Bought this car with 188k. It failed emissions in colorado (went to auction) cats are bad, I plan on test piping it. Far as timing chain goes I have no clue if it's ever been replaced, or any other thing besides the records vin check pulled up on oil changes. Appears the valve covers has either been leaking or still is (dirt build up on the oil). It uses or leaks a quart to 2000m est since I first changed it. But then I've only put 2000 or so miles on it. Runs and drives great. Power, shifts good. Should I worry about the chain or just drive it till she dies?

 

I'm at 170k on my '04 G, and it burns about 1qt/2,000 miles. My other one had 250k on it, and it burned 1qt/1,000 miles. Keep an eye on the oil level, especially nearing 200k miles.
The timing chains on these cars are fairly resilient. If oil changes have been done regularly, the chain and tensioners should last the life of the rest of the engine. Do you have any noises or rattles at start up?
The main chain tensioner is easily accessed through a cover on the DE engines. The newer OE tensioners have the year stamped on them, that may provide you some insight if it has been changed recently.
My current G had a mild 'zing' noise that lasted maybe half a second upon start up in the morning. I replaced the main tensioner and the noise went away. The old one was easily compressed.

 

Yah I have no abnormal noises at start up or at any time. Curious to know what oil you use? Still using synthetic? No clue what they used before in this but I put mobile 1 high mileage 10w-30 synthetic. Did you have a valve cover leak or do they just burn it?

 

The chain used in the VQ is considered "life of the engine" it doesn't have a recommended maintenance interval and unless the car is driven hard regularly it's probably fine. You can remove the primary tensioner cover and check how far out the plunger is extended, that will give you an idea how much stretch and wear it's got on it. Permatex ultra grey the cover back on.

 

I'd still recommend using a synthetic in any VQ. They are hard on oil. Just get the high mileage version.
Mobil-1 5w-30 High Mileage synthetic is what I've run in the past, 10w-30 in the summer. Oil analysis have come back looking very good. I'm trying out german Castrol as of this last oil change.
My valve covers do 'weap' a little, and it seems to be worse in the last month since the switch to Castrol, or my gasket just decided its time to leak more LOL.

 

What's your thoughts on using synthetic blend?

 

Better than running conventional, helped slow a few of my leaks. Usually run the cheap walmart supertech for 4500 miles or so.

 

I rather buy the mobile 1 at walmart. It's cheap enough, just not synthetic blend

 

Yeah I used to do the same, used to buy extended performance mobil 1 used it for everything. Talked to a friend who went to jiffy lube with his g37, every 5k or so usually late, got the cheapest conventional changes with the coupon, he'd spend no more than $30 there, car had over 180k with no issues by the time he sold it. After hearing that I stopped used the good stuff.

 

I run full synthetic for the sake that on occasional canyon runs I drive the car reasonably hard, where I would be concerned of a conventional oil thinning out.
For a daily driven vehicle, full synthetic is probably only a necessity for extreme temperature (at or beloew freezing or above 100* ambient). Towing is another circumstance where synthetic might be a good idea.
Look up videos of conventional vs. synthetic oil @ freezing, then you'll see why synthetic has an advantage.
I had a 2005 G35 with over 250k miles on it, I bought it with around 240k. I knew the original owner, who ran nothing other than full synthetic its entire life. No leaks, not even the original valve covers!
In my neck of the woods, Mobil-1 is $23 for 5 qts at Walmart. Even cheaper at Pep boys after $15 mail in rebate. Figure ~$7 for the filter. Hard to beat for a DIY oil change.