Synthetic Oil?

rs83cj7

I'm sure this has been talked about many times. But do you recommend replacing non synthetic oil w/ synthetic oil in an engine that has not been rebuilt? Some say this...and samoe say that. But I was looking from some of your opinions.....

tufcj

In a high mile engine, it's probably not worth it. Most of the gains are from using synth from day 1. If you have any leaks, they WILL get worse with synth. Bob tufcj

rs83cj7

tufcj wrote
In a high mile engine, it's probably not worth it. Most of the gains are from using synth from day 1.

If you have any leaks, they WILL get worse with synth.

Bob
tufcj

I heard that it will increase leaks if any are already present.
Next question...best oil to use (weight/brand).
Thanks Bob.

BREK

Bulltear 15w40 or castrol 10w40 Outside temp should also be taken into consideration when choosing oil weight. If it is cold I'd say 10w30 if it's above say about 50-60 I'd say you're safe with 10w40

rs83cj7

BREK wrote
Bulltear 15w40

or

castrol 10w40

Outside temp should also be taken into consideration when choosing oil weight. If it is cold I'd say 10w30 if it's above say about 50-60 I'd say you're safe with 10w40

I just started using Castrol in my car.

jeep_man_401

I have used synth for many years now. I started using it in a 360 AMC I built in high school...Mobile 1 20-50W was the only oil that would mantian good oil pressure in city traffic after a long drive on the highway. I used Mobile 1 5-30W in my 90 Beretta GT 3.1 v6 when I bought it...about 60000 miles...I got to around 250,000 when some girl running late for school nailed me in the drivers door...totaling the car. But it ran like a top! I am now using Mobile 1 15-40W I think :-| in my 460hp 401 in the truck...I now add 2 bottles of Crane Cam brake in lube to add the zinc they take out. Oil cap. is around 9 Quarts otherwise one bottle would be enough. I still have the Beretta...I would love to take the motor apart to see the wear...but that has to wait. I never had problems with oil leaks on the Beretta other than replacing the valve cover gaskets once and at around 180,000 you can't blame the oil. 8) If you are thinking about using syth. take a quart of say 5-30W reg. oil and a quart of 20-50W Syth. Put it in the deep freeze overnight and pour them in the morning...you will have you answer then. :?

rs83cj7

jeep_man_401 wrote
I have used synth for many years now. I started using it in a 360 AMC I built in high school...Mobile 1 20-50W was the only oil that would mantian good oil pressure in city traffic after a long drive on the highway.

I used Mobile 1 5-30W in my 90 Beretta GT 3.1 v6 when I bought it...about 60000 miles...I got to around 250,000 when some girl running late for school nailed me in the drivers door...totaling the car. But it ran like a top!

I am now using Mobile 1 15-40W I think :-| in my 460hp 401 in the truck...I now add 2 bottles of Crane Cam brake in lube to add the zinc they take out. Oil cap. is around 9 Quarts otherwise one bottle would be enough.

I still have the Beretta...I would love to take the motor apart to see the wear...but that has to wait.

I never had problems with oil leaks on the Beretta other than replacing the valve cover gaskets once and at around 180,000 you can't blame the oil. 8)

If you are thinking about using syth. take a quart of say 5-30W reg. oil and a quart of 20-50W Syth. Put it in the deep freeze overnight and pour them in the morning...you will have you answer then. :?

I wasn't sure which way to go because I did not rebuild the motor. I just replaced gaskets (valve cover, oil pan, new oil pump gears, etc.).

hotratz

I know this might be received as being biased but this is from the Mobil 1 site:

Myth: Mobil 1 will leak out of the seals of older cars.

Reality: Mobil 1 does not cause leaks. In fact, new Mobil 1 was tested in dozens of industry standard and original equipment manufacturers (OEMs) tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made. If an older engine is in good condition and does not have oil leaks, Mobil 1 provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1. ExxonMobil also recommends following the automobile manufacturer's manual for the proper oil to use.

More Myths

Now for some real stuff.....

Heres some pictures I took at the last oil change on my wifes 95 Camaro. The car has 220+k miles on it and has had a steady diet of Mobil 1 since it's first oil change. The spark plugs in the picture where pulled with about 40K miles on them from an engine with 220+K. The picture of the oil level on the dipstick shows even tho' this motor has so many miles it still does not leak or burn any oil. This oil has been in the engine for the last 5K on an engine with 220+k miles. Don't know if the credit goes to GM or Mobil but I am impressed.

jeepsr4ever

You can see some benefits from running good quality synthetic oil. You may see some seepage however it should go away in 20-30 days. Never too late to switch :wink:

ironman_gq

the myth about synthetic causing oil leaks was due to the first generation of synthetics. They didn't put enough ester in the oil to keep the seals soft so they would harden and shrink therefore leaking. The new synthetics have solved this problem.

Goose

Well I will add a bit of observation to this thread. I used the Mobil 1 synthetic in a 1999 peterbilt. 500 hp Detroit diesel.. this truck was running 14 to 16000 miles per month, and the only complaint that I found with the synthetic over Delvac was the price.. The recommended oil change interval on regular oil in this engine was around 14000 miles (or once a month) this is 44 quarts 11 GALLONS of oil and 50 bucks worth of filters, figure 200 dollars with a chassis lube)) now the Synthetic should have gone 50,000 to 100,000 before a change..problem is at about 25000 miles the truck began to use 1 gallon of oil every 12000 miles at 30 bucks a gallon so in a month I was spending 120 dollars in add oil. I went back to Mobil Delvac (regular oil) It wasn't leaking, it was working past the rings as it broke down. SO If you can keep it in the engine and dont mind the cost, It does wonderfull things for preventing wear. This engine has at this point 1.4 MILLION miles on it and still puts 414 hp to ground on a chassis dyno.. I guess regular oil changes regardless the cost do save money.. (it cost about 20 grand to overhaul one of these). Geez I am a wordy Bastige arent I ? :roll: (Happy St Pats Day!)

73hornut

Watch the video.
http://www.mobil1.com/USA-English/MotorOil/Synthetics/Product_Testing_Las_Vegas.aspx