160K - Bad idea to change to synthetic oil?

I'm buying a 1 owner (owned by my Sister), 2wd 2004 Tacoma Xtracabthat's in mint condition that's been maintained by my local Toyota dealer since it was new. (As a side note, she's going to sell it to me for $3,000 - which seems like a good price?)

I like Mobil 1 oil and I'd like to switch to that brand in hopes, of course, of having the motor last as long as possible.

When I called Mobil 1 and asked for a recommendation, they suggested "Mobil 1 High Mileage" because it ..."contains seal conditioner to help prevent leaks." - http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_High_Mileage_5W-30.aspx

Mobil 1 said they suspect the dealer uses mediocre oil (even though it's been changed by the book). They said if you switch to Mobil 1, if there IS any sludge, etc. deposits around the seals...the synthetic oil might clean that away and the truck might start to develop leaks!

What do you guys think?

Ed

 

Not a recommendation - just my own experience.
I bought a 2001 V6 with 155K. Well maintained with regular oil changes.
I changed to Mobil1 5w-30 just because I use it in everything else I own.
One year later and I have seen no adverse effects or oil leaks. Starts right up at -6* here in the east. FWIW

 

Good deal, I switched to synthetic after buying my truck (135k) idk what the PO ran. Seems to be OK lol

 

I'm no expert but I dont see how it would make anything worse and IMO it would be better for the engine.

 

Welcome to TW, Ed!

Like others, I see no downside to switching. I've also done so on a couple of "well-worn" vehicles with NO ill effects.

 

I was thinking about doing the same thing to my Tacoma but someone told me that switching to synthetic can break up sludge that has built up. They said that the sludge could mess up the engine and also eat away at old oil fittings. Don't take my word that's just what I was told

 

Dealer maintained doesn't mean squat. Take a look under the oil cap. You can see part of the head, if you see silver looking metal your good, goldish color means varnish...not bad, could use a little clean up. If it's black tar looking you've got more issues than what's worth. It can be cleaned up but do it slowly. Over cleaning it could clog the pickup screen which could starve the engine of oil. I would go with a blend for a couple of changes, maybe 2000 miles between changes along with filter. After that use what ever you want.