1999 or so. These VVT and AFM engines don't pass the crud down to the filter and soldier on like the looser less sophisticated engines of the 70's & 80's.

The GM 3.6L timing chain and VVT setup must've been concocted by BMW engineers. The stories of timing chain and VVT woes remind me of the BMW M62.
The government mandated EV changeover is right on the horizon so there's not much incentive to improve internal combustion engines. I, for one, think this mandate will bite us in the gluteous maximus like a rabid dog.
 

·
Registered
Joined
·
167 Posts
5000 miles, full synthetic oil, premium oil filter, that'll do the trick in most cases. I also run BG44K and BG MOA and BG EPR products as well. Carbon build up is a real thing with direct injection engines.
 

·
Registered
Joined
·
1,363 Posts
5000 miles, full synthetic oil, premium oil filter, that'll do the trick in most cases. I also run BG44K and BG MOA and BG EPR products as well. Carbon build up is a real thing with direct injection engines.
Agreed. 5,000 miles is just fine on most modern automobiles.
Between 1980 & 1989 I did 3,000 - 3,500 mile ish intervals. Just the way things were then.
My 1.8L 1984 Subaru GL Hardtop, 1973 Pontiac Catalilna 400, 1973 Pontiac Grand Prix with the Catalinas' 400, 1972 Pontiac Bonneville Wagon 455, and my 1969 Dodge Polara 383 were pretty dirty running engines. Not as bad as my 1979 VW Rabbit Diesel that turned the oil black on the first startup, but, the oil woild be a very dark mahogany brown that you could no longer see through by the time 5K rolled round on those odometers.
On top of the leaps forward in fuel systems. The oil was just not as good back then. I've seen exponential leaps forward in quality lubricants since the 1970's & 1980's.

It'd make me feel young again to have the Polara or the Grand Prix now but life, as they say, goes on.
 
  • Like
Reactions: sheila

·
Registered
Joined
·
5 Posts
I have changed both intake and exhaust actuators cleared codes started car and every thing was clear until I restarted car next morning, engine light came back. Took it to a service station he replaced the intake actuator and same thing happened. He said he done some research on 2.5 and others have had the same problem, changing timing chains, with the same result . Told me I should go to dealership and have them do a diagnostic check on it, where they told me they would have to do an engine tear down to further investigate, and if timing chain is ok they would have to replace engine. My mechanic doesn't believe its the timing chain because there isn't any noise from it. Here is where I have the problem the only time I notice anything wrong with the car is on starting engine, sometimes it will stall, when restarted it runs smoothly. Help!!!
Oil level is a big deal with those engines too along with correct viscosity.
 

·
Registered
Joined
·
20 Posts
I have changed both intake and exhaust actuators cleared codes started car and every thing was clear until I restarted car next morning, engine light came back. Took it to a service station he replaced the intake actuator and same thing happened. He said he done some research on 2.5 and others have had the same problem, changing timing chains, with the same result . Told me I should go to dealership and have them do a diagnostic check on it, where they told me they would have to do an engine tear down to further investigate, and if timing chain is ok they would have to replace engine. My mechanic doesn't believe its the timing chain because there isn't any noise from it. Here is where I have the problem the only time I notice anything wrong with the car is on starting engine, sometimes it will stall, when restarted it runs smoothly. Help!!!
I got 372,000 miles out of a 3.9L 2010 LTZ Impala. Never had any issues with the VVT system. I think you have the inline 4. Our 2012 Equinox has the inline 4. I had to change both valve timing actuators a while back. Did not waste my time on aftermarket. You will be rolling the dice. Use factory GM actuators not from amazon but from a dealership parts department. O know you said the dealership said the new actuators were working ok. Maybe on a diagnosis or bi-directional test, but, if they don't actuate like the ecm wants, you may still get that code. I don't know that the vvt actuators will cause your problem though. They might. Our 2.4 in our Equinox didn't exhibit any starting propblems when the actuators failed.
 

·
Registered
Joined
·
1,363 Posts
I don't think the 3.9L has the VVT.
Actually... Starting in 2006 the 3.9L had VVT according to Popular Mechanics.

You can find cam phasers on Rock Auto for the 2006 Impala 3.9
 
  • Like
Reactions: sheila
1 - 13 of 13 Posts
Top