Occasional knock on cold start

1TrackJack

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Dec 31, 2019
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Clearwater, Fl.
Occasionally I get a knocking or more like momentary rattle on cold start with my 04 TJR 75000 miles.. I changed back to Mopar oil filter because I heard it has a better check valve. Would an oil additive help?
 
For years I ran Shell Rotella 15W40 in my Jeeps and the current one almost always had a lifter ticking for a couple of seconds on startup. Just before the last oil change I added a half quart of tranny fluid to the oil and ran it for about 50 miles or so then changed the oil to Pennzoil 5W30 about a 1,000 miles ago and haven’t heard a single tick since. Not sure if it was the detergent in the tranny fluid that cleaned the lifters or the change in oil viscosity.
I’ve only used Wix 51515 filters which are the longer version of the stock filter
 
Do not add anything to the oil. If it is momentary it is no problem. Change brands of oil next time but don't worry about it at all.
 
For years I ran Shell Rotella 15W40 in my Jeeps and the current one almost always had a lifter ticking for a couple of seconds on startup. Just before the last oil change I added a half quart of tranny fluid to the oil and ran it for about 50 miles or so then changed the oil to Pennzoil 5W30 about a 1,000 miles ago and haven’t heard a single tick since. Not sure if it was the detergent in the tranny fluid that cleaned the lifters or the change in oil viscosity.
I’ve only used Wix 51515 filters which are the longer version of the stock filter

Isn't 5W-30 too low of a viscosity for the Jeep, but then I noticed you live in Alberta, Cananda. The lower viscosity oil is probably warranted in that cold climate....
I also use Wix filters, but didn't know about the longer version of stock filter....
 
Adding a bit of 15/40 to get extra zinc is fine, too much can be hard to pump immediately upon startup. Switch to a 10/40 minimum. Running a 1/2 qt of atf or marvel's mystery oil before an oil change won't harm anything. These are tough engines that have a lot of years on them to get gunked up inside.
 
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