rxmatt

I'm looking to replace my valve springs in my 03 C5Z when I take it out of storage this spring.

I know the valve spring kit is part number 12499224.

My research on here says that I should also replace the seals (12482062 -exhaust, 12482063 - intake).

Are there any other parts you would recommend? I think someone mentioned the valve cover gasket (12637683 - left and right).

I'm told this install should take 3-4 hrs max, but every Chevrolet dealership near me is quoting 6-7 hrs labor.

I'm also going to replace the spark plugs and wires. Does anyone have the part number for the wires?

The car has 67,500 kms (~42,000 miles) with a build date of August 2002.

Thanks in advance for any help/advice!

MY03C5Z

Mine is an 03 with an August build date as well. I replaced my springs, plus and wires last summer at 40k. I ordered the LS2 springs (blue) from a gm parts sponsor here, bought NGK tr55 plugs, and MSD (red) pre made plug wires. I did the valves myself using a compressed air fitting tool to hold the valves in place. Used an LS spring compression tool for two springs at a time. I didn't replace the valve seals or cover gaskets. Cover gaskets are o-ring style, I really doubt they needed replacing. Probably a good idea to do valve seals but I didn't do them. I've heard dealers can charge $500 or more for this job. Took me more than 8 hrs but I took my time over 2 days.

getkong

I replaced the seals on mine, and it only takes an extra 30 seconds per valve. i didn't replace the gasket.

It was my first time in the engine, and it took me probably 10 hours total, but that was because i lost a single keeper when it flew out, and i spent almost 2 hours looking for it since no store had them in stock. ended up having to go to the dealership the following day to get one. Also broke a rocker bolt in the head, but was able to back it out with the broken piece since it was jagged enough, so that took another hour or so. If i was doing it again, I could probably do it in 4 or 5 hours.

I also replaced the plugs and wires, and used the same red ones my03c5z did.

MY03C5Z

It is very easy to lose one of those keepers. Even using a pen magnet I still dropped one, luckily it fell on the ground clearly and not into the abyss at the bottom of the engine bay, lol.
That sucks about breaking the rocker stud too. I guess my replacement went pretty smooth in comparison.

rxmatt

Thanks for the replies. I'm not a DIY kind of guy when it comes to engines, so I'd feel much more comfortable paying someone to do it. I may be able to get a local mechanic to do it for a better price than the dealer. I'll look into those plugs and wires you guys had mentioned.

onspeed

Just did mine yesterday. Probably took ~4 hours with breaks to stretch my back. I would suggest spending the extra money on a tool that does 2 at a time. And a friend. A friend + 2 dual spring tools I would have been done in an hour.

Do note that if you get the dual valve springs (small spring inside a bigger spring) the 1 piece GM valve seats won't fit.

bumble-z

Dual Valve Springs running a stock LS/6, 42K mile cam isn't a wise
replacement spring.

Paul 75 L82

A couple of tips, a little grease on the valve keepers keep them from falling off. Get the fitting for the plug hole for you compressed air hose, it's the easy way to hold the valve up. The dual spring compressor works great, buy it from Summit Racing.

David426

Replaced mine with the GM replacements 12499224, a year ago and they are trash at 5000 miles, with only 55-60 lbs of spring pressure.. Doing a cam job right now,, The cam is chewed up.. I never would have known if I was not doing this job.. NO WAY in Hell I'd use or recommend those springs on the stock cam,, Brian Tooley Racing dual springs are going in with my new 230/234 camshaft.. Here is a picture of my stock LS6 camshaft. I am very dissapointed at the Blue OEM Springs.. The reason I replaced them last year, was because of the Yellow Stock Springs failures from breaking on 2002-2003 Z06,, they still had 80lbs of seat pressure when I changed them out last year at 51,000 miles..I Should have just left them in knowing what I know now..

getkong

I wouldn't really say i am either. it's the first thing i've done in the engine more in-depth than putting in a new intake in any car. wasn't difficult, but it does take time and some patience.

kl2oo0

is this a common problem? I recently bought GM replacement springs, but haven't put them on yet

onspeed

I don't think so. My car has a LS6 crate motor that was installed in 2010. My stock cam with ~20,000 miles looked just fine when I replaced it last week. Not sure exactly which springs they were, but I assume the were the GM replacement for the stock LS6 motors. Definitely was not C5 Z06 OEM equipment.

David426

I don't think this is a common problem at all, but neither is the spring breakage problem on 2002-2003 Z06 Corvettes.. Really upset me that I only got 5k miles out of the springs and they were shot.. I'd really like to know what the spring pressure was when they were Brand New.. I really question if they were at 90 lbs, which is the correct OEM spec for those springs,, 57-60 lbs of pressure is totally unacceptable.. I'd have your new springs pressure tested, If I were you.. My new Brian Tooley Springs are all at 155lbs. I had the Machine shop check them while I was standing there..