[ctrlz]

Originally Posted by N Camarolina

I'll look forward to that.

https://www.corvetteforum.com/forums...0-vs-0w40.html

I'll dig a bit and see if I can find more. Oil and gasoline are damn complicated chemical mixtures!

[articblueSS]

[QUOTE=arpad_m;11298243]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.[/QUOTE

Yes, my failure did not result in a sudden drop in oil pressure. The only symptom I had was a strange noise coming from the front of the engine. I had changed the idler pulley and belt, thinking that was the problem, but that wasn’t it. Im guessing the pump never failed completely, because the car ran fine. Oil pressure remained around 40 or so. I asked for an oil sample, so I can send it out for analysis. I’m curious to know if they put the correct oil in it when they last changed it and if there is any metal in the oil. I will update when I get the car back and the oil analysis results.

I have to say, with one more year of power train warranty left on my SS and the looming specter of lifter failure, the new Mustang is starting to look more attractive to me.

[Jeb114]

This is not the 70's. These engine's are designed to run very specific oil viscosity's. Tolerants are very small. use what is recommended for the engine that's why they print it on the cap.

[N Camarolina]

Originally Posted by ctrlz

https://www.corvetteforum.com/forums...0-vs-0w40.html

I'll dig a bit and see if I can find more. Oil and gasoline are damn complicated chemical mixtures!

Thanks. That link (and data) was indeed informative. Amazing to see that the viscosity of the 0W in 0-40 is higher than the 5W in 5-30.

Since I track mine and do some DD, all on 0W-40, I think the take home is to baby it (keep RPM quite low) until the oil starts warming up. I wonder if there is any benefit in letting it idle for a minute or two before pulling out of the driveway?

[3.8TransAM]

Originally Posted by 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

1)Cheap ass materials are the root cause since 99% of the time failues are from affected batches, with a few outliers for the most part



2)) It's possible it contributes to the issue, but we have a very large sump on these cars in general, more likely related to materials and lowest cost vendors


3) our oil pumps were specially designed for anything, the style has been around for ages in one fashion or use or another in other engines and trans.


4)Meh, street oil wise and anything in the owners manual is about par for the course across the board 5/30 to 0/40 isn't a massive difference and it would coming down to testing all available oils at both ends to assume anything and we have large sumps so once its pumping its not going to want to cavitate, caviation comes from low flow(oil) or air in the system.


5) see answer for 4


6) im willing to bet drain back was there to keep oil in the pan for the sump to pick up due to the extra cornering ability from the tires that come on the ZL1 1LE cars, one part for all LT4 to address the issue from special parts and u have stepped up to 50 weight if tracking the car(leads some credence to the higher viscosity(at that point its something to go on)


7) yeah there was a couple bad batches of pumps for sure on the LT4, but I'm willing to bet its a materials issue due to lowest cost supplier.


I always hated the manufacturers when they never admit to the actual issue, but if u go into any LT engine I would tell u to go with a quality oil pump.