2002 Isuzu Rodeo

I am hearing a water flow sound under the right side of the dash when I turn corners or stop.
It started when the radiator cracked. I have replaced the radiator and water pump.
I have filled the radiator with the front of the SUV up and the engin running. Also tried jacking the rear of the SUV up.
I have flushed the heater core. And re connected the hoses blead air at the top of the hoses from the heater core, the return from the water pump to the radiator, and at the radiator to the water pump. Yesterday I pulled the dash out and found the heater core to be more center of the dash behind the climate control. The sound seems to be coming from more right behind the glove box.
Any suggestions before I reassemble the dash.
I have removed and cleaned the lower half of the ac coil/condenser box. There was no fluid in it and the drain line was not plugged.
Thanks for any help.

Sound has an interesting way of bouncing around objects and can be deceptive. If you’ve eliminated any possible sounds of free water flowing behind the glove box, the heater core is a strong suspect. Are there any signs of a problem with the heater core? When mine went recently, I had wisps of steam on the windshield, but only found a touch of dampness on one corner of the heater core. Once I replaced it, I had no other problems. Since you have it exposed, be sure to thoroughly check it out, or consider replacing it. They are typically inexpensive with the labor to expose it the costly item.

I don’t see any signs of a leak. I have not pulled it out or removed the plastic box around it.
This thing is a pain to get to.

How about the smell? Any antifreeze smell in the car?

Nope no smell at all of antifreeze.

Your condensate drain for the ac might be plugged.

I have pulled out the the lower half of the box and it was not pugged.

Ok all
Got the heater core out and get the same sound tipping the heater core back and forth when it is not full of water.
Any ideas on ensuring it is full after reinstalling it

@Bluemm Since the heater core is making that strange sound when you have it in your hand, uninstalled, why not just replace it

Get your hands on a new one . . . does it also make that noise?

Have you noticed any reduction in heater output since this noise started?

The only suggestion I have is to test the core before reinstalling it and then when purging the system be sure you do the final purging with the engine running and the heating system on. Lots of cars, yours may be one, have a valve that opens when the system is on to allow coolant flow through the heater core. If that valve isn’t energized when you do the purge, it won’t allow flow through the heater core and any air in there will stay in there. If coolant can’t get in, air can’t go out.

@bd4690 seems nobody has one in stock special order it will take till Tuesday to get one and at $70 seems pricy when this one is not leaking and does not seem to have any flow restriction.

@insightful no we have not noticed a reduction in the heater but I do live in Southern California so we don’t use it often.

Ok no signs of corrosion vanes all look good. In my hands with the core full of water there is no sound of water. So like you said sound bounces around and is misleading.
I have reinstalled it. Used a garden hose with very low pressure and flushed it until there was no air bubbles. Reconnected all the hoses. Slowly removed each hose to let any remaining air vent out while filling from the radiator. Lastly vented air from the supply hose at the top of the radiator while keeping the radiator full.
I am hopping this will help.
After I get the dash back in I will purge as “the same mountainbike” suggested.
Hope to get it running again for Monday.

If you recently replaced the radiator, I suspect you have an air bubble trapped somewhere. If the temp gauge is behaving normally, if there’s no smell of antifreeze, the windshield isn’t fogging up, and there’s ample heat, I’d probably just ignore it and it will work itself out eventually.

Sometimes on difficult to purge vehicles you have to move the heater controls through a range of settings while air purging to get all the air out. Does this car have air bleed valves to assist air bleeding the coolant? Vehicles with those tend to be the ones where this is necessary.

Made it through another weekend of working on it. Seems I have managed to get all the air out cuz the sound is gone.
Thanks to all. I think the old radiator had an air bleeding valve but the new aftermarket does not.

Glad you got the last of the air out. Good for you. Thanks for posting the update.