Ryano

[quote=jaybird531;33073 Does anyone know where the coolant temp switch sits on the 432 engine? Where the book says it is, it ain't...[/quote]

Glad to hear it worked out

The hayes manual has the temp sensors for v8 in chapter 3 (3-5) picture 6.1a and 6.1b

ranzo

I suspect that you may have some air trapped in your cooling system. I always use one of those Super funnels that hook on the radiator and keep the water level higher than the rad. and helps force air out.

another trick is to Jack the vehicle up about 15deg and rev till 2500 rpm with the cap off. I have seen some vehicles not overheat but not get proper heat unless revving due to air trapped in the system. Have seen it cause the problem with the lower hose not getting hot as well not that common but has happened.

jaybird531

My last post had a typo...I don't have a 432 engine, I have a 4.2 engine....Still looking for the temp sending switch. Where the book says it is, it ain't....By the way, again, thanx to all who have helped...I now have heat, but still the coolant flow issue...Someone said that the switch took care of an issue they had, and so I want to replace mine, but I can't find it. Any help would be appreciated. Slowly but surely this thing is getting fixed.

Ryano

Whats the issue?
If you have heat its circulating !

I assume this is on a truck, if it were a car a ele fan comes into play with one of the temp sensors! The other sensor is for guage reading only. I cant see any infulance this would have to do with coolant flow

phatchopper300

I have some of the same problems have 2003 f150 4.6 and no heat. I was told that there is a bleeder screw on the radiadator. Air is in the system and needs to be released. I will post as soon as I have it fixed. I was explaining my problem to the person working on my truck and he finished telling me what was going on and he know right away what to look for. We will see.

jaybird531

I tend to agree with phatchopper300...Though I am looking at all options...I am reading all responses. I am going to try the jacking up of the truck to see if air does come out. I have heat, which means that there is flow. The cold lower radiator hose is throwing me. I also agree that the sending unit is just for the dash guage. But, so far, except for the flushing of the heater core, nothing has made sense with this truck.

Ryano

If you have air in the system do as Ranzo sugested in his post above!

The lower raditor hose should be cool, the anti freeze has cooled after going through the raditor!

Good old Bill

A new commer to the mixed ideas. At this time don't be concerned about the different temperatures of the radiator hoses, if this engine is not overheating then the cooling system is doing its thing. Concentrate on the heater hoses, are they near the same temp? Asking that, I want to add this, my 02, 4.2L, manual AC, the temperature blend door is electrically operated. Perhaps its in the cold mode and is not moving toward heat. Perhaps a simple fuse.

jaybird531

An update. I replaced the waterpump...The impellars were good...I flushed out the heater core...have heat...does not overheat...I have been driving it now for a couple of weeks...no issues...I still need to know where the coolant temp sensor is on the 4.2 is tho.

dantenbusch

Thanks for the tips above. In my truck, the air works fine, there are no leaks, and the engine doesn't overheat. I verified my blend door actuator was moving by removing the center cover by the floor under the radio console. With the engine warmed up, the inlet hose to the heater core was very hot, the return from the heater core was hot, but not quite as hot. With the engine off, I pulled both hoses off (engine end - much easier than getting to the firewall). I blew them out backwards with an airhose, ran some CLR in, let it soak for 10 minutes, rinsed with around 5 gallons of water, then re-connected the heater core hoses to the engine. Heat works great now! Obviously a plugged heater core.