Arrived on site to diagnose a 1998 Lennox system. Arrived on site and spoke over with client and stated system hasn’t been really running or heating recently. He cycled heating mode on system would not operate properly as system would then have intermittent issues as found system wold not operate properly or go into second stage heating. As system would keep trying to turn on second stage system would lock out and shut off. Advised client one control board looks to have been replaced and not installed properly. Advised client would recommend replacing both control boards as they could not be faulty and will continue to have issues if left in same condition. Found inducer motor leaking heavily oil as motor itself has a thick layer of oil and dirt build up over the past years of operation and self wear and stress it has developed. System also has a air purification system and U.v bulb and core has system has never been replaced. Recommend replacing system system to help better air qua