1997 tahoe valves sticking

I have a 1997 Chevy Tahoe that the SES light has been coming on the code is 305 cylinder 5 misfire they are telling me that I have a valve sticking and the heads need to be rebuilt . The vehicle only has 72,000 miles and this problem has been going on since about 55,000 miles. Has anyone had this problem or heard of such problem? I am having a hard time with the dealer on this and need all the info possible. If anyone has info it would be greatly appreciated .

Is the truck running poorly? Hope all works out.

The vehicle runs fine most of the time but every once in a while it starts to shudder and then the SES light come on .It also will come on if towing.

First things first. Have you done all the proper maintenance? New plugs-Delco or OE type from Auto, Champ, or NGk, new ignition wires-BWD or Taylor, switched to any Synthetic oil-0W30 or 5W30, ran fuel system cleaner thru gas tank to clean combustion chamber of carbon build up, checked Distrib Cap and Rotor for signs of defect or excessive wear, ran a can of Cat Cleaner thru gas tank to clean carbon build up from EGR, O2Sensor, and Cat Conv, installed a new Air Filter, a new PCV valve, a mid range thermostat, and changed your AntiFreeze-Dexcool should be changed every 2 years or 36,000 miles. 5 years or 150,000 miles is for suckers that want their intake gaskets to blow. When you have done all this and still have said problem then and only then would I consider major surgery. You can pay me now, or you can pay me later. Long live Chevrolet.

Danny Demon first of all yes to most of your questions and even more the only thing that has worked is running fuel system cleaner thru and then the misfire goes down from about 3600 to 800 but still has misfire so now what do you suppose I do?

If you have done "ALL" of the things I have suggested and still have said problem then I suggest you go to another dealership and see if they tell you the same thing. Act like you don't have a clue. The difference from one dealership to another can be night and day. Another thing you might try is either higher octane or another brand of gas. You might also try Marvel Mystery Oil. Put a can in the gas and a can in your oil.

Did you buy your Tahoe new? If you did, then get hold of your Regional Customer Representative and let him know about your situation. I had a 2000 Silverado that the carrier bearing went out of the transmission at about 50,000 miles and GM fixed it under their goodwill policy. If you have taken good care of your Tahoe you shouldn't be having to have your head examined. At least not paying for it. This is where personal integrity comes in. If you know your situation is not your fault make GM believe it is theirs. Don't take no for an answer. Long live Chevrolet.

i wonder if there could be a broken valve spring?

I have a 1997 Chevy Tahoe that the SES light has been coming on the code is 305 cylinder 5 misfire they are telling me that I have a valve sticking and the heads need to be rebuilt . The vehicle only has 72,000 miles and this problem has been going on since about 55,000 miles. Has anyone had this problem or heard of such problem? I am having a hard time with the dealer on this and need all the info possible. If anyone has info it would be greatly appreciated .

Valves sticking in the guides of these engines is not an uncommon occurance. Especially # 3 or #5 cylinders.
Usually I can duplicate the complaint by revving the engine in Park and watch the missfire counters on the Tech2 as the engine comes back down to an idle.
It is also important to perform tests on the fuel injection and secondary ignition to eliminate those systems and then to perform a static and dynamic compression test to eliminate burnt valves,broken springs on any other internal engine concern

The fix is to remove the heads and have the valve guides replaced.

Depending on the dealers relationship with GM (which is the result of many factors), the dealer may or may not be able to offer you some assistance after the 3/36 warranty period.
Also "Goodwill" extensions to warranty include your relationship with the dealer also.
At 72k I can tell you that you have a less than 1% chance of getting assistance from GM

after rebuilding your heads you should have an engine that will go a looong time.... remember, as of now, your intake manifold gaskets could be getting close to leaking, rebuilding your heads now will solve 2 problems now.....

SA200 I dont feel that I should have to rebuild the heads when vehicle only has 72,000 miles and when I have taken very good care of the vehicle .I have been in contact with GM customer care and really have gotten now where only to have them say that if I want to purchase a new gm product they will give me a discount Oh boy that makes me want to run out and buy another gm product. All my vehicles have always been chevys and now I think that is going to change! Anyway thank you for your info Danny Demon and GMMerlin I do appreciate it .

I can say a sticking valve is rare. I wouldnt pull off your heads unless i was positive that was the problem. Any brand vehicle will have problems. I like GM products because they are easier to work on and ive had good luck with them. I have a 94 Blazer 5.7 with 150,000mi on it with only 2 mechanical problems. A leaking water pump 1 time, which was easily replaced and intake manifold gasket. The water pump cost $50 and the gasket set cost $15... I think GM parts cost less than other makes. I think you should get 3rd and 4th opinions on your engine and fix it. There is a lot of miles left in your Tahoe........ Just maintain it well.. Have you changed the fluid in the trans, differentals, transfer case, ect, ect? There is so much to keep up with in a vehicle.
Goodluck!!

I wouldn't take Merlin's "No" for an answer. In fact, for me, his advice that your chance of getting GM to help you is less than 1% is reason not to take any of his advice. Sorry Merlin, you're fired.

With that done, have you tried the Marvel Mystery Oil? It is famous for freeing sticking valves. That Carbon has a tendencey to build up in #3 and #5 cylinders is a design flaw. All engines have design flaws. All. Synthetic oil will lessen, if not eliminate, this problem. I am not convinced with all you have stated previously that you have to go internal. I would at least try the Mystery Oil first. I assume you are getting good spark to your plugs. If all else fails then the good news is that you can replace some gaskets with newer design gaskets if you have to do surgery on your Truck. Don't take No, especially from a dealer, from GM without going through their complaint procedure. Their is power in boldness. Be polite, but be assertive. In the end only you can decide how much effort on your part is worth it. Sometimes the best thing to do is bite the bullet. Lots of luck whatever you decide to do. Try the Mystery Oil. Though the OBD2 is quite a self-diagnostic tool it is still an early iteration into the world of computer cars. It still takes a good mechanic to discern what the computer as yet cannot.

Merlin may be right about his diagnosis of your truck's problem. He also may not. He is wrong in telling you to give up on trying to get GM to stand up to the plate and act like a World Class Car Company. If he thinks so little of GM then maybe he should go work for someone else. Or maybe he is just another go along to get along type of guy. The corporate world is full of yes men. Never take a no from a yes man. Such people never change anything but oil filters. In the end none of us know each other here. Merlin might be the best friend any one could ever hope to have. But you came here looking to find help in getting your truck fixed, and if what you have stated is true, to get GM to fix a problem that is not your fault. Common sense dictates that we be very careful with whom we listen to on the internet. Consider the source. Then make your own decisions. That is what I do. The squeaky wheel gets the grease. Long live Chevrolet.

I would put a vaccum gauge on the engine. Watch for the needle to bounce at idle. If the needle does not bounce, it's highly unlikey a vavle is sticking. A good normal functioning engine will have a steady needle. If the vaccum is fine, then do a compression test on #5. If the compression is 120lbs or more, then no burnt valve. I'd then try adding a can of the Marvel Mystery Oil to the engine oil.

Tony

Well said Tony, well said.

Danny Demon

I do know that the compression is good and i will try the Marvel mystery oil to the engine and see what happens and let you guys know.And again thanks for the help

If you really want to know if it is a valve train issue, you must try the vacuum gauge. It will tell you if the valve train is bad or not. It will be the best $15-$20 you'll ever spend on a engine diag tool. It's old school and is a very simple tool. Good compression is a plus. That means it's valve train(but not a burnt valve), fuel, or ignition problem. The more I think about the 305 obdII error, I keep thinking ignition system. I saw something similar in a 95 tahoe and after the guy spent a lot of $ on the trans, he found a bad distributor. You said you did replace the #5 spark plug, #5 spark plug wire, cap and rotor, right? I had a 302 error (which was a misfire cyl#2) on a Ford F150 and it was the spark plug wire. The vaccum gauge is still goingto tell you the deal. I will be glad to help you diag the vaccum gauge reading, if needed. I will just need a good desciption of what the readings are and what the needle is doing while the engine is idling. Is it steady, bouncing, moving back and forth slowly. Does the SES light go out by it's self or do you have to reset it? These test shouldn't cost you much if anything. Let me know if I can help.

Had the same problem with my 97 tahoe so I replaced the wires and plugs but kept doing it. Ended up being the non gm cap that I had put on 10,000 miles before the problem.

Wish this guy would of finished out this post so that we all would know what the fix ended up being.

I suggest having your injectors cleaned before you do the head if all else fails. Do everything here that is listed from other users and if no satisfaction even after the mystery oil then do you injectors. You can take them out yourself, send them off to be thoroughly cleaned and flow tested. This should cost anywhere from $12 per injector to $25. Search the net and you can find good deal. Just make sure you mark which injector goes with which cylinder so when you re-install there is no problem. Good luck and let us know. I just realized, you may not have actual injectors, you may have a throttle body injection to which my advice would be incorrect.

If it is a sticky valve, try GM's "Sea Foam" top engine cleaner. You will have to change your oil after the proceedure.

Valves sticking in the guides of these engines is not an uncommon occurance. Especially # 3 or #5 cylinders.
Usually I can duplicate the complaint by revving the engine in Park and watch the missfire counters on the Tech2 as the engine comes back down to an idle.
It is also important to perform tests on the fuel injection and secondary ignition to eliminate those systems and then to perform a static and dynamic compression test to eliminate burnt valves,broken springs on any other internal engine concern

The fix is to remove the heads and have the valve guides replaced.

Depending on the dealers relationship with GM (which is the result of many factors), the dealer may or may not be able to offer you some assistance after the 3/36 warranty period.
Also "Goodwill" extensions to warranty include your relationship with the dealer also.
At 72k I can tell you that you have a less than 1% chance of getting assistance from GM


How do you perform a DYNAMIC an STATIC compression test?
What what does each do?

How do you perform a DYNAMIC an STATIC compression test?
What what does each do?

A Static compression test is done with all the plugs out and cranking the engine.
A Dynamic compression test is done with 1 plug removed (compression gage installed)and the engine running...

Static compression readings should be in the 140-180 range (depends on engine) and the dynamic test results should be at least 50% of the static.
If the static test fails (1 cylinder less than 70% of the highest) then a cylinder leak down test should be performed.
If the static test passes, then run the dynamic test.

Old school test was to use a compression gage and observe the vacum with the engine running, if it dips then you could have a valve concern.
personally I like the compression test better (more consistant results), but I do use a vacum gage quite often.

A Static compression test is done with all the plugs out and cranking the engine.
A Dynamic compression test is done with 1 plug removed (compression gage installed)and the engine running...

Static compression readings should be in the 140-180 range (depends on engine) and the dynamic test results should be at least 50% of the static.
If the static test fails (1 cylinder less than 70% of the highest) then a cylinder leak down test should be performed.
If the static test passes, then run the dynamic test.

Old school test was to use a compression gage and observe the vacum with the engine running, if it dips then you could have a valve concern.
personally I like the compression test better (more consistant results), but I do use a vacum gage quite often.

OK, I did that today and all cylinders showed 170 Static and 75 Dynamic.
Thats less than 50% of static.