i have always liked to use synthetic however since this car was used for 40k and i assume it used conventional.

i have always been told that you can switch from conventional to synthetic. any truth to that w/ TLs

 

Absolutely true. You're fine. You can continue to switch back and forth with no problem.

 

made typo..

i have always been told that you can not switch from conventional to synthetic.

 

Not true. You switch to either, from either.

 

i would not bother changing from dyno to synthetic....never had a car die yet due to oil issues and I have has multiple cars go 150K plus

 

Doesn't matter which one you use just keep up with the oil change intervals.

 

Some feel that if you use synthetic too early in an engine life, that it will not break in properly (metal to metal). There is some truth to this that I have seen with my own eyes on Big Block muscle car engines that tend to get stronger for the first 5000 miles. However, once the engine is broken in, I will use whatever. I have 400K on a 92 accord and I use whatever is on sale - syn or conv.

 

I mostly agree. The only problem I have with that is many people using the oil as the scapegoat for other issues. I've been through 4 engines and always around 2,500 miles it magically gets quicker as if the boost were turned up a few lbs. Also greatly depends on the cylinder/rings used. If you want to be safe, wait 5,000 miles. I know some things like moly have an effect on how the engine breaks in. The part I have a real problem with is thinking that a synthetic is so slippery that it won't allow an engine to break in. I've seen studies where a syn is marginally better if any in this department.

 

Just switched over from whatever the dealer put in the car for the previous owners 75k miles, to Mobil 1 Synthetic and filter. My engine has yet to melt or light on fire.