I just had my 2001 4.7 heads machined after overheating them...had a lifter pop-off...when is the recommended mileage to change the oil?? had a friend tell me NO synthetic oil because of sludge build-up..only Valvoline 10w-30!
My truck has 120K on it.

 

about every 3k miles.

 

Whoever told you NOT to use synthetic is not very smart.

Use synthetic oil, it's better. I use only synthetic and change my oil every 5k miles.

 

Running full syn oil is good at your mileage. I run valvoline syn blend and I started at 75k at 91k now and my engine loves it. With new heads im not actually sure but I would change it a little bit earlier than normal like 1,500-2k. Im more used to doing it that way in atvs but im sure truck is way different im curious to what actually is the right time

 

i would change it around 2k a few times right after then go to 3k just to make sure you dont get any dirt or metal from the new heads in your oil. but me personaly i do not like full syn oil. i used it one time in my truck and about 1500 miles later my oil pres was low and when i changed it the oil ran out just like water.

 

using syn helps prevent sludge and the oil doesn't break down as fast

 

well if you seen how black my oil was you would think diff. and it was just like water runnin out my pan lol

 

I know you're not suppose to run synthetic in brand new engines until about 10k miles, I'm not sure if this includes new heads as well though. Honestly you don't need synthetic either way. It's more expensive and for your daily driver Dakota you're not going to see a big difference and since it already has 120k miles on it, I would say run a synthetic blend like durablend or synblend from Castrol if you want something a little better than dino oil but I think just straight conventional will be fine for now and for the duration of the vehicle.

Just my $.02 though.

 

if its black then its probably the detergents in the oil cleaning the sludge and grime out of the engine. it runnig out like water i have no response except to use thicker oil. i use full syn and change it every 3,000 miles and never had a problem

 

If your using full syn you dont need to change it every 3k my dad does his in his jeep every 8k cause he used full syn they say up to 15k. I use syn blend and change mine about every 3,500