at the new job we have a 95 superduty with a 460 auto trans with 180k miles on it.
truck was bought at auction in july of 09 for $400.
it sat all day running, and when they brought it home, found the radiator empty.
they rebuilt the trans, put a new timing chain and gears, new timing cover, new water pump, new radiator, and new heater core.
this truck purrs like a kitten, and the temp gauge sits at mid gauge after 1 hour idling.
both heater core lines are hot, and the top rad hose is hot.
now for the weird. no heat at all.
ice cold air out of the vents yesterday at 32º external temps.
there are some vacuum lines disconnected and open, but the heat/defrost/dash vents all work the way they should.
also, if you try driving the truck, it will overheat within 4 miles and loose coolant.
i did a rad pressure test last night, and it held 10 lbs for 2 hours.
the only thing i can see or think of is that
1: it has red coolant in it,mixed 50-50 with water
2: there is no lower shroud in front of the radiator

this is primarily a snow plow truck, and the boss asked me if i could try to figure out the problem with it.
i am stumped, and decided to come to the people that know for answers



thanks, Tom

 

Usually the door that opens to let the air flow thru the heater core is vacuum operated.

 

i know. but seeing that the vent doors work as they should, that means the proper vacuum signal is getting to the heater circuits, no??

 

Some are mechanical and some are vacuum driven, who knows until you look. Have you dug in to it to see if the hose is still hooked to the motor or the vacuum valve at the control panel? Is the motor good? Is the door jammed? Just because there is vacuum to the control panel lever and something else works don't mean squat.

 

Hi Tom,

My thoughts on your cooling system issues…

No hot air from heater - Blend door non-functional causing heat to be in the Cold position permanently. My ‘86 blend door is cable actuated. Could be a control issue or it could be a rodent nest (you did mention that this vehicle sat for a while). Maybe pull the blower and have a look in there too.

I don’t understand the “overheat within 4 miles”… When it overheats and looses coolant, does it “boil over”? Where does it loose the coolant from?
A few things I can think of here are:

Air trapped in the cooling system preventing coolant flow. I’ve seen that A-hole Boyd what’s his face vacuum out the air from a car on his TV show. I avoided this issue when servicing my cooling system by using a “12 volt marine pump” from Harbor Freight, a pair of old washing machine hoses and a hose pincher. I pumped the new coolant into a Tee on the supply heater hose until it showed up at the radiator opening.

Thermostat not opening? Is the lower hose hot as well? Can you feel hot air being discharged from the radiator? My 460 will go from cool to hot while the thermostat is doing its thing at idle in the driveway. The fan clutch will also have a noticeable reaction to the hot air temperature and pick up the tempo.

I’ve seen head gaskets that leak only under load (combustion gasses into cooling system). This presented itself as a squealing sound under load followed by a discharge of coolant from the over flow reservoir.

I'm not sure about the red coolant, is this new?
I don't think the shroud is an issue, specially in Winter.

Good luck and keep us posted.

 

the overheat in 4 miles is what they told me. i can not test it until i put new brake lines on it. i went to use it a few weeks ago and popped a brake line before i even left the yard, so i just parked it at the time, and forgot all about it till Friday.
they did say the gauge goes to hot and the heat stops blowing, and once it cools off the rad is empty. not sure if it is boiling out or burning it.
i figured it was a air intake problem with the no heat, since it worked last year.

i have to assume the thermostat is opening, otherwise it would have overheated while it was sitting running in the yard for over 1 hour.
i did not have my infrared thermometer Friday, so was not able to test the upper to lower hose temps.

i was thinking along the lines of cracked heads also.

 

Question, I am having the same issue with the heater. Where is this door? Behind the glove box like the heater core?

 

yup. the blend door in inside the heater plenum. you need to remove the heater core to access it.

 

My money is on a malfunctioning T-Stat. If there is no visible leak than it must be internal.

 

upside down t-stat? also, i found in my 95 E350 w/ 460 that if i used a stant style t-stat i had no heat in the cab and no heat in the engine - went to a dealer - i was on vacation - and bought an OEM ford t-stat. it was a balanced thermostat (robertshaw style) and all problems solved immediately.

the stant piece was not defective. tested it when i got home - bought another stant from a diff store and got the same results...

 

i forgot all about this thread.
the heat problem was the door outside in the engine bay before the heater core. the vacuum controller was bad, keeping the door closed not letting air through the heater core.
the over heat problem was multiple issues. the red coolant had a lot to do with it. it runs fine now with green coolant in it. it now only runs hot with the snow plow on it. we are going to put a shroud between the grill and lower rad support to replace the one that is missing. i am thinking the plow alters air flow into the grill, and with the missing shroud, the air flows rite back out the front of the rad support instead of going through the radiator.

 

it's fixed!!


at 3 am this morning, i was laying in bed thinking to myself there is simple and hard ways to do things.
and then it dawned on me, "yo stupid, don't over-think things."

(i do a lot of thinking at 3 am as i try to decide whether to get up or try to go back to sleep)


then i i realized, FAN CLUTCH!!

i kept on over-thinking the problem, and never thought of the little things that cause the big problems. when NAPA opened, i got a clutch and put it on. 1/2 hour driving around with the snow plow all the way up straight blade blocking the grill, and the temp gauge never went over 1/2 way.

 

^^^^yer funny. pretty sure that would have been on the top 3-5 of my list.

having some similar issues with my daily driver cavalier. just put a new water pump and t stat on. i think i have a bad t stat though. car overheats to about 240* then the t stat opens and the low coolant light comes on. need to flush the system again as well. lot of rust in the new coolant and in the process of it repeatedly boiling over the new resevoir cap i put on is now fubared too. stoopid chebbies.

 

like i said, i tend to over think things.

 

i tend to under think things. makes life fun