Switching To Synthetic
 

I've decided to take a chance by switching to Mobil 1 supersyn 15w-50. Anyone using this grade? How is it working for you? I'll be crossing my fingers and hope that no leaks occur. We're taking off Saturday for a weekend jaune up north on Hwy 1 to Fort Bragg, CA.

It's going to be in the 100's in the sacramento valley over the weekend so the coast will be in the 70's.

I was in the MobilOil site and it recommended full syn Mobil 1 trk & suv 5w-40 for my car.

Carl,
I've got M1 15W50 in my '77. It had a rebuild 35,000 mi ago and has the upgraded chain housing covers (that go with the hydraulic chain tensioners) and Carrera valve covers.

It doesn't leak. I've only had the car 3 months but have the records that indicate its had mostly synthetic oil but with the occaisonal non-synth change as well.

I'd go go for it.

Am I the only one using blends? I use Valvoline Dura-Blend 20/50, and I think it is great! Even after DE's and Texas heat, the oil from my 122K motor looks great when I change it. I don't run the risk of the seal problem, and I get the benefit of synthetic IMO.

If you're concerned about leaks, why would you want anything but the most viscous M1 oil.

I switched to Mobil 1 in my old car and the leaks went from adding a quart every 1000 miles to 300 miles.

Consider a synthetic blend (the castol one isnt bad). I know widebody911 uses it and it works quite well, even on the track, with just minor leaks.

____

Just had major tune up approx 2-3 weeks ago. New valve cover gaskets, already had the upgraded chain tensioners and I believe I have the Carrera valve covers. My compression test was excellent at 165, 164, 165, 164, 165, 164. The last grade I used was Castrol GTX High mileage 20/50.

Just curious though, I know that not all the oil drains out and that about 2 qts remain in the system. Is it harmful for the Mobil1 supersyn to mix with old oil? I really don't feel like disconnecting any of the oil lines to drain the rest. I was thinking of using my old shop vac to suck out the rest through the oil tank.

Carl:
There is lots of information (and mis-information) regarding oils.
Here's some light reading for you. There are some very knowledeable oil guys here though. The beauty of this board is that there are lots of guys with diffrent areas of expetise, in which they know stuff cold.
Oil is pretty important, so read up.

I am likely one of the minority who has dino, and refuses to switch...had a leak problem once before. I only have to drop a bowling ball on my foot once to know it hurts.

Pat

http://forums.pelicanparts.com/showthread.php?s=&threadid=224155&highlight=dino+o il

http://forums.pelicanparts.com/showthread.php?s=&threadid=222404&perpage=20&highl ight=dino%20oil&pagenumber=1

Not an oil expert, but to answer your question, I've been using Mobil1 15W50 for the past year and a half without any leaking.

BTW rebuilt, enlarged engine has approx 75000mi on it.

____

On both you 911s, how old are your seals and gaskets. Mileage on your 911s?

Using M1 15w50 in my '88 3.2 Carerra. Doesn't leak a drop. I think it has had synthetic only since day one. Oil return lines have been redone once. Only 40k on the clock so far. The PO only put on 16k in 12 years! It seems to use about 1qt/1500 miles.

I don't know if I would switch TO synthetic after many miles of dino in a car but I'm comfortable with staying with it when there are no apparent problems.

No problem at all. Today's synthetics are fully compatible with dino oils. You will have an 80/20 blend of synth/dino for the first change interval (assuming that you have a 10 qt capacity and you leave 2 qts in the lines) and once you change the next time, there will be almost no dino left.

Go with the 15/50 viscosity.

Amsoil makes a 20/50 high performance synthetic oil for those who want to keep the same viscosity grade and try something different.

Don
www.lubedelaer.com/dstevens

10/40 synthetics and it is working good

Last year Mobil 1 0w40. Untouched engine at 90k miles. No leaks.

This year Castrol 5w40. No leaks.

I just switched from Kendall GT1 to Mobil 1 15-50 Extended Life. 88 Carrera, stock motor, 114,000 miles.

The slight weeping I have at my cam towers has not worsened. Oil consumption has not changed.

Just used AMSOIL 20W50
 

I just changed my oil and used the AMSOIL 20W50 Racing Oil for the first time. I always use the Mahle OC54 filter and I replaced that too. I just put 3700 miles on the car, so I wanted to get the oil changed and try the 100% synthetic AMSOIL since everyone I know uses it and raves about it. We'll see...

So many "synthetics" today contain a mix of type III (HC dino) and IV base stocks that you're really getting a blend. Some suggest even Mobil 1 is. The leak question is a non-issue and shouldn't be a basis for choosing an oil unless your engine is using NOS seals that were manufactured over 25 years ago.

I just did an oil change this past weekend on my 88 911.
I've been doing way too much reading here and on other sites.
I like synthetics and used to use Redline 20/50. It got hard to
get here where I live. All my reading lead me to Mobil One
V-Twin oil. V-Twin is VERY expensive !!! about $8.00 a quart
at Wal-Mart. Wal-Mart also sells Mobil One 15/50 full synthetic
by the 5 gallon jug for about $24.00. I'm a risk taking kinda guy,
I also am not wealthy so $100.00 oil changes are out of the
question. I was spending about $70.00 for the Redline so...
I thought try 5 quarts of V-Twin and 5quarts of the 15/50
kinda make my own blend thing. I feel good about the combo
from what I read, this should do the trick. The way I see it...
oil is kinda like vitamins. You get what you think you need
to protect you !

Chuck

An old engine such as a non-rebuilt 1983SC that has seen dino oil all it's life may well result in some significant leakage with a pure synthetic.

Be ready for it.

Hmmm, tell that to my 2000 Audi A6 2.7T (110,000 miles) that just started leaking within a few days of switching to synthetic along with a good friend who just switched his '99 BMW 325 (125,000 miles) to synthetic and now also has a leak. I am not calling you a liar, I just have personal experience that leads me to believe that the high mileage synthetic switch can indeed sometimes cause leaks.

Agreed, Tim. The hell it isn't an issue.

It is a "known" and happens more often than not.

I switched to Mobil 1 last summer at 50,000 miles. I was concerned about leaks (it had never leaked a drop before). So far, it still has not leaked at all.

the deal is that the syn cleans out the debri in the sealing lips which was blocking the oil leakage with the dyno oil. If you rebuild an engine and syn from the begining no problems

Yep, switching on a HIGH mileage car is asking for leaks.

My engine leaks with Castrol 20W50, so I'm really not too concerned about that, but I'm curious to see if there's any difference with the AMSOIL 20W50.

When bought my 84 it had been using M 1 5-30 , it had 171,000 plus at the time , no leaks, now at 191,600 still NO leaks !!!! (:
M 1 has gone up in price, thinking of changing to another synthetic oil, not sure which one , or would that be risky ??
cheers, Peter

:D
My 911 has a slight leak or two also, and I have always used Castrol 20W50.

With 12 qts of oil, I don't like the thought of buying synthetic when I know my BMW has always run on the Castrol dino and is still going strong at 278,000 miles.

I switched my recently acquired 110k mileage Audi back to synthetic because it has twin turbo chargers and was designed to run synthetic. A week after switching my wife started complaining of a burning smell when the car was sitting at stop lights. Sure enough my cam shaft seals are now leaking. :(

Same holds true for a friend who swithed to synthetic is his high mileage '99 BMW 3 series. He called me to ask why he started smelling oil while sitting in traffic (he is not mechanically inclined so he calls me every time his car acts up). I asked if he might have left his oil cap loose or something and he said that he recently had the oil changed and was proud to tell me he just upgraded to synthetic. ;)

I know it is not guaranteed to leak when making the switch on high mileage cars, but often it does.

In my '89 Carrera 3.2 with 14,500 miles(!) I'm using Valvoline VR1 20W-50. PO's had used Kendal GTI 30W so for now I'm going with a multi-viscosity dino oil. I understand the VR1 has a higher level of ZDDP.

So far with 1,250 miles the only leak is the one that I had when I bought the car. Its the left side cam feed oil line. It leaking/seeping at the hose/fitting crimp. Its not really anything...I just wipe it up after a drive. I know I need to replace it. Other than that engine is clean and dry.

So far at 1250 miles on oil I've not used any yet.

I'll probably switch over to a synthetic at the next change. I want to get the quicker/better oil flow at start up that a synthetic would give.

I use sythetics in all my other cars and bikes. I guess I've fallen somewhat for some of the folklore regarding our older air-cooled Porsches.

David

Tim,

I'm surprised to hear about the leak in your audi-and more surprised that you/ or PO wasn't using Syn on it to begin with? I belive that all the audi dealers out east anyway have used solely syn for a long time, and I thought that Audi has used only Syn as factor fill since the late 90's-and recommended that only syn be used (others such as BMW, Saab, Porsche have also done this for quite some time). For a turbo motor as well, syn is your best bet.

I see people making comments about leaks switching from one to another but after exhaustive search I have yet to actually see any post with a user here or on the other boards that have actually suffered from this.

So for me its total BS especially since we have no users that can directly say yes it happened to me and yes it was the cause.

I switched mine after 90k of using dino oil to a pure synthetic "royal purple" NO leaks at all.

DONT believe the hype or hear-say friend of a friend BS.

Try Royal Purple or Silkolene they stand up well.................

As for that matter I very rarely see any engine kabooms that can be directly related to the type of oil but the delivery or mechanical health

I can say I directly experienced leaks after switching to synthetic. The GF's old 924S started leaking internally into the coolant system at the oil cooler within a week of switching...she had the oil changed by a local mechanic who told her how much better it is for the car. Maybe it was a coincidence...

Pat

yeah I can agree the syn will clean out an engine.

I know others disagree, and I hear the stories, but I have never experienced a leak as a result of switching from dino to synth (M1 15/50, AMSOIL 10/40, and AMSOIL 20/50) This includes 3 911's ranging from 60k miles to well over 100k at the time of the switch, my recent 930 with 33,500 miles, a Land Rover ( they leak when empty!) various BMW's, Jeeps, and my wifes LX450. Even my lawn mower!!!! I guess I've been lucky, but this is my experience.

Now they'll all leak tomorrow!!!

I think the advantage is worth the chance....

tim.

it all depends how good of shape the seals are in and climate

Efhughes 3.....I'm a dino user also. Maybe we should have our own string?

I've had an '88 3.2 for about 14 months. PO's used either Castrol, not my pref or Chev Delo....I've had three oil changes in the past 10k with Pennzoil multigrade (10-40), no leaks to speak of either before or after.
Been using about 1 qt per 3k oil change. Been following various oil strings and just bought a case of Brad Penn from Navarro. Oil change next week and will see how it looks. More interested in wear factors as mentioned previous strings.

M1 15W50 - its a good oil

Petrolblue, I was suprised also! After buying the car, with about 100k on the clock, I started fixing a few items. The PO had just recently had the oil changed and I did not give it a second thought, but later I found a few receipts in the glove box from a small town oil service place and it listed Quaker State dino oil!
:eek:

I knew about Audi's stringent oil specs (I spent a small fortune on their special synthetic power steering fluid and automatic transmission fluid already ;) ).

Anyhow it did indeed start leaking after I switched to synthetic and in the next month or so, I will be yanking the front bumper and radiator, pulling the timing belt so that I can reseal the front of the engine. I found a nice kit with new timing belt hardware, water pump, Audi coolant and front seals for around $300. The bummer is that the timing belt had been changed at 80k and was not due yet, but no way am I pulling all this apart w/out changing the belt and water pump as it is all a PITA to get to on the Audi.

Hey loaded, I am happy you have not had any leaks due to switching to synthetic on HIGH MILEAGE cars. I HAVE and I know others who have also. I am not making this up and all said, I guess I really don't care ultimately whether others suffer this problem. I knew it might happen when I switched my high mileage Audi, but it needed to be done IMO, with the twin turbo's and all. I am 100% confident that my 911 does not NEED to eat synthetic though so I choose to stay with dino in that car.

I can't say that I know of any 911 owners who have suffered a problem, but I know of BMW's and obviously an Audi that suffered the problem. Many 911's have a few leaks to start with, so that might tend to mask the situation, or maybe the seal design on the aircooled cars is a bit more tolerant of the switch.