Have you checked your heater core to make sure its not partially blocked? If it is water will not circulate properly.

 

Is the heater core the same as the radiator? I had the radiator flushed and they did say it was stuffed up. On the inside of the old radiator hoses they were all caked with white deposits and im sure the same was inside the radiator too.

 

AH-HA ! No its not the same,look at the back of the firewall on the pass side,there are 2 hoses where it connects.The coolant circulates thru the core whether your heater is on or not.Ill bet its plugged with that same stuff.To replace it you have to go thru the dash,its not to hard to do.If you want to just check it first take the hose loose from the block,take the other hose off the core and hook it to the block,that way you have bypassed the heater core.If the core is bad they are only about 30$ .Hope that helps.

 

if it was so caked with crap i cant believe that the mechanic wouldnt tell you so you could get the heater core boiled as well or replaced. I bet its plastered with crap! Rick, i cracked up when i saw your ah-ha moment, i had the same thing. lol

 

If your truck is overheating when driving, then you have a coolant circulation problem. If it overheats at idle, then you have an airflow problem. Make sure that your radiator hose is not collapsing when you rev up the engine. Good Luck.


Joe Flash man

 

We got the water temp sensor and the temperature switch changed out and so far it seems to be fine. I am going to give it another longer test run tomorrow. Either way though I am going to change out that heater core. I dont think the mechanic said anything because the mechanic (me) didnt even know what a heater core was until you guys mentioned it. So far it looks like we are making progress.

 

the heater core can be bypassed and not cause overheating issues.
in fact a common mod is to install a shut off valve so you can stop coolant flow through it in the summer months for a more efficient A/C-cooler cab.

you likely didn't need to change anything at all but your sensor.
always start with the simple things first.before changing parts like water pumps/thermostats,etc.it's good to know if you even have an overheating problem in the first place.
the fan is very loud they say when it kicks on.so if that wasn't even engaged and you didn't smell antifreeze,nor see anything boiling over,the first thing to check would be the temp from a reliable source.
test first.spend $ for parts after.

the heater core,is basically a small radiator in an enclosed case in the cab.the blower mower pushes air through it,so when you turn the heat on,thats how you get warm inside when its cold out.
thats why whenever your engine starts to overheat in the summer,you can roll the windows down,and crank the heat.this helps to expel heat from the coolant (provided you opened your valve back up,if you installed one.)

 

Thanks for the breakdown. Ill search for some more information on doing that bypass. That seems pretty interesting. Yeah, I probably spent more for parts than I had to, but honestly at 170,000 miles I figured it was about due for things like a waterpump. Now I know for a fact the parts are good. And I am preparing this van for an end of summer road trip through the desert so I am glad its all getting done. So far it seems like it is not overheating now after changing the sensors. But since the radiator was caked with crap and my hoses were caked with crap too its likely that the heater core was caked with crap too so might as well get that done as well. I think by the time I am done this van should be pretty solid in terms of larger wear parts being done. About to dive in and replace the front end too. At least that stuff I KNOW is going bad.

THANKS everybody that chimed in on this thread.

 

I have 92 f350 7.5
have changed rad-themostat-allhoses-waterpump-and sensor on drivers side &I have by pass heater coil-new fanclucth ad belts still over heating about a mile after I dive it any suggetuons -it just started ti do it in one day I pull no loads

 

You have a 7.5 (460)? Or do you have a 7.3 diesel?

If you've got a gasser, you'll get better advice if you ask your question in this forum.

Otherwise, same advice as above. Don't rely on what your factory temperature gauge is telling you -- either install an aftermarket one (I like Autometer) or get a laser thermometer and verify that you are actually overheating.

When your factory gauge says you're overheating, pull over, pop the hood, and see if it feels like an oven. If so it's probably overheating. If not, something else is going on.