Coolant drain

Topher · Post by **Topher** » 24 Sep 2018, 14:25

Just wondering if anyone else has experienced this. I have a 1999 s80 twin turbo that for some reason been draining coolant after I shut the car off. I can take a 4 hour drive and nothing but as soon as I shut the car off it just dumps coolant. After I let it cool off and refill it there is no leaking under the car.

Post by **SuperHerman** » 24 Sep 2018, 14:50

First question is where is the coolant dumping from? Overflow tank?

I would start by replacing your coolant cap if you want to throw parts at it. Otherwise do a pressure test of the system and make sure the test includes the coolant cap.

Topher · Post by **Topher** » 24 Sep 2018, 14:54

Ok I'll give that a shot, it's the overflow tank that's emptying

Post by **SuperHerman** » 24 Sep 2018, 15:20

To be on the safe side, buy a Volvo cap. I have had issues with non OEM caps not even fitting, needing the non OEM bottle to work.

A site sponsor has a non OEM version for $5.00, they claim it will work. It appears your part #9445462, but confirm.

Call the dealer, but be prepared for a $40 price. If the problem is the cap, $40 and moving on the same day is not that bad. Your coolant bill can add up so factor that in if you are driving and filling.

If you buy something at a national chain, make sure you can return it even if it has been opened.

Post by **June** » 24 Sep 2018, 17:03

Last year my car experienced "After Boil" as I have heard it referred to causing the coolant in the engine to boil out the cap after hard driving or when shutting the engine off even after normal driving. In my car's case the cap had been replaced by me the year before due to age since the thermostat and waterpump were done with the timing belt I felt why not. It ended up my coolant had been diluted to the point of lowering the boiling point causing the excess heat in the turbos and block to boil shortly after shutting off the engine. In my cars case my dealer loves to add water to the tank overfilling the coolant tank which I promptly removed after every oil change diluting the coolant.

You may want to completely remove the existing coolant and replace it. Only using one gallon in our S80 T6 equipped cars will not give you a 50/50 mix you either must buy premixed or two gallons of pure coolant and distilled water. I assume you have been adding water to replace what boiled out? If so you are making the problem worse. I run the black cap for a 240 which runs half the pressure as the green cap which is factory to protect my heater core. It's been that way for nearly 15 years now, so less pressure seems to be ok, but less than a 50/50 mix is not from my experience with my T6. Also my car has had nothing but genuine Volvo coolant installed by my dealer at a 50/50 mix as specified by Volvo. June

Cees Klumper · Post by **Cees Klumper** » 27 Sep 2018, 14:07

I would also suspect the cap and possibly the exansion tank itself. Go with Volvo, with the money you save by doing it yourself, it's easy insurance.