Synthetics and Seals

[2003TRD]

Has anyone ever had a problem running synthetic oil for thousands upon thousands of miles? I ask because someone on here was saying that dino oil makes seals swell, while synthetics, I think maybe RL esters cause them to shrink, make them less pliable, or something along those lines??? So would it be healthier for your engine to occasionally run a short dino OCI once a year for the seals? Or am I being overly concerned....

 

[Chris Meutsch]

I've been running Amsoil 0w-30 for 46k in my '01 Honda Civic and the ground below the engine AND transmission (Amsoil ATF) is dry every morning. No leaks as of yet. We'll see if that is the case in another 45k but so far, so good.

 

[ARB1977]

Ive been running full synthetics (Redline 45K) and Amsoil 13K) and havent had one leak.

 

[doctormdds]

I've run Mobil 1 in my 2001 Sequoia since 12,000 miles. I now have over 100,000 miles and there are NO leaks whatsoever. I also have Mobil 1 ATF and Mobil 1 gear oil in the rear end. All have no leaks.

 

[Steve S]

The syns on the market are additized for the proper seal swell.

 

[Rodbuckler]

It is mainly a problem with Mobil 1 in my experience. If I start an engine with M1 or a M1 - dino blend, the engine never leaks even at high mileage. I can switch between a M1 blend and straight M1 with no problem in these engines.

But I have never been successful in using M1 in a higher mileage engine that wasn't raised on M1. They always leak, or at least stink, because the gasket and seals don't seem to stay tight. I have just started using Pennzoil Platinum in a high mileage engine that wouldn't hold M1. So far the PP is staying in just fine.

 

[GoldenRod]

From what I gather, it's the esters that cause seals to swell; and the PAO's have the oposite effect. Oil companies try to find a delicate balance between the two in order to prevent seal damage.

 

[m2200b]

What year , model and current mileage are you considering this conversion for ? three year old toyota truck? no problem.

 

[wn1998]

I must be the exception! I didn't start running synthetic in my wife's 97 Cavalier until after we were dating for 2 years. The car had about 120,000 miles on it when I did two auto rx treatments. At 127,000 miles I added my first fill of M1 5w30. The car now has 161k with no leaks and it doesn't burn a drop.

 

[abimanyu]

I live in hot humid tropic and been using full synthetic 5w30 and many people say this is too thin? My 2003 Corolla has 31,000 miles in it. Should I go thicker? I'm reluctant to change the oil brand(Igol) and type because it's been great so far, no oil consumption or leaks whatsoever. And great gas mileage too! But I notice there's more noise coming out of the engine when the engine is warm/hot. But I read somewhere in BITOG to not judge oil by the engine noise?It seems quiter when I was using 5w40 from the same brand.

"If it ain't broke don't fix it?"

What should I do? My next oil change is next week. Should I go back to 5w40 or 10w30?

Thanks

 

[pbm]

Originally posted by abimanyu:
"If it ain't broke don't fix it?"

What should I do? My next oil change is next week. Should I go back to 5w40 or 10w30?

If the owners manual says 5w30 is OK for your climate I would stick with it. 10w30 full synthetic should also be good in the tropics. I recently read a GM engineers article that said thin oil doesn't cause wear and I'm beginning to think that its best to use the thinnest oil that your manual allows.

 

[surfstar]

I bought my car with 81k miles (some consider that high - just broken in to me) and switched to M1 the first oil change. It now has 187k miles, no noticeable leaks, and doesn't consume oil between changes.

I think you're being overly concerned.

 

[IslaVistaMan]

It is indeed best to use the thinnest oil your engine (read: owner's manual) will allow -- and even thinner in many cases.

 

[Wasatch]

Just did my first OCI with M1 (5w30) at 101,000 been using Motorcraft dino 5w30 before, so far so good.

 

[BrianWC]

Never had synthetic cause a leak in a seal...

 

[RichR]

I remember reading on a maillist(remember those?) a few years back to add a quart of dino to synth for seal swelling/anti-leakage.
How is this thought of members??

 

[Rodbuckler]

quote:

---

Originally posted by RichR:
add a quart of dino to synth for seal swelling/anti-leakage.

---

My general rule until recently was to never use a crankcase full of dino without a quart or two of M1 mixed in for added protection and cleaning. And I stuck to the converse as well: Never use a crankcase full of M1 without a quart or two of dino thrown in to get control of the parts set noise, and chase the M1 through the gaskets that weren't used to it.

 

[hounddog]

Changed a 82k Chevy 305 to Amsoil 10w30 full syn and sold car with 252k and ONE set of valve cover gaskets.Also changed oil every 25k with filters at 7500 and top offs.No issues.