Need help - which oil for Northstar Flat Tappet?

[abs]

I've been a long time lurker on these forums and finally have a reason to post and ask for some help. I have a low mileage '98 Cadillac with the Northstar engine and flat tappets. I want an oil that provides high levels of ZDDP and has a minimum sheer rating of 3.5. Also, this engine has a tendency to build up carbon on the rings resulting in blow-by and oil burning so I would like an oil with a high flash point and high levels of detergents. Lastly, I don't want to pay a lot of $$$ for an exotic synthetic . . . So, with this criteria, which oil would you recommend for this car?

One more quick question, GM calls for a 10w30 for this engine can I consider using a heavier weight oil (15W-40 for example) in this motor and if so, what problems might I encounter if I did that?

Thanks!

Andrew

 

[aquariuscsm]

Don`t HDEO`s have more zddp than PCMO`s? I`ve always been curious,how can you tell which engine`s are flat tappet and which are roller?

 

[addyguy]

A 1998 Caddy Northstar wouldn't have flat tappets - it would be a roller valvetrain.

Detergents in oil aren't really going to clean-up stuck rings - a piston soak, Auto-Rx, or some hard 30-60 mph full-throttle blasts are what is needed to 'break the rings free'.

A good oil that meets your requirements is GC 0W-30.

 

[ekpolk]

That, or perhaps Mobil 1 10w30 HM.

 

[hounddog]

Two VEGA motors welded together.LOL I told a Caddy factory rep that and he got red in the face!

 

[RWEST]

Originally Posted By: hounddog
Two VEGA motors welded together.LOL I told a Caddy factory rep that and he got red in the face!

 

[abs]

Thanks for all the quick responses.

The pre-2000 MY Northstar engines all have flat tappets, the converted to roller lifters in 2000. This is also one reason why, I believe, a minimum of 10W was selected by the manufacturer. Too thin of an oil and premature wear to the cam and tappet would likely occur. This engine has low miles and does not yet have any ring or oil burning issues and I want to keep it that way!

I've run GC 0w30 in an Audi allroad when I owned it and I thought it was decent albeit very thin when cold - I could hear the turbo's whining a bit until the engine warmed up.

From my research it appears that most HDEO's have more ZDDP and could be better suited to this application due to higher detergent levels and better additive packs, hence my question about the 15w40 (Rotella/Delvac/Delo all come in that weight).

epolk - can you point me to any stats on the Mobil 10W30 HM? Does it have a lot of ZDDP and/or is it API certified with a newer spec?

Regards,

Andrew

 

[lexus114]

Originally Posted By: hounddog
Two VEGA motors welded together.LOL I told a Caddy factory rep that and he got red in the face!


two Vega motors welded together??

 

[UNC017]

Originally Posted By: lexus114
Originally Posted By: hounddog
Two VEGA motors welded together.LOL I told a Caddy factory rep that and he got red in the face!


two Vega motors welded together??

Not LITERALLY. But sometimes you'd swear....

The Northstar is actually a wonder of design and packaging. Incredible power from a *super* compact and lighweight v8, very efficient, and really good driver-friendly power delivery and low vibration. But the sacrifice is that its darn near a disposable engine. When big things start to go wrong, it's usually fatal to it. Its also notoriously hard to service in some respects- starter motor located under the intake manifold, head bolts prone to pulling the thread material out of the block if you ever have to remove the heads, etc. The Northstar is a great engine for people who like a powerful, comfy, luxurious car and buy their car new and replace it every few years. Its less than good for people who keep a car 400,000 miles or buy it used, no matter how careful you are with maintenance.

 

[bountyh]

Originally Posted By: abs
I've been a long time lurker on these forums and finally have a reason to post and ask for some help. I have a low mileage '98 Cadillac with the Northstar engine and flat tappets. I want an oil that provides high levels of ZDDP and has a minimum sheer rating of 3.5. Also, this engine has a tendency to build up carbon on the rings resulting in blow-by and oil burning so I would like an oil with a high flash point and high levels of detergents. Lastly, I don't want to pay a lot of $$$ for an exotic synthetic . . . So, with this criteria, which oil would you recommend for this car?

One more quick question, GM calls for a 10w30 for this engine can I consider using a heavier weight oil (15W-40 for example) in this motor and if so, what problems might I encounter if I did that?

Thanks!

Andrew




You can just add the ZDDP yourself. I don't trust oil companies these days, they could change the formula at any time without notice.

This is what I use:

http://www.zddplus.com/

 

[bountyh]

Originally Posted By: hounddog
Two VEGA motors welded together.
If you are as old as me, you remember the Vega was the worst catastrophe GM every dumped onto the world.... and it won Motor Trend's "Car of the Year" award when it was released.

The engines had aluminum blocks (no sleeves) with the cylinder walls "hardened"..... VW had done it successfully, but GM got it wrong and the engines were wearing out in 20k miles.

http://en.wikipedia.org/wiki/Chevrolet_Vega

Quote:
According to Jacobson, customers began complaining to dealers of excessive oil consumption. When the customer came in and complained that his car was using a quart of oil every 200 miles (a litre every 340 km), the mechanic would peer down the bore scope and observe cylinder scuffing.


Regardless of the cause, damaged cylinder walls were common - a problem that presented the Vega owner with three choices:

* Have the block overbored and re-etched, and have new pistons installed.
* Overbore and have aftermarket cast-iron cylinder liners pressed in.
* Replace the short block with a brand new unit.


YEOWWWW! A quart every 200 miles....

 

[Steve S]

Originally Posted By: 440Magnum
Originally Posted By: lexus114
Originally Posted By: hounddog
Two VEGA motors welded together.LOL I told a Caddy factory rep that and he got red in the face!


two Vega motors welded together??

Not LITERALLY. But sometimes you'd swear....

The Northstar is actually a wonder of design and packaging. Incredible power from a *super* compact and lighweight v8, very efficient, and really good driver-friendly power delivery and low vibration. But the sacrifice is that its darn near a disposable engine. When big things start to go wrong, it's usually fatal to it. Its also notoriously hard to service in some respects- starter motor located under the intake manifold, head bolts prone to pulling the thread material out of the block if you ever have to remove the heads, etc. The Northstar is a great engine for people who like a powerful, comfy, luxurious car and buy their car new and replace it every few years. Its less than good for people who keep a car 400,000 miles or buy it used, no matter how careful you are with maintenance.



G.M. quality

 

[abs]

Folks are actually converting the head bolts to head studs when they replace the head gaskets to help provide better head tension and eliminate the issue with destroying the threads in the block. This is a very big issue and seems to affect about 50% of the cars on the road with this engine and can be a very expensive repair depending on who does the work. On the other hand, the lower end of the engine, from what I'm told, is fairly bullet proof and wear to the cylinder liners is generally very, very low even after 100k+ miles. The flat tappets are an area of concern (although also fairly durable all things considered) hence my original post.

So, I'm still looking for more oil recommendations for this engine and thoughts on using weights heavier than recommended by the manufacturer such as Rotella 15w40.

Thanks,

Andrew

 

[hounddog]

Yea and they resurrected it and called it a NORTHSTAR.When I went to the Caddy ride and drive when the Northstar depute and according to GM it was a WORLD CLASS ENGINE ! Early on with the oil usage GM replaced motors.Then they revised that to a different design piston and ring.They also had some stuff to pour into the cylinders and let soak for x number of hours.There are a number of TSB's out on the subject.

 

[abs]

Originally Posted By: hounddog
Yea and they resurrected it and called it a NORTHSTAR.When I went to the Caddy ride and drive when the Northstar depute and according to GM it was a WORLD CLASS ENGINE ! Early on with the oil usage GM replaced motors.Then they revised that to a different design piston and ring.They also had some stuff to pour into the cylinders and let soak for x number of hours.There are a number of TSB's out on the subject.


This is also true and one of the reasons I'd like a high detergent and high flash point oil . . . Need to keep those rings clean!

Andrew

 

[artificialist]

Originally Posted By: abs
Folks are actually converting the head bolts to head studs when they replace the head gaskets to help provide better head tension and eliminate the issue with destroying the threads in the block. This is a very big issue and seems to affect about 50% of the cars on the road with this engine and can be a very expensive repair depending on who does the work. On the other hand, the lower end of the engine, from what I'm told, is fairly bullet proof and wear to the cylinder liners is generally very, very low even after 100k+ miles. The flat tappets are an area of concern (although also fairly durable all things considered) hence my original post.

So, I'm still looking for more oil recommendations for this engine and thoughts on using weights heavier than recommended by the manufacturer such as Rotella 15w40.

Thanks,

Andrew

Also, the blocks were treated as junk when the head bolt threads were destroyed....

But I knew some guys that brought them back to life by installing several heli-coils in the bolt holes.

Anyway, I'm not sure if anything special is needed to lube this engine, because I see many from 1994-1998 that are going strong on whatever bulk oil is dealt by the oil change place.

One 10w30 I see that is more recommended than most is Shell Rotella 10w30. It has all the additives to get a diesel rating, but is still okay to use in a gas engine.

 

[mechtech2]

Cosworth Vegas had silicon type aluminum bores.
When properly finished, they worked very well, and are used today on expensive engines.

 

[ThirdeYe]

I would recommend Shell Rotella T 10w30 for your Caddy...

 

[Art_Vandelay]

Originally Posted By: bountyh
I don't trust oil companies these days, they could change the formula at any time without notice.



Lol. They're out to screw us! The proof lies in the MSD sheets with last years dates on them.

 

[daman]

Rotella T Synthetic 5w40 or Mobil 1 10w30 HM has nice tip of zinc and would work great in that engine.