Radiator cap failure update - Gurgling sounds important information for all owners

Okay well I purchased a new radiator cap for the 2000 Subaru Outback Lancaster 6 which is the same 1.1 Bar cap as for any of the H6 3.0 liter engines from the looks of things. Also the same as the 2005 Subaru Legacy 3.0R.

The old cap has a light tan coloured plastic which has simply deteriorated with age and heat and just sheers and the spring comes out and all the bits fall into your radiator. The plastic has gone so soft I can just pick bits off it.

The new replacement part is Subaru CAP ASSY 45137AE012 and I would recommend that anyone with the older cap should replace it BEFORE it fails. The plastic on the new cap is BLACK and not a tan/brown colour.

Continued running on a faulty cap will lead to overheating and coolant loss and eventually you will kill a head gasket.

Well bad news, the failed cap has actually already killed the engine head gasket and its just got worse and now chucks all the coolant back into the reservoir. The Engine was leaking a bit of oil but now with the engine stuffed the car is basically scrap value as the repair work would cost more than the 2000 Outback is worth.

The only positive is that I have replaced the cap on my 2004 Legacy 3.0R BEFORE it fails due to this experience.

Cannot stress strongly enough that you replace your old radiator cap NOW because failure results in the coolant loosing its 1.1Bar pressurization and hence the engine overheats and you stuff the head gasket.

Basically there is black flakes in the coolant from the head gasket and also when you rev the engine with an airtight funnel in the radiator you just get coolant shooting up in the air and bubbles from the exhaust gasses getting into the coolant.

Any gurgling sounds when you first start the car means there is air in the coolant or a lack of coolant in the system and it needs to be sorted ASAP. The real problem is the temperature gauge shows perfectly normal, even now with liters of coolant missing due to the amount of air being dumped into the system so this gives you no indication there is a problem looming.