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Clutch fluid reservoir was nearly empty (M7 owners, check yours)

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Old 07-09-2019, 11:34 PM
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chronage
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Default Clutch fluid reservoir was nearly empty (M7 owners, check yours)

2016, 9k miles. I was having a squeaking/squawking sound engaging first gear from a stop. Sounded like the throwout bearing was going bad (someone posted videos of the exact sound here). Per a recommendation I checked the fluid level and sure enough it was nearly empty.

As I understand it GM fills it to "MIN" from the factory (why?!). Well, mine was underfilled or I have a leak. Re-filled with quality DOT 4 brake fluid to the 3/4 mark and it shifts better/quieter than when I got it new. I haven't heard the noise since but need to test more.


Last edited by chronage; 07-09-2019 at 11:35 PM.
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Old 07-10-2019, 02:06 AM
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Pineapple
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Something is wrong there. Check under the driver side footwell and see if you have a leak where the clutch pedal piston meets the firewall
Old 07-10-2019, 08:59 AM
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captain vette
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That is weird thank you for posting
Old 07-10-2019, 09:05 AM
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Corgidog1
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Thanks for the heads up!
Old 07-10-2019, 09:07 AM
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Z06_Ruff
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Interesting. I'll be checking mines today.
Old 07-10-2019, 09:21 AM
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JerryU
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Originally Posted by chronage
Per a recommendation I checked the fluid level and sure enough it was nearly empty.

As I understand it GM fills it to "MIN" from the factory (why?!). Well, mine was underfilled or I have a leak. Re-filled with quality DOT 4 brake fluid to the 3/4 mark and it shifts better/quieter than when I got it new. I haven't heard the noise since but need to test more.
Have never had the fluid go down at all and have been doing the Ranger Method every year for 6 in my C6, 3 1/2 in my 2014 C7 and 2 in my Grand Sport. You have a leak! Could be as simple as the hose that attaches to the bottom of the reservoir. Note, the reservoir can pull out of the holder. Look at the bottom. If the leak is the hose connection a the throughout bearing much harder to get out!

GM doesn't have to fill more because it should not use any fluid!

I do recall when I got my C6, many years ago, the cap was lose! But to have the reservoir empty would take more than a lose cap!

PS: It's NOT recommended you take the cap off very often. Brake Fluid picks up water is like a sponge. That is way they recommended always using a new container. I buy a new one each year (12 oz) when I Use the Ranger Method which takes about 7 empty, refill, 30 clutch pumps and repeat to get clear fluid. Once that aluminum seal on the opening is broken water vapor from the air will get at.

Last edited by JerryU; 07-10-2019 at 02:28 PM.
Old 07-10-2019, 10:09 AM
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Landru
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Nice catch, has source of missing fluid been discovered?
Had to go somewhere, sure didn't evaporate.

On C7 ZR 'RepoPilot' experienced something similar on a brand new ZR1.
Not only did his fluid disappear, it then returned!
Dealer cannot decipher IF it happened (no codes) nevermind where it went, apparently temporarily, only to return.
AH/SC acted wildly when this happened, car strongly pulled then returned to normal function.
Old 07-10-2019, 02:21 PM
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VinceBlack
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I had the same thing happen to me when I purchased a 2016 Stingray from Carmax a couple years ago. I got the car home and started checking the fluids. When I pulled the cap off the clutch fluid reservoir, there was absolutely no fluid. Went back to Carmax and spoke to the salesman. We went over to where the vehicle had been parked and no fluid was seen on the ground. Never could figure out what happened, refilled the reservoir and it never gave me a problem in the year I owned the vehicle.
Old 07-10-2019, 03:31 PM
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w0rM
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I guess I need to look at this when I get home.
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Old 07-10-2019, 05:50 PM
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iclick
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There was an earlier thread where it was reported that low fluid level was observed from the factory, so perhaps this isn't unprecedented. Everyone should check theirs upon purchase.
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Old 07-10-2019, 05:55 PM
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kaplana08
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I have seen this before. my friends car was also very very low out of factory. Also a friend with a new C6 in 2013 also had no fluid in the Res. typical GM

Last edited by kaplana08; 07-10-2019 at 06:02 PM.
Old 07-10-2019, 06:08 PM
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I would certainly get the car checked over for a leak. And of course keep an eye on the level from now on.
Old 07-10-2019, 06:34 PM
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VinceBlack
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This post made me go down and check the clutch fluid in my Z06. As I shared above, I had an empty clutch reservoir in my 2016 Stingray so I got a little nervous after looking at this post. Additionally, I've been experiencing a faint grinding noise/burning smell and clutch chatter. To my surprise (or maybe not so), the reservoir is nearly empty with just a small amount of dirty fluid lingering at the bottom. I bet a million bucks I've got a leaking slave cylinder that's responsible for the issues I've been having lately. Oddly, there is no fluid on my garage floor...this is probably a small, slow leak. I need to get this thing to the dealer ASAP.
Old 07-10-2019, 07:40 PM
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Originally Posted by Landru
Nice catch, has source of missing fluid been discovered?
Had to go somewhere, sure didn't evaporate.

On C7 ZR 'RepoPilot' experienced something similar on a brand new ZR1.
Not only did his fluid disappear, it then returned!
Dealer cannot decipher IF it happened (no codes) nevermind where it went, apparently temporarily, only to return.
AH/SC acted wildly when this happened, car strongly pulled then returned to normal function.
?? His car is an Auto... I've driven it?!
Old 07-10-2019, 07:42 PM
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jbretthorton
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Originally Posted by Landru
Nice catch, has source of missing fluid been discovered?
Had to go somewhere, sure didn't evaporate.

On C7 ZR 'RepoPilot' experienced something similar on a brand new ZR1.
Not only did his fluid disappear, it then returned!
Dealer cannot decipher IF it happened (no codes) nevermind where it went, apparently temporarily, only to return.
AH/SC acted wildly when this happened, car strongly pulled then returned to normal function.
?? His car is an Auto... I've driven it?!

Edit.... NM he was having the similar issue with his brakes...
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Old 07-11-2019, 11:05 PM
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mneblett
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Originally Posted by chronage
As I understand it GM fills it to "MIN" from the factory (why?!).
If the C7 slave cylinder arrangement is anything like that on the BMW motorcycles with dry single plate clutches with which I am familiar (and I strongly suspect it is), the slave cylinder piston actually moves backward as the clutch wears, pushing fluid back to the reservoir. In other words, reservoir level *increases* as the clutch wears. Thus, the GM min level factory fill makes good sense.
Old 07-12-2019, 01:18 PM
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phalse
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hahaha and how do we confirm that? because if that be the case, then many ppl reading this thread who topped theirs off might have a little issue in the future, haha

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Old 07-12-2019, 06:51 PM
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VinceBlack
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Originally Posted by mneblett
If the C7 slave cylinder arrangement is anything like that on the BMW motorcycles with dry single plate clutches with which I am familiar (and I strongly suspect it is), the slave cylinder piston actually moves backward as the clutch wears, pushing fluid back to the reservoir. In other words, reservoir level *increases* as the clutch wears. Thus, the GM min level factory fill makes good sense.
That theory doesn't sound very likely. If that was the case, it would be detailed in the owner's manual (kinda like how they detail proper procedure for checking oil levels).
Old 07-12-2019, 07:17 PM
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Avanti
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It's hard to believe, given previous experience with GM, that they would plan ahead for clutch wear. Might we think they are expecting differential fluid to increase with usage, as well?
Old 08-01-2019, 02:05 PM
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chronage
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UPDATE: I did not find any signs of leakage in the engine bay or footwell. Looks like it was just underfilled by GM . Fluid level is holding.
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