Need heat

[idiburner]

Hey everyone I need a hand. I drive a 93 f350 crew cab dully 7.3idi auto 4x4. It makes no heat. The temp gauge moves to just before the N and no more. I replaced the heater core, thermostat, fan clutch. Truck still doesn't push any heat out the vents. The blend door does work and moves freely. So what else can be wrong. Thanks guys.

 

[Clb]

Circulation problem???
One of the small line connections plugged , would be my first " look at" items.
Cables on heater controle valve next.

 

[IDIoit]

the first thing i would look at is if the HVAC motor is working.
if yes,
then does the dash vents or defroster even work?
where are the heater core lines connected to the engine?
its cold out there and no need to be driving a refer truck!

 

[OLDBULL8]

Did you use a Motorcraft or IH t'stat?

Was the ball check in the T'stat neck free, shake it, it should rattle.

When up to temp (~180*) you shouldn't be able to hold your hand on the upper rad hose.

Get a HF non contact Laser temp. Black Friday Sale. They really come in handy. http://www.harborfreight.com/Non-Co...zIjoiMjUuOTkiLCJwcm9kdWN0X2lk IjoiOTM4MiJ9

 

[idiburner]

Hey guys thanks for the replys. The HVAC fan does work, the cable works and no vacuum lines are broke. For the heater core hoses for were they connect to engine and radiator should I take them off and look for clogs? How can I check for circulation? Thanks again

 

[idiburner]

For the thermostat I did not use a motorcraft one, is that a problem? I believe the little ball is still there, what's it's purpose

 

[Clb]

Yes pull the hoses 'take a garden hose to the heater core( if you get one of the hose end repair deals for 5/8" hose )you can use it to flush the core both ways , then try the block both ways and see what ya get.

 

[idiburner]

I'll do that tomorrow. How much coolent do I need to replace.

 

[Clb]

Hit the stickies!
Search button is your friend.
Next get an fsm

 

[Kevin 007]

You also want to use ONLY a Motorcraft T-stat. All others may look and fit the same but there is something different about them (I don't remember what). Someone will chime in im sure or you could definitely find other posts on it.

 

[Hydro-idi]

Non-factory thermostats will not work properly in these engines. Aftermarket thermos will not pass sufficient water when fully open, which may cause overheating problems. In my case, the aftermarket thermo that was used in my truck physically broke. Two of the arms that keep the center in place actually broke, so truck would never warm up in the winter. Also had mild overheating symptoms when pulling hard.
I no longer have overheating issues and truck warms up 10x faster in winter weather with the motorcraft thermo.
That ball bearing in upper radiator neck helps purge air from the system when you perform a coolant change. I purposely took mine out and haven't found that truck takes any longer to warm up in the winter months. Purging air from my cooling system doesn't seem to be a problem either without it. Figured removing the ball bearing may help with cooling when working truck but don't think it matters all that much.

 

[IDIBRONCO]

One problem I see is that you said your heater hoses connect to the engine and radiator. However this was done was not the right way to hook them up! One hooks to a nipple on the passenger's side head while the other attaches to the water pump. If your hoses aren't attached like this, you may not be circulating any coolant through the heater core. Also, don't rely on the factory gauges as anything more than a guess at what they're supposed to read. Use a good aftermarket gauge if you want to know what your engine is really doing.

 

[idiburner]

Thanks everyone. I ordered a motorcraft t stat and I will have it Tuesday. I'll check all lines for clogs. quick question when i was doing my heater core i noticed that there are two blend doors. They both open and close how they should but the one on the left lets cold air in when heat is on. Is this right? Is it supposed to be open or closed when heat is on? Thanks

 

[Stu Bailey]

You ever find out what went wrong here? Sounds like I am in the same boat amigo.

 

[franklin2]

You ever find out what went wrong here? Sounds like I am in the same boat amigo.

You can do some quick troubleshooting.

1st thing. Is the engine actually heating up? If you believe the crappy factory temp gauge, is the engine actually warming enough to get heat? Remember this is a diesel, it is not going to warm hardly at all unless you get out on the road and use the engine.

2nd. You can do some quick troubleshooting. If you think the engine is warmed up, when it's running lift the hood and grab the heater hoses. If the engine is up to operating temp (about 190F) you will quickly let go of the hoses, they will be hot. If the engine is fully warm, but the heater hoses are not very hot, suspect no flow through the heater core because of a clog.

3rd Another way to verify the engine is fully warmed up is to grab the upper radiator hose. If it's cool to the touch, the thermostat has not opened yet. When you start the engine cold and it is starting to warm up, if the upper hose is warm, the thermostat is stuck open.