B5100E cooling problem

[tackepj]

My '78 B5100E blew the fan belt last weekend. I found a new one (OEM) online, and replaced it. Gotta say, either I did it wrong, or there was about 5 times as much work to do the job than on my old Toyota pickup.

Started it up, and it runs fine, but I appear to be losing quite a bit of coolant. When I bring the throttle up, the fans sprays a nice mist of coolant all over the place and it gets pretty steamy. I can't *see* the leak, but there seems to be a puddle under the bottom of the fan when it's running. I don't remember spilling that much when I emptied it or when I filled it back up.

I never lost any coolant in the past, and I'm worried that I may have somehow damaged the rad. Not sure how, but who knows. This is my first dance with these "thermosiphon" type systems, so maybe i'm in over my head.

Any ideas? I appreciate it.

 

[Stumpy]

I'd be surprised if you damaged the radiator just by changing the fan belt. Thermosyphon systems are even simpler than forced cooling systems except they're less efficient and more sensitive to any loss of efficiency (dirt in the rad, restrictions, ect).

You'll have to find the leak. Start with the radiator cap and then examine the hoses, at worst you aggravated a crack in one of the hoses. Could just be a loose hose clamp. It might be helpful to remove the fan or it's belt so it doesn't spray coolant everywhere while you're looking for it.

 

[Apogee]

Hi Tack,

"My '78 B5100E blew the fan belt last weekend."

I'm wondering if the alternator bearings seized up and cracked the fan pulley housing, thereby starting the leak. Did you try turning the fan while you had the belt off? Did it turn smoothly?

I hope it's just a hose as that would be great.

Please keep us posted and perhaps post pics so we can all learn.

Thanks,

Steve

 

[tackepj]

I'm getting new hose clamps today and I'll give it a try. I have to admit that I buggered up one of the clamps pretty bad when I removed it, so maybe that's the spot.

The alternator/fan moved fine when the belt was off. The belt had been in pretty poor shape, so I think it finally just gave up the ghost. I guess if I had to, I could pull the rad and have it pressure tested at a shop somewhere. The replacement rad is $400, so I'm in no hurry to go that route.

It's not possible to overfill it, is it? When I drained the rad, I didn't get out as much as I put in.

I continue to be amazed at how well engineered this thing is. Feels like it was built to last 100 years, but it ain't trivial to work on it...