[tirebiter]

I have been daily driving this 2001 Jetta for about 5 years now and putting up with a foggy windshield etc from a slow leak in the heater core. The leak has gotten worse with clouds of fog coming out all of the air vents into the interior when I switch the heater fan on. Damn distracting while driving.

I am planning to bypass the heater core over the weekend. Yes I am taking the lazy way out. I already have a new heater core ready to go in but I am not in a position to dismantle the interior/dashboard at this time. Just in case something prevents me from completing the job before I have to use it again to get to and from work.

I was wondering though ... can the heater hoses just be pinched off to prevent coolant flow through the core and stop the leak ? Or are the heater hoses relied on to flow coolant or overheating would result ?

I have been searching for a diagram that shows coolant flow through the entire cooling system but I find nothing for the 2.8 AFP engine in a Jetta. Does anyone know if such a diagram exists and if so where can I get one or view it ? I have the two volume Bentley manual but I do not see one in there.

 

[Anaxios]

I would try something like wine corks and clamps for a quick temporary fix. I really doubt it will overheat as the heater core is connected in parallel, not in series, with the engine. I just did an R&R on my heater core (99 1/2 Jetta with split box). Labor intensive but there are good fyi videos on the tube. Worst part is I had to go back into it after it was done. The foam covering over the blend doors had completely rotten off leaving huge holes.exposed. I thought that was normal, but damn, no hot air blowing. Good YouTube fixes for that too. Good luck. Stay warm.

 

[tirebiter]

Thanks for the reply Anaxios. I ended up using 1inch PEX brass elbows. Two of the 90 degree elbows with a hort piece attaching them, oriented to mimic the same angles the fittings are at. One straight and one at 45 degrees. I discovered the herater hoses are 19mm inside diameter and the 3/4 inch PEX fittings were too small. I hadseen in another post or forum or somewhere that someone had used the 3/4 inch PEX so that's what I got at first. I had to put everything back together to go get the larger PEX brass fittings. This is a stop-gap measure until I can get another project vehicle I own to the point I can drive it instead, while I do the heater core. It's the early version like yours. I have seen the videos and plan on doing something better than the foam material on the flap doors. Why VW used that foam is beyond me. I have been getting bits of it for the past esvereral years as the ehatign system deteriorated to the point I am finally forced to do something about it. This past Winter was brutal with the cold and the interior fog machine combined.