I bought a 1977 Ranchero last weekend from a friend.
Runs great, needs a little body work & has some "delayed maintenance" issues.
Most troubling at the moment is the coolant vapor coming in to the inner windshield, and the general high running temp. It's not getting to "H" but it is in that neighborhood. I see the fogging of the coolant vapor when I go onto the freeway - ie speeding up to 70mph I get a hazing that's hard to see through.
I've been told there is a valve on these that goes bad, rust & corrosion takes it's toll - is that the problem, or is it somehting else (heater core related)?

Thanks

Rick Bastedo

 

Sound like a heater core to me,but just for the sake of varification,check the firewall for any holes or missing rubber seals that would let the vapor into the cab,either way something is leaking,so make sure you ck the fluid level in the radiator right away.

 

Thanks for the help,
when I got it I checked all fluids before driving, coolant was down about a quart - I filled to the top and it hasn't gone down by much yet (I've driven it about 120 miles since bringing it home).
This only happens when going up to hiway speed. Makes me think it's related to load & heat.

 

textbook sign of a heater core about to blow. you can try some radiator stop leak, or if it's warm enough for you, switch the hoses to by-pass the heater core. it'll buy you some time to dig in to the dash. i would try the stop leak first. i like the "alum-a-seal" kind, it doesn't sit on the bottom.

 

I added the sealant & that problem went away almost immediately!

Now to discover the cause of the seemingly high running temp (idiot guage says it is getting too hot). Wondering if I have a pump or radiator problem...

 

I had a 289 that would run just below the red at freeway speed in hot weather - found out that it was punched out to .060 over and the Ford shop manual says not to punch it over .045 over. Hope it isn't the cause of your problem - I ended up geting another block and did a rebuild using that block and the correct standard pistons for it. Haven't had a problem since.

 

it turned out to be just a stuck thermostat