2018 Pathfinder timing chain questions

[Sea Urchin]

Hi all, thanks for letting me join. I'm a proud papa of 2018 Pathfinder Platinum, 140,000 kms on it. Never had any issues whatsoever, knock on wood. Just recently timing chain started to slap a little, well, more than a little, loss of power, sluggish response and fuel consumption went thru the roof. Decided to do the chains, crankshaft and oil pump sprockets and tensioners myself without pulling motor out. Frustrating and tedious process but, vehicle has been good to me so I don't mind. My question is, my chain was so loose and tensioner was stuck in compressed position. When I took the cover off I noticed that my colored links did not match up with marks on sprockets on all three chains. Also, inside of chains cover was scratched by chain. Picture attached. I found manual on this site for 2016 Pathfinder, does timing set up from this manual work for my vehicle? Also, how do I make sure my crankshaft and camshafts are in the right position when I install chains? Does lining up colored chain links on sprocket marks and sprockets with camshaft dowel sufficient to set them in the right position? Given the labour involved I really don't want to take this thing apart again.
Any info would be appreciated. [/img]

[VStar650CL]

Yowch, that has to be a failed tensioner. There's a ratchet inside those things to keep the chain in place on startup when there's no oil pressure, so once they pump up, they can't return to a compressed position unless something breaks.

There are no big differences from '16~'18 on the VQ35DE, so the '16 FSM should work for you. I'd be worried about how that tensioner failed, I think you must have had some oil starvation to the front cover. Check the front cover carefully for cracks and use new o-rings. I'd also change the oil gallery gaskets while you're in there (see pic). Nissan doesn't sell those separately but you can get nice silicone replacements from Z1, CZP, and several other vendors. When those leak you lose pressure to the cover at idle, so they may be your culprit.

'18 VQ35DE Galleries.jpg (71.16 KiB) Viewed 10406 times

[VStar650CL]

PS - Some of the '18's had DE's, some had DD's. The chains aren't different but the DD's have electric intake valve timing. You need to do an IVT learn if you have a DD. It's pretty simple, and you only need a scanner to clear the codes after performing it:
1) Turn ignition switch OFF.
2) Disconnect electric IVT control actuator harness connector (actuator side).
3) Turn ignition switch ON and wait at least 70 seconds.
4) Turn ignition switch OFF.
5) Reconnect the disconnected harness connector.
6) Start engine and let it idle at least 15 seconds.
7) Turn ignition switch OFF.
8) Check and erase DTC.
The actuator connectors can be a b!#ch to remove with the engine mount in place, but not so hard to get back on. So leave them loose after she's back together and do steps 1~7 as part of your startup sequence.

One other thing (for all Nissan engines), make sure you pull the fuel pump fuse and crank dry for at least 30 seconds before you let the engine fire. If you don't build oil pressure before letting it start, there's a very good chance of jumping your brand new chains (usually the bank1 cam chain on VQ's).

[Sea Urchin]

Yowch, that has to be a failed tensioner. There's a ratchet inside those things to keep the chain in place on startup when there's no oil pressure, so once they pump up, they can't return to a compressed position unless something breaks.

There are no big differences from '16~'18 on the VQ35DE, so the '16 FSM should work for you. I'd be worried about how that tensioner failed, I think you must have had some oil starvation to the front cover. Check the front cover carefully for cracks and use new o-rings. I'd also change the oil gallery gaskets while you're in there (see pic). Nissan doesn't sell those separately but you can get nice silicone replacements from Z1, CZP, and several other vendors. When those leak you lose pressure to the cover at idle, so they may be your culprit.


'18 VQ35DE Galleries.jpg
Hi, thank you for the tip. I wonder if it was my oil pump chain tensioner that was the culprit. I found that the spring has slipped and there was no tension on it at all. I did replace both oil galleries gaskets, covers have no cracks. I noticed that my crankshaft oil sprocket does not lock onto crankshaft at all. just spins freely, is this normal? How does it lock on to crankshaft to operate oil pump?

Another question, I got all three chains on as per manual, guides and tensioners as well. Torqued it all, rotated my crankshaft clockwise to make sure pistons don't hit valves. It all rotates freely, no interference, but now I noticed my main chain marks do not line up with marks on camshaft sprockets. Is it due to VVt springs? I was watching carefully to make sure chain doesn't skip and I didn't see it skip. just the springs wound up and spun cams.
Should I re do it again and not worry about rotating it until its fully assembled? Or is it ok the way it is? I checked my marks 4 times before rotating engine with a ratchet to make sure I had them right.

[VStar650CL]

Once you rotate you need to go some number of revolutions before all the marks line up again, where N is an integral of the number of links on the main chain to the ratios of the crank and cam sprockets. N can be a weird number when the main chain has an odd number of links. The only thing "fixed" is that the cam sprocket teeth are always double the crank teeth. Your assumption is also correct that the VVT's can pretty much go where they please when there's no oil pressure. So the bottom line is, if you're sure you had it right before rotating, then it's still right. Forget about it.

[VStar650CL]

Hmm, I didn't catch the first part of your question. None of the gears should spin free. IIRC there's one woodruff that spans both the crank and oil pump sprockets, is it sheared?

[Sea Urchin]

Hmm, I didn't catch the first part of your question. None of the gears should spin free. IIRC there's one woodruff that spans both the crank and oil pump sprockets, is it sheared?

, OEM
woodruff key on my crankshaft only catches timing chain sprocket and harmonic balancer, OEM replacement look to be same size as he one i have now.

[VStar650CL]

Well, it certainly won't be driving the pump if it sits there spinning, so there's a problem someplace. I can't imagine what, but it's definitely supposed to be keyed.

[Sea Urchin]

PS - Some of the '18's had DE's, some had DD's. The chains aren't different but the DD's have electric intake valve timing. You need to do an IVT learn if you have a DD. It's pretty simple, and you only need a scanner to clear the codes after performing it:
1) Turn ignition switch OFF.
2) Disconnect electric IVT control actuator harness connector (actuator side).
3) Turn ignition switch ON and wait at least 70 seconds.
4) Turn ignition switch OFF.
5) Reconnect the disconnected harness connector.
6) Start engine and let it idle at least 15 seconds.
7) Turn ignition switch OFF.
8) Check and erase DTC.
The actuator connectors can be a b!#ch to remove with the engine mount in place, but not so hard to get back on. So leave them loose after she's back together and do steps 1~7 as part of your startup sequence.

One other thing (for all Nissan engines), make sure you pull the fuel pump fuse and crank dry for at least 30 seconds before you let the engine fire. If you don't build oil pressure before letting it start, there's a very good chance of jumping your brand new chains (usually the bank1 cam chain on VQ's).

Appreciate your help. I got P34C4 code and P0300 code, once I did the IVT learn codes went away, she purrs like a kitten now. Gas milage is much better and it drives like new car. Also, I was told oil pump sprocket does not need Woodruf key, it is held in place by torquing harmonic balancer against it. Proper torque is critical to spin that sucker. Loose balancer, lack of oil pressure. Awesome forum peeps, keep it up. If you ever end up in Winnipeg, dinner and drinks on me.

[VStar650CL]

I was told oil pump sprocket does not need Woodruf key, it is held in place by torquing harmonic balancer against it. Proper torque is critical to spin that sucker. Loose balancer, lack of oil pressure.

Lol, I've had a bunch of those apart and I guess I never noticed that the keyway wasn't contacting anything. Weird s#it that it has a keyway if that's the case, though. I'll have to look closer next time we have one opened up.

Anyway, glad you got it straightened away. One thing I'd add while we're here, to make sure it stays happy -- watch the J-hose which connects the PCV to the plenum like a hawk. On Muranos and Pathies they have an unfortunate habit of collapsing and sludging a perfectly good engine. Sometimes they delaminate and the outside of the hose looks fine, making the problem invisible unless you palpate the hose for soft spots. For the long term, you might want to put a reinforcing spring inside it next time you're doing maintenance, that's what I do for my good customers.

Happy to help, happy motoring!

[Sea Urchin]

I was told oil pump sprocket does not need Woodruf key, it is held in place by torquing harmonic balancer against it. Proper torque is critical to spin that sucker. Loose balancer, lack of oil pressure.

Lol, I've had a bunch of those apart and I guess I never noticed that the keyway wasn't contacting anything. Weird s#it that it has a keyway if that's the case, though. I'll have to look closer next time we have one opened up.

Anyway, glad you got it straightened away. One thing I'd add while we're here, to make sure it stays happy -- watch the J-hose which connects the PCV to the plenum like a hawk. On Muranos and Pathies they have an unfortunate habit of collapsing and sludging a perfectly good engine. Sometimes they delaminate and the outside of the hose looks fine, making the problem invisible unless you palpate the hose for soft spots. For the long term, you might want to put a reinforcing spring inside it next time you're doing maintenance, that's what I do for my good customers.

Happy to help, happy motoring!

I wonder if the keyway on oil pump sprocket is there only to allow it to come off the crank without removing Woodruf key. On another topic, over the years I found when replacing sway bar bushings with brackets that have slotted bolt hole on one side, bushings last longer and front end is tighter if you squeeze brackets in a vice to make them about 1/4" narrower. They are a bit tighter to slide onto the bushing and when you install bolts you have to tighten them going back and forth in order to have them seated over the bushing properly. Big thanks again!!!!

[VStar650CL]

I wonder if the keyway on oil pump sprocket is there only to allow it to come off the crank without removing Woodruf key.

That's what I'm thinking, yah (and that's probably why I never noticed it was clearing the keyway when installed). Or it might be an interchange part with models which do have a key. I dunno. Not that it's bad, but it is a trifle weird.

[sm2023]

Quick question - when working on the timing chain, since you have to remove the top engine mount, do you need to support the engine from the bottom or the engine is safely held by the other mounts? Usually you can use the oil pan, but in this case you have to open the oil pan to expose the bottom 2 bolts. If the engine needs to be supported, what is good way to do it? Thanks in advance!

[VStar650CL]

It won't fall out of the car with the nose mount removed, but it will drop quite a bit. Once the lower pan is removed, you can jack it on anything except the oil pickup. Use a pad or board, but nothing else down there is particularly fragile. Or you can use a hanger bar and chain from the top, but I never liked doing that, you end up constantly working around the bar.

[sm2023]

@VStar650CL - Got it! Thanks for a quick response!

[VStar650CL]