I have a coolant leak, somewhere. I can drive for 200 miles and no smell or loose of coolant, IF I take easy - no hard acceleration. I can do 80mph though.

Other times I can start the van go around the block and water is pouring onto the ground. Is pouring off the right front lower control arm. I can't see where it starts though.

When I have the van in the air I can see all over the exhaust and engine where coolant is being burned off.

I did have a leak in the thermostat housing which has been fixed.

THIS is what leads me to believe it's a heater core. If I get on the accelerator a bit I can smell anti freeze. I may also steam up the wind shield. Last week drinving home I was getting on the expressway, was accelerating to merge and had steam pouring out from the passengers knee area (heater core).

BUT I have NO fluid inside; no wet carpets, no dripping, nothing.

Is this a heater core - or maybe the inlet just outside the heater core.

In the 1997 E150 is coolant routed through the heater core with the heater control temp selected to full cold?

Thanks in advance for the help....

1997 E150 4.6L 225000 miles original heater core and lines.

 

Coolant leaks are always fun to chase.........not.....

Could be a small by-pass hose leaking too??

The best way to find a coolant leak is to use a tester, you can "Borrow" one from many of the main parts stores (Autozone/Advance/ect.) with paying for it, using it, and then returning it for a full refund. As long as you don't break it.

Hook it up to the radiator or overflow bottle, hand pump it up, and any cracked hose, loose hose clamp, bad gasket will show up in seconds, saves a ton of time chasing leaks.

 

This sounds very much like a heater core leaking; smell and fogging of the windshield inside is a clue.

It's entirely possible the leaking coolant is running out the evaporator case during driving so there'd be none collecting on the floorboards.

With Wildman's suggestion of a pressurized leak test you could rule out any visible leaks anywhere on or around the engine and its cooling plumbing. If nothing can be found then we have to further assume its "hidden" from view as inside the evap/heater case.

 

I changed a leaky heater core just a couple months ago in a 2011. It was just a pin hole leak, but the smell was very obvious in the cab and the defrost setting worked as more of a "frost" than a "de-frost". It wasn't leaking into the passenger area either however it was just damp feeling inside and I knew I had a heater core problem. When I took it apart I noticed that there is a drain hole in the housing that would route coolant leaks outside the van, so that would explain why you don't see anything inside.

I have some handy dandy water hose clamp pliers I picked up at harbor freight for not too much that allow you to pinch off coolant lines in order to change things without draining the system. If you got a couple of those, you could pinch off the heater and see if your problem goes away. They'd come in handy if you ended up changing the core anyhow.

 

Your van has lower control arms???

Sixto
93 E150 Chateau 5.8 190K miles