Any opinions on Amsoil oil?

[zachv]

I am looking to change my oil to Amsoil 100% synthetic oil on my '85 300 D. I am aware that the seals may leak a little, but the added advantage of less wear and possibly better mileage are worth it. I am primarily concerned about the turbo bearings. Any opinions?

[Benzmac]

I am in the opinion of, if it isn't broke, don't fix it. I have seen these engines run for 300k plus on regular oil (the oil they were designed for). Why not stick with it.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

[fz500sel]

I totally agree with Benzmac. From everything I've heard and read, using synthetic oil is great but AS LONG AS IT'S BEEN USED SINCE DAY ONE. As Benzmac has said "if it aint broke, doan fix it"!


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FrankieZ
84 500SEL EURO 87K
85 300DT 267K (not my miles tho)

I kind of wonder why you guys would not be a strong advocate of synthetic. It is much cleaner. Checked my oil after 3,000 (synthetic) still clean as pancake syrup. Check it after 3,000 (regular) dirty as tar.

Isn't the syntetic better for any car?

However, I can certainly see your opinion on don't fix what aint broke. What about the 2000 models, do they get synthetic?

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'89 420 SEL
'90 300 SEL
'84 300 SD (sold it)

[Bill Wood]

I'm not a tech but, here's my cut at your question...

There is no issue with synthetic oil per se. It is better than dinosaur oil in almost every respect (except cost). The issue is switching a car over to synthetic after it has used dino oil all of its life.
Over time, dino oil tends to build up deposits in the cracks and crevices inside the engine. These deposits act like "false seals". When you switch to synthetic these false seals are removed which often causes oil leaks at the gaskets. This creates a costly problem that would have never occurred if the car remained on dino oil.

When Benzmac rebuilt his 190E 2.3 16V he switched to Mobil 1 and said that was all he would ever use in it. He would not have switched if he had not just replaced every gasket in the engine.

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Bill Wood - Webmaster
MercedesShop.com, LLC

Folks,

This discussion has been way too tame. Time to throw some gasoline on the fire.

Here is the "devils advocate" thought: Since one of the main functions of motor oil additives is to clean the inside of the engine, is it really a good thing when the oil stays perfectly clean. Of course, oil staying clean is an indication that everything is well with the innards, however, if one oil in the same engine stays cleaner than another, is that really a good thing?

I suppose that it would be possible for one oil to cause some sort of reaction that would cause it to be dirtier than another.

Don't get me wrong, I'm not an opponent of synthetic oil. But I've always taken the trail of changing the oil twice as often with an oil that costs half as much. When I take apart one of my engines, it is always very clean inside. It seems to work for me. And I'm sure that synthetic is working just as well or better for others.

My $0.02,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Amsoil is made in Superior, Wisconsin, so we hear quite a bit about them here in MN. Their sales pitch is a little smarmy, but it is a good product. I'd say no better, no worse than Mobil 1.

I've used both brands and changed oil, gearbox and differential fluids when I've purchased cars with anywhere from 20K-60K miles them. The cars previously had used petroleum products and I have had no seal leaks with the switches to synthetic. However, I have heard similar stories like Mr. Wood has mentioned. I'd be curious to know what percentage of folks who switch to synthetic have seal problems.

[Aaron]

My 745i has had Amsoil synthetic used in it for quite some time. When I bought it from the original owner, I switched to Mobil 1 10W-30 synthetic and find it works equally as well, I just prefer the Mobil brand to Amsoil.

On another note, I switched over to Mobil 1 synthetic (10W-30) in my 380SE right after doing the new chain and new rails and tensioner at 110K miles. We left for our trip to Atlanta the next day, loaded down with luggage and four people. When we got back to Ohio, I checked the oil again and found it had used about a quart. It had never used any dino oil before. We've owned it since it was new, however this is the first long trip it's ever been used for, and I think that with all that weight running at a constant 90+mph for a total of 1,600 miles, it would tend to use some oil, so I'm not all that concerned. In addition, I did notice a great improvement in fuel economy. We averaged about 25mpg!! WOW!

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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'85 BMW 745i Turbo

[Lee Scheeler]

I've seen a 95 C36 that had been run on the dino stuff for its first 45K-50K hemorage oil from just about every gasket/seal once it was switched to Mobil 1 15w-50. The car had been driven irregularly and there was a bit of gunk in the engine. Upside of the switch to synthetic was that the gunk in the motor disappeared and now its as clean as a new motor. Of course, the first few oil changes had the Mobil turning dark/dirty after only 3000-3500 miles. The car didn't use any oil before or after the switch. Don't have any info on power or fuel economy changes.

Just my pair of cents...Lee

[Crosbo]

So if a recommendation were made, what would be the best synthetic oil and which weight is the proper synthetic weight for my '89 300E? I live here in south Texas and the weather stays relatively warm all winter and of course hits the 80's to 100's in spring and summer.

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'89 300E 3.0
'82 350SD

[Aaron]

Crosbo,

I would say that Mobil 1 10W-30 synthetic would be your best bet for a year round choice in your 300E. I believe we use both 10-30 and 15-40 synthetic at the shop, but I tend to prefer 10-30 or 10-40. Hope this helps!


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'85 BMW 745i Turbo

Your best bet is to check and see what viscosity your owners manual says to use for the temperatures you intend to operate your car in. If the car has a lot of miles or you are going to tow with it, etc., you could probably get away with the Mobil 1 15W-50. Otherwise the 10W-30 should suffice.