Knock if left to idle after oil change.

[TFjed]

Hello all,
So I had no issues like this until after getting my oil changed. About a week afterward I was in my in-laws apt. and left my truck run since it was cold and I was basically in & out. I come out and hear that horrible lifter knock and immediately figure my engine is blown. With little choice and assuming the damage is already done I start driving the short distance home only to have the sound disappear within 2 blocks. I was parked at an angle and could tell it was the driver rear area that had no oil. Checked the oil level and it was maybe 1/2 quart low. This knock has happened again so now I can't let it idle too long and has happened at the drive thru but not consistently. No issue when driving. I watched the oil pressure right after the first time and is was probably around 25 while driving but would fluctuate, even at idle. Not 100% sure of normal behavior tho as this is a new issue for me in general.

Could this be the result of a bad oil change? Not sure what the shop put in as I didn't get the usual paperwork this time. I have considered just changing the oil myself to see if that fixes it. I wanted to do it myself anyways but it was winter in MN and I don't have a garage. I've read about filters with anti-backflow? Ironically I got pulled over for a headlight that first night and the cop and I chatted about what I was dealing with. He had a Tahoe with a 5.3 and said something about a Bypass filter that solved an issue with his truck?

If I do a change myself I do plan on switching to full synthetic and a quality filter. She's got 190k but overall runs strong, shifts beautifully and no rust so want to take good care of it. Any help will be appreciated!

 

[EXT4ME]

What model is your truck?

You profile pic seems to indicate a first gen.

Helpful forum hint: if you put your truck's details in your signature, then anyone that views your post will know what you have.

Now, if you really are driving a first gen (2002-2006) then hot oil cruise RPM PSI should normally be well above 25 PSI.

Probably 40+ PSI if everything is healthy.

And if it is ever going much less than that, well, that's not really a good thing.

More than likely, when you let your truck idle, the idle oil pressure was so low the lifters did not have enough oil pressure to keep them fully pumped up.

When they go flatter, they most certainly will make more noise.

As you drove and the oil pressure was up for a bit, the lifters were pumped up better and they got quieter.

Given the age and mileage of your engine, it would be in the correct range to be suffering of one or more of the most very common oil pressure related issues.

Probably most common is the failing oil pick up tube o-ring.

As the o-ring ages, it can become hard and flattened along the surfaces where it normally would be tight and sealing the pick up tube to the oil pump inlet.

The most common symptom is at engine idle, the oil pressure will read abnormally low and as the engine RPM's rise, the oil pressure rises, but not always to full pressure.

What's happening is, at engine idle, as the oil pump is drawing oil up the pick up tube from the crankcase sump, as the oil passes the worn out o-ring, crankcase air is drawn into the oil stream and the oil and air mixture does not allow for a full pressure condition.

As the engine RPM's increase, the oil moving past the defective o-ring draws in less air and the overall oil pressure will increase somewhat.

Think of a drinking straw with a crack somewhere along it's length.

If you use that straw to drink your soda pop and you give it a light draw, you will get quite a bit of air with your soda.

If you bear down and really go after it with a hard pull, you will draw in more soda with less air, until your next easy draw.

Another consideration is a possibly worn out oil pump.

In my EXT I first had the o-ring changed and it helped for a short period of time.

I ended up having to have the oil pump changed and that completely solved my problem of low oil pressure.

My EXT had just over 225K miles on it when I finally solved that problem and now the oil pressure is better than it has ever been since I've owned the truck.

One other possibility might be a less than optimal oil filter was installed at your last oil change.

Maybe you can start by simply swapping out the oil filter with a good quality, name brand filter and refill the oil to it's proper level and see if that makes any difference.

Personally, I use NAPA Platinum (made by WIX) oil filters and Mobil 1 5W-30 motor oil in all of our trucks.

But, my money is on a bad o-ring.

If it is, it's totally fixable.

 

[TFjed]

What model is your truck?

You profile pic seems to indicate a first gen.

Helpful forum hint: if you put your truck's details in your signature, then anyone that views your post will know what you have.

Now, if you really are driving a first gen (2002-2006) then hot oil cruise RPM PSI should normally be well above 25 PSI.

Probably 40+ PSI if everything is healthy.

And if it is ever going much less than that, well, that's not really a good thing.

More than likely, when you let your truck idle, the idle oil pressure was so low the lifters did not have enough oil pressure to keep them fully pumped up.

When they go flatter, they most certainly will make more noise.

As you drove and the oil pressure was up for a bit, the lifters were pumped up better and they got quieter.

Given the age and mileage of your engine, it would be in the correct range to be suffering of one or more of the most very common oil pressure related issues.

Probably most common is the failing oil pick up tube o-ring.

As the o-ring ages, it can become hard and flattened along the surfaces where it normally would be tight and sealing the pick up tube to the oil pump inlet.

The most common symptom is at engine idle, the oil pressure will read abnormally low and as the engine RPM's rise, the oil pressure rises, but not always to full pressure.

What's happening is, at engine idle, as the oil pump is drawing oil up the pick up tube from the crankcase sump, as the oil passes the worn out o-ring, crankcase air is drawn into the oil stream and the oil and air mixture does not allow for a full pressure condition.

As the engine RPM's increase, the oil moving past the defective o-ring draws in less air and the overall oil pressure will increase somewhat.

Think of a drinking straw with a crack somewhere along it's length.

If you use that straw to drink your soda pop and you give it a light draw, you will get quite a bit of air with your soda.

If you bear down and really go after it with a hard pull, you will draw in more soda with less air, until your next easy draw.

Another consideration is a possibly worn out oil pump.

In my EXT I first had the o-ring changed and it helped for a short period of time.

I ended up having to have the oil pump changed and that completely solved my problem of low oil pressure.

My EXT had just over 225K miles on it when I finally solved that problem and now the oil pressure is better than it has ever been since I've owned the truck.

One other possibility might be a less than optimal oil filter was installed at your last oil change.

Maybe you can start by simply swapping out the oil filter with a good quality, name brand filter and refill the oil to it's proper level and see if that makes any difference.

Personally, I use NAPA Platinum (made by WIX) oil filters and Mobil 1 5W-30 motor oil in all of our trucks.

But, my money is on a bad o-ring.

If it is, it's totally fixable.

Changed my signature, thanks for that!

Ya when driving it's not at 40, and I was thinking it had been but wasn't sure enough to say "Yep that's wrong." I looked up some info but some of it contradicted other sources. So my pressure is then low even when driving as it's typically below 40, bouncing around. I also wasn't certain how much variance to expect when accelerating/stopping and so on.

This definitely looks like the solution and will likely be my next auto related project. Thanks a lot!

As soon as summer actually arrives in S. MN....

 

[TFjed]

What model is your truck?

You profile pic seems to indicate a first gen.

Helpful forum hint: if you put your truck's details in your signature, then anyone that views your post will know what you have.

Now, if you really are driving a first gen (2002-2006) then hot oil cruise RPM PSI should normally be well above 25 PSI.

Probably 40+ PSI if everything is healthy.

And if it is ever going much less than that, well, that's not really a good thing.

More than likely, when you let your truck idle, the idle oil pressure was so low the lifters did not have enough oil pressure to keep them fully pumped up.

When they go flatter, they most certainly will make more noise.

As you drove and the oil pressure was up for a bit, the lifters were pumped up better and they got quieter.

Given the age and mileage of your engine, it would be in the correct range to be suffering of one or more of the most very common oil pressure related issues.

Probably most common is the failing oil pick up tube o-ring.

As the o-ring ages, it can become hard and flattened along the surfaces where it normally would be tight and sealing the pick up tube to the oil pump inlet.

The most common symptom is at engine idle, the oil pressure will read abnormally low and as the engine RPM's rise, the oil pressure rises, but not always to full pressure.

What's happening is, at engine idle, as the oil pump is drawing oil up the pick up tube from the crankcase sump, as the oil passes the worn out o-ring, crankcase air is drawn into the oil stream and the oil and air mixture does not allow for a full pressure condition.

As the engine RPM's increase, the oil moving past the defective o-ring draws in less air and the overall oil pressure will increase somewhat.

Think of a drinking straw with a crack somewhere along it's length.

If you use that straw to drink your soda pop and you give it a light draw, you will get quite a bit of air with your soda.

If you bear down and really go after it with a hard pull, you will draw in more soda with less air, until your next easy draw.

Another consideration is a possibly worn out oil pump.

In my EXT I first had the o-ring changed and it helped for a short period of time.

I ended up having to have the oil pump changed and that completely solved my problem of low oil pressure.

My EXT had just over 225K miles on it when I finally solved that problem and now the oil pressure is better than it has ever been since I've owned the truck.

One other possibility might be a less than optimal oil filter was installed at your last oil change.

Maybe you can start by simply swapping out the oil filter with a good quality, name brand filter and refill the oil to it's proper level and see if that makes any difference.

Personally, I use NAPA Platinum (made by WIX) oil filters and Mobil 1 5W-30 motor oil in all of our trucks.

But, my money is on a bad o-ring.

If it is, it's totally fixable.

One other question... Oil Pump brands? I looked quick and don't see any brand names I recognize. I don't use cheap parts unless it's literally no difference, but still not with stuff like this. I see Melling coming up quite a bit?

 

[EXT4ME]

I used the Melling Automotive Products M295HV324S Oil Pump kit on my 2004 EXT with the 6.0 LQ9 engine.

I believe this is the same kit for the 5.3 engine.

Cold oil idle oil pressure is 45+ PSI.

Cold oil WOT oil pressure is close to 80 PSI.

Hot oil idle oil pressure is 45 PSI.

Hot oil WOT pressure is 65+ PSI.

I am very pleased and highly recommend this kit.

It comes with the new oil pump, oil pick up tube and the correct o-ring.

If you decide to just replace the o-ring, understand there are a couple of o-rings and you should research to make sure you install the correct one for your application.

I did not have to be concerned with that since the correct o-ring for this setup is included.

 

[TFjed]

I used the Melling Automotive Products M295HV324S Oil Pump kit on my 2004 EXT with the 6.0 LQ9 engine.

I believe this is the same kit for the 5.3 engine.

Cold oil idle oil pressure is 45+ PSI.

Cold oil WOT oil pressure is close to 80 PSI.

Hot oil idle oil pressure is 45 PSI.

Hot oil WOT pressure is 65+ PSI.

I am very pleased and highly recommend this kit.

It comes with the new oil pump, oil pick up tube and the correct o-ring.

If you decide to just replace the o-ring, understand there are a couple of o-rings and you should research to make sure you install the correct one for your application.

I did not have to be concerned with that since the correct o-ring for this setup is included.

I'm just now seeing your reply, thanks! It has not been running 40 most of the time even when hot. I was looking at brands just today. I actually was thinking of getting the exact same kit and not just the o-ring. I'm of the opinion that if something is a pain to get to or whatever, I'll replace the whole part. Like ball joints/bushings, I do the whole arm. (Granted it's always been on higher mileage cars anyways where joints and bushings were shot and I don't have the tools to press them in)

Obviously I've never done a project like this as I did not realize I'm exposing the timing chain, thought the pump was in the oil pan. So with nearing 200k I'm figuring on doing the chain as well so I hopefully don't have to open things up again. I've got a steering gear box leak and I think the oil pan gasket is as well considering the mess under there, so I have a decent sized project coming anyways, along with likely doing ball joints, tie rods etc.

 

[TFjed]

Update: In this instance, this was the fix. Installed a new oil pump and all is well.