Theta

The following How-To covers the explanation of the Engine Oil Drain/Fill incl. Oil Filter Replacement for Dry Sump and includes specifications, schematics, etc.

These How-To guides are neither endorsed by or property of Corvette Forum or myself in any way/shape/form. All liability stemming from any actions taken in relation to these guides is solely placed upon the user.

We hope you will find these guides useful.


Note: The info in here AND in the Helms manual says to wait 2-5 minutes to check the oil level, this should read 5 - 10 minutes to get an accurate reading for the oil level. Believe it or not, GM made a mistake. GM repeated the 5 - 10 minute wait for the oil level measurement for all models of the C7. If the 2 - 3 minute interval is what is needed to check the oil, they would have changed the 2015 - 2019 Owner's manual to reflect the shorter interval.

Elmer

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NoOne

What is a Z52 option?


I only have Z51, I feel cheated

Poor-sha

Owners manual says oil capacity with filter for Z51 is 10.3 Qts

KenHorse

There's an addendum to the manual, changing the capacity to 9.8 quarts. You didn't receive the addendum with your manual?

KenHorse

Interesting that the service manual excepts posted say NOTHING about warming the engine to "at least 175 degrees" when checking the level. I bet that's a major reason dealers are overfilling

What's up with that?

Poor-sha

Are you serious? I'll have to go look but that's a pretty fundamental thing to have wrong in the owners manual.

Theta

I'm not sure why you'd doubt the official numbers here, but yes... The owner's manual is incorrect. An addendum sheet was included with every car from day 1, not that I saw it at first either.

This was a fundamental issue (and real concern) that was discussed at length early on, but you don't hear much about it now.

Thankfully you read this first, as it may have saved you from overfilling.

KenHorse

Mine (took delivery at the end of February - VIN 11822) had 2 addendum sheets (they're replacement pages). One for the new capacity spec and the other with a new dipstick pictorial.

And Theta, curious as to your thoughts about the lack of mentioning engine temp in the official service manual the dealers apparently use. Oh, and my local dealer tells me they don't have an actual printed manual - it's all online for them.

Theta

Ken, same here, and took delivery October 02, 2013 - so we can be sure they've been there from the beginning. I'm going to guess that somebody had 30,000 manuals printed and didn't want to pay to run another batch with the correct number. Sadly, it's kind of a big goof, but...

Not sure why they don't mention the warming-to-temp, but I'm going to assume they either think the dealer will be working on these soon after the customer drives in, or they assume that it's common practice. Unfortunately, a newer tech may not know this (as these guides are not made for the DIYer by GM) and overfill, causing the issues we've seen on the forums with burping/overfill.

As for the service 'manuals', they don't exist in printed form, which is why I've brought these How-Tos here (which has taken a lot of time and money). The service guides and parts catalogs are both online only, and together cost me around $5000/year to access...

Many have assumed that a $100 manual will be printed, but that will be November at the earliest, and would only be able to contain a fraction of the 50,000+ pages of service info on the C7.

So at the end of the day, I'm glad when they end up helping people, but not thrilled when people question the info that's put here to help them.

KenHorse

I thought the same thing - they assume the engine is already warm BUT that doesn't properly warm the oil, certainly not by running the engine for what? 30 seconds tops to "check for leaks"? Hell, I bet less than a quart is moved from the reservoir during that time.

And I agree - as I stated before I bet that's a major factor why there seems to be so many dealer overfills. As I said, when I take mine in soon for the free oil change, I'll take a copy of the TSB and talk to the tech to make sure he KNOWS the proper way to do it

Poor-sha

Theta, I wasn't doubting you as much as I was very surprised. In the end this was my mistake though as I was looking at the owners manual PDF you download off the Chevy site which is still incorrect. However, my owners manual in the car was correct and there was no supplement. I appreciate the heads up.

Theta

No worries, and that was poorly worded and not meaning to point entirely at you. I, unfortunately, get a lot of PMs asking if the info is correct, etc. so it adds to it.

At the end of the day, this was a stupid mistake on their part that should really have been corrected at the very least on the digital owner's manual. That's unacceptable that even that version still has the old versions, as it's free to fix and re-upload. Hell, I'll do it for them for free...

The scary part is that the dealers were still filling the 10+, as the original TechLink from September/October showed the manual amounts.

You have to figure that in that volume, the manuals were costing around $2 a piece. Let's say that had a maximum of 30,000 printed. For $60,000, they could have corrected this issue... less than the price of buying back on car that gets lemoned out...

GM makes me scratch my head at times.

iBladesi

Ah, just curious. Why are there two drain plugs? This is my first Vette. So apologies if this common knowledge or an oft-answered questions.. Though, I couldn't find the answer anywhere. Also, which port will have the least "woosh" of oil.. Never fun to estimate that arc/angle for placing of the drain pan and have it go wrong.

Theta

Per GM: One drain plug drains the external oil tank via the oil transfer supply line. The other drain plug drains residual oil from the crankcase sump.

I pop the higher one first for a better arc, then go to open the low one once the high starts to dribble.

15C7Z51

Change my oil before and after track - all went well. I was surprised by 22 lb ft for filter- tough to tell but seemed like at least 3 full rotations after gasket made contact. I am use to the 1 turn after gasket contact. Worked fine at 22 lb ft but I was anxious that was overly tight and might compress gasket too much and leak. It didn't