Since it was a little warmer today I decided to do a little work on the Jetta after work. I back blew the heater core by connecting the air hose to the outlet and putting the inlet into a bottle to be able to see any sediment that came out. I blew it out and didn’t get any sediment or dirt at all out of the core, and the pressure was high enough to almost blow the hose right out of the bottle so I really don’t think there is a clog in it. I drained all of the coolant from the system, blew air through the whole system to make sure I got it all then refilled with 50/50 to make sure the mix was correct. Also, I left the outlet hose of the core disconnected to see if anything was coming through and the coolant did start to come out so I know it is flowing through the core. I have minimal heat, but nothing like I should.
I did notice that it either the NORM or the MAX buttons are pressed (“on”) the fans are coming on. The fans don’t seem to have any affect if I disconnect the radiator coolant temp sensor and the only thing that shuts the fans off is by making sure neither NORM or MAX are on. Is this normal? I read in the Bentley that its normal to come on with MAX and on defrost, but nothing about NORM. Both the inlet hose and the outlet hose are about equal in temperature.
I don’t mind replacing the heater core if I have to, but I really don’t want to pull that whole damn dash out just to find that wasn’t the issue… lol. Any ideas? And yes, the thermostat is good. Car gets up to running temp and stays there.
Waterpump. You have an ABA the water pump is probly the original and still has the plastic impeller that becomes disconnected from the shaft. They have since revised the design and now have metal impellers
Friend of mine had the same problem but on a VR6 and it was the pump. I think this is the same problem as my fiance’s Passat
I thought about that, but if the pump wasn’t working, the hose for the heater core wouldn’t be hot b/c there wouldn’t be any coolant flowing. I was thinking about possibly putting a pressure gauge on one of the hoses and seeing what the pressure was… but I’m not entirely sure what it should be so I don’t really have anything to compare it to.
IT would still get hot it could still be spinning but not at optimum performance to give you heat believe me ive had it happen on 3 different ABA’s
Then I guess I’ll swap out the pump first and see what happens. Either way, it sounds like it wouldn’t be a waste if they are that prone to going bad. Rather do it now before it really f’s up and its no longer drive-able. That and the pump is a HELL of a lot easier than the heater core… lol.
Seriously the pumps are prone to going bad. Now when you do the pump you can do the whole housing or just the pump. IF you do the housing do the thermostat.
i just did the thermostat, but for the $15 extra, I’ll probably just do housing and all.
Is the car overheating ever? If no your waterpump fine. You just did your thermostat so thats good. Only thing i can think of at this point is the hot/cold blender is stuck partially open going into your heater core?
hot/cold blender seems fine. I checked all of the cables and they are all going all the way to the stops. The only thing with the blender that could possibly be is maybe the little seal could have been chewed by mice b/c I know that a few of the other seals are pretty much shot.
As far as overheating, I haven’t really had the car running on a real hot day yet so I wouldn’t really know if it was overheating since its been cold enough to pretty much keep it cool.
I am going to… and part of that is because I have to do the power steering pump anyways so I might as well do them both at the same time. Now if the p.s. pump was as cheap as the water pump. lol.