Frankly I dont really know how to reduce noise other than what ive done below. Looking for other ideas.
Ive got a 3.0 montero Sport 2001,about 145k on it. The valve train is noisier on start up than usual and only when the ambient temp is below 50 degrees. After 2 min, the noise virtually disappears . When its above 50, theres very little noise on startup..
I use 5-30 wt"high mileage" It is at wallymart . HighTeck I think , with Mobil1added 1qt oil My next move might be to a lower (startup) viscosity than 5,but I may have to order it as Ive never seen it in stock.
Anyone had this issue and solved it with oils or even"snake oil" additives?
Ive put a lightbulb next to lifter cover over nights,below 50 so the startup lifter racket wont be so hard on it until I can get lower wt oil or some additive that may work.

 

You don't mention the type of oil used. I ran full synthetic Valvoline VR1 5-40 with decent results. Noise would always come back when oil became dirty.

jim

 

Have you tried to do a proper VLA bleeding procedure? Also, I'm not 100% sure, but I think you need a higher low end viscosity oil. The reason you have VLA noise is the oil is draining out while the engine is sitting around. Having a lower viscosity oil will only drain more oil out of VLAs faster.

 

Hunter
In addition to draining faster as you say,it also gets more oil to the engine parts sooner on start up and when you put the pedal down. BTW we dont usually think of the fact that when we floor the pedal the demand for oil increases enormously.
.
Heres my take on oil viscosities

the first number is the viscosity for cold temp startup performance .The saying is true that the highers percentage of wear to an engine is in the startup part. The second number is high operation temp performance viscosity for the higher temps once warmed up.
The oil is more efficient as it starts with a lighter viscosity and reaches lifters and other areas of the engine quicker with more oil and as temps rise switches to the increased viscosity which adjusts to the higher temps. The lower viscosity wouldnt continue to lube the engine adequately at those higher temps.

Since I had just changed the oil and lifters were still noisy,Im suspecting oil passages may be obstructed with god knows what,varnish,oil,carbon and the like, in the oil.
Since I cant clean the passages out, my reasoning was to go to a lower startup viscosity and that just may facilitate the passage of more oil to those noisy lifters. If it doesnt go away,then Ill just place a drop light against the valve covers a couple hours before attempting to start it when the ambient temps are below 50 degrees, since that is when they are really loud for about 2 min,which is 2 minutes too long. I use a timer for that task so I dont have to get up earlier. Thats a good reason to have a block heater . I wonder, were these options for mSports?
Now I hope I dont forget and let my wife drive off in it before I can remove the droplight.

 

PalmSprings, your reasoning is interesting, but I'd have to disagree somewhat. First I disagree with you about higher demand for oil when you floor the gas pedal. More oil is supplied because the oil pump runs at higher RPMs, but I don't think there is a higher demand for it. You are correct, that with the lower viscosity at low temps, oil will flow easier, but I don't think it will flow faster. The speed at which oil flows depends 100% on the oil pump output. In fact, I'd argue that with the lower viscosity oil you'd have harder time maintaining proper oil pressure. I also don't think that all of the oil is draining out of the top of the engine and out of the lifters overnight. The clearances between the engine parts are small enough to retain the residual oil needed for the cold restart until the flow from the oil pump delivers fresh supply. I think the issue of oil draining out nearly completely comes only when your vehicle is sitting without being run for very long time (month and month).

Now that is probably enough for a philosophical discussion Lets try to solve the issue you are having. The noise in the lifters indicates that there is air getting into them. Since it does go away after some time, it is reasonable to assume that the oil supply is OK. However, if I was dealing with this, I'd do the following:
1. Check oil pressure in the system. Both cold and hot engine. If your pressure is low, that may be the reason for all the trouble you are having.
2. Run VLA bleeding procedure. You did not say if you ever done it yet. I had VLA noise at different times and after the bleed procedure it is all good (210k miles on original engine).
3. You could try the snake oil additives. Not sure in which direction to steer you on this. If you are convinced that the VLA's passages are clogged up, you need to find something with extra detergent additives to clean the passages. It would be good to run the additive through the system and then do a clean oil change to remove the gunk out.

BTW, how often do you do the oil changes? Have you ever had your valve covers off? The reason I'm asking this is to determine if there is a chance of some gunk and sludge build up in the upper parts.

 

I found this a few minutes ago
Tech: Minute Mod
The 5 minute V6 lifter Noise Fix

http://www.4x4wire.com/mitsubishi/te.../lifter_noise/ Short Cuts
Author: Doug Miller, March 12, 2000. Editor: Phil Hansford



Applicable Vehicle: Any Montero/Pajero/Montero Sport/Dodge Raider with 3.0l or 3.5l V6
On the 3.5 and (I believe) the 3.0 V6's as well, there is a device in the valve train called a valve lash adjuster (VLA). This device is like a little piston and cylinder filled with oil. It is different from a hydraulic lifter, and functions to keep the slack in the valve train to a minimum as the engine ages. The VLA has a little ball valve held in place by a spring, and uses oil pressure to take in oil and place constant pressure on its valve. Dirty oil from even several oil changes ago (or a previous owner) can leave particles in the ball valve that hinder its ability to remain pressurized. This leaves slack in the system and you hear it as clicking. It is also caused by getting air bubbles past the check valve that is now stuck at the top of the little cylinder, unable to leave via the ball valve at the bottom.

SYMPTOMS: A valve train clatter on startup that does not go away when the engine is warmed. If it goes away, this is not your problem.



Causes
Low oil - now or previously.

Dirty oil - now or previously.

High oil - now or previously (con rods slap the too high oil and "foam" it). Note that high oil can be caused by coolant contamination from a blown gasket, not just by overzealous owners. Parking on a steep hill - now or previously. With the engine off, this encourages the VLA to drain its oil (running steep hills are not a problem, unless it's so steep the oil is getting "foamed" by the con rods).

Parking for long periods - now or previously. Over time they'll drain.


The Fix (the VLA procedure you suggested Hunter)
Now that I've made you all paranoid, here's the laughably simple fix. The VLA's were designed to respond to a pattern of gentle revving to flush the oil out of the little cylinders (those clever Mitsu engineers, eh?)

Warm up the engine.

With the engine in neutral, gently rev it from idle to 3000rpm over a period of exactly 15 seconds. Your goal is a constant gradual increase to 3000rpm. At the 15 second mark, drop the throttle (foot off the gas) to idle. Now let it idle for 15 seconds to complete one 30 second cycle

Repeat the 30 second cycle in #2 from 10 to 30 times. If the problem persists after 30 cycles, this is not your problem. It fixed mine after only 5 cycles - total silence.

 

==============================
My answers:


If no improvement then follow up with these 3 suggestions
1- will do vla bleeding

2 extra detergent additives to clean components (Valve medic was recommended by mfg tech I spoke with). It would be good to run the additive through the system and then do a clean oil change to remove the gunk out.


3- will ck oil Pressure

Thx Hunter

 

I performed the VLA proceedure as hunter suggested ,in an attempt to quiet my valvetrain .

RECAP:
As I mentioned in the beginning of this thread;My 240K+MS 3.0 only made valve train racket the first few minutes after startup,when the ambient temps were below approx 50F. Otherwise quiet.

As of last weekend the nights had been about 70 degrees, but the forecast was to be abt 50 in a couple days.

I went ahead on sunday and performed the VLA proceedure a couple days before the temp drop and only did 3 or 4 cycles. This morning,wed, the temps had fallen to 50F. I went out and started the MS and the valve train noise quieted down to a near enough normal level . Huge reduction in the noise level.

So it worked fine for me.....for now.
Thx Hunter for the VLA suggestion. I considering ur suggestion to increase the startup viscosity from the current 5 to ooohhh, lets try 10? Ill do some more reading up on that one

 

The next morning I started the MS and the noise returned.
I shut the engine off less than 20 seconds after starting it.
Immediately restarted it and the noise had gone.
Cant explain any of that.
At this point I dont know what to expect
If this keeps up Ill try changing oils and or viscosities like others mentioned.

 

It sounds like you have a bad VLA that just keeps draining too much when engine is off. For now try to warm up the engine before going anywhere, rev up RPMs vew times (kind of like VLA bleed but not the whole procedure) to prime the VLAs with oil. If you can quiet them down you are good to go. Plan on replacing them some day in the future.