DamnedButDetermined

My 79 Ford E250 has been over heating and i cannot find the problem...
changed thermistat, fluid, temp sending unit, water pump, and it still runs hot.

I am thinking of running with thermistat and am wondering what it will do?

thanks,
DbD

jOeHaCk98

bleed system.

w/o thermostat, problems.

ultraDorksGarage

coolant systems runs on a cycle system. the thermostat is what makes the cycle(there is a little amount of bypass though)

but if u dont run a thermostat on a ford ull overheat....ford half ton van im assuming 302. if u decide that no thermostat is the way to go, strip the guts out of it and run an open thermo(not NO THERMO. rather OPEN THERMO.

peeps will say no thermo wont overheat...WRONG. too much flow on a ford = no heat transfer into water.

on the ford, this is common... check timing, if timing is retarded it will overheat under load

ultraDorksGarage

also u didnt say if u checked ur fan clutch...

Al_S14

if you remove the thermostat car will run cold and may not reach operating temperature. wear on friction parts will slightly increase but it wont cause any catastrophic problems

ultraDorksGarage

actually on iron block motors like the ford 302 hes prolly talking about, it will prob. overheat due to the coolant not having enough time of contact to heat transfer. allum. block motors have less of this prob. but still...search an american motor forum...ull find it there.

DamnedButDetermined

I have the 460CI engine, and I got fed up and just took the thermostat out, and it seemed to take a lot longer for it to reach operating temp, but it never went over the middle of the gauge when it finally heated up. The radiator itself is a four core and the entire system holds about 5 gallons of liquid or more!

One more thing i was told at the parts house today that a 190 degree thermo would make the engine run cooler than a 180 degree thermo????????

This seems to make no sense to me because isn't the degree rating what temp the thermo opens at?

The fan works perfectly, I took the radiator cap off when the van was idling and revved up the engine to see if any of the fluid was moving (if nothing moves it would indicate a severe blockage in either the engine or the radiator) and the water was flowing very nicely!

This whole thing is very frustrating, but I will buy a new thermo tomorrow, install it and see if the problem remains. If it overheats again then I am going to run an open thermo for now on!

thanks for the help though,
DbD

ultraDorksGarage

honestly run a 160 or gut ur 180, dont run open.

in regards to parts house, 460 and such big blocks need heat cycle to cool off coolant, but thats normally the case for 160 to 180 degree thermos

edit: im bored so im gonna explain in more detail:
the hotter coolant is above ambient temp, the more efficient the radiator will work. radiators have best heat transfer when its closest to boiling point so if u have no thermo, yes it will run colder, but whenu put massive load over long time periods, it will over heat. u see, if u equalize all ur temps(no thermo) u will have hot 190+ coolant in radiator and motor. but if u have thermo, u will have cool water somewhere, and this cool water will then be cycled to motor when motor water gets hot(thermo temp).

so another words.. the motor temp goes up, thermo opens, hot water goes into radiator, cool coolant to motor, now that radiator has hot water(much above ambient) radiator will work at max effieciency while motor is not overly hot.


i have had 2 460's, one is a new efi motor(new lol, make that a '96, one is a cobra jet head, 11:1 comp factory motor.

i run 160 thrmos on both. my efi motor overheats when pulling trailer up super steep grades for xtended time. the cobra jet runs like [email protected] so noone uses it. holley we got on it is just too big. but we sold that truck like 2 years back.