R12 & R134 mixed

<** edited to add add'l comments based on the replies...

I believe I'm going to stick with the R12 and just want to clarify what was said: To take this approach I will simply need to flush, replace the filter drier and recharge with R12, right??!!

And the potential issue of the fan not running could be due to a low charge in my system right now vs. malfunction and to verify I need to check the voltage to the fan--but, for a numskull like myself, how do I do that?? I've looked at the fan assembly and cannot see anywhere that I would be able to do that very thing...help!!

Thanks for the replies--I appreciate it!!

end of editing **>

I know there are a lot of threads about these chemicals but think I might have a new and interesting scenario to present (maybe not??). A/C blows really cold while moving once the car is cooled down a bit but if I need to stop at a light after the car has been sitting in the wonderful heat here in AZ then it is almost useless.

Took car (1990 300D, 147K miles) into the shop for this and other check ups early this week and the mechanic told me I've got a mix of 73% R12 & 27% R134 and that he wouldn't be able to recharge unless the system was evacuated (which he couldn't do). Apparently PO did this as I have not done anything with the AC to this point.

Will this cause me any significant problems until I can find someone to evacuate and recharge with R12 (that is what he said should have been in there)?? Also, how much should I expect to pay for this??

He also said my auxiliary fan (driver's side) was not turning on and I'm wondering what troubleshooting can be done (if any) to determine if the fan itself is bad or whether it might be a sensor or something like that?? He wanted to replace to the tune of about $200 (not including some other repairs) and I said to hold off for now.

Thanks for all your help! Mike