I decided to switch from 5W-30 to 10W-40 because of the hot weather and high mileage. After the oil change, I hear a "chugging" sound like an exhaust leak. So, I put it on ramps and look for what I think is an exhaust leak being unable to find one. The sound seems to come from in back of the oilpan. I did'nt notice this til after the oil viscosity change. Can this happen? Also, it has a stumlbe after revving down from a cold start which I'm thinking also due to the oil change in weight and it does'nt do it the rest of the day once the car is hot. Whaaaa?????

Ken

 

My elders always told me high viscosity for high mileage engines.. the thicker stuff helps "fill in the gaps" when you have worn engine internals.

 

probably your oil pump protesting having had a thicker oil when its made for 5w30, or 10w30. you only need to run a thicker oil if the car will see like 100* or higher days on a regular basis, and by thicker i mean going 5w30 to 10w30.

Cold regions use 5w30
Moderate regions can use either
and Hot regions use 10w30

I change oil in cars all day and i have seen people come back after bein told by some "mechanic" to run this thicker oil and they have problems. BUT they wanted the thicker stuff so... now that mostly applys to going strait 30w or mabe to 20w50 but still it does make it harder on your Oil pump.

 

Run 10w-30 now...