Heater Core Bypass Question

[Ncostello]

Maybe a dumb question... but you never know



Can I just use a section of 5/8 hose to jump my engine coolant tubes at the heater core connections? I'm removing the under dash assembly to clean it out real good and perhaps install a new heater core and evap core... depending on how they look. I don't have any leaks now... just a cleaning and inspection of the insides.



I know it makes sense to install new stuff while its out... but I've had new cores fail just the same. So I figure if they look good with no signs of corrosion... I'll just reinstall them. Can an AC shop pressure test the evap core?



Anyhoo... I didnt know if jumping the coolant tubes would cause a problem. I'm 99% certain it won't.

 

[B.G. Smith]

a bypass should be fine. I doubt you will find anyone to pressure test the evap. because they would have to have the special connections to connect and block off the lines. Like you said, if the fins aren't eaten off or other evident damage I would re-install. If the system has not been opened up before then the internals should be ok, moisture in the system is sure death to the evaporator. Heater core is another question, if the coolant has always looked clean it might be ok but its getting pretty old. bg

 

[GCroyle]

If the lines will not offer a reasonable bend for your section of hose, you can get 5/8" caps for the steel lines. I found them at a local parts store, made to do exactly what you are trying to do. I think they were called bypass caps.

 

[PToombs]

While I was working on my truck I just pulled 1 hose at the core and the other at the tube. The one still on the tube I just bent around to the other tube. Worked good. No heat though.

:-laf :-laf

 

[GCroyle]

Warning It Didn't Work

I used some 5/8" bypass caps on the heater core supply lines to cap them off until I get motivated to R&R the core. One lasted about 100 miles then last night, it busted a hole in the end. Good thing it happened at home. Truck just finished a 6 mile round trip, wasn't even up to a full head of steam.

 

[Ncostello]

A bypass loop is what I'm doing. Don't want to deadhead any coolant anyhow.

 

[GCroyle]

I'm going to set up a loop also, I'm p/o'd at the cap failure, lost a lot of coolant afterall not to mention what could have happened.