I am looking for some advice on repairing a Karcher K 5.85 electric pressure washer. Unfortunately I forgot to move the pressure washer from the garage to the basement this past winter, and it is possible that it was subject to freezing temperatures. The unit is only 4 years old, and has seen little use. When I try to use it now, it will not develop full pressure, and the pump appears to be pulsating. I have not yet contacted Karcher customer service or one of the repair centers. I'm pretty handy, but have not yet been able to find a repair manual anywhere, or even troubleshooting directions. If I did crack the pump housing, is it cost effective to replace the pump, or should I just retire the unit?