[ctrlz]

Where I'm going with this is that I think heavier weight oils (e.g. 0W-40) may be implicated in oil pump failures.

The long-winded background info:
1) The pictures of a damaged pump show a cracked stator as seen in the below link. I believe this favors an internal cause of the damage.
https://www.camaro6.com/forums/showp...4&postcount=13
The Katech aftermarket pump uses different material for the stator.

2) I believe the problem may be pump cavitation, which is caused when a pump is starved on the inlet (suction) side, and vacuum pockets ("bubbles") form within the pump. When these collapse, it creates damaging forces and vibration.

3) Our pump (shared by LT1 and LT4) was initially developed for the Chevy Cruze to improve fuel economy. Estimate in that car was about 3% mpg improvement. Recommended oil for Chevy Cruze is 5W-30.

4) An oil pump is more likely to cavitate with higher viscosity oil (slower drainback, lower velocity in pump suction line)

5) 0W-40 is more viscous than 5W-30 at all temps. Despite the "0W" winter designation, this ends up being true.

6) The LT4 has modifications to the "oil passages" to "improve drainback." I put that in quotes because that is the level of specific detail provided by GM. Suffice to say, the LT4 must have had some issues requiring modification.

7) LT4's seem to have the most reports of oil pump failures on Camaro6

[Mark R]

If the oil pump is so weak that slight viscosity differences in oil will make or break an oil pump, it needs to be replaced. It's too weak.

We can all debate the real cause of the problem until the cows come home, and probably never know for sure. It really does not matter. The harsh reality with the ZL-1 is that if you don't want to suffer an oil pump failure, you need to get it replaced with the only one offered on the aftermarket: Katech.

[Vtor_ZL1]

Track guide says to run 15W50.. so i dont buy 0w40 being cause.

[LT4Greg]

I run 5W30 synthetic in my ZL1 and haven’t had any issues so far at almost 25,000 miles. I use Lucas oil and either a Mobil 1 or Napa Gold oil filter.

[KingLT1]

In a stock engine I see no reason to deviate from synthetic 5w30. In a modified LS/LT engine that has a cam and modified valve train I would run Castrol Edge 5w50 or Mobil 1 15w50. I don't see oil viscosity causing oil pump failures. I can see it causing valve train issues because of the lifter oil passages not being designed for heavier weight oils... causing starvation to the top end of the engine.

[JSH]

Originally Posted by KingLT1

... In a modified LS/LT engine that has a cam and modified valve train I would run Castrol Edge 5w50 or Mobil 1 15w50.

Interesting. I haven't used either of those. I've been using Mobil 1 5W30 for some time and it doesn't use a drop, but it does consume a bunch of 0W40. I think I have some 50 weight oil in my garage.

[Scraps0f]

I have been running Mobile1 ESP Synthetic, 0W40 since I changed my oil after break in period. I am in WNY and only drive in the warmer months, and have about 30k miles on my ZL1. Never have I seen any issues in oil pressure. Nor have I experienced any burn off. Hopefully it stays that way.

[articblueSS]

My oil pump failed at 20k miles. I’ve always run 5w30 oil in it.

[ctrlz]

Originally Posted by articblueSS

My oil pump failed at 20k miles. I’ve always run 5w30 oil in it.

Well, there you go.
What was the situation? Tracking, hard use, or just normal driving and it went?

[articblueSS]

Funny you ask! The car is my daily driver. I’ve never tracked it or driven it hard at all. I haven’t even done a burnout! Ironically, this just happened this past week. The car is currently at the dealership and I’m told I should have it back in a week or so.

[Val Walkinshaw]

My manual says 5w-30. So outside of track days where it says 0-40, I always run 5w-30.

Top end issues are more likely the result of running the wrong viscosity. Aka premature failure.

Remember 5 is for winter and how thick it is at winter temps.

30 is less viscous/less thick at high temps compared to 40. Location and heat play a factor here.

[arpad_m]

Originally Posted by articblueSS

Funny you ask! The car is my daily driver. I’ve never tracked it or driven it hard at all. I haven’t even done a burnout! Ironically, this just happened this past week. The car is currently at the dealership and I’m told I should have it back in a week or so.

Let us know what they find. As I said in the other thread, your failure looks substantially different from all those other LT4 pump failures.

[ctrlz]

Originally Posted by Val Walkinshaw

Remember 5 is for winter and how thick it is at winter temps.

30 is less viscous/less thick at high temps compared to 40. Location and heat play a factor here.

The reality is the "warm" number has bearing on the "winter" viscosity.
When cold, 0W-40 is more viscous than 5W-30. I will find a link and add to this post later.

[N Camarolina]

Originally Posted by ctrlz

The reality is the "warm" number has bearing on the "winter" viscosity.
When cold, 0W-40 is more viscous than 5W-30. I will find a link and add to this post later.

I'll look forward to that. I incorrectly assumed that these oil weight ratings were absolute (0W always < 5W) and corresponding to a particular, fixed viscosity. If what you say is correct, then that 5W-50r would presumably be thicker cold than 5W-30 and therefore not an acceptable choice for an LT1.