Car Doctor Q&A

Q

A fewyears ago, I had the factory air conditioning on my 1970Oldsmobile converted from Freon R12to R- 134a. This summer the air conditioner only blew arm air. My question is can I convert back to Freon and do I need to stay with R134a and howmuch do I need? I cannot find a chart that goes back to the 1970s.

A

the problem with R134 is it runs at higher pressures and has smaller molecules than R12( Freon) and ismore apt to find a leak. The older air conditioner hoses didn’t have the same sealing as the new hoses and the R134can seep through the hose. Actual R12 hasn’t been made in years and if you can find it you are supposed to be both licensed to buy and sell it. The last I heard original R12 was selling for a up to $ 100a pound, you can find it. According to one of the databases that I use mitchell1 the typically the A/ C system in a 1970Oldsmobile unit used four pounds of R12. Looking online, the conversion from R12to R134a is 3.25 pounds. I suspect you have a leak— perhaps try a DIY can of R134a with a dye and sealer and see what happens. You may stop the leak, or the dye will help you find it.

Q

MY 2004 Malibumaxx is leaking antifreeze- I can see it on the ground. This has only seemed to have happened after I have replaced the radiator, oil and transmission gaskets as well as some hoses. What do I do?

A

The very first thing is to check the coolant level, driving with low coolant in the radiator will cause the engine to overheat and possibly damage it beyond repair. I would return to the shop that replaced the radiator and explainwhat is going on. They should pressure test the cooling system to look for a leak. Possibilities include a leaking radiator, engine freezeplug, other hoses or even a defective radiator.

Q

IN July I bought a low mileage 2016Nissan Rogue SV. After a month or so, I started to notice a vibration in the steering wheel primarily when driving between 20- 45mph at a constant 1250RPMS. I took the vehicle back to the dealer and they looked at it for a few days. They told me they found and replaced a bad exhaust mount and that the vibration was virtually gone. Unfortunately, that didn’t take care of the vibration. I took the Rogue to a second dealer and was told that transmission is designed to cause the vibration. I asked themwhy I didn’t feel the vibration in any of the other newor usedrogues I test drove. They just answered that the car is supposed to have a vibration and suggested that I call Nissan if I wasn’t happy. I can’t believe that Nissan has sold over 1 million Rogues, and all have a built- in vibration in the steering wheel. I really like the vehicle, but the vibration is annoying when driving on local roads. Do you have any suggestions?

A

Some continually variable transmissions ( CVT), like the one used in your Rogue, have a somewhat undesirable vibration, but it is a characteristic of the design. Before I wrote this offas normal, I would want the dealer to check for any technical service bulletins that address vibration. Using Alldata, the technical database that I use I found one that describes a low speed vibration caused by the electric controlled coupling for the rear drive unit. In addition, I would want the dealer to perform a vibration analysis to determine the source of the vibration to determine if it is in fact a normal characteristic or if something wrong.

Q

I have a 2006Toyota Solara and it’s time for a