[Gav3.5V6]

Ok so this problem has really made my head flat.

Some of you may remember that i have posted about this when i had blown head gaskets.
Anyway that was sorted but the noisy lifters continue(at least thats what i think), cleaned, bled and 2 oil changes later..
So replace!!

I was not going to pay the stealers price and did not know about the place that someone mentioned go for R40 ea, So i searched online and ordered them from the states, landed for R1050 for all 24.
I bled them according to PDF document, and installed, was looking 4ward to peace and quite and peace of mind.
but not much difference unfortunately

So now im at a loss.

I found this post by nicomar and it sounds identical to my sound

When hot and i accellerate to around 3000 refs, it will go away, but as soon as decellerate and run against decompression, the rattle is back? It is intermittent.

Under 3000RPM i hardly hear anything but on 3000 if i let go of the accelerater its loud and rather scary if you ask me, if i accelerate over 3000 then the sound becomes more audible. Mine is NOT intermittent.

Can the problem still be lifters or do i start looking elsewhere... I have not used Delo or over filled as i have now read.

Now to chuck in a spanner..
I saw a post from HBannink about Oil Pumps, since this is something that was bugging me, I installed a cheap oil pressure meter and got strange results, it has High Pressure when start then drops which i think is normal, but then it acts like a revcounter when i climb on the pedal, this is supposed to be stable since it is supposed to have dump vavle
Maybe this noise we here is a faulty pump, (not sure how the pump functions and whether it can make this noise and the noise is on the top from what I can hear)
But maybe we not getting enough pressure up top even though the meter shows high since it gets its reading from the bottom

So to all those experienced forum members, I NEED HELP!!
I need to sort this out and am worried i can damage the motor if its not the normal noisy lifters.

Gav

[HBannink]

Lets Look at the oil pressure gauge, on a cold start the engine and the oil is cold so the oil is thicker and the tolerances in the bearing surfaces are smaller hence the high reading. As the engine reaches working temp the oil becomes thinner and the metal expands and the reading would drop. On both the previous instances I have assumed that the engine is at idle and that is our next variable. Faster engine speed would have the pump working harder but the oil temp and tolerance in the engine would be constant for all practical purposes so with the increased oil flow from the pump the pressure would go up and down with engine revs, nothing strange about that. If at 3000 rpm you find the reading dropping like when decelerating it would indicate a loss of lubricant, either low oil level or the pump picking up foam.

The first you would hear is the valve adjusters as they rely on pressure to function properly and if you are losing pressure the bearing surfaces would be slowly but surely be damaged to the point that a bearing knock would be the noisy culprit. I would have a look at the normal reading just before the noise and compare it with the reading when you hear the noise.

I have accidentally come across the overfill tip and it sorted my problem completely, 500ml would not harm the engine and could just do it for you as well. As for the oil bypass valve, this comes in to operation as a safety and not as a regulator and is there to protect against over pressure at high rpm. Believe it or not over pressure can harm a motor as much as low pressure if not more

[Gav3.5V6]

Thanks Hbannink

I will check the readings and take it from there, what is too high though I will check mine tomorrow and put the figures here, I dont recall it ever dropping at 3000 revs. so i dont think lack of pressure is a problem.

Is it possible to still lack pressure on top if the reading is high on the gauge( is the dump valve after the preasure pick, if you know what i mean. ie can the dump valve be stuck open?)

As for the sound, to me it sounds like it is coming from the top of the motor. What does the bearing knock sound like?
the motor has 220k on so is good for plenty more unless it had bad history, does have service history.

I think i will add 500ml for good measure.

Thanks for the info, I would like to do a trip in june and need to have peace of mind bout the motor.

Gav

[HBannink]

Hi Gav

In general the bypass valve opens above 5,5 bar and that kind of pressure is only reached in extreme conditions. The normal route for the oil to travel would be from the pick up in the sump to the pump and then to the filter before going to the engine, the bypass valve is fitted in the filter housing and if you have taken the feed for the gauge from the existing sensor you would have a pretty accurate indication, pressure in the system should be the same top and bottom and a stuck bypass would drop he reading immediately.

The sound of a petrol bearing knock is best described as sounding like a diesel , oom 4E might protest with this analogy but that is the most gentle way to describe it

These v6 motors are pretty tough and reliable and would take some serious knocking before it leaves you stranded. From my experience I would look at the condition of the water hoses and go through the history to see if they were changed. Do not forget the heater hoses as they will cost you an engine if they fail.

[Gav3.5V6]

Hi Hbannink

Thanks for the info, I have not had time today to check the readings and add more oil but will check ASAP.

Well surely bearing knock is a gradual thing,, well i suppose so would the lifters be.... Why i say this is because the noise happend quite quickly, i remember doing a trip last year to JHB july and when i turned down the radio i heard that the engine was noisier. Shortly after that i found out i had blown head gaskets which was redone, thats when i check all hoses and the all seemed in a good condition.

I hear what you say about the noise sounding like a diesel , i would almost say know thats not what it sounds like, wish i could record it somehow.

Gav

[HBannink]

Just a tip concerning the hoses, from the outside they might look good and if the salesman who sold the vehicle did his trick with silicone spray they would look new, Inside is what counts

[RoelfleRoux]

Henk,

If you were still up at 1am this morning, I hope it was because you were watching Pink Floyd's The Wall.

[Gav3.5V6]

Ok so today I added 500ml extra oil and yes it definitly made the motor run quieter. But i still hear that noise on de-acceleration just not so bad anymore.

I also routed the preasure gauge through the side window to monitor while riding.
once the motor warms up the preasure reads just under 2 bar but increases rapidly with higher revs, @ 3000rpm the gauge reads just under 6bar and the max i saw was bout 6.5 maybe a tad more.

Is that to high or still withing spec?

I bought wynns engine flush and will do that soon with some new oil and filter.

GAV

[Scubadude]

Dont want to be a prophet of doom ... but that could be big end bearings ...

[HBannink]

Henk,

If you were still up at 1am this morning, I hope it was because you were watching Pink Floyd's The Wall.

Now you are giving your age away

Dont want to be a prophet of doom ... but that could be big end bearings ...

I do not agree. The mitsu factory spec is a minimum of 0,8 bar at curb idle speed with a warm engine. That is 11.4 psi or above, seems to me it falls in the above category

I bought wynns engine flush and will do that soon with some new oil and filter.

GAV

Be careful with that stuff in my opinion it dilutes the oil viscosity and affects the lubrication if it was my engine I would only let it idle not load it by driving the vehicle. Most hi end oils have a good detergent property so make sure you get a decent one