Is it ok to use conventional oil on a 1.8t?

 

nope
just full synthetic unless you want engine problems and sludge

 

synthetic oil only please

 

no it is not ok

 

Yep 1.8 full or say hello to problems.

How about the 2.8? Wasn't sure at 96k miles what the previous owner put in when I bought it so I put semi-synthetic in. I just know that if they used conventional and I started putting full synthetic in....Leaky, leaky perhaps.

 

what weight of synthetic should be used 99a41.8T

 

Depends a little on where you live and the time of year. Summer vs. winter, Alaska vs. Arizona will matter a bit.