So I've put about 160 miles since I got the Zo6 yesterday.
I'm trying to follow the break-in procedure to the T. I spent the past hours on back roads varying the RPM/gears constantly between 2500-4500 and 2-6th (I must have looked like an idiot trying to show off to other drivers). Checked oil levels at the end and it looks good despite the temperature being colder than ideal.
HOWEVER, I am in Canada and the temps are around 50 fahrenheit outside. I found it impossible to get the temps of the oil past 167 fahrenheit. (Ideal is around 194-212)
Is this bad for break in? Should I do anything differently? Will I ruin anything if I continue to break it in despite the relatively low oil temperatures? I've never had a car do such a good job at cooling itself down. My C7 would have been on fire if I did this in it even during the dead of winter lol

 

no, don't worry about it. just clock those remaining miles and have fun.

 

Z06 runs ridiculously cool.

Only time 194-210 will be seen you just let it idle forever or on the track.

Normal oil temp for me with OAT in the 50's is 150-160 F with the RPM hanging around 3000-4000 RPM doing 50-60 MPH. Summer time with OAT in the 70-80's I can do 170-180 F with the same driving habits.

 

I broke my car in this time last of year last year. I did exactly what you did and I've been just fine. I also asked questions about the engine oil temperature never ever reaching 175 when the ambient temperature is under 65 degrees and was told to not worry about it on here (though there were some folks suggesting it could be an issue and that i need to worry about oil dilution from fuel). Over time, I've gotten more comfortable with just driving the car for a reasonable amount of time before I start to use the revs and not paying as much attention to the oil temperature. In other words, I'll let it get to whatever temperature it's max'ing out at and then slowly drive the car with more throttle and revs. The only time I've seen my oil go over 180 or 185 for more than an instant was an autocross events or when it was 100 degrees out and I was going from stoplight to stoplight- the car would then immediately cool the oil by like 20 degrees once I got to a steady cruising speed of 45+ mph. It's quite an impressive system. At Ron Fellows, it was 105 degrees out and I didnt see the car go past 220 (even while wailing on their car pretty hard) - and it would manage to sit at like 205 after a track session idling.

 

I found setting cruise control on the hiway to whatever, then manually shifting gears up and down all the while staying at cruise speed, prevented me looking too retarded while varying engine RPM for the first x miles.

 

I prefer cold outside temps over brutal hot summer for new motor breakin

 

Thanks for all of the insight. I get the impression that this car runs MUCH cooler on average than the C7 variant now that I've read the replies.
I can't wait to get this thing broken in. What's available to me right now in terms of performance and sound is extremely impressive so I can only imagine how much more fun I'll have once it's fully unlocked.

 

for what it's worth, i have 700 miles on mine, and soon as I hit 500 i got way way more spirited, i can not get this thing to go over 153F, and i've tried!

 

Just finally finished the first 500 miles!!! Even got a video of the tach red line changing from 6,500 to 8,600….

Modern engine oils are very good at maintaining viscosity across temperatures. Generally performance cars have problems with temperatures that are too high vs too low but I’m confident any oil temperature above 150 degrees is fine.

I see people mention keeping the car under 4,000/4,500 RPM… I had to remind myself the Z06 break in Redline is 6,500 (Stingray is 4,500)… I drove gently the first 200 miles letting the car shift itself, usually a little over 4,000 but after that I occasionally increased the RPM closer to the 6,500 RPM break in redline to use the engine across the range they recommend before taking the training wheels off and exploring 7,000-8,000 RPM

8,000 RPM will be my personal redline… saving that last 600 RPM just because… I’m very confident I will be going fast enough at 8,000 RPM… and holding on for dear life 😳

 

Back when the Z06 first came out and the engineers were giving their briefings on the new LT6 I recall them stating one of the changes they had made was where the oil temp was taken. Previously the oil temp was taken when it exited the engine, which, of course, was plenty hot. On the LT6, however, they designed it to take the oil temp in the tank because this was the more crucial number to follow when racing. Consequently, we cannot compare the tank temps to the old exit temps we were all used to.

 

Actually, the engine oil temp sensor is located in the main oil gallery located after the oil filter.

 

The Z06 cooling system is built more for competition use than regular street driving. In colder weather with ambient temps below 60 degrees, I block the auxiliary engine oil coolant heat exchanger with a large shop mat. This heat exchanger - located inside the driver's side air duct flows coolant that is split off from the return coolant exiting the front main radiators. This coolant is further cooled with this heat exchanger and then sent to the engine oil cooler. Also, the engine uses a 160 degree thermostat, so the engine coolant runs cooler than most other engines. Even with the aux radiator blocked, my oil temp will not go much above 150 degrees even while sustaining 100 mph.

What you should be concerned with is fuel dilution. Direct injection engines generally dilute the oil at a higher rate than port injected engines and lower oil temps aggravate this problem further. I have oil analysis results on every oil change done on my car and, in my case, I see fuel dilution at the rate of 1% for every 1000 miles - which is high. So, I do frequent oil changes as a result. You might want to send an oil sample off to a lab so you can see whats going on.

This is a copy of my latest lab report plus the trends over about 12K miles of oil changes. The last analysis was after using the latest Dexos R.







As you can see, my engine was not fully broken in until around 8K miles.
Tin in the analysis is likely from a fuel additive I use.

With regard to oil temp, below are photos of the dry sump oil fill cap I took after driving 100 miles at 80+ mph with the auxiliary cooler blocked and oil temp never exceeding 155 degrees.

 

Wow thanks for all of the info.
Took mine out for another break in session and managed to get the temps to 160 while it was 44 ambient outside. It was very hard to keep it there though. Sucks because I JUST got the car after waiting 2 months because of the recall hitting on the day I bought it but I'm considering just garaging it for most of the winter because I don't want to risk damage due to fuel dilution. I would do frequent oil changes (at least 2x a year and 3 if I track it, like I did with my C7). But I'm getting the impression that this is a much more sensitive car in some regards. Maybe I'm just being too cautious because it's new to me.

You seem to have more miles on it than most I've seen, have you had any issues with it since buying it? What's the coldest you'd drive it in?

Also while I'm on the topic of break in, here's my break in procedure based on many chats with ChatGPT (which I don't fully trust tbh because it still thinks you need to shut off the engine to check the oil despite me showing it the manual saying otherwise) and the vague instructions from GM.

I find an empty back road and put it in 3rd or 4th and cycle it between 2000-4000 RPM. When I reach 4000 RPM I let off the throttle and let it coast back down to 2000 before repeating the cycle as much as I can, varying the throttle between 30-60% and giving it a few 30-60 second breaks where I drive "normal" while still trying to vary the RPM a little. Occasionally switching gears to fit the speed limit...ect.
Did this for about 150 miles today. Is this correct or am I messing anything up?

 

You should be fine. The most critical event when firing a new engine is the initial 30 minute run in. In that regard, GM has stated in the past that they run each engine on an engine dyno which includes maximum power settings and the oil and filter are then changed.

I purpose drove my car for break in for the first 500 miles (and beyond) and then did an oil change. It would be safe to say that you can simply drive your car normally, but avoid constant speed settings and don't lug the engine if you have the trans in manual mode.

Keep an eye on your oil level. In fact, check it the next time you have the car out. Many have see very high oil levels from the beginning. You must check the oil level with the engine running at idle and at operating temp. Your oil temp will tend to increase the longer you idle the engine. also, the oil level will raise up on the stick with increasing oil temp. So, note the temp when checking it and check it again at the same temp. Fuel dilution will likely show as a rising level on the dipstick.

I put my car away during the winter - which means I don't drive it below around 45 degrees.

 

Got it. Thanks for the help!
When I checked the oil earlier today while the engine was running I saw it at about 80% up the indicator. It was cooler than the recommended temps (could only get it to 158), so I figure I'm fine since it would read slightly higher if I was up to the recommended temps. Only put about 260 miles on it so far.

I'll probably finish the break in while it's still above freezing outside and then get an oil change and garage it for the rest of the winter. It's going to be a LOOONG winter haha