JamesR

I've had my 88 Carrera(107K)for about six months
now. Serviced by Porsche mechanics just after
purchase. They used Chevron Supreme 20W50 for the oil change. There is a Shell Rotella sticker in the engine compartment. I live in North Georgia.
Dam hot here now, can get very cold in the winter.
Should I switch to non-dino oil? Is there a process involved when changing from dino to non-dino?
Thanks.
James R.

Carlos Artal

James,

I live in Madrid... scorching hot in summer, quite cold in winter. Synthethic oil is the best of both worlds, as you get instant pumpability on cold weather, and less thinning in hot weather.

I´d go for synth. oil anytime. I did as soon as I bought mine...

Mobil 1 is to me the best. Just my opinion.

Jim Michaels

James:

Lucky you; I think you can do whatever makes you more comfortable. I owned an '88 Carrera for six years; did DEs, autox, and street and never felt the need to switch from dino to synthetic. Now I have a '93 RSA raised on Mobil 1, so I keep that going. Modern dino oils are very good compared to those of just 30 years ago. Your car's already gone over 100k on dino; probably good for another 100k or so before major engine work. Some who've switched their older P-cars to synthetic have reported the onset of minor oil leaks, while others have reported no problems, and sometimes cooler running. The engine of you car was designed to be well lubricated with the dino oils of the time, and synthetics cost a lot more. On the other hand, If you run at high rpms and temps (as in DEs), synthetics supposedly provide a better margin of protection. Bottom line; you can do whatever makes you more comfortable.

johnnyquest

I've been warned several times that switching to synthetic for my 89 Carrera will cause blow by, i.e., the piston rings can't contain the synthetic oil and you'll start to burn it.

Jim Michaels

James:

I guess you're really confused now. One for switch, one for stay, and one for do whatever you want. Wait another day or so and take another count. Oh, and did you take into account that the Porsche mechanics put in dino at the last change?

Also, we forgot about your other question. No special procedures to switch that I know of; just drain out the old oil and pour in the new.

Bill Gregory

The current Porsche recommendation (June 2001) on oils for use in all 4,6, and 8 cylinder Porsche engines since 1973 is:

Castrol/Syntec......................... 5W-50
Mobil 1................................ 0W-40, 5W-40
Sun Oil/Sunoco Synturo Gold............ 5W-40
Texaco/Havoline Formula 3 Synthetic.... 5W-40
Valvoline/High Performance Synthetic... 5W-30

Viscosities recommended for the Turbo are 0W-40, 5W-40 and 5W-50. The nW-30 weight oils are approved to 85 degrees F. Greater than 85 degrees F should use nW-40 and above. Alan Caldwell (PCA Technical expert on 1989 and earlier 911's) has noted that conversion to synthetics in 1978 and later engines should not cause any undo problems.

I switched to Mobil 1 15W-50 in my 81SC at a bit over 100K miles, and didn't have any leakage or other problems with it.

john d 81SC

Bill,

Bill,

As an 81SC owner and Mobil 1 user (15W-50),I'm extremely curious of your choice of 15-50 in spite of Porsche's recommended 0W-40 & 5W-40. The driving conditions here in the mid-Atlantic area are probably similar to yours in CT, although I'm certain that your DE lap times are significantly shorter than mine! *G*

James, in coversation with some fellow SC drivers at DE events formerly using Dino juice,(and I realize this is purely anecdotal) it seems that the synthetics are helping keep running temps down this hot summer. And, similar to what Jim Michaels commented, some have had minor oil leaks, others haven't had any problems. I'd be curious to know with what frequency the P mechanics performed the oil changes - factory recommended intervals or shorter. I think the key Q is what kind of engine temps are you seeing? You can cook your oil pretty quickly at a DE event on a hot track...although the Carrera cooler is supposedly more effective than the loop & 28 tube brass cooler found on the SC's. I've had the 'pleasure' of the stop & go traffic on 400 into and out of Atlanta, and know how that can elevate engine temps, but usually it's within the parameters of safe operating temps. If you're not experiencing unusually high temps (>225 degrees)I'm wondering if the cost is worth it?

gerry100

While we are on the subject;

I've got an '86 3.2/88K with no leaks and raised on Castrol.
My mechanic suggested synthetic during the last DE prep, I had him stay with dino 10W-50.
I have heard that once you switch to synthetic that switching back to dino causes problems.

Is this an "urban garage myth" or is there some truth to this?

I'll probably stay with dino as everything is so good with the motor right now, but attributes of synthetic have some appeal for the future as I do more AutoX and DE.

Schuey

The Bill Gregory post says it all...

Bryan Moore

Just to add to the confusion, the owner's manual for my '80 SC recommends 20-50. As far as I can tell, the recommendation seems to be for conventional oil. I'm using Mobil 1 15-50 in spite of Porsche NA's current recommendations for 5-40, etc.

Steve Weiner-Rennsport Systems

[quote]Originally posted by JamesR:
<strong>I've had my 88 Carrera(107K)for about six months
now. Serviced by Porsche mechanics just after
purchase. They used Chevron Supreme 20W50 for the oil change. There is a Shell Rotella sticker in the engine compartment. I live in North Georgia.
Dam hot here now, can get very cold in the winter.
Should I switch to non-dino oil? Is there a process involved when changing from dino to non-dino?
Thanks.

James R.</strong><hr></blockquote>

Hi James:

You asked a good question and I'm afraid there is no quick answer. Let me clarify,........

All things being equal, synthetic oils in air-cooled engines are really superior in every way to dino oils;

1) Far better temperature tolerance; 260 deg vs 390+ F.

2) Far better lubrication at startup, the major cause of wear in any engine.

3) Better lubrication overall,....superior film strength for bearing and piston skirt protection.

4) Cleaner engine internals and much less coking due to superior temperature tolerance and no carbonization.

All that said, there are some things to be aware of when contemplating a switch to synthetic.

The majority of synthetic non-racing oils have a high level of detergents that really work well in keeping an engine clear of combustion-related deposits. This serves to scour out an engine that has been running on dino oils and in some cases, can trigger some oil leaks as the carbon deposits behind a gasket or parting line are cleaned out. When this happens, one can experience a seep or drip. Each & every engine is different and the only way you'll know is try synthetic oil in your car and see.

Synthetic oils, in and of themselves, do not cause any additional blowby or leakage. If one had less-than-perfect ring or valve sealing, nothing will change as long as the viscosity range is similar.

Now, about the viscosity issue,.......

Porsche recommends these thinner oils for the express purpose of fuel economy and emissions efficiency. Plus, these thinner oils will flow better in temperature extremes and provide better cold-start lubrication, just when the engine needs it most. Given the current Factory recommended oil change intervals (which I disagree with), Porsche recommends a year-around oil that works well under most conditions.

These viscosities may not work the best for some very high outside temperatures seen in this country and for track use where the engine sees high RPM and load for extended periods of time; something that doesn't always happen in street driving. For these conditions, I do use and recommend the 15w-50 type oils for their extended high temperature tolerance and protection.

Now, back to your original inquiry,... I would have no reservations about installing a good synthetic like Mobil 1 in your Carrera engine. Your choice of oil viscosity lies with how you use your car and how many track events you do. Its possible that you might need to have your mechanic go over the engine and make certain that the various covers are tight, but my advice is to try it and see. The benefits outweigh the risks of some leaks and its well worth it, IMHO.

I hope this helps a little bit,...

TPink

1. Any issues with switching back and forth between the two types based on summer/winter or specifically for DE events?
2. Are there any independent, objective tests comparing the different synthetics?

In my case, I just changed oil using Castrol syntec 20/50 for 2 days at DE. No scientific data here, but it seemed to run cooler than in the past. Temps were in the 70's so it was not particularly hot, but my temps. were 210-230 all day. I was about the slowest in yellow, so you're not hearing from a hotshoe here, but even when I was more aggressive in the pm, I did not see the temp spike up and I know my brakes and tires were hotter.

I chose 20/50 (maybe erroneously) thinking it would be plenty warm for the 20 end and not so thin that the oil would leak where my normal 20/50 Castrol syntech blend did not...well, relatively speaking - it is a Porsche.

Steve Weiner-Rennsport Systems

[quote]Originally posted by TPink:
<strong>1. Any issues with switching back and forth between the two types based on summer/winter or specifically for DE events?
2. Are there any independent, objective tests comparing the different synthetics?

In my case, I just changed oil using Castrol syntec 20/50 for 2 days at DE. No scientific data here, but it seemed to run cooler than in the past. Temps were in the 70's so it was not particularly hot, but my temps. were 210-230 all day. I was about the slowest in yellow, so you're not hearing from a hotshoe here, but even when I was more aggressive in the pm, I did not see the temp spike up and I know my brakes and tires were hotter.

I chose 20/50 (maybe erroneously) thinking it would be plenty warm for the 20 end and not so thin that the oil would leak where my normal 20/50 Castrol syntech blend did not...well, relatively speaking - it is a Porsche. </strong><hr></blockquote>

TPink:

You may certainly change viscosities according to the season, but my advice is to stay with using a synthetic oil. I do not think highly of switching between synthetic & dino oils,....

Synthetic 20w-50 oil is just fine for all around use down to 20 deg F. 20w-50 dino stuff should be changed to something thinner for temps below 32 deg F.

I hope this answers your question.

Bill Gregory

[quote]<strong>As an 81SC owner and Mobil 1 user (15W-50),I'm extremely curious of your choice of 15-50 in spite of Porsche's recommended 0W-40 & 5W-40. </strong><hr></blockquote>

Since I spend 15-20 days at the track each season (that's Spring to Fall, with no operation in the winter), with some during the summer when it gets very hot, the extra coverage of 15W-50 is worthwhile, and in my mind, neccessary. For someone not tracking their 911, the Porsche recommendations should be considered.

Todd

I have been struggling with this as well as I am doing many updates to my 73. It has run dino. I would like to use Mobil 1 (10W-30). I have had excellent experience with Mobil 1 in other equipment that has long outlasted its projected longevity, and in a tow vehicle which ran consistantly 15-20 deg. cooler than with Dino. But, I am one of the lucky ones who has NO oil leaks in my 73, and don't want any. But, would really like to go to Mobile 1. I am curious as the Porsche bulletin says 73 and later, but then someone says not to put synthetic in older then 78...