4.0 V6 conventional to synthetic oil change at 150k miles

Hey, sort of a 2nd gen question. I recently got a 2007 4-runner with the 4.0 V6, similar to a 2nd gen Tacoma from my original owner dad. He religiously changed the oil every 3k miles with conventional oil. I don’t know why; he’s old school. It’s a solid 18 year old 4-runner I know the history on that was friends and family priced. I’m inclined to switch to synthetic. Is there any reason not to?….detergents or seals or some scientific mumbo jumbo above my brain power.

I’m not looking to start a never ending “my brand is better than your brand” thread. I’m just curious if the switch from conventional to synthetic could have some negative effect. I’d ask in a 4-runner forum, but I don’t want to deal with that and the knowledge and sarcasm is strong on TW. I’m keeping my 3rd gen Tacoma.

 

Let's keep it simple.
There is no reason not too.

End Thread/ (wishful thinking)

 

Not so fast. Let's light this on fire: will switching to synthetic oil harm the PCV valve?

 

Only one way to find out.
And it's not by asking us fine folks on the internet......

 

Both oils meet spec, either is fine on their own mixed or alternating. This is what API, etc.. standards exist for.

 

In the beginning, when Mobil 1 first hit the streets, there was talk of leaking seals and that may have been so. Now that condition is in the past.

 

I switched at 125K when I bought my '06. A "High Mileage" synthetic is suppose to have additives to keep seals from leaking. Now at 180k and never had any leaking issues and oil changes are always clean.

 

The only potential issue that I am aware of is that synthetic oils may help clean out some of the residual waxy deposits that conventional oil may have left behind.

 

Did a synthetic oil change at 170k. Not sure what the PO used, but oil is oil. These engines will run off vegetable oil and wishful thinking, you'll be fine.

 

No problem at all. I switched to Costco synthetic oil on my 2007 4Runner V6. There were probably some intervals where I didn't have it on hand and just said screw it and went conventional.

 

I don't see how. Only potential issue I see is the remote possibility of seal seepage or oil burning. But the positives of synthetic oil (like API SN+) far outweigh that risk. I've only run quality synthetic oils since brand new. The engine does not burn a drop and runs better than new after 181K miles.

 

In the scenario you presented above and along with the 3k oil maintenance history of the previous owner, the answer to your question is simple: "No"

 

Change to synthetic every 5000 miles now. All will be right as rain.

 

Thanks all, I ended up changing my mind. I’m just going to use bananas. Better for the environment and all that… https://www.youtube.com/watch?v=v5TzpLBfP2Y

 

Send itttttt

 

I don’t think it will have any negative effect just more expensive.I run synthetic in my Tacoma no issues.

 

U guys recommend doing ur own oil or taking to dealer? Pros n cons

 

I personally do all my work on my trucks no one cares as much about your truck as you. The dealer can make mistakes and also expensive just use an oem filter and any quality synthetic oil.

 

I did the same thing at 145K when I brought this truck. Because I am old school, I change the oil about every six months or 5K miles.

 

use 5w30 synthetic which is the weight it calls for. I used conventional pennzoil 5w30 in my 08 4runner every 4K miles. No problem switching to synthetic, I just wouldnt use 0w20 which is what majority of vehicles get now (my 2013 5 lug tacoma included)