Hi folks,

I tore into the Pathfinder this weekend to try to determine the cause of my cold start rattle. I found a couple of possibilities.

1. The primary chain tensioner is a little sticky.
2. The orange plastic of the top guide is sliding around the black plastic a bit, I'm not sure whether this is normal.
3. The bank 2 secondary chain tensioner seems to be losing tension.

Of these, I believe option 3 to be most likely to be the fault. The rattle seems to be coming from the top of bank 2, and the bank 1 secondary chain is not losing tension the way that the bank 2 chain is. Additionally, I'm hearing some oil gurgle coming from the bank 2 secondary tensioner when I turn the chain.

My questions are, what is the best way to replace the secondary tensioners? Can I do it without removing the cam sprockets or chains? Can I do it without removing the primary chain?

I ended up removing the sprockets, tensioners, chains, valve covers, and front camshaft caps. Getting to the secondary tensioners is involved, but not extremely difficult. The bank 2 secondary tensioner is definitely bad.

Thanks for posting back with the results. Hope it all went together well.

I have not yet put anything together, so I can't say whether the bad tensioner is the cause of the rattle, but it definitely collapses with just a slight bit of pressure, and was causing that chain to slack. I'll keep you all posted.

I replaced all three chain tensioners, but did not replace any of the chains or guides. The rattle is still there.

All said and done, this job probably took me 24 hours total. Most of the time was spent scraping and cleaning old RTV off the mating surfaces. I also spent a good deal of time making sure everything was going to be installed correctly, cleaning bolts and threads, as well as researching parts.

For one, varying OEM sources had conflicting information, but also I just could not make up my mind what I wanted to replace, how much money I wanted to spend, and how quickly I wanted to get done. In the end I opted for less money spent and getting the job done relatively quickly. The three tensioners cost me just over $200, and another $150 for an O2 sensor and incidentals: gaskets, hoses, etc. Inspecting the parts, I decided that the chain and guides were in good enough condition to last a few more years, or until the next time I pry the cover off. Some of the o-rings were hardened, and I wish I would have ordered these sooner. I would have preferred to replace these cheap yet crucial parts. I was a bit upset that the secondary tensioners did not come with new o-rings, nor the primary with a new gasket. The OEM parts websites don't make this explicit. I would have also liked to replace the o-rings that feed oil to the VVT system via the main camshaft cap, rear timing cover, and front timing cover; as well as the curved gasket at the bottom of the front timing cover.

I also popped the water pump out and inspected it, as well as its housing. Back in 2015 I broke off a water pump bolt inside its threads, and this caused a crack to form. There was some sludge accumulated at this crack between the two water pump o-rings, which I cleaned. I put JB Weld in the crack and smoothed out some of the burrs with a file. I was relieved to realize that the crack had actually occurred inside the rear timing cover, and not the block. Back in 2015 this caused me some stress, as I thought I cracked the block.

Needless to say, I am disappointed that the new tensioners did not cure the noise, but am glad to have gotten re-acquainted with the engine. It was nice to get to work on it inside a garage with a bench and the right tools, a luxury I did not have in 2015, which is the last time I performed major work on the car.

The power steering pump, alternator, and starter removal was a pain. I popped out the starter to jam a screwdriver in the flywheel teeth in order to remove and install the crankshaft pulley. The timing chain sprockets took a lot of leverage to remove. My wife held an adjustable wrench on the camshaft while I pulled on a long breaker bar at the sprocket. We could not remove the bank 1 exhaust sprocket, as the location of that camshaft did not let us get very good leverage. I was able to slip the chain off that sprocket and did not have to remove it, but if I ever need to remove that camshaft, I'll have to come up with another plan. I assume that if I remove the engine, the awkward location won't be as much of an issue.

While the valve covers were off I took the time to inspect my PCV valve, it seemed fine. I took the time to clean up the tops of the covers. Some of the spark plug tube gaskets were cracked, but these covers are the plastic ones, so replacing the tube gaskets isn't an option. Instead, I put RTV in the cracks. Taking the time to unclip the wiring harness from the engine and pulling it aside made a big difference in being able to get to certain components. Replacement of the rear bank 2 O2 sensor wasn't very difficult, nor was access to the heater hoses. I made the mistake of ordering aftermarket hoses, but somehow Nissan made these hoses smaller on one end. I wasn't about to install a hose too big for my heater core pipes, so I sent the hoses back and just put new clamps on the old hoses, which weren't in terrible condition. Putting RTV on everything was a pain as well, and I swore that next time I'll use a caulk gun, which should make things a lot easier on my hands and patience. I haven't had any oil leaks yet.

Previously I couldn't find any but one of the colored links on any of my chains, nor the marks on any of my cam sprockets. This time I got lucky. I rotated the crankshaft over and over, inspecting it and the sprockets each time the red link lined up with the mark on the crankshaft sprocket at 4 o'clock. The correct configuration had the red link lined up with the mark on the crankshaft sprocket, another mark on the crankshaft sprocket lined up with a notch on the rear timing cover at 11 o'clock, and small oval marks on each of the intake camshaft sprockets pointing toward the top of each respective head. This mark lined up with a blue-ish link on the primary chain. When all four of these were lined up, gold-ish links on the secondary chains also lined up with small circular notches on the exhaust sprockets. The marks on the intake sprockets were difficult to see because they were stamped on a recessed portion of the sprocket. Once I found them, I marked their location by tracing an invisible line toward the top of the timing cover, and painting a line on the cover with permanent marker. Thankfully I made a mark on top of the cover; when I cleaned the RTV off the mating surface the permanent marker came off as well.

All in all this was a satisfying job. It would have been a lot more satisfying if the noise had gone away, but I am happy to have had some good cleaning, lubing, and inspection time with the old VQ35DE.