Coolant swap and now it's overheating

**dhacking** · 02-08-2016 08:14 PM

Hey, so I foolishly put the green coolant in my A$ 1.8t and I was getting an check engine light from my coolant temperature sensor which thought the car was overheating on cold starts. So I decided to do a coolant swap (to G12) and put a new sensor in. I flushed the system with Distilled water once and put the sensor in. the fans turn on at normal operating temp so the sensor is good but I don't think there is good circulation of coolant in the engine because the radiator isn't very hot when the car is overheating... and it's overheating. anyway, the heater was blowing cold but I ran the car with the cap off the reserv and it started blowing hot. I tried un-doing the heater core hose with the hole in it but didn't get much air out. Is there anywhere else to bleed air from (what Im assuming is wrong since it wasn't overheating before). I've read somewhere there is a bleed valve on the water pump but have no idea where... anyway any suggestions would be helpful. thanks.

**Fast4esT** · 02-08-2016 08:53 PM

There's a bleed valve on the coolant hard pipe along side the fuel rail. These are a pain to bleed and I would pay a shop to do it.

**NOBR8KSS** · 02-09-2016 11:46 AM

They are a pain sometimes, but you can usually bleed the system at home without any special tools.

Let the engine cool completely
Remove the coolant reservoir cap and elevate the coolant reservoir to get good head pressure
Remove the bleed screw from the top of the coolant hard line (over the intake manifold)
Add coolant to reservoir until you see coolant come out of the bleed screw...then reinstall bleed screw.
Loosen top heater core hose and pull away from hard line to expose the bleed hole.
Add coolant to reservoir until it comes out the bleed hole...push hose back onto hard line and reclamp.
Replace coolant cap and get up to operating temp.
If still overheating, then you prob need help.

Sometimes, you can loosen the top heater core hose while the engine is hot and it will shot out the steam...be careful though cause it be real damn hot.