My 2010 Soul's 2L engine has always had a bit of top-end clatter, fairly common on these engines. Quiet when started, and then after about 5-7 seconds you get this clattery rattle from the valvetrain that lasts for a while. Does not ALWAYS do it; just more often than not. Kinda unpredictable.
This spring I changed the oil with GTX HM 5W-30 and a pint of STP blue bottle. Figured with the GTX HM being about 12 cst, with the STP the oil was now a 14cst-ish 40 weight, and it would 'cushion' and quiet down the clattery valvetrain.
Interesting this happened - engine starts much, much better and faster. Engine used to crank 3-4 times before catching; now it starts before the key hits the end of its travel, and you can feel that it is cranking faster. However, the engine got LOUDER by a lot. Same quiet start, but after 5-7 seconds, the clattering is now way louder, and you can't miss it. I'm sure I can also hear the clatter sometimes when I am driving.
Best 'theory' I can come up with is that the thicker oil mix has increased the oil pressure in the valvetrain, so the 'loose' parts are banging around more from the increased pressure. Thought it would cushion parts, maybe having opposite effect?
Thinking of trying 2 'fixes' - add a can of Molyslip Mso2(sp) to see if it helps actually cushion the parts; or add a pint of MMO to the sump to thin the oil back down and reduce 'pressure' a bit. Might also just leave it on a 9 year old car with 145k. Doesn't really owe me anything.
This spring I changed the oil with GTX HM 5W-30 and a pint of STP blue bottle. Figured with the GTX HM being about 12 cst, with the STP the oil was now a 14cst-ish 40 weight, and it would 'cushion' and quiet down the clattery valvetrain.
Interesting this happened - engine starts much, much better and faster. Engine used to crank 3-4 times before catching; now it starts before the key hits the end of its travel, and you can feel that it is cranking faster. However, the engine got LOUDER by a lot. Same quiet start, but after 5-7 seconds, the clattering is now way louder, and you can't miss it. I'm sure I can also hear the clatter sometimes when I am driving.
Best 'theory' I can come up with is that the thicker oil mix has increased the oil pressure in the valvetrain, so the 'loose' parts are banging around more from the increased pressure. Thought it would cushion parts, maybe having opposite effect?
Thinking of trying 2 'fixes' - add a can of Molyslip Mso2(sp) to see if it helps actually cushion the parts; or add a pint of MMO to the sump to thin the oil back down and reduce 'pressure' a bit. Might also just leave it on a 9 year old car with 145k. Doesn't really owe me anything.