Oil Viscocity Opinion

[Hodge]

Sooooo....

I use Castrol GTX High Mileage 20W-50 in my 95 M42B18 and have since I have owned the car, and also still even after throwing the DASC on. Engine has right around 160,000 original miles.

I live in Florida, so temps stay above 30*F and it's mostly hot and muggy here.

What would you all recommend as what I should put into the engine next time I change the oil?

1) Stay with GTX 20W-50
2) Swtich to a blended Synthetic
3) Switch to full Synthetic (probably Redline 10W-40?)

BTW< car runs mostly cool now, and really the only reason I am asking this is because my friend is bugging the hell out of me to change to full synthetic.

[iamcreepingdeath]

you have a DASC???   link me to pics and vids, and please tell me your experience with your DASC, sorry to thread jack, i'll be searching your posts shortly....

[Hodge]

Will link later...but yes I put it in back in March of this year.

It's great. Definitely worth every penny. The kit is very well put together and the fit is perfect (minus the dipstick, mine didn't line up with the intake elbow so I found other means )

The only thing I have had to replace so far were two vacuum hoses that were a little too short and they started to crack on the ends. There goes $2

Plus, the sound of the blower is the sweetest noise...yummy. Makes me smile evertime I hear it

[wannam42]

Simple answer: Stick to Castrol GTX and change every 3,000 miles. Ignore your friend. I'd personally recommend Chevron Delo 400 Multigrade 15W-40. It's the best bang for the buck out there period.

Long-winded answer:

If you're looking for *slight* increase in fuel economy, you could switch to 5W-40 or even 0W-40 (not available in dino oil version). 50 is "thicker" than 40 at operating temp and you only need that level of protection (even 60) if you're keeping the revs up for long periods of time like in race conditions. 40 is ok for occasional and brief trips to the redline

If you plan on going for extended drain intervals (>5,000 miles), switch to synthetic. If you change sooner while using synthetics, you're just throwing good money away.

If you're going synthetic, go for the lowest winter grade so that oil flows faster and gets to the parts quicker during a cold start. 0W- is the lowest you can go. 5W- is ok too. Forget 10W- (typically 10W-40) - you might as well go dino with 15W-40.

[Hodge]

Thanks....

Don't worry, I planned to ignore him anyway...at least while on the stock build of the motor. Whenever (if ever) I get a rebuild, than I will have a more appropriate viscocity.


Good advice....most M42 people should look at this post.

[stangimon]

Speaking of money. I use the cheapest oil. Epi rating same. 8 bucks 5 qt. change it often
Dickie

[eric16v]

Has anyone used Rotella t syn. 5-40 for their stock m42? any opinions? Its like $20 for the big jug.

[AcSchnitzer318is]

^I used it for 1 change before turbo.  Worked fine.  Didn't notice any performance change or cooling change over my old trusty mobil 1 0w40.  Have to switch now with the turbo to something like 15w40 as per the other guys suggestions on here.

[tjts1]

Has anyone used Rotella t syn. 5-40 for their stock m42? any opinions? Its like $20 for the big jug.

I've been using it for 3 years now since i got the car. I change it every 7k or so miles. I've never had a problem. The car is coming up on 170k miles. Can't beat $19/gallon at wally world.

[1991 E30 M42]

I've been using the Rotella T Synthetic in everything for the past two years.I have been using the 5-40 in the stock E30 and couldn't be happier, the only car that doesn't get it is the E30 with the built engine, it gets Mobil1 or Royal Purple 5-30 or 10-30