Rotella Syn and Seals

[Ironhorseman]

Does anyone here have an opinion on how Rotella Synthetic would be on the seals of a higher mileage engine that has always seen 10W-30 dino. This is a '94 5.4L GM gas engine.

Thanks

 

[pooter WS6]

Shouldn't be a problem, but my question is, did GM make a 5.4 liter in 94? GM has never made a 5.4 liter, that I know of. Are you sure its a GM and if it is, maybe it is a 5.7 litre/350 cu in.? Ford has a 5.4 litre, but I don't think they had it in 94. Just curious. As far as oil, Rotella should do great in the engine. As far as seals go, there is always a worry with synthetic and old seals. If the seals are in rather good shape no problem should take place. If you have seals that are semi bad, synthetic will usually find them and leak a little. Good Luck

 

[Ironhorseman]

Yea, that was a typo. Dang 4 and 7 are too close together on the number pad I guess (He who can't dance blames the floor) I guess I should review my posts before adding them.

Thanks

 

[Blue99]

As Pooter pointed out,this question always relates to the current condition of the seals & how dirty the engine is. If sludge is present, the cleaning tendencies of the HDEO may loosen it up & cause some minor short term leaks.

Rotella 5W-40 synthetic is a GRP III and does not generate seal issues like the PAO based HDEO's & PCMO's. GRP III's may need some additive help to generate seal swell, but not as much as a PAO, and performance is closer to a dino.

Several used oil analysis's are posted in the UOA forum. Take a look at this one by MNGopher:

Rotella 5W-40 in F-150

 

[Andy H]

Ironhorseman,

The varnishes that form when petroleum gets hot coat the insides of the seals. This layer keeps the seal conditioners in oil from keeping the seals swollen shut. Sometimes old seals will crack, and these cracks can be filled with sludge and varnish from the oil.

Using a diesel oil with it's extra detergents, or using a synthetic or blend (because of the syn's natural cleaning ability), or using an engine flush, can remove the varnish layer and allow the seal conditioners in. These can also remove the sludge that's plugging the cracks.

Running a flush, or a short drain of a synth blend, might expose some slight leaks initially. Often, tho, they leak will stop for good once the seal conditioners get in the seals swell shut.

It's a pretty common practice in farm country to clean engines with a diesel oil. In parts of the Far East, engines are filled and run with biodiesel as a flush.

Andy

 

[Jelly]

quote:

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Originally posted by Andy H:
It's a pretty common practice in farm country to clean engines with a diesel oil.

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Well, guess that finally explains why I grew up running Chevron Delo in everything and have witnessed with my very own two eyes how clean a low-dollar convetional HDEO keeps a gas engine while all the "city folks" on here will tell you how bad it is...

Ironhorseman,

Since you're in Texas, and driving a 350 Chevy, start out right now with Mobil Delvac 1300 and a AcDelco filter. Run this "combo" for a good, long while...

Later on, switch to Rotella 5w-40 if you so desire.

 

[Hirev]

quote:

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Originally posted by Ironhorseman:
Does anyone here have an opinion on how Rotella Synthetic would be on the seals of a higher mileage engine that has always seen 10W-30 dino. This is a '94 5.4L GM gas engine.

Thanks

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It won't be any better or any worse as the 10w 30. Because Rotella Synthetic is not a true PAO or ester synthetic. Group I,II,III, and Group IV base oils all use some seal swell conditioners.