Drain plug magnet is clean ????

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Jul 4, 2003
This is a 2001 4.8L 1500 GMC P/UP with 65000 miles that I have personally changed the oil every 5000 miles. The fisrt 45000 miles the truck lived on Mobil 1 10w 30 with Wix or Baldwin filters. This truck has had a loud rattle in the valve train for as long as I can remember. So at 45000 I switched to 15w 40 pennzoil long life and it did help cut down the clatter when hot but not gone (added 10psi oil pressure at hwy speeds). At 60000 I ran a wix filter 5 qts Pennz LL and 1 qt of Lucas HD oil stabilizer. No change in noise maybe a little higher oil presssure cold and warming up. But when I drained it out the magnet on the plug was clean !!!!!!! This truck has had dark grey residue on it every time but this one I make a point of cleaning it off with a clean paper towel every time just to monitor the amount (the first two changes the magnet was fuzzy). This time CLEAN nothing but oil ???? Was it the Lucas.
Well, the grey residue you speak of is ferrous material.....mostly iron from the cylinders and valvetrain. The first 2 changes I ever made on my car showed a lot of metals on the plug. The plug looked as if it had an "Afro"
....it gradually decreased, but it still would show some. There might be something in the Lucas oil that displaces the metal from the magnet...maybe some kind of ester or something?

Just a thought!
You'll probably have to run a test on the LL with and without the Lucas to be sure of anything.

I've just changed the oil on my 5.0 to Pennzoil 15W-40, so I will also be interested in the iron level with my next UOA.

I have a rod magnet on the plug, only catches the gray paste, but it dropped the iron levels in my last UOA by half. $4 well spent.

Quite Interesting.

Had you run an analysis during any of this? Visible iron scares me, but I always wonder if such events such as yours are a fluke or the lube combo actually stopped some wear
The magnet droped the iron in your uoa?
That is just hidding the truth in the uoa, the engine still generated the wear your magnet just pulled some of the truth for the uoa that's all.
That's right, but I can still trend the iron with the magnet in place, this is the first UOA I did with it installed.

The lead and aluminium were also down a point, whether that had anything to do with the lower iron in the oil, I will leave that to the experts.


[ May 03, 2004, 04:44 AM: Message edited by: DavoNF ]
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