[Z06] 04Z valve spring poll
Thread Starter
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
04Z valve spring poll
I don't know how to post a proper poll, but I can tally numbers.
2004 was supposed to be the year the valve spring issue was resolved. That said, there are 5 recorded failures of 2004 models.
https://www.corvetteforum.com/forums...-failures.html
So I'm curious:
-How many of you "04 people" are rolling the dice?
-What is your build date?
-Mileage?
-Are you nervous if not replaced?
-If you did have a failure please note that also
Me:
Build date 09/03
46,000 miles
Rolling the dice so far, kinda nervous
Have springs and seals, thinking of replacing this winter
2004 was supposed to be the year the valve spring issue was resolved. That said, there are 5 recorded failures of 2004 models.
https://www.corvetteforum.com/forums...-failures.html
So I'm curious:
-How many of you "04 people" are rolling the dice?
-What is your build date?
-Mileage?
-Are you nervous if not replaced?
-If you did have a failure please note that also
Me:
Build date 09/03
46,000 miles
Rolling the dice so far, kinda nervous
Have springs and seals, thinking of replacing this winter
Drifting
Joined: Apr 2008
Posts: 1,464
Likes: 32
From: Ocala FL
I replaced my '04 springs with the newer oe springs but only because I tracked it and had a lot of hours on it.
If you're that nervous get them replaced but I wouldn't worry about it personally.
If you're that nervous get them replaced but I wouldn't worry about it personally.
Last edited by JeremyGSU; Dec 11, 2015 at 03:17 PM.
Melting Slicks
Joined: Aug 2013
Posts: 2,491
Likes: 315
St. Jude Donor '15-'16-'17-'18-'19-'20-'21-'22
I don't know how to post a proper poll, but I can tally numbers.
2004 was supposed to be the year the valve spring issue was resolved. That said, there are 5 recorded failures of 2004 models.
https://www.corvetteforum.com/forums...-failures.html
So I'm curious:
-How many of you "04 people" are rolling the dice?
-What is your build date?
-Mileage?
-Are you nervous if not replaced?
-If you did have a failure please note that also
Me:
Build date 09/03
46,000 miles
Rolling the dice so far, kinda nervous
Have springs and seals, thinking of replacing this winter
2004 was supposed to be the year the valve spring issue was resolved. That said, there are 5 recorded failures of 2004 models.
https://www.corvetteforum.com/forums...-failures.html
So I'm curious:
-How many of you "04 people" are rolling the dice?
-What is your build date?
-Mileage?
-Are you nervous if not replaced?
-If you did have a failure please note that also
Me:
Build date 09/03
46,000 miles
Rolling the dice so far, kinda nervous
Have springs and seals, thinking of replacing this winter
Last edited by laurent_zo6; Dec 11, 2015 at 09:01 PM.
Racer
Joined: Sep 2014
Posts: 494
Likes: 12
From: Aubrey Texas
In Mid 2003 GM changed the springs in these cars. They were used in late 2003 and all 2004 models, since they were less prone to break, they also used these springs in the LS2 for the C6. I've seen some cases also where aftermarket springs have broken on these motors. I have an 02 and do not worry about it even though I am high risk. I wouldn't worry about it but a set of aftermarket springs isn't that expensive. But as they say "an ounce of prevention is worth a pound of cure." You could almost do the job yourself if you have the right tools and trust yourself enough. This is what I've seen and read browsing the forums, I'm sure someone will come along and chime in. After all that's what we're here for. 
Thread Starter
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
In Mid 2003 GM changed the springs in these cars. They were used in late 2003 and all 2004 models, since they were less prone to break, they also used these springs in the LS2 for the C6. I've seen some cases also where aftermarket springs have broken on these motors. I have an 02 and do not worry about it even though I am high risk. I wouldn't worry about it but a set of aftermarket springs isn't that expensive. But as they say "an ounce of prevention is worth a pound of cure." You could almost do the job yourself if you have the right tools and trust yourself enough. This is what I've seen and read browsing the forums, I'm sure someone will come along and chime in. After all that's what we're here for.
Melting Slicks
Joined: Jan 2007
Posts: 2,318
Likes: 243
2022 Corvette of the Year Finalist -- Modified
2021 C5 of the Year Winner - Modified
No problems thus far for me - although I only have 6,400 miles on my Z. That is why I bought an '04 so I didn't have to worry about the spring issue.
Former Vendor
Joined: Aug 2005
Posts: 16,897
Likes: 412
From: Lewisville TX
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
Depends on how the car is used.
I like to be safe so on stock LS6's I generally tell our customers you should do springs every other season on a stock car if you are going to heavily track the car 10-15 weekend events every year. This does not count any kind of mechanical over rev. If that happens change them then.
Street cars we have seen them come in here broken at 50, 55, 60, 65k with mixed street and light track use.
It is much cheaper to put a set of springs on it, than pull a valve out of a piston.
I like to be safe so on stock LS6's I generally tell our customers you should do springs every other season on a stock car if you are going to heavily track the car 10-15 weekend events every year. This does not count any kind of mechanical over rev. If that happens change them then.
Street cars we have seen them come in here broken at 50, 55, 60, 65k with mixed street and light track use.
It is much cheaper to put a set of springs on it, than pull a valve out of a piston.
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Thread Starter
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
Depends on how the car is used.
I like to be safe so on stock LS6's I generally tell our customers you should do springs every other season on a stock car if you are going to heavily track the car 10-15 weekend events every year. This does not count any kind of mechanical over rev. If that happens change them then.
Street cars we have seen them come in here broken at 50, 55, 60, 65k with mixed street and light track use.
It is much cheaper to put a set of springs on it, than pull a valve out of a piston.
I like to be safe so on stock LS6's I generally tell our customers you should do springs every other season on a stock car if you are going to heavily track the car 10-15 weekend events every year. This does not count any kind of mechanical over rev. If that happens change them then.
Street cars we have seen them come in here broken at 50, 55, 60, 65k with mixed street and light track use.
It is much cheaper to put a set of springs on it, than pull a valve out of a piston.
Heel & Toe
Joined: Dec 2015
Posts: 17
Likes: 0
From: Roseville Northern Ca
I picked up my 04 recently.
Previous owner claimed at 83k it broke a valve spring, leading to a dropped valve. It now has a crate motor with about 22k miles on it.. Just to be sure I will be putting in upgraded springs.
Will edit with build date
Previous owner claimed at 83k it broke a valve spring, leading to a dropped valve. It now has a crate motor with about 22k miles on it.. Just to be sure I will be putting in upgraded springs.
Will edit with build date
Heel & Toe
Joined: Dec 2014
Posts: 15
Likes: 8
From: Chicago IL
Melting Slicks
Joined: Aug 2013
Posts: 2,491
Likes: 315
St. Jude Donor '15-'16-'17-'18-'19-'20-'21-'22
If you remove the oil cap you can see part of a spring.
Here are the part numbers if you have to make a change:
12499224 is the set of 16 springs
12482063 are the intake valve seals
12482062 is the set of exhaust valve seals
12637683 is the number for valve cover gaskets
Race Director
Joined: Aug 2015
Posts: 12,260
Likes: 4,749
From: SE WI
The stock springs which could break were yellow. The new ones are blue.
If you remove the oil cap you can see part of a spring.
Here are the part numbers if you have to make a change:
12499224 is the set of 16 springs
12482063 are the intake valve seals
12482062 is the set of exhaust valve seals
12637683 is the number for valve cover gaskets
If you remove the oil cap you can see part of a spring.
Here are the part numbers if you have to make a change:
12499224 is the set of 16 springs
12482063 are the intake valve seals
12482062 is the set of exhaust valve seals
12637683 is the number for valve cover gaskets
Former Vendor
Joined: Aug 2005
Posts: 16,897
Likes: 412
From: Lewisville TX
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
I do still suggest spring replacement on a pretty regular basis for track cars, again it is just cheap insurance because in the heat of the moment there are always a number of over rev's that you just do not catch (unless you have a data system on the car) and do take their toll on the cars over time more so than a street driver.
Racer
Joined: Sep 2014
Posts: 494
Likes: 12
From: Aubrey Texas
2004 Recorded Instances
There are only 5 Recorded instances located in this thread.
Username: Description of broken spring.
Speeed-Racer 2004: 04 Z06, broke the #7 valve spring at 21K miles. Under normal driving conditions (at the time). I was told this was a bit more rare on the '04's.
Badd LS6 2004: i have an 04Z and just had a exhaust valve spring bust on me this past summer
24hr Z06 2004: My #8 cyl. spring broke a little after passing the 15,000 mile marker on my 2004 Z16.. Almost always warmup the oil temp to 170 before getting on the car (have been a few times where I went above 4k but not past 5800)..
Rev limiter was set to 6900rpms, never missed a shift, nor have I ever hit the limiter.. Maybe went past 6700rpms once before this happened..
Day the #8 went, I was chasing down 2 bikes for about 10mins, and driving the car pretty hard.. Started to slow down, and about 5mins later it broke..
Mods.. Tune, intake, t-stat, and headers.. Good excuse to upgrade the springs, so now the car is ready for a cam..
RANsTRZ06 2004: I had on fail at about 45000 mile on a stock motor 2004. It took out the block.
Dude. 2004: This one does not have a link that I could copy the description of.
Thread Starter
Le Mans Master
Joined: Sep 2014
Posts: 5,278
Likes: 539
From: Kelowna BC
Included are the users on Corvette Forum compiled from the Build Date/VIN Analysis sticky thread.
There are only 5 Recorded instances located in this thread.
Username: Description of broken spring.
Speeed-Racer 2004: 04 Z06, broke the #7 valve spring at 21K miles. Under normal driving conditions (at the time). I was told this was a bit more rare on the '04's.
Badd LS6 2004: i have an 04Z and just had a exhaust valve spring bust on me this past summer
24hr Z06 2004: My #8 cyl. spring broke a little after passing the 15,000 mile marker on my 2004 Z16.. Almost always warmup the oil temp to 170 before getting on the car (have been a few times where I went above 4k but not past 5800)..
Rev limiter was set to 6900rpms, never missed a shift, nor have I ever hit the limiter.. Maybe went past 6700rpms once before this happened..
Day the #8 went, I was chasing down 2 bikes for about 10mins, and driving the car pretty hard.. Started to slow down, and about 5mins later it broke..
Mods.. Tune, intake, t-stat, and headers.. Good excuse to upgrade the springs, so now the car is ready for a cam..
RANsTRZ06 2004: I had on fail at about 45000 mile on a stock motor 2004. It took out the block.
Dude. 2004: This one does not have a link that I could copy the description of.
There are only 5 Recorded instances located in this thread.
Username: Description of broken spring.
Speeed-Racer 2004: 04 Z06, broke the #7 valve spring at 21K miles. Under normal driving conditions (at the time). I was told this was a bit more rare on the '04's.
Badd LS6 2004: i have an 04Z and just had a exhaust valve spring bust on me this past summer
24hr Z06 2004: My #8 cyl. spring broke a little after passing the 15,000 mile marker on my 2004 Z16.. Almost always warmup the oil temp to 170 before getting on the car (have been a few times where I went above 4k but not past 5800)..
Rev limiter was set to 6900rpms, never missed a shift, nor have I ever hit the limiter.. Maybe went past 6700rpms once before this happened..
Day the #8 went, I was chasing down 2 bikes for about 10mins, and driving the car pretty hard.. Started to slow down, and about 5mins later it broke..
Mods.. Tune, intake, t-stat, and headers.. Good excuse to upgrade the springs, so now the car is ready for a cam..
RANsTRZ06 2004: I had on fail at about 45000 mile on a stock motor 2004. It took out the block.
Dude. 2004: This one does not have a link that I could copy the description of.
The main reason I posted this new question however (and why it's second only behind who hasn't done it yet) is about the build date. I was wondering if a particular run of 2004 models were the ones that failed. I wonder if some of the old springs carried on into 2004 models... and if so, the build dates of those cars.
Melting Slicks
Joined: Nov 2011
Posts: 3,187
Likes: 265
From: Virginia
I have an 03Z and that is one of the first things I did, mostly for the piece of mind. If I had bought the car new then I prob wouldn't have changed them, but it was used and had two previous owners so I didn't know anything about it's history. If you are the original owner and have been relatively easy on it then I wouldn't worry. If you bought it used I would change them. Just my opinion.
