Hey yall, looking to buy a 2005 Lexus GS300 with 150k miles for $5k. What common issues or red flags are there to lookout for on this model year? I myself have an ES330, so I'm somewhat familiar with the "oldies" Lexus, but could use some insight. So far, I've heard leaking cam seals as one of the common problems. I've also heard mention of ball joints, but was this issue improved on the 2005 model?

 

Balljoints were a weak spot on all 2nd gen GSs. They're cheap though. Buying a nearly 20 year old car expect repairs needed. With 150k miles, if it's been cared for it should have a lot of life left. Oil leaks aren't uncommon but also usually not too difficult to address. The HVAC actuators that control the blending of the air temperature and or operate the doors for the air type (fresh vs. recirculate) as well as the ones that control the vents through which the air blows fail at this age. Also, power door lock actuators commonly fail and require replacement.

 

Mileage in this case plays not the major role, it's the age that are. Wear and tear, underbody / subframes rust, plastic and rubber (including sensors, connectors, wiring harnessess etc) don't go well with time and weather around.
So you can expect repairs all over a places around the car, that can take you a while to address them all.
And I am not talking about anything major, like rear main seal, automatic transmission or rear differential repair / replacement.
Then you may need a shop to do some work on the lift that easy will cost you thousands per job.
Well, some of them are. Tell me how to replace the oil pump O-rings No. 1 and No. 2, which sit between the engine block and the oil pump housing, or the rear main oil seal without difficulties.

Thread starter, check engine for possible blown cylinder head gasket. It's not uncommon for some drifters / street racers to push this car into the sky.
Also be aware that the suspension systems on this car are very well made and last a long time, but are very expensive to repair.
And pathologically does not tolerate non-OEM spare parts.