5-w30 in 99 N* ??

[Elmer Fudd]

Mine is a 99 N*, Concours (the 300 hp). The manual clearly says 10w-30 PERIOD. I have heard that starting in 2000 they went to 5w-30 as ok. I know there were some small changes in the engine that year too.

Question is, I have a slight lifter tick that is not bad,but enough to really IRRATATE me....... I have tried various snake oils...no luck. Some have suggested lighter oil to get in the blocked ports (assuming that is the culprit). My 98 Buick (3.1) ticked and tapped a little until it got real warm on 10w-30, but it was much better on 5w-30.

Did Caddy switch to saying 5w-30 was ok due to simply re-thinking, or was the change in the engine the reason.

In short, what do you think about a crankcase with 5w-30 in the 99??????

[jadcock]

Originally Posted by Elmer Fudd

Did Caddy switch to saying 5w-30 was ok due to simply re-thinking, or was the change in the engine the reason?

The change is in the engine itself. The valvetrain went from flat tappet (1999 and previous) to roller tappet (2000 and beyond). The roller tappets provide a huge reduction in friction, and don't require the same "level" of lubrication that the flat tappets do. The flat tappets act directly on the valves, and that's a fairly major friction point, and proper lubrication there is critical.

Originally Posted by Elmer Fudd

In short, what do you think about a crankcase with 5w-30 in the 99??????

That said above, the difference in 5W-30 and 10W-30 is relatively minor, and should be non-existant once the oil is warm. But if you have a lifter tick cold, and you're sure it's not piston slap or combustion chamber deposits, I don't think it would hurt to try a 5W-30 for one oil change and see. I personally doubt you'll see a difference, but I don't think you'd hurt anything by trying.

[JimD]

Originally Posted by Elmer Fudd

Mine is a 99 N*, Concours (the 300 hp). The manual clearly says 10w-30 PERIOD. I have heard that starting in 2000 they went to 5w-30 as ok. I know there were some small changes in the engine that year too.

Trust your manual. The engine changes in 2000 were more extensive than "small".

Did Caddy switch to saying 5w-30 was ok due to simply re-thinking, or was the change in the engine the reason.

Engine differences is your answer. And roller cam followers is the main reason.

In short, what do you think about a crankcase with 5w-30 in the 99??????

Not for me.

[Elmer Fudd]

Thanks Jim aand Jad...sounds like I had better stay with 10w-30 or better. The lifter tick is not just when cold, it comes and goes at all temps. Most of the time you cannot even hear it from inside the car.....I am just a perfectionist I guess.....

Didn't understand about the tappets, thanks again......

[jadcock]

I would investigate a little more, if you already haven't, to ensure that it's a true lifter tick, and not something else, like combustion chamber deposits, a loud fuel injector, etc. Lifter noise (and valvetrain noise in general) is very uncommon on the Northstar engine. I haven't heard a lifter noise in either of my Northstars (the '97 has 157k miles, the '01 has 57k miles).

[Ranger]

I still use 10W30 in my '03 DHS, my daughters '02 SLS & '04 Grand Am. In talking to the Guru about this once I got the distinct impression that GM went to 5W30 to satisfy CAFE and tree huggers, but left to their own choices, they would have stayed with 10W30. That said. I would think a thinner oil would make it worse, not better.

[Elmer Fudd]

Originally Posted by jadcock

I would investigate a little more, if you already haven't, to ensure that it's a true lifter tick, and not something else, like combustion chamber deposits, a loud fuel injector, etc. Lifter noise (and valvetrain noise in general) is very uncommon on the Northstar engine. I haven't heard a lifter noise in either of my Northstars (the '97 has 157k miles, the '01 has 57k miles).

It has been diagnosed as such both by the Caddy dealership and an independant mechanic. It has the classic rise and fall in volume over about a 6 second period (would an injector do that??). Plus ius actually seems to be less when the engine is cold.

The Caddy dealer did a upper engine cleanout anyway....no difference.

[clarkz71]

What brand of oil are you using ??

[Elmer Fudd]

Originally Posted by clarkz71

What brand of oil are you using ??

hehe, tried Mobile 1 10w-30, Castrol 10-w30 dino, and Rotella T 15-w40 Dino

No significant difference.

It is really hard to judge. It is not constant. Some days it is really noticable, others you cannot hear it from inside the car at all.

Have tried cleaners (Cd2, Risolene, MMO, and MOA) in the various oils too. Again, no difference substantial enough to say for sure. This started before I got the car according to the dealers records at about 95 k. Their diagnosis was harmless lifter noise, and ignore it. Now at 118k and it hasn't changed at all.....

I suspect an actual mechanical problem...spring maybe??? I say this cause the dealer had records on this car and it had 3000 mi oil chages with Mobile 1 since the day it was born.

hehe, naturally the day I test drove it was one of the days it wasn't noticable.....

Otherwise it runs great....super gas milage, more power than I really need, oil consumption about right (1 qt. every 1000 - 1500 mi.) no coolant useage...etc.

Just standing outside the car at idle it ticks like a gift from Bin Laden.......

[Ranger]

Originally Posted by clarkz71

What brand of oil are you using ??

[clarkz71]

Originally Posted by Ranger

I'm trying. I like a good oil thread.

[AlBundy]

Are you trying to piss you know who(the hater of oil threads) off? Whats wrong with you?

[Ranger]

Originally Posted by clarkz71

I'm trying. I like a good oil thread.

Don't you mean oil war?

[clarkz71]

Originally Posted by ALBUNDY

Are you trying to piss you know who(the hater of oil threads) off? Whats wrong with you?

Who is that?

Originally Posted by Ranger

Don't you mean oil war?

War/discussion/debate. Fudd took it as I meant it, a joke.

[codewize]

I put 10W-30 in everything, cars new and old, trucks, lawn mowers, weed whackers, everything. 10W-30 is the universal answer. Unless you live in Alaska or some other part of the world where it's below 0 for extended periods of time.