Synthetic Oil - Can I tell?

[kwimberly]

Just got my '03 quattro 1.8t yesterday. I know I'm going to have to treat her better than my 2.0 Jetta - i.e. premium gas.

I tried to switch the Jetta to synthetic oil when it was about 7 years old, and it developed leaks, so I had to switch back to dino.

Short of trying the same experiment in the A4, is there a way to tell what kind of oil is in there without draining it? I'm worried that if it has had dino in it and I switch to synthetic that the same thing will happen - leaks.

[pondside36]

Is is used from a private seller or the dealer? If it is from the dealer they most likely used synthetic oil. Or call the private seller and ask them... if I were you that is what I would do.

[sailor]

i only buy used cars and I always use synthetic oil in them. I've never had a problem. You need to use synthetic oil in turbo engines.

[3ohAvant]

synth only. you prob won't really be able to tell right away. but when the engine is sludged up, your wallet will be able to tell.

as for the jetta, when you went synth, you picked the wrong brand, or wrong weight.

[A4TL]

drain the oil and pay the $20 for analysis you'll find out quick whats wearing out. But really i bet they'd (smart) switch to synthetic before selling it.

i keep receipts of napa (i know rip-off but 1 mile away and always in stock mobil 1 0w40) - time is money

and receipts for all work procedure done (1 mile away mechanic, time is money, i bill out at more than the mechanic or audi dealer charges).

Anyways $20-25 for analysis of oil; it should show you the magic;

Otherwise check the turbo return line for coking (oil) or have a mechanic do this.

It's a good place to look for sludge. not a bad idea to replace this line as it leads to turbo failure when the flow is restricted by coking. i've not heard of this much from many people except with dead turbos.