Clatter on start-up

[twobuckbear]

Bought my 3.5L, auto, 4WD 2004 Nissan Pathfinder in June 2012. While awaiting insurance proof and registration, I let the car sit a few days. As most newer FI engines do, the engine starts right away and races right up to 2000 RPM or so. It also knocked a bit then settled down as oil circulated. I figured the oil filter anti-drainback valve wasn't working like it should. Does the 3.5 have hydraulic 'lifters' that take the slack out of the valve train so adjustments aren't needed?

In December of 2012, I bought a 2007Chrysler Town & Country with the 3.8 HO engine. Same story, only add the clatter of lifters & pushrods that are taking time to 'pump up'. Did oil changes with 10-40 semi-synthetic valvoline for High mileage engines and better quality (I hope) Bosch oil filters. Much better on start but is there any oil additive that will really work on the lifters or will the new oil change likely make the difference. Both car were privately owned 1st owners and had about 100K miles and reflected care. Never quite experienced the clatter on my mid-90's Dodge and Mercury vans and mitsubishi Expo that these replaced, even with bargain filters and substantially more miles.

[Chris.m]

Does the 3.5 have hydraulic 'lifters' that take the slack out of the valve train so adjustments aren't needed?

No

And I've looked into getting the valves adjusted and it's just not worth it.

[Towncivilian]

How cold is it where you live?

Bosch Premium filters do indeed have silicone anti drain back valves. They are nearly identical to Purolator PureONE filters which I use on my Pathfinder and I have no startup rattle.

An exhaust heat shield can be causing your rattle. Many members here have simply removed them without issue.

How come you chose to run 10W40 oil?

[twobuckbear]

My newer cars are for trips and "special events', get driven 8-10 K a year. I do a spring oil change and a fall oil change. I live in Joshua Tree / high Desert @3500'
oil recommended is 5w-20 but i figure that is for a new tight engine.
given the clatter and the 100+ heat coming, I opted for 10-40 on the spring Summer change. The low end is only 5w more...anticipate need for heat protection.

[twobuckbear]

Does the 3.5 have hydraulic 'lifters' that take the slack out of the valve train so adjustments aren't needed?

No

And I've looked into getting the valves adjusted and it's just not worth it.

So you live with a little noise at startup or have you found an oil filter combo that helps

[fastpakr]

I'd use an oil that's a little lighter weight so it gets up into the valvetrain faster on a cold start. If you're really concerned with keeping it thick enough at high temperatures, consider something like Rotella T6 synthetic that's a 5w40.

[Towncivilian]

Hot ambient temperature does not affect engine oil temperature significantly. The cooling system keeps the operating temperature within range. A 5W30 will provide better cold flow and sufficient protection in all temperatures and seasons. Of course, if you live in a hot climate, 10W30 or 10W40 are okay to use, but 5W30 would still be thinner at startup even in 95F weather, which still counts as a "cold" start for the engine.

[twobuckbear]

Hot ambient temperature does not affect engine oil temperature significantly. The cooling system keeps the operating temperature within range. A 5W30 will provide better cold flow and sufficient protection in all temperatures and seasons. Of course, if you live in a hot climate, 10W30 or 10W40 are okay to use, but 5W30 would still be thinner at startup even in 95F weather, which still counts as a "cold" start for the engine.

I'm no expert and I get your point, my thought is that an oil that maintains higher viscosity during heat will drain back more slowly, clinging to part for the next start up. When i did the oil change after buying the car, the oil was very tin and drained quickly. I'm sure gas dilution has some effect that way. 10-40 for my spring-summer oil change and 5-30 for my winter. As I understand it, a multi viscosity oil tries to stay at 30 weight acting as 5w would in cold and a 30 or 40 wt when hot, but stabilizing viscosity around 20-30 wt. What is your take on it. Supposedly tighter engines and the drive for fuel economy begs the lighter oil, as well as advances in bearing and oil technology.

[fastpakr]

Your concern on a cold start is less about the remaining oil on the parts in the valvetrain than how quickly oil gets back to it from the pan. That's why you need a lower base viscosity. There's no need to run a 40w oil in your situation.

[Towncivilian]

For more information about engine oil than you probably care about, I would suggest reading this article. It's rather lengthy, but it is a good read and generally eliminates confusion regarding grades of oil.

[Chris.m]

So you live with a little noise at startup or have you found an oil filter combo that helps

Actually the valvetrain noise is always there, hot or cold.

It isn't super noticeable, and I've heard other Pathfinders, QX4's, even late model Mercedes that are much worse than mine, so it doesn't bother me.

If your noise is just at start-up, maybe we have different noises

[Towncivilian]

I believe injector ticking at operating temperature is common with our engines. Mine does it for sure.