MB fluids questions (not engine oil thread)

[ktlimq]

MB ATF, MB differential oil, MB power steering fluid seem to be petroleum based products.
However, they are more expensive than the Mobil or Amsoil synthetics.
Why?

Are they better than synthetic?

What if I have put Mobil synthetic, but an MB dealer tops up with MB fluid?
Those synthetic fluids are compatible with conventional fluids, but mixing reduces performance benefit.

Synthetic engine oils leak more. Synthetic AFT leaks more too? A book tells me to live with small ATF leakage because the repair costs much. Currently, my tranny has no leak after 1k bucks repair at dealer.

By the way, how much more expensive are MB fluids at dealer than Febi fluids at online aftermarket retailer?

[Kestas]

I don't think any of those fluids are originally specified as synthetic for your car, with the exception that MB now recommends using synthetic for the pre-96 vehicles.

I don't know if the MB products are guaranteed to be synthetic if you buy them from the dealer and specify they are for your 92 300D. And if they are synthetic, I personally don't think they're significantly better than other synthetics available over the counter. Mobil and Amsoil make great products and they should work well in your car.

Any fluid (motor oil, ATF, diff) you buy for your 92 300D - regular or synthetic - should be okay for your car as long as it's the correct type (motor oil, ATF, diff) and viscosity. It should also mix with whatever you have in your vehicle with no ill effects.

I don't recommend mixing regular and synthetic in the same application... there's no harm done, but what's the point in doing that?

[yal]

Good answers Kestas!
But I fear this thread is only just getting started

[ktlimq]

A called a dealer parts department.

Powersteering fluid: $12 / liter
Coolant: $24 / gallon

Differential fluid: they do not sell MB differential fluid. A good 90 weight differential fluid would be OK for my car.

ATF: A good Dexron III approved ATF would be OK for my car.


By the way, is Amsoil AFT really Dexron III approved?
I am asking this because most of their engine oils are not API approved. They just recommend whether API ** is specified. Many of their oils are not approved by MB either. They just recommend their oil where MB Sheet 2**.* is specified. Such recommendations are determined by their additive supplier.

[Kestas]

I don't know how strongly you feel about synthetics, since this is a hot topic on any auto forum, but you can do better. I personally don't believe in using synthetics, unless an application specifically states to use synthetic fluid or if it's for the differential.

PS fluid - For that price, the dealer better be selling synthetic fluid. I use Valvoline ps fluid for $2/qt. If you want synthetic, you may get something cheaper from Amsoil or Mobil.

Coolant - The last time I bought MB coolant two years ago, it was $11 from the dealer. Has it doubled in price since then? Zerex G 05 is the same thing and is available from my local auto supply store for $9.

Diff fluid - Use a 90W fluid, preferably synthetic. I believe MB specifies 85W-90, which I hear is widely available in Europe, but not very popular in the US. An 80W-90 should do fine. Use synthetic because any extra you pay in price over the few quarts of regular fluid is made up in the incremental gain in fuel economy, which adds up over time.

Transmission fluid - I haven't done enough research on what you can and cannot use. An eight quart charge is a lot of fluid to pay for the premium of using synthetic. The choice is yours.

[lee polowczuk]

well, I went synthetic in the tranny...here's why.

I got 7 quarts of Mobile One for 4.99 qt.

7qts of Dexron III I think I could have bought for about 1.49 qt.

Difference in price is still substantial.

However, you leave the tranny fluid in for 30k miles....

I can't justify synthetic oil at the same price for 3k miles.

Also my car is a 1989..... I think if I had a newer Benz...say 1995 or above, I might do synthetic oil....

however.... i really like the 103 engine..... it's so easy to work on..

[ktlimq]

Mobil 1 Synthetic ATF?

I saw Mercedes Factory Approved Service Products September 2003. I cannot find Mobil 1 Synthetic ATF. On the other hand, I can find Valvoline ATF Type D, Quaker State Dexron III/Mercon, Pennzoil ATF D, Exxon Superflo ATF Dexron III, Castrol Dexron-III/Mercon, Chevron ATF Dexron III, etc. on that booklet.


By the way, can flash point of ATF be 60* C?
http://www.febi.com/medien/pdf/T-1093183260.pdf
Febi web site recommemds this ATF for my 1992 300D 2.5 turbodiesel.

[Kestas]

Just because a fluid isn't on the Approved Products List doesn't mean it won't work on that application. Not being included on the list can mean any number of things... maybe the manufacturer doesn't want to spend the money to be certified.... maybe the reason is political. I'm pretty sure M1 synthetic tranmission fluid can be used anywhere Dexron III is used in automatic transmissions (manual transmissions are a different story).

Lee, your math makes me rethink about using synthetic for MB transmissions. In the back of my mind I keep thinking about how most American cars need 12 qts to exchange the fluid. It's not so bad for MB transmissions.