Valve Springs

JrSyko

Jerry Maguire
Has anybody heard of the valve springs on a 99 Chevy Tahoe going bad with only 45k miles on them? The dealership is trying to tell me mom that they are bad and need to be replaced and that is the root of all her problems (like why it loses all its hp when going up a hill)
 

empire231

Well-Known Member
no extended warranty? what motor? 350/397? regardless though, it shouldn't go that soon
 

tkr

Well-Known Member
Ya, its sadly a common problem. GM had a lot of strange vavletrain problems there for a few years.
 

michael_loomis

Well-Known Member
that motor is a 5.7 / 350 . ive never heard of that "problem" before and it shouldnt be all that common unless they got bad material when the springs were made. i was searching google last night for GM truck sites and a few had recall info. i would think that if it were a problem the factory would take care of it .
 

BlueCoyote

Well-Known Member
How would valve springs effect HP under load??? HI rpm yes, load ???
Do know that some GM's had an issue of the valve guides being too tight and causing valve stick. Could it be that the guides are tight, causing the valves not too seat fully. Problem is then the guides, not the springs.
Suprised the dealer did not blame the blinker fluid resevior too...
 

Greg

Well-Known Member
It still makes no sense to me but my dad had a 98 z-71 that would just about shut down pulling a steep grade or pulling a trailer and that is what the dealer told him, valve springs. Well, i thought they were full of it, but they did everything under warrantee and it ran like a new truck after that. maybe there is more to it than just valve springs, but what ever they did worked great.
 

tedmales

Well-Known Member
they can be tested, but they have to be removed, so if your gonna pull them off, just replace them. maybe add a set of rockers to get more lift, and more power.
 

JrSyko

Jerry Maguire
Greg, your dad did have the springs replaced? The problem he had seems very similar to ours.
 

michael_loomis

Well-Known Member
Trav .... is the check engine light coming on . It should be , does it flash then turn solid , or just go solid ?

my truck loses power and the light comes on (flashes) when i accelerate up hill on the freeway . from what ive read , the flashing is due to a misfire ( yes it does ping a small amount when this happens ) directly related to malfunctioning computer sensors. if it just comes on solid , maybe it IS somehow a mechanical problem. if the springs were to loose some of the tension against the valve , maybe it would be possible to "float" them at lower RPMs under load , leading to power loss , overfueling , bad computer readings , etc . ???

i dont know , just a brainstorm lol
 

JrSyko

Jerry Maguire
The light does come on all the time under power up hills. It has miss-fired something like 756 times in one month alone in the number 6 cylinder (I think). Basically, it is a POS and we are going to get rid of it, but I wanted to see if the dealer was trying to rip us off or if he had a legitimate solution.
 

Greg

Well-Known Member
Those were exactly the same symtoms my dad had with his truck, we kept chasing wires and plugs and egr stuff, turned out to be the valve springs, there was a recall, so it was free for him, and it ran great after that.
 

tedmales

Well-Known Member
Does the truck have the new ls motor, or is it the old style vortec? The new engines have coil packs on the valve covers. I think its the older vortc motor. If you have to pay to get the service, i would buy aftermarket valve springs, and new rocker arms to get a little more power out of it. sounds fishy to me, but if it has happened to someone else, could be. It would seem that it would float the valve all the time, not just under load, but i guess it would be hard to notice just revving it up. How can you tell it misfired? If it is pinging then there could be a prolem. the knock sensor could be bad. They really should not ping. I had a dodge that pimped unless you ran 92 octane, and it turned out to have a problem in the egr system. but i lived with it for a long time. good luck.
 

michael_loomis

Well-Known Member
ok sooo ...... how much do you want for that POS GM product . all this ABUSE must have taken its toll on everything TOP and BOTTOM in that motor .... proly needs a new transmission and rearend also !! sounds like you'll have to give err sell it REAL CHEAP TRAV !! im first in line !!
 
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