I didn't mention oil consumption in my last post, but that is because there is no difference. There is no need to add any between changes. FWIW, I changed it over at 183k miles which I'm pretty sure up until then it ran on Castrol 15w40 (most records show this) which I guess is OK. (eBay definition, it works but could be better) :rolleyes:

84 300D, Delo 400 5w40 synthetic in motor, Mobil 1 atf in trans and PS, Mobil 1 in rear diff. 93 C2500 6.5TD, Delo 400 5w40 synthetic in motor, Amsoil 75-90 in tranny, Mobil 1 atf in PS and Mobil 1 in rear diff. 89 VW Jetta 1.6l NA diesel, Delo 400 5w40 synthetic in motor, Royal Purple GL4 lube in transaxle and Mobil 1 atf in PS. No trouble with any of them. Choose a good quality synthetic and don't worry about it. RT

Synthetic Oils
 

Most people think that the best reason to use Synthetic Oils is the extended mileage between oil changes - it isn't. The #1 advantage of Synthetics is their 'film' qualities which allows them to keep an oil film on bearing surfaces and cylinder walls etc. rather than just draining back to the oil pan over time. This dramatically reduces friction wear during initial engine starts. Even if you do change your Dino oil every 3k or less, you cannot duplicate the friction-reducing advantages of synthetics.

Synthetic oils were first developed for cold climate applications where Dino Oils were so 'thick' due to the sub-zero temperatures, you were lucky if the engine would turn over. Under these conditions there was little or no lubrication during cold start-ups so engine wear was very rapid. Synthetics not only flow easily in cold temperatures (another reason to use if you live in colder regions) but the ability to keep the oil film on the metal surfaces really helps reduce wear and aid starting.

Obviously these same qualities will benefit Transmission and Diff's as well.

Andy :)

Here is an interesting oil study.

http://neptune.spacebears.com/cars/stories/oil-life.html

Note that Chevron Delo 400 is a dino oil and not a synthetic. Very good dino oil, though. :p

Well after working on my term report (on bypass filters, maybe I'll post it online here when I'm done too) for tribology (lubrication, friction, and wear) for the past few hours I checked my email to find this. I can't help but find irony in that.... :)

Goldenbear/Chris
You may not be aware but Chevron does in fact make a SYNTHETIC Delo 400 5w-40.... This is not the regular dino Delo. RT

FYI
 

Mobil Delvac 1 is now available at Wal-Mart under the name Mobil 1 Truck & SUV Oil. The price is $4.77 per quart.

I just picked up the last 8 quarts that my Wal-Mart had... time for an oil change. :cool:

The Delo Synthetic is a class III oil as any good dino oil, Mobil Synthetic is a class IV oil. Do the search on the internet for the difference. It is a big differance. That being said, Delo Syn is a good quality oil and will serve you well. It's just that the Class IV synthetic is better for certian applications. I seen many 55 gal drums of Mobil 1 sent to gas turbine US Navy ships over the years.

Synthetic oil was developed by the germans durring WWII for use in the jet engine and further use in all engines do to lack of oil in Germany. Allied jet engines durring this time frame had 30 to 45 minute life span before rebuilding due to lack of synthetic oil. It was about high film strength to protect bearings at 25,000 rpm, and extreme heat range (hot & cold) and a few other minor things. To put it in simple words, no synthetic oil, no jet planes.

Class III or class IV is irrelevant in my case. Since I am not going for extended drain intervals, the Mobil 1 is overkill. I only use the synthetic Delo to ease starting in winter. Put a quart of dino and a quart of Delo synthetic outside overnight in winter and then do a side by side pour test. The Delo synthetic pours much easier, almost like a summer day. Not arguing that the Mobil isn't a superior oil, it is, just double the cost. RT

I think I kind of said that between the lines. It's is all about what meets your needs and leaves you with peace of mind. :cool:

I don't drive that much since I've retired and a 5000 to 7000 mile oil change with high dollar Mobil Delvac 1 is no big deal once a year for me. If I was doing 3000 mile oil changes every 2 or 3 months, I would probably be doing the same that you are. However if you do the use the class IV oil and are able to safely go 2 or 3 times the distance between oil changes then it can even become cheaper to use then a Class III oil. I've never done a 3000 mile oil change on any of my cars in the 30 years I've neen using synthetic oil (Mobil 1) and all have been taken past 150,000 mile with ease. :D Usually I would do 7000 miles before changing the oil, except the '81 Datsun truck which would normally get 10,000 mile oil changes. That truck was well past 200,000 miles and had no oil leaks.

Accusump Pre-Oiler
 

Just curious. Has anybody used a Pre-Oiler system in any of their cars?

A friend with a Porsche 944 race car has an Accusump system fitted primarily to reduce engine damage in the event of a severe oil pressure loss. The system does however have a Pre-Oiler feature which raises the engine oil pressure to normal levels before the key is turned.

He says it is amazing, the starter only has to move the flywheel a very small distance before the engine fires up due to the lack of friction. No churning hot or cold.

Andy

I have gave it a little thought before but never tried anything because I don't want a check valve killing the flow in the lines. Here is a link on a person doing it to a Dodge Ram Cummins turbo diesel.

The distance the starter has to turn it before starting should be the same on a gasser, perhaps if it is cold it could change on a diesel but for the most part this wouldn't change. What would change is the starter could spin the motor faster and with less wear on the starter. Any good synthetic oil should leave a film on the moving parts for at least several days if not longer. (anybody know how long?!)

RT,

Thank you for correcting my erroneous assumption.

Ok, I'm most likely going to change from dino oil to synthetic. I think I read it correctly. After I change from dino to synthetic, I should replace the oil filter 1000 miles after the oil change to synthetic was done, and then every 6000 or so miles afterwards. Correct?
-Joe