Yes, call me dumb, but when I was at my local friendly AutoZone I spied with my little eye a bottle of MaxLife "Engine Treatment."

"Sir, may I ask if this would be a worthy product of my purchase this evening?"

"Why surely it would my fine fellow, just replace half a quart of oil with the magical engine treatment potion."

Ok, so the conversation didn't quite go like that, but as I remember... anyway, I put the stuff in, replacing a half quart of my 5w30 Maxlife Oil with this stuff that *at the time, didn't ring a bell* looked like syrup, or more like molasis. But since I put the stuff in I started the truck up, ran fine for about 30 sec, and then began to rattle.

It donned on me that the stuff probably changed my oil viscocity and so I went to my girlfriend's cousin and he thought that it sounded like a Exhaust valve lifter had gone bad since the sound echoed throughout the exhaust. I changed my oil again the next day with 5 qt of valveline 5w30 and still the sound persists. Is this something that I can ignore until I can get some money saved up, or is this going to be a priority?

It's really only noticable at idle or low speeds, but seems to go away even with a little gas. What should I do?

 

I don't think the "engine treatment" did anything to your engine. Whatever was causing the noise was there before the treatment.

The 4.0L can make a "marbling" sound sometimes, and some people say gets more pronounced right after an oil change on their truck (i.e., a change in viscosity). Are you hearing something like that?

 

Yes, a marbling or like a pea in a can sort of sound. And I might have noticed it prior to the oil change, but even IF it had been around before hand, after the oil change the sound became much more distinctive. I didn't change the viscocity aside from adding the treatment... The mechanic I talked to looked at the oil I drained out (the oil with the treatment in it) and said that it looked more like a thick 10w30 thanks to the stuff.