Hello, I am really close to getting my new engine. I will be getting a rebuilt GM 4.3L from my dealer. I wanted to know what oil is recommended to put in it. Someone told me I should put in 5w-30 but I want to be sure. I was thinking Castrol GTX 5w-30 (regular white quart) if 5w-30 is correct. Thanks.

 

5w30 is for pretty much all temperate climates. You should be fine there. I would go with a decent conventional oil for the first few oil changes to ensure that the rings bed in properly, then feel free to switch to whatever you want, synthetic, synthetic-blend, etc.

 

Ok great. One last question, though. After how many oil changes? 5 or 6 maybe?

 

For these engines, my opinion is that conventional oil will do just fine unless you just want to change over to a synthetic at some point, but several used oil analysis reports have shown me that conventional goes ~4,500 miles in mine with no problem.

 

Sounds good then. I'll also be saving a bit because synthetic isn't cheap either. But thanks to both of you for all the help. I really don't want to screw up this engine by putting in the wrong oil. Thanks again.

 

Follow the instruction sheet that comes with the engine. Make sure you install the oil pump pick up with the installing tool. (Available from Aut Zone as a loaner) I also installed a GM Goodwrench 4.3L Remanufactored Engine. I now have over 70K on it and it runs very solid. I also installed a GM Remanufactored Transmision as well. I have been very happy with both. When I installed my engine I also installed a new radiator, water pump, thermostat and fan clutch and transfered every thing else. When I started the engine I tore up the belt due to not having the power steering pump pulley on the shaft far enough and the belt was running crooked. Good luck with the install. By the way I run full synthetic as it helps with mileage and there are no impurities in the oil. (Personal Choice)