06 MGM
103k
just did an oil change. I went with SAE 5W-20 High Mileage oil= Quaker State

drove home after work and pulled in to the car port and at idle I can hear what sounds like a lower end knock...if I ramp up the rpm's to 1200+ and hold them, noise goes away.

I did not use a Motorcraft filter, but I went with the silver Fram Xtra-guard (all they had in stock)


I remember ALL the Towncars at my old Limo company had the same sound at idle, and never was a real concern and those engine lasted 250-325K easily.

thoughts? Is this common?
Car was bought in December right before christmas and this was its first oil change since purchase. old oil came out looking normal...just had 3500 miles on it, so I changed it.

Probably just normal noises amplified and bounced back to your brain housing from the wall(s) of the carport. Also, could be that your motor isn't completely happy with the 5W-20 oil. Or just your ears. And the motor doesn't care. I think I tried 5W-20 once and thought it was a little noisier. Went back to 5w-30. sounds fine.

I think I'll go with a thicker oil...old sticker on windshield had 5w-20 on it...cap states 5w-20...I went with hi-mi 5w-20.
I can hear it after it warms up even out of the car port. warmer viscosity needs to be thicker I guess.
I'll drain and fill w/ 5w-30 before next week's road trip I guess.
darn...there goes $24 worth of walmart-priced oil! lol

thanks for your input.

Maybe you can use the oil in your lawn mower or something. I know they spec the lighter stuff for newer cars, due to CAFE standards. Or you could just limit the idle time and live with it. And go for the old 3 months/3K miles, whichever comes 1st. Especially if you're frugal. Should come up pretty quick with some traveling. As for the filter, Wally world has the whole town bracketed here. If one is out, it's only a few miles farther to check another loc.

It's a well-known phenomenon on BITOG that an oil can sound "noisier" in some motors and "quieter" in others. Mobil 1 is famous for that.

Case in point: my 2000 GMQ. I always used Motorcraft 5W-20 since I bought it in 2012. Last change I ended up using a jug of Quaker State Ultimate Durability I had purchased for use in the ex's Marauder, but didn't realise I had accidentally picked up 5W-20 instead of the desired 5W-30. Since that car has 200,000 miles with the last 100,000 on 5W-30, I didn't want to switch grades so I just hung on to the QSUD and used a jug of Pennzoil Platinum 5W-30 I had for my own Marauder.

Fast forward a while and I figured why not use the QSUD in my DD...I had already paid for it. Ran it for almost a year and a half and just switched it back to my usual MC last week. On start-up I heard a little extra valve-train noise but after driving the car around for the day that noise abated and it now sounds just as quiet as the expensive synthetic did.

FWIW, the ex's Marauder has had a sort of nuk-nuk-nuk sound at idle since we bought it at 87,000 miles and now has over 200,000 with the same sound. I gave up worrying about it long ago...

Drain a couple quarts & replace with 10W-40, instant 5W-30, or at least close enough...

I like that idea. But if I'm going to "drain a couple quarts", I'll just drain it all. I work at a shop so it's more work to rack it and lift it than to remove the drain plug. I'll let you all know. I'll go with 5w-30 syn-blend (house oil) and see how it goes.

I'm cheap enough that chances I'd drain new oil into the recycle container are zero & none... I'd use anything drained as add oil in my old truck, or lawn mower as mentioned...

well for me, $25 to potentially save the bottom end of my engine is well-worth the money.
In this industry, CHEAP - expensive.
skimp on the important stuff to save a buck usually costs 2 bucks or more.

I've seen 2 employees who get paid $24/hr talk for 15 minutes about how to save the company $10 on something.

It's your money to piss away - in 50+ years of vehicle ownership I'm yet to lose a engine from inadequate lubrication...

HM oils are blended to be slightly thicker than "normal" oils so HM 5W-20 is going to be almost a 5W-30. If your lower end is making noise because of using HM 5W-20 then it's already damaged (Doubtful). As you stated, many mod motors make this sound and last a very long time.

You mentioned you used a "silver Xtra-guard"...did you mean the Tough-Guard? That's the only FRAM filter that's silver. If so, it at least has a silicone ADBV so you shouldn't have to worry about it. I would switch to the Motorcraft if you are going to change the oil out again, or at least use the gold FRAM Ultra-Guard.

1.) Motorcraft FL-820s or Wix 51372 or Napa Gold 1372. These are the only filters that should be used on these engines. Fram should be avoided and there are many websites showing why. They are junk!

2.) Mobil 1 will make my 4.6's sound like sewing machines. It is annoying but will not harm anything.

3.) Do not dump the oil just because. Dump the filter however.

Agreed. This is relatively well-documented on BITOG.

I used M1 for one OCI in my DD and could immediately tell the engine was a bit more chatty. It's nice and quiet on MC 5W-20.

For oil filters I would add the Amsoil EAO-11 filter as well.