Slight knock after oil change.

[Haywire6000]

I have a 93 Ranger 2.3l. I am getting a slight knock from bottom left of engine(if you are facing the truck). The knock started after I change from 5w30 to 10w40. Also it only knocks after it has warmed up and when it's idling. If I pick up the RPMs to about 1000 the knock disappears. Any ideas?

 

[Mark_88]

Mine always does that...it's just saying how happy it is to have some attention...

The bad news is...the bottom left of the engine is somewhere near or about your oil pump...well, actually, it's probably bottom right...but it may be heard all through the engine when it starts to go...I'd suggest putting in a half bottle of something like Moly Slip or Lucas to see if it goes away...otherwise, keep an eye on your oil pressure and if you see it drop off suddenly then you will know the pump is gone...time to replace it...hopefully not the case, but nothing else down there other than the bearings...

 

[Haywire6000]

so what do you think, pump getting hot and not producing enough pressure or just on of the connecting rod bearings opening up when the oil thins out? I just think it's weird that his just happened after I changed to 10w40 ( because of the weather warming up). I am going to put 5w30 back in and see how that goes. If it doesn't help hopefully the knock wont get worse.

 

[RonD]

Reads like the oil pressure is low, too low when oil gets warmed up.

Raising RPM raises oil pressure.

But usually you will get lifter taps first if oil pressure is too low, however the 2.3l has an overhead cam so no lifter/pushrods taps

Lower engine knock is usually a connecting rod bearing noise, so an important noise to get rid of.

I would change the oil filter, maybe the new one is limiting flow, defective.

Might be a good idea to get a real oil pressure gauge and see what the oil pressure really is at idle when warmed up, Fords use "senders" which don't tell actual pressure.

 

[Haywire6000]

hmmm, I didn't think a filter can cause that. I am go to switch back to 10w30 tomorrow like I said, I might as well spends the 6 extra bucks and change the filter. I hope it's something as stupid as a bad filter.

 

[Haywire6000]

I am really hoping that it's not bottom end, also where this just literally started the same day I changed the oil and filter.

 

[RustedRanger]

Bad filter was my first thought too. If your motor has a lot of miles,it'd be better to stick with what you put in....try just changing the filter to a Motorcraft. Lucas is a good idea too...they also have synthetic Lucas oil treatment that is way thinner for newer engines.

 

[RonD]

Oil pressure comes from flow(volume) vs back pressure from the oil passage outlets, like bearings.
As bearings wear they allow more oil to pass so less back pressure and oil pressure goes down over time(miles), which is normal.
Thicker oil is harder to pass out the bearing gaps so oil pressure is higher, as the oil warms and thins it passes easier and oil pressure is reduced.

On the other side is the flow(volume) created by the oil pump, it pushes oil through the filter, if the filter gets clogged or isn't passing full flow from the pump then oil pressure will also be reduced.
When you raise RPM(oil pump speed) the flow is increased so oil pressure goes up.

 

[RustedRanger]

But if it's a heavier weight then it will thin less when it gets hot. I have never had pressure drop after putting in heavier weight oil in a worn engine. Rusty is number 35 over the 29 years I have been driving. Some was for parts but many I drove was in sad shape by the time they got to me lol

 

[PanamaExpat]

Check out http://www.bobistheoilguy.com/. You will learn a lot about oil that I never knew. Some of what you read there will blow your preconceived notions about lubrication and viscosity right out the window.

 

[chazzone]

It's a terrible idea using a higher viscosity oil in these engines. I never cease to be amazed at guys who don't know the first thing about oil or lubrication, but think "thicker is better". It is not. Higher viscosity oils will increase wear and lead to more problems.

In fact, if you're in Maine, you should be using 5w30 or 0w30.

Use what they are designed for, and they will last longer.

 

[97ranger xlt]

goodness gracious lol it NEVER gets 'warm' in maine -just use 5w30 and a motorcraft filter.

 

[RustedRanger]

Depends on the miles and clearances and as far as thicker oil I wouldn't jump that much higher....it's not like putting 20W50 in it was suggested,to thick is a bad idea and a waste of power to drive the oil pump. I wouldn't jump from 5W30 to 10W40 anyway. If it has a ton of miles or was abused then I'd go to 10W30 if it was mine.