I bought a 97 4.6L 4x4 EXT cab Windsor engine which was in pretty rough shape a few months ago. The current issue that I am working on is the heater. It acts like there isn't enough coolant in the system, as in, it gets hot when the engine is reved but blows cold while at idle.

When I bought the truck and was cleaning it out, I noticed an empty bottle of bars stop leak on the floor under the seat. So I am assuming that there was/is some leak somewhere in the system, though I can't really put my finger on where it might be. No noticeable leaks...

I flushed out the entire system using the add water and drain till it comes out clear method, then I used a prestone flush product, got that all out, and then I added this crap in an orange can that fixed the headgasket on my probe pretty well. let that dry out for a day and then flushed it again with water, and finally filled it back up with fresh prestone green, which I have heard many people on this site claim meets Ford's specs. The heater is still doing the same thing.

One thing I found odd in this whole process, is that not once has the temp gauge ever gotten more than half way up. When I have done this to other cars, it usually gets hot, like, almost overheating hot before I shut it off and let it cool, but the truck never got much above normal operating temp.

So, do you think there might be air in my system? if so how much does it cost to have it purged roughly? Should it be done at a dealer? or can any garage handle that? The main reason I am learning about cars is that I can't afford to pay someone else to do the work for me, but I suppose if it's something that I can't do, I'll just have to accept that.

What else could the heater problem be?

I have also noticed that the coolant is very foamy after driving it... is this normal?
soulmonkey3@yahoo.com

 

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Are you saying that you think the thermostat is opening up too early? There is a little mark on the temp gauge that shows normal op temp, and it likes to stay right around there, although since I've been doing the flush it seems to be a couple of milimeters above that.... I wouldn't think it was the t stat.

 

Nope, I don't what's going on with it, it might not be working correctly. I would drain it and start over from what you said. You didn't say nothing about the stat so I was curious. I posted what I thought might help.

 

Vacuum leak. Not enough vacuum at idle to keep blend door open to let hot air in cab.

 

No, it isn't normal. I'd suggest taking it to any ASE shop and have them pull a CO2 test on the radiator. I believe yer gonna find you have a head gasket issue.

 

With the engine at operating temp heater on hot and fan on high feel the heater hoses. Are they hot? To purge the system of any air you have to run the engine with the degass bottle cap off. There is a small rubber hose on the driver side of the rad that leads to the degass bottle. Check to see that it isn't plugged up with all that sealer shìt you put in the cooling system. If the system has air trapped in it the water pump will churn it up and give you bubbles.

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Ok, so just to test the t stat, I timed the warm up... it took about twenty minutes. 5 to start climbing 15 to reach peak temp and another 5 to fully open the t stat. I also checked the heater hoses, and while one did feel slightly less warm than the other it was certainly not cool, although i suppose that could just be heat coming off of the engine warming up the outside of the hose.
The hose going into the degass bottle is not stopped up.
If there is a head gasket problem, it's not reacting the way my other car did, a 97 Probe, when it's head gasket went kaput. Though, I am learning that this truck is not like other cars...
The coolant isn't foaming like it was before the flush and the gasket fix crap (which worked wonders on the probe by the way) and I am inclined to think that it was the bars stop leak that the previous owners put in it that was foaming up.

I am still keeping an eye on the coolant levels, but they don't seem to be dropping much so far.

I have noticed that the heat seems to work pretty well when the truck first gets to operating temp, still runs hotter when revving it a bit, but even at idle the heat is working, then, as the heater blows over a period of about ten minutes or so, slowly it seems to get colder, even when running up the RPMs. Still some heat, but nothing like it should be... then if it sits for a minute or two at a stop light it gets to be cold air blowing out.

I don't know the first thing about the vacuum, or how to check it for leaks??? Please forgive my ignorance, I am learning about mechanics out of neccessity. I can take a guitar apart and rebuild it blindfolded, but I am only learning about all of this stuff. It's still a bit of a mystery to me. I am trying to save an abused truck from certain doom.

 

When it starts to blow cold check the heater hoses again. They should be as hot as the rad hose.

Regards

Jean Marc Chartier

 

OK... One is as hot as the radiator hose, the other is just warm.

 

I just went through what your are talking about.I did not get heat till I got above 2000 rpms, then when I stop is would go cold.It was my water pump there was no fins left.I have heat that is roasting me out now.I just hope this was causing my overheating problem now.Check the pictures in this thread.Was you coolant brown and rusty the first time when you drained it?

https://www.f150online.com/forums/v8...al-tool-2.html

 

well, I am having no trouble whatsoever with it overheating. I could sit and run it at 6k rpms all day long and it won't get much over normal.

 

I could let mine run for hours and not over heat, it only over heated when I drove it but not everytime.After taking the water pump out I know why it was over heating, not fins to move the collant.If you are only getting heat when you have higher rpm you have a flow problem, either a blocked radiator, heater core, or a bad water pump.20-30 minutes of time you could have the pump off to check it.

 

Or air in the heater core or a vacuum leak so the blend door is not opening.

 

Does the 97 have a Heater Control valve? If it does, maybe the bars stop leak clogged it up or possibly the heater core itself may be blocked... Just my 2cents............