Switching to syn oil?

[Vanilla Gorilla]

I've been using regular old dead dinosaurs for oil for the 90k miles I've put on this truck. I'm sure that's all it had before that, too.

Would there be any issues now if I were switch to syn? I like Mobil 1 for my bike, and I'd like to use it for the truck too, if I could. I'm wondering specifically about creating leaks that didn't exist before, things like that.

 

[Stresst]

I recently switched over to synthetic on this truck and it had over 100K miles. My regular stuff used to get dirty within a few short weeks only a few hundred miles. Totally not the case with the synthetic!

I think its an old wives tale about synthetic causing leaks. I heard it a 100 times but over the years many of my cars were used with high mileage I switched to synthetic on most and never had an issue.

 

[ChiTahoe]

No issues except better wear protection.
Myths Mobil 1

Valvoline Myths (Read through)

 

[19Yukon97]

i bought my truck with 150,000 and it had been using just the cheap castrol stuff. (have receipts from previous owner) i switched to mobil 1 synthetic the first day i bought the truck. i dont have any leaks at all. the only leak i have is the rear-main seal leak, which is always happeneing with these trucks... so i say go for it. better for the engine in my opinion... GL

 

[sparg93]

go for it - just watch for leaks!!

I have an '89 Mustang that lived on conventional and when I switched to syn, it leaked. I switched back to conventional, no more leaks.

It's all about your vehicle and how it responds to the new oil...for some it works great, others just need to switch back.

The only thing i would be cognisant of, can syn ********* some of the goo that has sealed itself around the seals...essentially causing a leak that cannot be sealed by switching back to conventional. I've heard from some it can, others feel different...that part might be an old wives tale, but where there's smoke, there can be fire. (sorry I have no scientific insight for you on that one)

 

[Dalton916]

i bought my truck with 150,000 and it had been using just the cheap castrol stuff. (have receipts from previous owner) i switched to mobil 1 synthetic the first day i bought the truck. i dont have any leaks at all. the only leak i have is the rear-main seal leak, which is always happeneing with these trucks... so i say go for it. better for the engine in my opinion... GL

Never known one to leak on these trucks.....if it's 4wd check the bracket for the oil filter for your leak. Big filter used on 2WD won't fit so an angled bracket is used to turn the filter 90°. The bracket will leak at the block connection and where it shows up will make you think it's the rear main.

 

[yukon2004]

I bought my Yukon in December with ~105k miles on it. I have no idea what kind of oil was in it before, but when I did my first oil change, I switched to AMSOIL. I used this to flush everything out first:

Then filled up with this:

I'm at almost 112k now, and my oil still looks good and have no leaks!

---------- Post added at 07:07 PM ---------- Previous post was at 06:51 PM ----------

I used this before on an F-350 with high mileage, no problems...

 

[arctic388]

I switched to AMSOIL in mine at 211K over 220K now and no leaks.

I did not use any engine flush.

 

[gfb007]

Caused leaks on mine

Bought an 01' Yukon XL with 120k miles. Changed oil at 123k miles regular oil at Firestone. Speaking to my mechanic friend and he recommended I use Seafoam in the oil and then put in Synthetic. Ran the Seafoam and then put in Synthetic. Started leaking right away. Spent $600 on oil pan gasket, rear main seal, rear cover seal, rear cover gasket, and labor. Synthetic works better though and my motor will last alot longer.

 

[gpracer1]

Switched a long time ago on my 93 TBI with about 90k on it, started leaking then quit after about 5k or so miles.

Switched my 99 and it started a very small leak, hope it quits soon.

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