Hydraulic tappets change required?
 

One or more tappets started making the noise they do about 500 miles ago and have worsened but seem to reached their loudest. I can do the adjustment procedures (15 seconds at 3,000 RPM/repeat) and the noise goes away for up to 48 hours and then returns quickly.

I recently had the intake and all that off while removing the butterflies for air trim and really don't have time to dig back into it now.

Can I drive it as is without causing more damage? It's just the tapping from the hydraulic slack trim right? No harm to drive on it for a few thousand miles?

No harm usually in driving as-is for 3-4,000 miles?

Thanks!

You are correct - what you describe is the hydraulic valve lash adjuster noise. It does sound like at one of them does not want to hold pressure even after you run through the re-bleed procedure. How many times you repeat the process? You need to repeat the 15 second revs/15 second idle cycle 10-30 times to get full effect of removing any trapped air. If no change occurs after 30 times - replace lash adjusters. If you can get even 48 hours out of it, at least do the bleed procedure every other day until you have a chance to replace them. But first try to bleed them with more then few cycles.

The VLA noise stops after 8 to 11 times of doing the rev cycles but returns after 2 days of city speed driving. Are you saying to do the rev procedure 30 times to complete the air ejection, and then it may not return? I'll try that once or twice if so. Can't do that every other day...wastes a bunch of gas...probably an entire gallon.

Could it be the type of oil I used on my last oil change? It started a couple hundred miles after my last oil change, I noticed. I rarely use the same brand of oil for changes.

Lastly, does it harm any other components to leave it noisy for a while? If not, I'll leave her be (noisy) until something else requires pulling valve covers off...and all that other crap on top. Thanks!

You can try once to run the procedure 20 or 30 times. As far as oil - what grade oil are you using? I stick with what is recommended - 5x30 grade. Some people use heavier grade. Not sure if that will help. Make sure your oil level is good. #1 thing that starts VLA noise is low oil level and sucking air into the pump.

I use 5w-30 also. This time I added Slick 50 last oil change, I'd gotten for free. Lol...did that mess with the motor? I don't know...

So now when I run the bleed procedure the tapping does not stop. I did it 50 times yesterday and still no success. It was clearing it up by try 12 just last week. It would get quiet and return a day or two later. The noise has gotten louder and seems to have reached peak. Sounds like a Yugo-diesel now, lol.

It still ceases the tapping at 2,900 RPM or above though. It gets entirely quiet at 2,900-3,000 rpm. And returns after it drops below 2,900.

Is it worth changing only one VLA, if only one is bad? Or maybe just that sides 3?

Is this harmful to the motor, or just noisy and annoying? I'm in no rush to repair it now but would like to drive it.

Since the noise does not go away after so many re-bleeds, you can conclude that the lash adjuster had failed. As far as how many to change - it is entirely up to you. On one hand, replacing the busted one is the least expensive (but you have to test every one of them in order to find the bad one). Option #2 - one head at a time - more money but you get all of them taken care on that side. Going for gold - getting all of them replaced is of course the most expensive, but you know that you are done with them all for long time.
The problem is that replacing even a single tapped involved tearing into the top of the head. You will likely need new valve cover gaskets and possibly cam seals, so having to repeat this in a few month would really suck. That is a decision you have to make.
I can't tell you if it is harmful for the motor to have a failed VLA. I do not have any experience with this myself. Personally, having the engine sound like diesel is annoying enough that I'd be looking for parts at the earliest opportunity :)

Timely response.

I'm rebuilding my 3.5L engine and have debated VLA cleaning vs replacement. Current plan was to clean which was this weekend's plan. My engine had a slight VLA tick for 120k miles and I was unaware of the bleed procedure prior to the engine spinning two rod bearings. Rock Auto sells new VLA's but they are $4.16-$5.42 each, so around $120 for a complete set plus shipping.

Given the effort I've been thru and the costs for same, I'm kind of thinking about replace all, but i don't know about the quality of the replacements nor how to do a detailed inspection of existing. Rock Auto has Enginetech, ITM, and DNJ brands of VLA's.

So there's 24 of these VLAs? One for each valve?

It's accessed through the valve covers right? As in taking the covers off and bang they are up high? Or down below other parts closer to heads?

I'm looking for something that shows pictures and explanation of process so I can do this at home one weekend.

Thanks..

Yes one for each valve. After valve covers are removed then you need to unbolt and remove the rocker shafts. Lot's involved, trust me.

https://mitsubishiforum.com/forum/mi...removal-48920/

There is an improved upon set of VLAs that have a 3mm oil hole rather than 1mm. The company says it reduced clogging from motor wear debris and improves lubrication.

The set is about $240. The company sells your set 3G74 on eBay but I've had to email and ask about if it has a set for my 3G75 3.8L motor.

Here's the link to company:
http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=290588332336&cat egory=9886&pm=1&ds=0&t=1460240013331

sales@spring-loaded.co.uk

Special tappet romoval tool doesn't appear to help
 

Got everything from the top side of motor required removed/disassembled except the rocker arms and tappets and I'm now stuck. I bought the special tool for $28 that I believed was used to lift the rocker arms and remove the tappets without having to remove the rocker tubes. Appears I'm wrong? From looks of it remove the 4-5 bolts from the locations down the rocker tube and pull the rocker arm assembly up and out? They're isn't a location I can see to use to pry up on the rocker arms to remove the tappets with the special tool. Am I missing something?

It looks like cylinder #1 (passenger side front cylinder) is open. I have to turn the motor to Top Dead Center right? Is the only way to do that by using the front Crank Bolt? Clockwise right?

Not sure what "special tool" you have. I'm guessing the on engine valve spring compressor which is useless for what you are trying to do.

Yes you need to loosen the rocker shaft bolts which will allow the open valves to seat taking the tension off the rockers. Then remove the exhaust rocker shaft as an assembly (the VLA's will fall out, so tape them to the rocker arm first), then remove the intake rocker shaft as an assembly.

Carefully take the components apart preserving the order, clean everything. Install the new VLA's in the intake rocker arms, use rubber finger tips to hold them in place, install the intake rocker shaft assembly and tighten bolts. Repeat for the exhaust.

More info here starting at posts 94 thru 102.
https://mitsubishiforum.com/forum/mi...-48920/page10/

The cams are where they are. As long as you leave the timing belt alone you can unbolt the rocker shafts, do your business, then reinstall. No need to rotate the crank. As you tighten the rocker shaft bolts, the rockers will engage the lobes that are off their base circle (i.e. On lift") and start to open the valves.

TDC not required to find
 

OK thanks for clearing that up because I was about to post a question about it. So when I loosen the rocker shaft bolts nothing will release and spring at me...gotcha. I haven't messed with the timing belt at all.

I'm a novice at this motor work stuff if ya haven't noticed. Decided to start doing all the this stuff for knowledge sake, and to save money.

Correct nothing will spring at you. Loosen all the rocker shaft bolts. Prior to lifting the rocker shaft assemblies, you will be able to slightly rotate the arms away from the valve stem tip. This allows you to use masking tape or the finger tips from rubber gloves to hold the VLA's in the rocker arms. The VLA's will fall out when you lift the assembly out if you do not do this. I don't know if the cylinder head oil drain back holes are large enough to pass a VLA into the pan which is certainly what you want to avoid.

Be very careful in keeping the shafts, rockers, etc in order and marked as to proper location. I did one head at a time.

Nothing wrong with being a novice. We all where at one time. Key is being confident and careful.

Amen to that!!!

Lifter failure findings
 

So I removed the passenger side rocker assembly furthest to wheel well...it had 7 or 8 bolts, the double rocker arms, and of course 6 lifters. This is the passenger side exhaust assembly from what I know. I used some masking tape to keep the lifters in place. I loosened all the bolts a little at a time until I could finger turn them. When I reinstalled I used the rubber glove finger method (works like a dream), tightened all finger tight, and then began wrenching on the highest bolts and worked my way a little at a time up and down the rocker tube until all where tight and then torqued to spec of 23 ft-lbs.

All the lifters were firm and looked okay, except for one that's end rests on the rod/spring was smashed in a little bit. Is this typical of the failure sign for them? I put about 300 miles on this Montero after the noise started. Some people said the lifters should give easily (be spongy or soft to compress by hand) and some say they should be firm to the hand (as in can't compress by hand). Which is it?

All of the used 6 were firm. And the new six I replaced them with were also firm, except two of the new ones gave slightly, but hardly at all, maybe 1/64", if not half of that.
The tube and head and rocker bearings all seemed good. All the small oil holes were clear. No sludge anywhere. This motor has 170,000 miles on it. No scarring anywhere on assembly or the head area.
Before I do the other 18 lifters (one tube at a time) I want to be sure I'm doing this right. I may find another as I go along but I doubt it. I'm pretty sure only one was tapping.

Can any other failure, related to that smashed lifter I found thus far, cause the lifter to be damaged? Before I do the other 18 lifters I want to be sure I'm doing it right and looking for the right signs of failure, related to the lifters or otherwise. Thanks for the guidance fellow mountain men!

My used VLA's were easy to compress significantly but then my engine had not run for about 1 year with the exception of a brief 10 minutes to warm the oil for draining then tear down. Several of the used ones had cracked seals.

The new VLA's would not compress.

The dented or hammered one may have contributed to the noise you heard. Look at the valve mating surfaces after you have the rocker assemblies out.

If it were me, I would do them all.

I was impressed with the finger tip method of holding the VLA's as well. I found that on some other Mitsubishi site.

The top of the valve stem the smashed VLA sat on looked and felt fine. Didn't seem to be damaged at all.

This motor only sat for a couple of weeks. I thoroughly tried the purging procedures several times so they should be primed and firm I would think, if they hold oil. Maybe the problem sometimes is the VLA stops compressing fully, can't excrete the oil (maybe due to debris?) so it gets beat up like this one? It would be nice to talk to one of the engineers of them.

Oh yeah I'm doing all 24 of them. This thing took me 5 hours just to strip down to the heads. I'm taking no dang chances!

I'll keep the old ones that look good as spares. I'm collecting used-good parts for these as test parts or to cannibalize if needed. I'm trying to get 4 or 5 of these early 2000s Montero's so I have enough parts to keep at least 2 running all the time if parts ever come hard to find. So far I have two 3.5L 2001s and this 3.8L 2003.

Hard to find in CO. Very few. I've noticed down south and east many more available. I need to make a trip down south or east and drive one back.

What I found so far that I thought was strange were the VLAs that were bad on the Passenger side head were both the third VLAs from the firewall. Not sure if strictly coincidence or if there can be a reason for that. The slightly dented one on the intake rocker tube wasn't as bad as the exhaust side, but still looks to be bad, due to dents on it.

You may have plugged oil passages on the rockers on that side of the engine. If VLA collapses due to lack of oil (and can't be re-bled), then it will be constantly banging between the rocker and the valve. I admit, this is speculative, but I'd make sure all oil passages there are clean and not obstructed.

Oil passages
 

The rocker shafts were all clear. Small and large holes Didn't see anything on or in the head. Hopefully that was just coincidence.

Intake butterfly clogging port? Any way for this?
 

In November 2014 I removed all the intake butterflies from their two shafts because one or two screws had come out of it's shaft mounting point and gone missing. I don't recall which side or intake butterfly had lost a screw. Is there ANY way the screw could have been injested into the cylinder and then ended up in the oil system? I think it would suck into the cylinder from intake and be blown out through exhaust valve. All cylinders had good compression at that time in 2014. That's the only known thing that could have clogged anything, but I don't know of a way for that tiny butterfly screw to have made it's way to the oil system.

I will stick a magnet into those oil ports of the head and see if anything comes out. Is there any other way of checking for larger metallic lodged debris?