Charles,

Somehow I knew it would not be simple. :)

" This also includes changing the oil too often. Against conventional wisdom, engine wear decreases as oil ages to a certain extent, which means that changing your oil more frequently actually causes engine wear; these findings were substantiated by studies conducted by the auto manufacturers and petroleum companies"

How does this work then ? Are we actually doing more harm than good with our very frequent oil changes ?

Whats too often ?

What's too often. There are some guys with 356's that believe you should change the oil every 500-1000 mi. That's frequent.

You should also consider the volume of oil a given vehicle takes in determining drain intervals as well as driving habits and average oil temperatures. GM has one of the best oil useage indicators around - from my reading, the computer's indication of time to change the oil is right on par with what the analysis shows for that oil. Your actual mileage may vary :-)

Is the indicator a sensor in the oil flow?

I know MB used to have something like that - not sure how it workd (capitance changes?) but it supposedly measured the buildup of chemical contaminants. No idea re abrasives, or depletion of additives...

To be honest, I'm not sure. I would assume it would take driving conditions into consideration when estimated oil life. I guess it's time to hit up google for more info.

So, if I'm using Kendall GT-1 (20w-50), 2-4 oz of EOS (every oil change?) is the way to go? I have a labrador and no cat :)!

Bring this back since it should be seen by all......

Any thoughts on Chevron Delo 400 vs Shell Rotella?

In my engine I use Shell Rotella T 15W-40 and I also try to not start it below say 40-45 degrees. I think Rotella has just about everything well in specification. Correct me if I am wrong.

My dad used delo 400 in all of his heavy duty marine diesels since as far back as I can remember, never a failure. No empiracal data, but a point just the same.

Cheers

I have a new to me 1970 T with the stock motor. Up until now I have pretty much run exclusively Mobil 1 products in my cars but they were all modern water cooled vehicles.

What do the experts recommend for my car given that it will never see temps below 35 degrees?

Is the Castrol High Mileage the way to go? Should I risk the leaks and run M1 15W50? I have changed over quite a few high mileage cars (obviously a lot newer models) and not had any leakage problems, even using 0W-40.

From what this thread and the thread on Rennlist said, Castrol beware. Mobil 1 is supposed to be some of the best, but to switch to it might cause leaks, some say. But if you are already using it and have no leaks, then keep using it, I say. I know Steve W likes Mobil 1, but not 0w40. He likes 15w50 and recommended to me for my 993. But for my 81SC he recommended Valvoline VR1 20w50 with 2 ounces of GM EOS assembly lubricant added. It is expensive, but not as much as Mobil 1.

I have also read up on Rotella T 15w40. It is what the AERA group (engine builders group) recommends for camshaft break in, because it is a diesel engine oil that has alot of Zinc and Phosphorus (ZDDP). It is very cheap too because it is marketed to truckers, but good stuff they say. I just put in new cams and I'll use Rotella to break em in.

The AMSOIL Series 2000 Synthetic 20W-50 Racing Oil that I use in my 911 has 1675ppm Zinc (ZDDP) and 1380ppm Phosphorus. Additionally, the base stock is a true Group 4 synthetic - 100% PAO.

Ok. Could someone please give me the bottom line? I have a 73.5 T new to me. No CAT. I just did the valve adjustment and am ready to put new oil in. It was not running synthetic oil before.

What oil - brand and weight should I put in? And, what additive, if any?

I live in VT - and rarely will drive in winter.

Thanks

Brad

This question is like asking if you want Andy Roddick or Roger Federer as your doubles partner for the club championship. Federer is the better player but either is going to be overkill in that situation.

Put any quality petroleum (non-synthetic) 20-50 oil in, change it every 3,000 miles and you'll be fine. All of todays quality oils are way better that what Porsche was recommending in 1973. Stop worrying and drive!

Thanks David.

you will be better off w/ Mobil One than a non-synthetic.

use the wt. that the manual says to use

Randy,

What about all this stuff I have read about how synthetics leak?

Brad

According to the tech talk section of aircooled.net synthetics leaking more than petroleum is mostly a myth.
Like you, I've heard many stories about synthetic oil leaking. Because of this, and the fact that my engine has the original seals, I've only used non-synthetics. If you decide to go the synthetic route, please post your findings.

Randy, the '73 manual calls for staight 30 weight "premium HD oil." A quality 30 weight is very hard to find these days! Since Brad says he doesn't drive much in the winter, I think a 20-50 will be appropriate for his summer driving - especially if he drives the car the way it was designed. :D

This is an inaccurate statement. The oils of today have way less ZDDP in it. That is better for catalytic converters, but not good for cams and rockers.

Earlier you asked for the bottom line. IMO with your 1973 I would put in Valvoline VR-1 20w50. Probably 3 bucks a quart.