lucki96gt

I have a quick question about changing my oil this is my first domestic and i usually did mobil1 sythetic on my previous m3. but looks like this car has always ran 10 30 regular and with the mileage 78,000 i don't know if i should stay with what it always had or switch to mobil1, someone said it might start leaking out because its thinner. someone please tell me what to do.

ProjMach1

go with what ever factory reccomends for it. synthetic is the best type of oil, but only if your engine is designed for it. If it isn't (ike my mach 1) then it could start doing more harm then good, by over cooling your engine and not allowing everything to expand properly like it should. The people that designed these engines spent alot of time in figuring out what type of oil runs best for that application, i don't think we are in a position to say that we know better than they do :O)

Tim37

since your in a 4.6 forum i would say 5-20 would be the proper oil. it won't do any long term damage to you engine to switch oil there my be a bit of smoke for the first oil change until all the detergents get changed.

Chopper

I run Mobile 1 5W20 or 0w20 in my 04 GT.As far as the engine not being designed for synthetic,I ran mobile 1 in my Mark VIII for 167,000 miles and never had any trouble.They had the same engine as the Mach 1.

nufan11

Factory for my 96 GT says 5-30 but everyone seems tobe saying 5-20?

starcam

cool site about oil:and coolant
http://www.boss302.com/oil.htm

Chopper

Here's another link http://theoildrop.server101.com/cgi/ultimatebb.cgi

neogenic83

synthetic will not harm your engine in any way. it is the weights you have to be concerned about. 99+ they started requiring 0-20W. alot of people used 10-30 and have had no issues. if U got the extra money it will not hurt getting the good stuff.

ShadowDrake

Jesus, PLEASE do not talk unless you know what you are talking about.

99+ do NOT require 0W-20.

He is right about 10W-30 though, it is alright to use. The manual says 5W-20. 10W30 would do you good in colder weather. Either of these will be just fine.

This is for my 04 GT anyway.

With your mileage, you could switch to synthetic probably still. Synthetic will not harm your engine. What they are talking about is if you put synthetic in an older engine which has had nothing but dino oil, some oil will leak through the seals, due to the oil having a different composition. If you're worried about your seals, stick with regular oil. In a newer engine, switching to synthetic shouldn't have any issues.

kartracer55

Synthetic oil suppsoedly gives "more" protection. Theres no harm in switching too it, but on an older engine that has always run castor oil, I dont see any need to go synthetic. Run what the engine was designed for. SOme people feel that once go you synthetic ou can never go back, because you will have engine wear issues. I dont know how true it is. My dad runs straight kendal 50wt in his $10K motor... not synthetic, castor. No porblems yet, thats what his engine builder recommended.

Jim