Truck Noise

[sdb479jr]

Started hearing a weird noise coming from the engine that sounds sort of like detonation from cheap gas, but not exactly. Used 87, 89, and 91...all the same. It is more like a clatter/rattle. It does not make this noise on idle, and only does it below 40 mph, especially when accelerating slightly.

If I accelerate moderately or hard, the noise also disappears.

Thanks

2000 Frontier V6

[Big-Bird]

Sounds like a cracked exhaust manifold(s). The 3.3L in the Frontiers and Xterra's have this common issue. Heck even the 3.0 V6 in the Pathfinders and Hardbodys have this issue.

If it sounds sorta like a metalic ping I bet dollars to donuts the source is at the exhaust manifold. Either 1 or both exhaust manifolds are cracked, a manifold gasket has fallen apart or a manifold stud has broken off.

The exhaust manifolds should be a normal rusty color from all the heat. Look for black carbon deposits at the exhaust manifolds. If you see black carbon ( not from an oil leak ), then you have a leak somewhere.

And given the age of your truck it won't be under warranty anymore. ( The 2000-2001's were under a 5 year warranty for this issue. I had both sides replaced on my 2000 Xterra...now I am going for a set of headers.

[sdb479jr]

Spot on my man...exhaust manifold crack.

Is this a do it yourself job? I'm decent with replacing O2 sensors and turning bolts. I know these will be tough to get out. Comments?

Headers or standard? Do not want to invest a ton of time or $$$

Thanks again...
Modified by sdb479jr at 7:53 AM 7/2/2007

[Big-Bird]

It can be a DIY job if you are prepared to drill out a broken stud from the head. The dealer in Canada charges about $600.00 (incl parts) to replace an exhaust manifold and in my case I let them fight with the studs when they break.

As for the headers I write for a Canadian 4x4 magazine so I get to try out cool stuff on occassion. This time it just happens to be headers. I can't divulge my source at this time because they are not in production yet.

[Desert Rat]

I got lucky on my 4 cylinder with the exhaust studs, but if you do break one, getting an extracter in there is tricky at best due to the lack of room to menuever. Get under there and take a look at the bolts on your exhaust system and decide if you think you can work with them, or if they're rusty beyond recognition.

A discount muffler shop would likely do the labor cheaper than a dealer if you took them the parts.

The header options for the 3.3 are thin right now...SLR is the only one advertising the parts, and I've heard enough horror stories on them to be very wary at the least. Also, they eliminate the precats, which may cause a smog inspection failure, depending on where you live.

[98s14inaz]

I'm having the same issue on my 3.3l frontier. Mine is an 04 with less than 40k. Is this the kind of thing where I just bring the truck in and they fix it for free under warranty? It is getting kind of annoying.

[Big-Bird]

It might be a warranty item on your 2004 model. Check the service bulletins on your model and see if it is covered.

The 2000 Xterra's and Frontiers were under warranty for 5 years or 160,000km whichever came first. I had both sides done under warranty, and the left side cracked again 3 years after it was fixed the first time. I'm holding out for headers now.