Enz512tr

Forgive me as this question has likely already been asked but for my 2017 Z06 track driving, the manual says to replace the oil with Mobil 15-50 which is understandable but then says to immediately change back to 5-30 after the track event. I plan to partake in a max of four track days between July and end of Sept. Assumming the engine is properly warmed up on every start up, would it be safe to leave the 15-50 in the motor for the season? The car will be stored from mid October to May 1st. Any guidance is appreciated.

glass slipper

You'll get a lot of opinions both good and bad but at the end of the day, you're the only one with a vested interest if things go wrong. Read the posts, sift through the BS, and then make the best decision you can based on how much risk you're willing to take on.

Having said that, the reason for changing to the 15W50 is for protection at the elevated temps while on track. The reason for switching back to 5W30 is the elevated ZDDP in the 15W50 will eventually cause an "early" failure of the catalytic converters. I put early in quotations because it could mean they fail at 100k miles instead of the 120k miles they're supposed to last and warranted for. Or maybe they fail at 60k miles, who knows. Regardless, it would seem like it would be difficult for GM to know you ran 15W50 for 3 months straight. A lot would depend on how many miles you put on it during those 3 months. A couple of hundred miles per month during that period wouldn't amount to much in the overall scheme of things. Certainly nothing will happen to the engine during those 3 months, 15W50 will provide the lubrication needed. And since you're in the hot part of the year, the 15W rating isn't as big of a factor and the extra ZDDP anti-wear additive will more than balance out any negatives.

Again, you will have to decide how much risk you're willing to take on. Have fun and good luck!

Questar

Here is what "Tadge" wrote on this topic...

https://www.corvetteforum.com/forums...-road-use.html

BearZ06

Many ZR1 owners have run Mobil 0W-40 for years because of the higher ZDDP with no issues. GM even recommended it for European owners. I know they are different engines but . . .

https://www.corvetteforum.com/forums...quieter-4.html

Enz512tr

Thanks Questar. I likely will not put on more than 3000km (2200 miles) per season. I will likely just leave the 15-50 in the system for the summer and replace in the spring (of course checking the level frequently throughout). Thanks to all that contributed.

64drvr

As said, lots of opinions on this. I run 15w50 M1 during the track season to include daily driving for several months and will be switching back to 5w30 during the off season.

jbsblownc5

I run 15-50 or Torco 20-50 at all track events, and since it's kinda like a track event most times I drive my car on the street/canyon, I leave it in then too...

Not too worried about the cats, one set removed already on my 17 Z, the other probably won't make it past September...

About the only time a may run lighter oil is for the few extra HP it might give me on a straight line event.

Questar

After I read the Tadge thread I decided to leave the 15w50 in full time... I'm not running the car in cold (sub zero) temps and I'm not too concerned about the shortened lifetime on the cats.

I take a little more care to bring oil temps up when starting... time will tell if this was a good decision but I feel confident it will be okay.

Enz512tr

You and I are in the same climate/province. I wlll be doing the same. Thank you.

Pacembellum

Will the dealer put this in at my 500 mile or do i need to do it myself?

davepl

Why do you associate higher levels of ZDDP with higher viscosity? Or why would buying a higher viscosity net me more zinc?

You're assuming a relationship I've never heard of before, so I'm curious. Tadge also says in one of his responses that "15w50 oil has higher phosphorous" but doesn't say why.

I run 10W60 (as specified) in my M3, and can't help but wonder if that's not even a better choice. More protection when hot, easier starting/warmup when cold. Seems ideal, although more expensive.

jdmdohcpower

I do about 2 events a month and run 15-50 all the time. Its a pain in the a$$ to switch back all the time. I was storing it, for example I had about 800 miles on the street oil and wasnt going to waste it. Swapped to track and stored the street. Put that back in after and saved the track. Now I just run 15-50 Not saying its right, but doesn't feel wrong to me

Poor-sha

I put 5w30 in the car after my last event in November. I run that until my first event in March when I put in 5W50. Then starting in May I put in 15W50 and run it until it's time to put the 5W50 in. Usually I end up doing at least one change on the 15W50 during the season.

thebishman

^ is the correct answer for all track rats.

BEZ06

Just an FYI concerning Cats.

I have a 2009 ZR1 and a couple years ago I had a bad limp mode problem with no indication at all what it was. I had been running the NCM HPDE at Sebring and above 5000 rpm the car just sorta started spitting and missing.

I took it to the dealer and told them I wanted to go for a ride with the tech to show him the problem and they said they would be right on it. About 45 minutes later I hadn't heard from them about going out to show the tech the problem, and went to the service writer. He told me the car was just completed and, they couldn't find anything, and it would be around for me to pick up in just a couple minutes.

I told him I wanted to talk with the tech and go out to drive the car with him. He said the tech had already driven the car and there wasn't anything wrong with it.

Well, after I blew my lid telling him I brought it there because there WAS a problem, and because I specifically had told him I wanted to go out with the tech, he told me okay, I could take the tech for a ride.

The tech got in with a computer hooked up, but said he had already driven it and there wasn't any problem. Well, as soon as I got out on the road and ran it up above 5000 rpm in 1st and 2nd and he saw it fall on its face above that rpm he said "well, I didn't drive it like that".

It took several days at the dealership with them working with the Tech Center, and they finally found the problem - it was a Cat!!

They ordered one for the side that was indicating bad, but when it came in it wouldn't fit - they had a new Cat and x-pipe for the newer model years, so they needed to get one in for the other side as well, along with the x-pipe. I was seeing $$$ for this repair!!!

They got both new Cats on and I went to pick up the car, expecting to have a BIG bill because the car was out of warranty - but the worksheet showed I owed $0.00!!!!

Bottom line - Cats are required to be warrantied by federal emissions law for 8 years/80,000 miles!!!

I don't know whether the oil I was running had anything to do with it, but the higher ZDDP may well have caused problems in the Cats.

But I'm very thankful for the federal requirement for Cats to be replaced under warranty for 8 years/80,000 miles!!

So....if you do have a problem with Cats and you're under 8 years and 80,000 miles, they're replaced under warranty even if your GM warranty has run out!!

.

VetterFlyer

FWIW, I had an experience with my 15 Z06/7, now with 9700 miles. At 500 miles I requested the dealer to put in 15-50 which they did at no charge. About 4000 miles later I went in for another oil change and requested to go back to 5-30. When I later looked at the bill and log it showed that they didn't get my latest request and put in 15-50 again. From a viscosity point of view I wasn't worried but I looked up the Mobil 1 spec and found that the Zink was very high and the Phosphous was elevated too. I wasn't concerned about the Cats at first but I noticed the 5-30 was also Dexso II rated and the 15-50 was not. My checking found that a dependable mechanic told me his GM car burned oil until he went back to the Dexso II oil. My understanding is that it has an anti foaming agent and more friendly to the Cats. After another 3000 miles on the second 15-50 I noticed big puffs of blue smoke every time I got on the throttle. Checking the oil I found it down about one qt. Rather than add any I changed the oil back to the 5-30 Dexso II where it stopped the smoking and it hasn't used any oil. If anyone else has any experience like this I would like to hear it, otherwise I do think the Dexso II has something to do with it.

Spacewalker

15w50 won't ruin your cats (Its rated for passenger cars in the US) -- http://www.mobil.com/english-US/Pass...SMobil-1-15W50

Just let the oil warm up a good bit before beating on it. You'll be fine. As long as you aren't in sub zero temps.

Dubai_Z06

same thing happened to my cts with lt4 i only changed to 0-40 mobil European formula dont know about smoke ..oil consumption was very high.. also EML came on dealer said TB was dirty ..i think from the oil

Warp Factor

Foaming can contribute to higher oil consumption.

The throttle body being dirty from the crankcase ventilation system blowing through it? Not likely, since the crankcase ventilation system on the LT4 goes into the intake system downwind of the throttle body.

If you have an "oiled gauze" air filter, that would be a more likely cause of throttle body or Manifold Air Flow Sensor contamination. At high air velocities, oil will blow out of these filters.

Dubai_Z06

dunno stock everything .. what caused dirty TB to a level that triggered EML unless dealer BS