Friends Mustang...
 

His Mustang is over 100,000 miles and is starting to get tired. Already up to 15W40 to keep the oil in hte pan instead of past the rings, etc. Also to keep from having it leak out the pan. Anyways, my friend is going to be having his pan changed. Until then, his dad recommended and filled his engine up with straight 30-weight oil to stop it from leaking. This is in Iowa. He drives home every weekend to Illinois (3 hour drive, 6 hour round trip), but I"m worried about while h's here. He doesn't even really let his car warm up. What's going to happen to his engine. I asked him to at least let it get warmed up a little bit - even just letting it high idle itself until it wants to idle at regular speed...

...And when I raised my concerns about his engine on the 30-weight diet with temperatures as they are (teens at night quite often..), he simply stated that his dad said it was perfectly fine.

What's the pour point of 30 weight? Isn't it like 12 or 15 degree's? Also...when he starts up his car in the morning, is the oil not like a literal sludge? I'm just worried. He plans on rebuilding the engine..but not for a while yet. What's you guy's opinion?

This is a 94 Mustang 302 automatic. Thanks....kinda upset me that he just brushed off my concerns so lightly - he doesn't know alot about oil except if it's smoking oil go to a higher viscosity.

I would have stayed with the 15w40. That 30 weight WILL be like pancake syrup in the morning. Guaranteed. I think I read in the manual for my Briggs and Stratton power washer not to use 30 weight below 60 degrees F. Different engine, but it should be an indication.

Ick, 30 wt bad idea, I bet that motor turns pretty hard even for 20 F.

5-40, or a 10-40 would have been much better choices.

Sounds like a rebuild is the only "real" solution.

If the motor is tired to the point where he feels he has to put in straight 30W oil to keep it all together, then it's obviously on borrowed time. The 30W oil is probably making the bearings wince everytime he starts the car in the morning. He really needs to change his strategy, if you ask me.

For example, why not just throw in a bottle of Lucas in with some 10W-30 oil? I think the general consensus around here is that Lucas is really nothing more than a "heavy" weight oil anyway, with a few additives. At least with the Lucas and 10W-30 mix he can maintain some kind of viscosity range. Has to be better than straight 30W, in any case.

20W-50 would be the next step up from 15W-40. It is still rated to crank and pump down to about 10F. Castrol puts a warning on bottles of 30 not to use it below 40F. I did a "freezer test" on Coastal non-detergent 30. It was a rubber-like solid at 0F.

Jim

He has 30 Weight AND some (not sure how much) Lucas's in the engine.

His dad had him put it in to "keep the pan from seeping anymore till it was fixed". Hopefully it is fixed this weekend...if it isn't I'm tempted to go buy him some cheap oil and change his oil lol.

It's not tired enough to need the 30 weight. It's "half way through 15W40" as I say, its been on it a while and its still got a ways to go, but he's still going through about a quart between changes. With the pan leaking, he's going through a quart every drive home and then another one on the way back. A reason his dad threw the 30wt in there.

That's what I told him...that at freezing temperatures it was going ot be basically a solid. He wouldn't even listen to me to at least let it warm itself up a little bit! All cause his dad knows what he's talking about, and not me. =( I feel bad for his engine.

I think I'll go buy some 30 wt at O'rielly's and put it in his freezer. And when he gets back, if hte pan isn't fixed...go and (try to) pour it in a bowl. I don't doubt his dad knows things..his dad does do engines and all that, but still...this is silly.

Sad story, especially since the 15-40 is the heavier oil!

Not when its cold!

True, but I'd be willing to bet that most of the oil leaks out the pan seal when the motor is running, not when it is parked, therefore the 15-40 would slow the leaking more than a 30wt.

Very true. I thought we were talking about oil flow to protect the engine. Point taken. :-X22