I bought my car with a bad valve and Gates heater hoses that were bent so bad they pinched themselves off.

All new Nissan pre bent hoses and valve ready to go on but I'd like to check the heater core for cracks/leaks while it's in the car.

Thought about temporary hoses to fill it with water then either applying negative pressure with a vacuum or positive with my air blowing attachment on my air compressor. 

Any thoughts on trying something like this?

Thanks for any advice.

Cliff

If the heater core is still in the car why not hook it up to the engine and test it? If it is leaking you will have to pull it out anyway.

 How much pressure are you going to use?

1 hour ago, grannyknot said:

If the heater core is still in the car why not hook it up to the engine and test it? If it is leaking you will have to pull it out anyway.

The potential mess, damage to electrical n that area.

 

1 hour ago, Mark Maras said:

 How much pressure are you going to use?

Whatever the rad cap's max is.

With that valve closed it completely bypasses the rear of the head by closing the path through the core.  I don't need heat but it looks cheap without those hoses and a plugged off head hose.

I'm getting close to my first car show!  Don't want some prick pointing out MY problems.  People with no car are the mouthy critics, penis holsters.

Testing with pressure up to the cap limit plus a couple sounds like the way to go.  If you wanted to get even more real-world you could dunk in a bucket of hot water, since a crack might open up when heated.

Or you could just fill it with epoxy since you don't need heat.  Or plug the inlet and outlet.

I can't figure out how to route the hoses without hooking in the rear of the head.  I'm trying to look stock.

Thanks Zed!

I could loop them together under the dash with a 180 copper fitting or two 90s. Come off the back of the head into the cabin, 180 turn around then back out to the bypass tube????

No heat though but I'll pressure test the heater core first before doing a simple loop.  Already bought all the shiz-nit. 8^)

If you just loop it under the dash then hot coolant will recycle through the engine, raising the operating temp somewhat. Easy enough to lodge tapered rubber plugs or other restrictors in the hoses, though.

If you test before installing the new valve and hoses, it might leak at corrosion pitting on the old valve, or at bad hose ends, before the core leaks.

Wish my heater and especially defroster worked. Have the parts but dread the job.

If you are down there with the valve off to be replaced why not just take out the heater core and have it pressure tested at a rad shop?  Might cost you $10 or so.  They will dunk it with about 8 pounds of pressure and look for bubbles.  That's how they did mine anyway.  It would give you some piece mind at least.

Car show folks aren't that picky in my experience.  The folks you wind up talking to are the ones that really like your car.

Edited May 9, 20177 yr by gwri8

8 minutes ago, gwri8 said:

If you are down there with the valve off to be replaced why not just take out the heater core and have it pressure tested at a rad shop? 

I was told something similar  from a girl I was fooling with. Very many dollars later she still needed testing. Needless to say she FAILED but it was a fun week. She was nuts.