I was told that Nissan micro polished the crankshaft journals and insist on using a Nissan oil filter because this 2003 - VQ35 has a tendency to let the oil drain down too much promoting a "dry start", where the rod bearings rattle a second during initial start. (Micro-polishing the crankshaft journals reduces dry bearing "scuffing")

I have 270,000 miles on my 03 Maxima and it is running great. Using certain oil and always using a Nissan oil filter pretty much eliminated any bearing rattle at initial start BUT this engine with 270,000 miles on it , is now beginning to "rod rattle".


Is there a way I can delay start-up so that the starter spins the engine a little longer thereby pumping the oil up to the bearings (which will eliminate the rod bearing rattle)? I manually disconnected the ignition, cranked it for 5 seconds, re-plugged in the ignition and it started up with no rod rattle. I did throw a code doing this and reset it myself.

So is there some way I can splice-in a switch run it into the under-dash area, delay light-off for a few seconds while cranking the starter, flip the switch and let it start? I was thinking if I switch off the fuel pump, this would delay light-off and not throw a code??

I am looking for any other suggestions (please don't be a smart-alec) OR if my fuel pump switch is a good idea, where is the most convenient spot to find the fuel pump wire?

THANKS!!!

 

How sure are you that it is the crankshaft journals? The timing chain guides wear out and allow the chain to slap when you first start the engine until the adjusters fill with oil. With your mileage, they are about due for their 3rd replacement.

 

Probably chain rattle from tensioner or IVT sprocket. I run 50 weight in the high mileage/abused engines. It doesn't hurt anything. You could replace the tensioner O ring.

Otherwise, your bearings would have been ground up and engine seized, already.

 

Right i was going to say the same thing. Its the tenisioner that makes the noise until oil pressure builds up. But idk about the guides wearing out on 5.5 gens, its the 6 gens that have the plastic guides that wear out. Ive never replaced on chain guide on my 02 i35 3.5 engine in 315k miles.

 

I get some rattle noise on start up if the car sits more than 20 mins. It's only had Nissan Filters. I figured it was the timing chain area.

94k, 03 I35

 

Thats normal, as long as its not doing it longer than that.

 

So out on the highway (70mph) yesterday under light throttle, the "start rattle" became very constant. I let off the gas, and it would go away, back on the gas lightly and it would start up again. I think the 5w30 may have thinned out too much since it was over 97F. Going to change the oil today and put a 40wt and see if it helps. I hope this isn't the beginning of another issue.....

 

That's either precat rattle (I seriously hope you don't have any) or IVT sprocket. I don't believe lack of throttle is going to make it go away if chain is slapping.

 

I'm surprised nobody has suggested this could be the paper oil gallery gaskets blown out and it only being a matter of time until a rod bearing goes. Sorry to freak you out but this is a real possibility.

The gallery can drain while the engine sits. If this were the problem the engine can operate at higher RPMs and survive for some time (until the leak gets worse) however when the engine is at temp idling, the rest of the engine can be starved of flow since the small amount of oil being pumped more readily flows through the leaking gasket.

 

Does the IVT sprocket act like the timing chain tensioner?

 

I thought the paper gasket issue was only on the early VQ37's?

 

Nope, same crappy paper gaskets in VQ35, probably from 2002 thru 2011ish. Ward's Top 10!

 

where is this oil gallery?

 

I guess they are called "galley" but my autocorrect likes to write gallery.

 

Not common (never seen it posted anywhere) and may not ever happen on early VQs. It's an HR, VHR, 2nd gen DE thing when production changed. Also, it should immediately be followed by IVT codes once pressure gets low.

I'm fairly certain an IVT sprocket is worn out. Use 50 weight oil and drive it till it blows up.

 

I think it's way more common than most assume, it took out the motor in my car. I suspect the diagnosis for the VQ37 just happened to trip more easily, that and some of those cars have an oil pressure gauge from factory means people notice it. It is probably either #1 or #2 reason these motors go, right up there with the pre-cats.

 

I also get a rattle at cold start and always figured it was the tensioner/chain worn.

Also I usually notice the rattle more when I am low on oil.

After topping it off with oil I usually get a few days without a cold start rattle.

In regards to IVT, I had that code pop up when I was low on oil too.

 

50 weight! Seriously?
I put in some 0w40 Mobil1, and it seems to have helped a little. Still rattles randomly on light throttle but no where near as bad as 5w30. I've never used anything higher than 10w40

 

Well, if it is knocking, then 50 weight will keep it alive the longest. 0w40 is pretty light.

I'm using 15w50 right meow (5w50 for winter).

 

Good to know. I'll give it a shot. Thanks

 

I don't know exactly what's rattling but it is getting louder and delaying start while spinning the starter (for maybe 5 seconds longer that usual) will allow the oil to pump up and eliminate the rattle (I tested this theory out and it works). I just need to figure out how to delay start more conveniently and not throw a code.