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View Full Version : What oil to use?


99SVTCobraVert
07-21-2005, 01:04 PM
I just got a 1999 Cobra with 40k miles on it and I wanted to change to oil. What are you guys using? I was planning opn goign with fully synthetic oil and just use that for the rest of the cars life. What do you all use or recommend?

And also, am i going to see any problems by switching over to synthetic at 40,000 miles or is it going to be ok. I've heard of people switching over at a high mileage and begin to see leaks and have to replace gaskets.

Thanks

Yeller'
07-21-2005, 01:21 PM
Mobil 1 synthetic.

99SVTCobraVert
07-21-2005, 02:52 PM
The manufacturer's recommended oil is 5w-30... Are you guys sticking with that or are you using 10w-30 or something different?

RF Cobra
07-21-2005, 03:17 PM
I would use what is specified for your car.

People that experience leaks after switching to synthetic do so because of preexisting problems they didn't realize they had. The sludgy dino oil can block small cracks. After they switched and the crud gets flushed out the synthetic slides right through and suddenly they have small leaks and blame the syn oil. :doubt:

The oil itself will not cause problems, it will help your engine. I use Mobile 1 full synthetic in mine.

Also, if you do a search you will find many posts in previous threads discussing synthetic oil and that should give you all the info you need (and then some). :)

99SVTCobraVert
07-21-2005, 04:19 PM
Alright thanks for the help...

Another thing i wanted to ask about was about the 5 speed. I was driving around today andi was slowing down to a light and got out of 4th gear and I couldnt get back into any other gear... I was trying to go down into third then 2nd to come to a slower speed but it just got stuck in neutral and wouldnt let me down anything but roll. And another time I was parked and was trying to get into reverse... I had the clutch all the way down and when I tried to get into any gear you could hear a very small grind so I just pulled it out real quick. I tried again after waiting for 15 seconds or so and it was ok. Do you guys now what may be going on??

Lumpydogs
07-21-2005, 04:22 PM
I would use what is specified for your car.

People that experience leaks after switching to synthetic do so because of preexisting problems they didn't realize they had. The sludgy dino oil can block small cracks. After they switched and the crud gets flushed out the synthetic slides right through and suddenly they have small leaks and blame the syn oil. :doubt:

The oil itself will not cause problems, it will help your engine. I use Mobile 1 full synthetic in mine.

Also, if you do a search you will find many posts in previous threads discussing synthetic oil and that should give you all the info you need (and then some). :)

I 100% Agree. Nice explanation :thumbsup:

RF Cobra
07-21-2005, 04:51 PM
I had the same problem one time when I was down shifting from 6 to 3rd when traffic slowed briefly on the interstate. It would not go into third nor could I get it back into any gear. I kept the clutch in and just wiggled the shifter left to right in neutral, paused, and then it finally went back into gear. My guess is something to do with the synchros? :scratch: Third gear seems to have the most difficulty on mine when downshifting into it from a higher gear.

redsnake99
07-22-2005, 08:07 AM
I have used Mobil 1 synthetic 5w-30 in my 99 since I bought it with 10,000 miles on it. Car now has 133,000 and still runs like it was brand new. I religiously change the oil and filter every 5,000 miles. Mine has a Vortex charger which takes an extra quart, so each fillup is about 6 1/2 quarts. Works for me.
:thumbsup:

Stavesacre21
07-23-2005, 01:05 AM
I religiously change the oil and filter every 5,000 miles.
:thumbsup:
I've changed mine every 3000 miles, under the impression that it's less stress on the engine since the oil isn't very close to being worn. Do you really think this is overkill, or does anyone else think this sounds normal? I'm thinkin it's not really obsessive compulsive


Oh yea, and 99SVTcobravert.....Mobil 1 5w-30 all the way! I'm not sure if there's any tie in here, but i was useing 0w-30 for the longest time, and had some engine tick...finally dropped to 5w-30, and the tick disappeared completely....just food for thought! :D

RF Cobra
07-23-2005, 12:03 PM
I've changed mine every 3000 miles, under the impression that it's less stress on the engine since the oil isn't very close to being worn. Do you really think this is overkill, or does anyone else think this sounds normal? I'm thinkin it's not really obsessive compulsive
I change mine every 5k miles. The synthetic oil lasts much longer since it doesn't have all the impurities. It is usually the additives/cleaners that wear out first. My father-in-law typically goes at least 7,500k in his 97 Cobra (Mobil 1 synthetic) and he has never had any problems.

Obsessive compulsive would probably be 2k or less or someone who just likes to :flush: their money down the drain assuming they have not meet the time interval for changing it. ;)

sssvtcobra
07-24-2005, 02:23 PM
I change mine every 2k miles. (Yes I am anal retentive). I have my dealer change it, so I just use what ever they use and recommend. That way there is record of it, if it ever comes down to needing it. Since I don't put alot of miles on my car I have always gone past the next recommendation date by the time I have hit 2k miles.