I have a 1994 (351W) that is using water. I bought it back in October of last year. I don't drive it everyday, maybe once or twice a week. I have found that when it sits for a couple of days I can see a small puddle of anti-freeze under it(about a quarter in size). I have looked to see where it was coming from and the only thing I can see, on the lower radiator hose is where its dripping. The hose appears to be fine though. I have to add a little anti-freeze about every two or three weeks. It has never run hot, until one day last week. I was on the interstate stuck in "stop and go" traffic (wreak). It was about 85 to 90 degrees outside. I didn't have the A/C running due to, at the time it wasn't working. I looked down and the temp guage was almost "pegged out". As traffic started to move and I was able to get up to 50 to 60 mph it started to cool back down to normal. I drove it about 3 miles and stopped, poped open the hood and took the radiator cap off (no pressure on it) and added about a pint of water. I let it sit and run for about 20 minutes, and it never got hot again. I checked with the radiator cap off and looked to see if the water was pumping through the radiator, and it was. I checked the Fan Clutch and its ok as well. I've looked around the water pump and thermostat and can't see any type of fluid new or old anywhere. I just fixed the A/C yesterday and now I need to find out what's going on with this leaking. Any Suggestions?

 

If the truck sits for a while. In time, rust will form and corrode metal. try draining the fluids. replace any real soft hoses ( i mean spongy soft) if you can't tell. It doesn't hurt to replace the hose for a peace of mind. clean all the connection outlets and inlets that has rust build up. I just use a piece of sand paper with a couple of passes. once everything is clean and installed properly. make sure you put the proper coolant mix (ratio) with distilled water. Distilled water has less minerals. It's one of those unnecessary expense. Then you shoud be fine to let the truck sit or not.


for another peace of mind, change the thermostat.

 

sounds like bad hose or hose clamp is loose.

 

I agree. Do the simple stuff first before jumping to wild and expensive stuff. Get in there and inspect all of the hoses, and tighten all of the clamps. There are several smaller hoses that carry coolant to the throttle body , so don't neglect those. In fact, you should change them even if they don't leak, because most of the time nobody ever replaced them or even knew about them, so they are original and far beyond their service life. Also do the heater hoses.

I also agree with thecos about changing hoses and cleaning up the connection area. Sandpaper works fine, but I usually use a plumber's wire brush (for cleaning copper fittings). The 3/4 size is good. I say to use the plumber's brushes asopposed to others is that they are small and easy to get into tight spaces. They sell them at just about any hardware store for about a buck.

I used to have a lot of problems with frustrating coolant leaks. Every time I fixed one, another would pop up. I ended replacing every single hose in my truck, as well as the radiator and cap, heater core, coolant recovery tank, water pump, and intake manifold gaskets. But all that got it, I havent had any leaks or coolant loss for 30,000 miles now.

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From your description of the problem I would be will in to bet its a bad radiator, with a intermittent leak at the seam between one of the plastic side tanks and the aluminum core where they are crimped together.

Just get a flash light and look down that seam on the front and back of the rad on both sides....left and right......chances you will see some coolant there or at the very least some stains/residue of the coolant. You could also "feel" and look around down at the bottom of the rad in the support and look for traces of coolant there also.

 

I agree do the simple stuff first.
If leak keeps comming back pressurize system and see if you can tell were the leak is coming from to fix it.
You can rent a tool do do this from most auto stores.
Thermostat housing is also a spot to keep a eye on they crack causing headaches.

 

First, you need to look at where the coolant is dripping. But my blind guess would be the waterpump, or it's gasket, if it's still the original. If that leaks, the coolant will run down on the engine and will drip further back.