I recently got a JDM engine put in my 2003 honda acord 4 cylinder. The owner's manual says to put 5w-20 oil in the car. The auto shop that put the JDM engine in said to use 10w-40 oil because it's hot here in southern california, about 100 degrees F in the summer. It's a JDM k24 honda accord 2.4L engine. There is no oil burning issues with the 10w-40 that is in the new JDM engine, since i replaced it 2,000 miles ago.

Is 10w-40 oil too thick? Will it cause issues with the oil pump? Or cause other issues?
Another mechanic i know who retired as a honda mechanic after 25 years, says to use Factory OEM Honda 10w-30 oil in the car.

What oil do you think? conventional or full sythetic? 5w-20, 10w-30, 10w-40, or something else?

 

The shop has no idea what they're talking about; the absolute thickest oil I'd use in that engine is 0W-30.

 

Look in the owner's manual to verify, but Honda recommends 5w-20 covering all temperature ranges. Stick with 5w-20.

 

Thanks the owner's manual does say 5w-20 and the shop had said 10w-40 because it's hot here in this part of southern california

 

one oil change shop, valvoline, said too thick of oil could clog the oil pump...which i definitely don't want. I plan to swap the 10w-40 out for 5w-20. what problems do you think could happen from too thick of oil?

 

thanks, what issues do you think too thick of oil could cause to the engine?

 

Engine/metal wear would be my biggest concern. Oil is cheap insurance to prevent engine wear, so I'd recommend draining the current oil and filling with 5w-20.

Long term, too thick of oil can cause metal wear on moving parts that need proper lubrication (like bearings, cam lobes/valve, cylinder rings, even the oil pump). I don't think heavier oil will clog the oil pump, but it may slightly reduce the volume the oil pump can move. The oil pressure is generated by the clearance of your crank bearings.