So my 94 f150 4.9 has been breaking my ya know, has no heat and overheating. Installed new thermostat, water pump and lower rad hose(no spring in new hose like there was in old one). Possible clogged radiator or maybe a bad heater core???. Please help thanks!!!

 

Welcome to FTE

You might try posting in the section for your truck -- more special knowledge there.

But,
If you've gotten air in the system, it COULD act like that. On some of the Ford cars, the hot trick was to disconnect the heater hose by the dash -- highest point in the system.

Google air in coolant for more, deal is that an air pocket can keep the coolant from moving around.

You have opened up the system a number of times, but it's still possible.

Also, feel your hoses by the heater core -- if the outlet stays cold, it's blocked.

Good Luck,

hj

 

My money is on a clogged radiator. Back in the day, before A/C was standard it was common to find a manual shut off valve in the heater core inlet hose to keep as much heat out of the interior as possible in hot weather. Don't think a clogged heater core will cause overheating BUT the fact that there is no heat either is interesting since the hot water for the heater core generally comes off the water pump and returns to the block. The radiator isn't involved. So either a blocked radiator AND heater core which is entirely possible in a 24 year old truck that might not have been well maintained or as ford2go stated, an air bound cooling system. Something that should be easy to fix. Oh yea, you did install the thermostat the right way, right?

 

So I've the truck now has a new radiator, water pump, heater core and thermostat and it's still overheating and no heat working. No fluids leaking either. Any ideas where to look next. Thanks

 

Does it overheat just sitting there idling or only when you drive it? Does it have a thermostatically controlled fan and is it working properly? Is there a vacuum operated valve in either hose going to the heater core?


How have you determined its overheating - are you going on an idiot light or gauge reading.


With the engine idling, CAREFULLY loosen the return hose from the heater core at the core end. Is there water flow thru the core?


Did this problem start all of a sudden or did you do ANYTHING to the truck just before the problem started?

 

hey there thanks for responding back. So nothing was done to the truck prior to this happening but I did notice additives in the radiator and such. Unfortunately the idiot light is my only guide to telling me it's overheating right now. I'll do the test that u mention and update ya afterwords. Any chance air is in the system. Does the coolant levels need to maxed for proper use.? Thanks again.

 

#1 - rarely if ever believe an idiot light! Does the top tank of the radiator get real hot? How about the top radiator hose? The hoses to and from the heater core?


Generally people throw that sealant crap in a radiator because the radiator or heater core are leaking. Sometimes it works, sometimes it doesn't. They also sell a heavy duty cooling system sealant that people use to fix a leaking head gasket. All of these have the potential to plug up cooling passages in the block and heads as well. And, of course a leaking head gasket can cause overheating. Are you loosing coolant with no other explanation?


If the system has an overflow tank like modern vehicles then the bottle should be kept filled between the full and add lines. As the engine goes thru a couple of hot / cool cycles air will purge out and the coolant level will fall in the bottle and need to be topped off. If there's no overflow bottle, the level should be about an inch below the cap in the radiator when cool.


As a last resort, you should try to find an auto parts store that rents tools and see if they have an infrared non-contact thermometer you can rent or borrow. You can check radiator, hose, block, head and heater core temperatures in about one minute.


P.S. You should put your location in your profile. Whether your in Alaska or Mississippi can have some bearing on these kind of problems.

 

Moved to the 87-96 forum. You should get some more direct answers here, the Garage and Workshop forum is more for discussing tools and workshop or garage issues.

 

If your heat isn't blowing hot, it's overheating, and you are confident there are no clogs....sounds like a head gasket. Are there any other symptoms? Blowing coolant out of the overflow?