What is the best oil to use in a 1986 420SEL? (180,000 miles) 50/50 combination city-highway driving, no hard driving and oil and filter changed monthly. I am currently using Castrol GTX 5W-30 on the advice of my mechanic. He said that many of the car he has worked on needed the cams replaced too often until they started using 5W-30 oil, after which the cams lasted much longer.



------------------
Jason Priest
1986 420SEL

How many miles do you drive per month? If you don't drive over about 1,500 to 2,000 miles per month. The oil you're using will be fine. The oil change frequency is the most important thing. Drain it hot, and change the filter every time.

This will be a fun thread to watch, get ready for the opinions. I've posted mine, and I will enjoy watching and respecting everyone else's.

Good luck,
Larry

Today I picked up a book called, "Drive it Forever," by Bob Sikorsky. Among other things, like recommending the severe service guidelines for oil changes, he mentioned it might be a good idea to mix synthetic and regular oil. For my car 7 quarts regular and 1 quart synthetic. Any opions on this. He claims it is much cheaper than using all synthetic and provides the benifits of both types.



------------------
Jason Priest
1986 420SEL

This may be okay, but it would worry me to death. I have been told that many times, particular combinations of oil additives don't work good together.

The ideal would be if you had a source of synthetic oil with no additives. Then by using universal oil like the truckers use, which have increased amounts of cleaning agents, you may be able to accomplish a positive without worrying about the negatives.

Good luck,


------------------
Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Ok ya'll here is my $.02 worth. I run Castrol 20-50w (live in south Ga) pretty much year round in all my vehicles and change it about every 3-5000 miles. I owned a vehicle with a 4 cyl. engine and around 125,000 miles the radiator came apart and the wife continued driving till it stopped (the rings were cooked and the pistons were scarred). I rebuilt the engine and outside of the damage that was done when it ran hot the inside looked brand new. You could still see the cross hatch on the cylinders. There may be better oil out there but I run the Castrol. I am also a big van of John Force and his sponser is Castrol.
As ya'll know though the secret is to change it often.
engatwork

Any and All API service oils can be mixed with each other without harm. It's one of the specifications (miscibility).

[This message has been edited by Lube (edited 08-01-2000).]

Lube,

It's interesting to know that one of the specs is that can be mixed. And as you said without harm. My question would be then, if you mix them, could this produce a combination of additives that would not work well together to accomplish what the additives are supposed to accomplish? In other words, it wouldn't be harmful, but could achieve a mix in which the additive combination wouldn't keep the engine clean, or provide the correct viscosity index?

Great response, I would like to know a source to learn a lot more about oil, additives etc.

Thanks,

------------------
Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

My brother works for Lubrizol and specialises in auto oil additives and detergents. He once advised me to change my engine oil and filter every 3000 kms, especiually so here in high ambient temperatures and plenty of stop / start driving in town. Change it often, change it hot seems to be the best policy and I have to confess all my cars have given me plenty of trouble free miles in this town. If the oil is changed frequently enough, I also believe you can do away with the engine flushes people round here want to sell me. Engine oil is the life blood of your car, would you really want to gamble your car's health for a few dollars worth of oil ?

andy,

My man!!!!!!!!!



------------------
Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Let's not forget the famous quote we were all taught at one time or another.

"Change it hot...change it often."

Hello 420SEL:

You can find lots of information on the topic of engine oil by doing a search of past forum discussions.

Driving in Canada, with the wide variance in temperatures between summer and winter seasons, presents a few challenges to selecting the best motor oil. 5W-30 is the standard recommendation for year-round use in our climate, but I always change to 10W-40 for the summer here in Edmonton.

I'll throw my 2-cents worth in and say that Red Line, Amsoil, Mobil 1 are the best synthetics and synthetics are the best oil.

However, if you have an older engine that is a little loose, you can benefit from running diesel-spec engine oil, which contains signifcantly more detergents and additives than gas engine oil but has the same lubrication qualities. Follow this link for a better explanation:
http://www.peachparts.com/ubb/Forum1/HTML/004821.html

Just hoping to add to the confusion...


------------------
Dean Albrecht
94 E500
99 ML320

www.need2speed.web.com

[This message has been edited by Dean Albrecht (edited 08-01-2000).]

Well, I am also a fan of Castrol GTX oil. I use the 10W-40 grade in all of my cars except for the BMW and the 380SE. In those two I use Mobil 1 10W-30 full synthetic. It's very important in cars with turbos (especially gasoline-engined ones) such as my BMW to use a high quality synthetic oil to prevent coking of the oil in the turbo bearing housing. Another benefit of synthetics is their higher lubricity which means they pump faster at startup and in cold weather. My 300SD is my daily driver, and at 183,000 miles it's still running great and has had Castrol GTX used in it basically since it was new. Sure, synthetics offer excellent protection, and if you drive hard (or don't drive often) they're great, but these older cars were designed to run using dino oil and many have traveled many hundreds of thousands of miles using it. I always refer back to the famous million mile 220D. It ran 902,000 miles on it's original engine using dino oil. Not too shabby!


------------------
Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'86 420SEL
'89 420SEL
'93 300E 2.8
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12
'84 BMW 745i Turbo

OK heres my two cents. Ive seen the results of Mobile 1 in a 380 SL with over 150K cross hatch still visiable. and this guy only change the filter and added oil (maybe why the timing chain let go so early) . I subscribe to the theory of if you change it on regular intervals you cant go wrong. I use mobile 1 in my truck, and Shell Rotella in my 300D, but considering some of the other post I am considering a change to castrol or mobile 1. My intervals are 5to7K on the truck and 5K even on the 300D. Ofcourse the Harley uses H.D. 20w50 at every 5K. For what it's worth.

------------------
Keith Schuster
99 Harley Davidson Ultra Classic
97 Dodge Ram 1500
83 300D
auto\hydraulic mechanic 20 yrs

[This message has been edited by shoe (edited 08-01-2000).]

Hi everyone who responded

I changed my oil on my 300E every 3000 kms with 5W30 in the winter and 10W30 in the summer and my camshaft still needed replacing at 135,000 kms. Mechanic said 15W40 could have prevented that. Wish I knew earlier!

Peter

I have been using various generic or house brand 15W40 and 10W40 oils the last few years in my cars with good results. I suspect most generics are made by major companies just using different containers. I also pick up major brands when the price is right. For example, the dollar store where I live has Shell 10w40 every day at 89 cents a quart. I have been changing at 4K but I am going to 5K intervals since my usage is not real severe. Seems like most of the people who recommend 3K intervals are in the business of selling/changing oil. Just my 2 cents.