Volvo Water Pump O-Ring - Reinz 1336255

This Water pump top seal ring is a great standby replacement part, and I encourage you to install it with a coating of Permatex Blue RTV so that it's completely covered on all surfaces/sides. Explanation follows: Ok, let's be honest of why this part failed and now you're leaking coolant. The seal swelled from oil contamination that dripped down from the camshaft oil seal. Why? -because the camshaft oil seal is the one with the most tolerance to it and will leak first when you have high crankcase vapor pressure. Why do you have high crankcase vapor pressure? -because something in the crank case ventilation system is clogged or partially clogged and causes a restriction to the escaping blow-by gases (part of normal operation). If you're replacing this part (1336255 water pump upper seal), take a few minutes to clean the flame trap housing (I personally don't run a screen in it), clean or replace the PCV hoses with good quality ones (not the cheap molded rubber ones that split in a year), and take the oil separator box off the car (two 12mm bolts) and clean out the upper vent port and the oil return port. A complete cleaning of the PCV system should eliminate oil leaks from the camshaft oil seal behind the timing gear, and thus prevent future failures of this water pump seal. In almost 15 years of servicing Volvo red-block engines, I can't stress how important this procedure is. -and you'll eliminate most or all of the oil leaks on your engine in the process. Again, don't forget to completely cover this water pump upper seal in Permatex Blue RTV when you install it. You never know how long it will be before someone services the PCV system again, and it's cheap insurance against a seal failure and coolant loss.