2012 Suburban 5.3L broken valve spring

[setha8]

I have a broken valve spring (I think it's an exhaust valve one) and while I am replacing that, should I do all 8 on the side? All 16 on both sides?

I'm assuming replacing a spring means replacing the valve stem oil seal too, but thought I would ask, since it looks like they are only sold in packs of 8. Any other parts that typically get replaced at the same time, like the valve spring cap? (I would think no on the cap since it's just a disk of metal.)

 

[setha8]

Also, I typically only buy OE parts for repairs, but I'm not wedded to that if there is a comparable or better aftermarket equivalent. Should I stick to OE on this for all parts? I noticed Felpro has the valve stem seal set (both intake and exhaust) on Rockauto for a quarter the price of getting the two sets from GM.

 

[Tonyv__]

How many miles and do you know if you bent the valve?

I just had this happen on my Yukon last year, only about 85k miles. Replaced the 1 spring and called it a day. It’s a relatively quick job so adding anymore work isn’t necessary imo

 

[setha8]

How many miles and do you know if you bent the valve?

I just had this happen on my Yukon last year, only about 85k miles. Replaced the 1 spring and called it a day. It’s a relatively quick job so adding anymore work isn’t necessary imo

I'm at 150k so kind of feeling like if I don't do it, would suck if another gave way in another 5k miles. I don't know if anything is bent at this point. I just confirmed the spring is broken as of this morning, haven't taken anything else apart to verify if there is other damage. Just trying to order parts and tools I will need.

 

[Tonyv__]

I'm at 150k so kind of feeling like if I don't do it, would suck if another gave way in another 5k miles. I don't know if anything is bent at this point. I just confirmed the spring is broken as of this morning, haven't taken anything else apart to verify if there is other damage. Just trying to order parts and tools I will need.

hmm I definitely understand your concern at 150k.

The way I look at it, that spring can be a 30-60min job. Doing all the springs and seals turn into a 2-3 hour job.

So what if they start to leak in 5k miles? unlikely, but if they do, what would it take to get right back to where you’re at now?

Engine cover, coil pack rack, valve cover. You’ll be at the springs in 10 mins. So IMO it’s unnecessary to do them right now

 

[SpareParts]

A broken stock valve spring on a stock engine is rare.
I would pull the valve shut and try to do a leak down test or just pressure up the cylinder to make sure the valve is not bent before i went further.
If the valve checks good then just put a new spring on it and run it.

 

[setha8]

A broken stock valve spring on a stock engine is rare.
I would pull the valve shut and try to do a leak down test or just pressure up the cylinder to make sure the valve is not bent before i went further.
If the valve checks good then just put a new spring on it and run it.

This is possibly a dumb question, but how to you pull it shut? By hand? And is there a way to tell if it is bent without pulling the spring off it?

I'm cautious about removing the spring without having the replacement parts since I don't want to risk losing pressure on the air tool (the one you plug into the spark plug hole) over a span of days and having the valve drop into the cylinder. It's sitting in front of my house, so I can't leave an air compressor out there either.

Thanks for the replies! It is a stock engine BTW.

 

[Fless]

To keep the valve from dropping into the cylinder, an old trick you can use instead of compressed air is to feed a length of small rope into the spark plug hole. Keep pushing it in until it fills the cylinder hole and supports the valve. It can help to get the engine turned so the piston is relatively high in the cylinder and on its way up. This obviously won't work if the valve has dropped but, then, neither would compressed air.

 

[West 1]

Use some soft cotton rope, shove it tight into the spark plug hole. Rotate the engine until the piston pushes up against the rope. Now your valve will stay forever if you wish as you search for parts. No noise involved and works 100% as well. Leave a few inches of your rope hanging out of the cylinder for easy retrieval.

When they make valve spring steel they will make a run until they find a flaw. That may be after they run 1000 feet of material. If they miss one of the flaws and make it into a spring that spring will fail. Does not mean your other 15 springs have flaws. Almost certainly they do not. It does happen but not often in manufacturing. IF they used the wrong material at the factory you would have these failures on nearly every truck built and at similar miles. We have not seen that. Your springs are good. Fix the bad one.

SBI has been trusted for years for factory valve springs so has Sealed Power. Fel Pro Valve stem seals are as good as any. Get a valve spring compressor, I like the good ones with a long arm to compress the spring. The screw type can work but are not as fast or reliable.

 

[Fless]

Use some soft cotton rope, shove it tight into the spark plug hole. Rotate the engine until the piston pushes up against the rope. Now your valve will stay forever if you wish as you search for parts. No noise involved and works 100% as well. Leave a few inches of your rope hanging out of the cylinder for easy retrieval.

When they make valve spring steel they will make a run until they find a flaw. That may be after they run 1000 feet of material. If they miss one of the flaws and make it into a spring that spring will fail. Does not mean your other 15 springs have flaws. Almost certainly they do not. It does happen but not often in manufacturing. IF they used the wrong material at the factory you would have these failures on nearly every truck built and at similar miles. We have not seen that. Your springs are good. Fix the bad one.

SBI has been trusted for years for factory valve springs so has Sealed Power. Fel Pro Valve stem seals are as good as any. Get a valve spring compressor, I like the good ones with a long arm to compress the spring. The screw type can work but are not as fast or reliable.

The guys at Jim's Automotive Machine Shop in Northern Colorado use SBI. Web site: https://jamsionline.com/ and see them on YouTube:

https://www.youtube.com/c/JimsAutomotiveMachineShopInc

 

[Foggy]

Just to add: the FelPro brand seals are very good. I've used them on 2 diff
LS based engines. My LS3 and my LS1. As good or better than Gm oe part

 

[setha8]

Last question, there is a "retainer" or "cap" on top of the valve spring. Is this typically replaced with the spring, or no? I'm thinking no, as it is a simple metal disk. I can't see how that would even wear, but just thought I'd ask in case. I see people re-use the keepers, so re-using the cap seems obvious. Never hurts to verify.

Edit...something just clicked for me so one more thought. I recently changed spark plugs and had one in particular that had a lot of oil on the tip. And of course my engine drinks oil like every other one this age. Now that I know there is an oil seal on the valve stem, seems logical to conclude that the seals on that valve are probably bad, and might be worth replacing while I'm at it since I'm getting a full set of seals to go with my one replacement spring.

 

[SpareParts]

Yes. Reuse your retainer and the 2 keepers.

 

[West 1]

Check the location of your one wet spark plug. The wet plug could be caused by the valve cover Oil vent. Some guys install catch cans to fix that issue. I could be a valve stem seal but most likely the valve cover. You will have the spring off so installing a new valve stem seal would be easy. If you are doing one you should also do both on that cylinder so Intake valve and exhaust valve.

 

[setha8]

Yes, I did exactly that. I got the set of felpro valve stem seals and replaced both intake/exhaust on the cylinder that had the issue. It was convenient that it was that same cylinder that had the spark plug oil goo on it. I have the 7 pairs of seals for if/when I decide to take on the AFM delete here in the future. I also had already bought the catch can, just hadn't installed it yet. I was literally going to do that the week the spring broke, lol.

Engine is back running again, so all the help was really appreciated, and exhaust valve stem would appear to be fine/unbent, so that's a big relief.

Not sure if I should start a new thread or ask here, because the one thing I discovered while troubleshooting, was another cylinder that does not appear to hold as much pressure as the other ones I tested. Keep in mind, #4 is the one that had the bad spring... I tested 1,2,3,4,5,6 (7 is a bear to get out, so I didn't test 7 or 8). #4 was zero obviously, and all others were 200-220 PSI on the compression test, EXCEPT #1 which was 160. Not being within 10% is a problem. I did the "tablespoon of oil through the spark plug hole" and repeated the test with no improvement in the compression test. I believe this indicates that it is not due to worn piston rings, but I don't know what the remaining list of causes could be or what I should do here. I have not done a leakdown yet, need to borrow a compressor from a buddy for that. Any thoughts on this?

 

[setha8]

Also, the rope thing was an awesome suggestion, and it worked like a charm! I actually prefer that now since it allowed me to not have to worry about breaking the pressure seal (using a compressor on the spark plug hole) while seating the oil seals and the spring. I used a 8mm diameter rope from hobby lobby, and the main issue I had with that was feeding it through the hole, due to it not being conducive to hand feeding. It was like pushing a rope uphill. It could have also been that the rope diameter was not much smaller than the hole itself. I had to use a screw driver to push it in and it was really slow work for such an awkward space. Should I have used a smaller diameter rope? Cotton isn't very stiff which is a big part of the difficulty.

 

[LtTahoe]

A broken stock valve spring on a stock engine is rare.
I would pull the valve shut and try to do a leak down test or just pressure up the cylinder to make sure the valve is not bent before i went further.
If the valve checks good then just put a new spring on it and run it.

not really rare I have replaced a dozen or so over the years it happens a lot more frequently than the older generations of sbc.

 

[West 1]

Your rope was too large, a smaller rope would allow you to push 6-8” in with each push and no effort. Once enough rope is in there just rotate the engine till the piston presses the rope against the valves and they will stay put. Maybe 6 or 7 mm next time should you ever need it.

With the valve cover off and trying to get compression you can tap on the valve head and see if compression changes. With a Leak Down I have seen this seal a cylinder. Tells you the valve is a little burnt or the spring may be weak. Maybe some dirt just fell in there when you removed the spark plug and happened to land on the valve seat making a small leak?

In this case a leak down test will give you better information and the air pressure might blow out any dirt if that was the cause.