Jetta - air in the coolant system?

[93SVT]

I replaced the radiator on my 2000 Jetta 2.0 (non turbo) and I’m wondering if it is needed to pull a vacuum on the system after its done, I’m not sure but I think there is air in the system, the temp needle doesn’t seem to move all that much, stays in the cold, only in very slow hot traffic does it go to the 190 mark or so, also the heat doesn’t seem to be as good as it should be. This is just my guess, its hard for me to know what normal is on this car because I bought it with some front end damage and had never had it before replacing the radiator, all my cars have been old school with the regular overflow coolant tank, not the fancy sealed ball thing, levels seem to be ok but something tells me there is air trapped in there and that’s why im not getting coolant in the heater core and wherever the temp sensor is, anyone on here know anything about VW’s? Thanx in advance!

[2 beer]

Did you run it with the cap off and the heat on until you got heat out of the vents?

[93SVT]

Did you run it with the cap off and the heat on until you got heat out of the vents?

You know I cant remember, it was over a year ago, I know I had the cap off but not sure how hot i let it get or if the heat was on, is what you described the proper way to do it? The car has run fine for over a year, I just think something is fishy and this is my best guess.

[95 whitestang]

The thermostat could be stuck open also.

[Iroc-Z]

I would say you have a junk thermostat.

[93SVT]

I would say you have a junk thermostat.

I normally would agree but my lifes experciance with cars has led to an almost certain conclusion, if something works fine before you start working on it and doesn't after 100% of the time you did something during the repair to cause it, random failuers of parts that are unconnected to the repair seem to almost never happen, the T-stat wasn't touched, worked fine before I put a new raditor in and refilled.

[5.0stang85]

air bubble in heater core you need to pressurize the system with a pump to "bleed" the system

napa has them where they screw into the coolant tank

and please tell me your running G12 coolant and not the green stuff otherwise better plan on doing a head gasket

[2 beer]

air bubble in heater core you need to pressurize the system with a pump to "bleed" the system

napa has them where they screw into the coolant tank

and please tell me your running G12 coolant and not the green stuff otherwise better plan on doing a head gasket

jesus titty fucking christ where should I go from here?

[93SVT]

air bubble in heater core you need to pressurize the system with a pump to "bleed" the system

napa has them where they screw into the coolant tank

and please tell me your running G12 coolant and not the green stuff otherwise better plan on doing a head gasket

yes its the right coolant, thanx for the help, I'm pretty sure thats what the issue is, just wanted someone to tell me if my theory made sense or not.


So you add pressure not vacume? I'm not sure I see where pressurizing an air bubble would force it out.

[2 beer]

turn the heat on. run the car. if you arent getting heat after the car is warmed up hold the throttle at around 2k for a couple minutes the added flow should force the air bubble out. If you get heat while holding the accelerator then you have an air pocket for sure.

[GoldenPlump]

1. Turn heat on.
2. Open radiator cap
3. Put front of car up in the air so the air rises to the highest point (radiator).
4. Run engine for a while, rev it up here and there.
5. Post on TCS about how awesome goldenplump's idea is.
6. Quote yourself for truth.

[2 beer]

Turn heat on.
Open radiator cap
Put front of car up in the air so the air rises to the highest point (radiator).
Run engine for a while, rev it up here and there.
Post on TCS about how awesome goldenplump's idea is.
Quote yourself for truth.

the radiator doesnt have a cap. The cap is on the "overflow" which is above the passenger front wheel.

[Max Power]

jesus titty fucking christ where should I go from here?

LOL...you got this guy and I'll take Majktkiowetjkitzokizautoworks and we are all good.

[93SVT]

turn the heat on. run the car. if you arent getting heat after the car is warmed up hold the throttle at around 2k for a couple minutes the added flow should force the air bubble out. If you get heat while holding the accelerator then you have an air pocket for sure.

Thanx will do, should I do that with the top off? Its been like this for over a year, would it have worked itself out by now even if the top was on?

[GoldenPlump]

the radiator doesnt have a cap

God damn I hate how germans build cars. Superior engineering my fucking ass. I discovered this while redoing the suspension on the lemon.