Originally Posted By: Jim Allen
Zee, I'm with you. Someone needs to explain, in technical terms, how and why an engine would knock with one brand of filter and not with another.
Unfortunately, I've never seen any reliable explanation from Hyundai or a knowledgable source. There are some "this is what my mechanic told me" explanations, but I don't put too much faith in those.
Originally Posted By: ZeeOSix
That's kind of crazy that an engine is so sensitive to an oil filter. Did you ever inspect the old filter to see if there was anything wrong or defective with it? I just can't wrap my head around an engine's oiling system being so sensitive to an oil filter, because any oil filter should flow way more than any engine can put out. Wonder if you got some piece of garbage counterfeit filter that was super restrictive or something?
Do these engines have a positive displacement oil pump, or is it some strange setup (ie, electric, constant pressure, etc)?
Well, I apologize to the OP for this thread going way off topic, but now that we're delving into this I'm going to take it farther off topic by sharing some info I found recently.
I wasn't able to inspect the filter. I took it to a dealer when it started knocking because I had just had it there a couple days before for another reason, so they agreed to look at it for free. They put on an OE filter and the knocking stopped. I forgot to ask for the old filter back, so I never was able to dissect it.
I've been googling this issue for a while and not too long ago I stumbled on to something that may be related to your point.
While thinking about this issue one day I decided to look at replacement oil pumps for this car, just to see what they looked like. This car uses an oil pump that's integrated into a balance shaft assembly that goes inside the oil pan. So, you can't buy just an oil pump, you have to buy an entire balance shaft assembly that retails for something like $600.
And, I found an SAE paper talking about the oil pump design, which is described as sharing the oil pumping duty between two smaller pumps. I'm not willing to buy the paper, but here's the link and the abstract:
http://papers.sae.org/2006-01-0405/
Quote:
The Balance Shaft/Oil Pump Module for the new Hyundai Sonata NF Inline 4-cylinder engine family combines excellent NVH (noise, vibration and harshness, or “pleasibility”) and power consumption performance with minimized contribution to oil aeration. A two-stage drive ratio step-up and a balance shaft operating shape control strategy help minimize drive system noise emissions. Oil system noise emissions are minimized by dividing work between two gerotor pumps, and by the avoidance of cavitation at high speeds. Oil system performance benefits include high displacement at low speeds without attendant high power consumption or risk of cavitation at high speeds. A jet pump is used to efficiently recycle unused engine oil at high speeds, to both preserve energy and to resist cavitation, by boosting inlet pressure to the low speed flow-supplementing gerotor.
So, is this oil pump design somehow related to the knocking some owners experience? I have no idea and I've never read anything reliable that makes a connection.
Here's an image from my service manual showing the balance shaft module, as Hyundai calls it (red rectangle added by me):
