Replacing hydraulic lifters

A dial indicator can be obtained fairly inexpensively at any tool shop. Do a search on the net to see what they look like, and what's available. You do not need a high end tool for this job. The magnetic base just holds the dial indicator in place. It clamps the dial indicator where you need it.

Just remove the valve covers, and check the lift at each valve one at a time. Might be useful to remove the spark plugs so you can turn the engine over easily using the belt or a tool on the crank pulley.

Ironhead said:

A dial indicator can be obtained fairly inexpensively at any tool shop. Do a search on the net to see what they look like, and what's available. You do not need a high end tool for this job. The magnetic base just holds the dial indicator in place. It clamps the dial indicator where you need it.

Just remove the valve covers, and check the lift at each valve one at a time. Might be useful to remove the spark plugs so you can turn the engine over easily using the belt or a tool on the crank pulley.

Click to expand...

Got it. I checked the tool out last night and it makes sense how it works. Will be a nice tool to have in fact. Although, I'm not sure how its going to tell me anything about the lifters??? So, if the lift at one valve is low, does that tell me that possibly that lifter is the one thats stuck? I guess that makes sense cause the lifter wouldn't be fully expanded. Am i on the right track?

All you are doing with the dial indicator is measuring how much each pushrod moves up and down. If one is different than the others, the next question is why?

Could be the lifter is stuck in its bore, maybe by varnish or other crud. In that case you should be able to see whether the affected pushrod is returning all the way back down or not. Compare to the other pushrods. If it is not, you might be able to unstick it with some sort of engine oil treatment, but if that doesn't work, you might have to go into the valley and clean up the problem the hard way.

If it is, that means the problem is that the lifter is not pushing the pushrod up enough. Since these are hydraulic roller lifters, the problem is not likely to be cam lobe wear, but something to do with the hydraulic part of the lifter, so the pushrod is not coming all the way up to actuate the rocker. Cleaner in the oil might fix this, but more likely you have to go into the engine and repair/replace the lifter.

If the pushrod motion is normal, the ticking noise must be coming from either loose valve clearance, or a lifter with a mechanical defect. You should be able to check valve clearance by pushing on the rocker arms. If one is loose, it could be because of a bad adjustment. You can fix this by rotating the rocker retaining nut. There is probably a YouTube on this, but it's real easy, just listening for the "click" then turning in a specified rotation on the nut.

If there's a mechanical defect with the lifter, say a bad roller, you 'd have to go into the engine again...

I know this is oversimplified, and I want to make sure to say that I am NOT a qualified mechanic, so for sure go see someone who knows way more than me.

thanks for the info Ironhead. All makes sense. and i hear ya on the not being a qualified mechanic, fortunately i have a neighbor who is, ill try and get him over here this next weekend while I'm doing more diagnosis work

I had a lifter tick. Went through all that Ironhead described. Everything 'looked' fine, but...





Caught it soon enough so it didn't kill the cam. Luckily.

sewlow said:

I had a lifter tick. Went through all that Ironhead described. Everything 'looked' fine, but...

You must be registered for see images attach

You must be registered for see images attach

Caught it soon enough so it didn't kill the cam. Luckily.

Click to expand...

well thanks for scaring me. ha. can you tell me what your lifter tick sounded like? did it go away after warm up? and what was the problem with the lifter, was it the roller that went bad? or was it part of the hydraulics?

What sewlow describes is certainly a possibility, but on the low end of probability. Roller failure like that comes from several potential sources. Foreign object damage from contamination, roller trunion failure causing the roller to gall on the cam, trunion failure that causes loose clearances and allows the lifter to bounce off the cam and damage the surface, high RPM's or weak valve springs allowing the lifter to be thrown off the cam and crash back into it, insufficient preload causing the same, etc etc. If it concerns you, pull an oil sample and have it analyzed. If you have high iron or wear metals, you may wish to inspect the cam and lifters. If not, don't worry about it. That'll cost you about the same as a set of VC gaskets, and a lot less time. Varnish in the lifter is a very common cause of a lifter tick, especially one that goes away quickly. Try the oil treatment first, as it is the least money and labor intensive and could do no harm if it doesn't work. If that produces no results, mechanically checking valve train integrity is a great idea.

Sent from my XT1585 using Tapatalk

sound advice SAATR. ill keep you all posted on how things go in the following week.

[QUOTE
I don't know why but i just assumed it was a sticking lifter, the tick goes away after about 60-120 seconds after a cold start up, so seems it wouldn't be a rocker???[/QUOTE]

Some very good advice here. Not trying to start any fights but just thought I would offer some of my experience. I have worked in the oil/lube business and worked as a fleet manager for a police department among various other technician jobs over the years. I have seen this exact problem on many L31 equipped police package Tahoes even with mileage much lower than yours probably has. As mentioned above, I too would start with simple things first like changing the oil. And I really hope you are running a quality brand 5w30 or if you must 10w30 oil and a quality filter. In the case of the above Tahoes I described in each case it was caused by using 5W40 weight oil except in one case where the engine was a little over a quart low. A lot of people still think even still that hard working vehicles need thicker oil than the manufacturer designed the engine for especially in hot climates. Such was the case with this particular police fleet and going back to 5W30 fixed the ticking issues. Now I am not saying that if you don't use the correct oil you will immediately get lifter tick or some other problem but chances are your not doing the engine any favors and problems will eventually show up.

For some reason many think 5w30 is only used for fuel economy and that may be half true and the motivation behind selecting it but the fact remains GM designed the engine tolerances around the use of the oil they tell you to use. Thicker oil will take longer to pump through the engine when cold and may not even adequately protect some parts due to clearance issues. These engines may seem old now but the machining on them was light years ahead from the engines of the 1960 and 1970s where using 20w50 or 10w40 in hot weather actually might have been a good idea.

Also, one other thing to explore could be an exhaust leak from the head to manifold or from manifold to head pipe. I have seen these go away when an engine warms up.

Good luck.

thanks for the input. and I completely agree. I do run 5w30 conventional oil. I tend to always stick with the factory recommended for the reasons you mentioned above. I have been thinking of exploring the exhaust leak option as well... with the noise going away in a few minutes it makes it difficult to diagnose. any tips on diagnosing an exhaust leak like this? one that would go away... I'm assuming we are thinking that things are expanding as they heat up causing the leak to seal up?