99 Astro Front Heater Core

Need help with Heater Core.

I can here water solshing around after vehicle has set.
It sounds like it is coming below the dash on passenger side.

There also was a 12" puddle on the ground by passenger front wheel.

Water level is radiator is very low.

I think it might be the heater core, but the carpet is not wet and no signs of water on the inside of van.

Service manual says to remove access cover for heater core replacement, but there is no picture showing if it is inside or under the hood.

Any help here would be appreciated.

If the core case drain is not obstructed, you won't always get coolant on the passenger side floor when a heater core fails. A pressure test would be best to determine if there is any leakage, and pinpoint the location. While it may be a heater core, it may also be an intake manifold leak. The coolant runs down the engine in any number of places, drips off the crosssmember, and can reach the floor at nearly any location. I had a "rear freeze plug leak" that turned out to be a front coolant crossover leak at the intake, just because the coolant drained along the most interesting path.

Thanks Blue Bowtie for the advice, will definitly pressure check it first.

I thought of the intake, but because of what I heard inside and where the puddle was I jumped right to the heater core.

If it does turn out to be the core, do I remove it from the inside?
The factory manual says to remove an access panel (screws)
Then remove the core screws and straps.
However there is no illustration, :frown:

Sounds pretty easy.

The pipes go through the firewall so I think it has to be inside the vehicle.

Thanks

the astro is the easiest heater core i've ever replaced. buy a new one first, about $40, so you know what you're looking for. remove the large black plastic cover under the dashboard on the passenger side that bulges out like a doghouse, held in with 7mm bolts. inside there's a strap across the core held in with 7mm bolts. then pop the hood and locate the hose connections near the blower motor and remove the hose clamps. if you have the spring loaded clamps, use a pair of pliers or channel loks to move them off the pipe and over the hose. on an old beast like this you'll probably need to cut the hoses off and replace them too. just use a razor knife to slice the hoses parallel to the pipes and peel them off. the hoses aren't premolded, just "cut to fit", two different sizes so you can't cross connect them. take them to the parts store for replacement lengths, and get new hose clamps too.