What is temp of heater air?

[James Morse]

Thank you everyone. I'll flush following RonD directions. Interesting about the vinegar, I wondered about using that, because I use it in other work to remove zinc plating from nuts, bolts, screws and to remove rust, so if there is build-up of rust from engine in the heater core that would make a whole lot of sense.

Before flush I am getting about 100F so that's low for sure.

RonD: One hose which has a valve on it, I can disconnect it on the heater core side of the valve, leaving a pigtail of hose out of the core (good, for flushing). It goes to a connection near the thermostat. The other hose, which goes to a point lower down than the other one, near the thermostat, has no place to disconnect it in its length because it is one solid piece, it can come off either at the heater core, or, at a place very hard to get to, so I wouldn't try taking it off there. What I was thinking is, disconnect that second hose at the heater core, then get a short piece of hose the right size and put on the core to aid in flushing, would make it a lot easier. Makes sense?

 

[19Walt93]

The hose leading to the water pump is the suction or return side, the feed/hot side would come directly from the engine. It would be a good idea to flush all the coolant, making sure to pull BOTH block drains, too. We looked for about 130 at the dash vents. If the discharge is nice and warm at a stop and cools off as you drive the core is probably partially plugged like Ron said.

 

[James Morse]

Thanks... so the hose with the valve would be the feed side... I think, right? Which would make sense as that was the slightly hotter hose - both being about equally hot would tell me the core isn't sucking the heat out of the coolant like it should.

The feed side comes off right below the thermostat, the return side lower, I'm guessing maybe that is the water pump. Then I'll reverse those at the core when I re-assemble per earlier advice.

Yeah, I didn't flush the core when I flushed the rest of it, which was a mistake due to rushing it. Once I get this heater core problem (or door, or whatever it turns out to be) knocked out I might do a complete flush again, kind of a waste of coolant, but the stuff that came out from the engine/radiator was --grody-- it had sediment rust in it and so it might not be a horrible idea to run it a while then do another flush of everything.

https://www.autozone.com/heating-and-cooling/universal-radiator-heater-hose/p/continental-6ft-x-5-8in-heater-hose/5022_0_0?cmpid=LIA:US:EN:AD:NL:1000000:BLH:8362355655&gclid=EAIaIQobChMIx9qi7-2X8wIVgYTICh2OxgQ_EAQYASABEgJ6h_D_BwE&gclsrc=aw.ds

or could use garden hose.

below is nifty tool for removing hose clamp at heater core connections. it doesn't slide off like pliers and you can come at it from the side, and it locks as you compress the clamp, and then you can easily pull the clamp up onto the hose with no problem. I highly recommend it. It's actually specifically made for those kind of hose clamps; the slotted jaw engages the larger of the clamp ends, and the concave end holds the smaller part, and it then is effortless to get the clamps off and on (compared to, say, using channel-locks).

 

[RonD]

Yes, about getting an extra length of hose, longer the better
OR
You can get a coupler of correct size and 2 clamps, and cut longer hose for flushing, and use coupler and clamps to reconnect

Whatever is easier

 

[James Morse]

yeah man, that's just what I did. I had old garden hose and cut about 4' or so to go from the 'in' of the core down under the truck so all the crap goes there plus I can see exactly what is coming out of it. then I attach just a short curved piece to the 'out' and a lot of gunk came out, it seems to be freely flowing.

put it back together, it went up to 110 (increase of 10 degrees so far) before the temp gauge was even at zero (not even between the hash marks) but then it went cooler and I am thinking, that since it's hot out, there's probably a temperature sensor that opens and closes the valve for the heater core? Because if so, at some point that sensor is going to say, ok, it's 95F in the cabin, that's way hot and in fact it borders on dangerous. So it would make sense that even if the core were capable of putting out, say, 150F, at that point it's not a good idea, if you heat the cabin to 150 that is almost like a slow cooker. If I'm right about the sensor and valve, then, is there a way to fool the valve to be always open, just for testing?

I back-flushed, a lot came out, then I put a plastic cap over the 'in' and put somewhat diluted store vinegar in and rinse that side and then did the vinegar from the other side (putting water in the 'in') and flushed that, but really I didn't see much come out at that point at all and it was pretty clear and seemed to be flowing about as much as I would expect.

Anyway, I'm thinking probably everything is ok and I am just being overridden in my tests by the cabin temp sensor and the valve that controls water flow to the core. I mean, it could be the door, too, I'm not totally ruling that out, but the fact it went already way higher than it did before tells me the core was at least part of the problem.

 

[RonD]

No, there is no "temp sensor" in the cab heating system

And valve in engine bay is an ON/OFF valve no partial control, CLOSED or OPEN are the only 2 positions

 

[James Morse]

OK, that's really interesting good info, thanks.

In most recent test what I did was (thinking there might be a sensor), ran the a/c and took a drive - more realistic situation - then came home and parked and put the heat all the way on the dash vents. It went up to 120 and it was still going up slowly at that point. That's a big difference from 100F which is just over body temperature. I could even live with 120. Target is still 130 but I might not get there, not sure what else I could do at this point except replace heater core but at 120 I can't see doing that. Of course in the winter would be the real test.

I suspect there is yet more crap in the core that wasn't knocked loose yet but might have been loosened up so I'd think it would only improve.

The first stuff that came out of it was more a slurry than a liquid. So I'd say that the core was the culprit, and, it's possible there is some heater door contribution. If my engine is running 190 then it seems like really efficient heat transfer in the core would yield air hotter than 120, when everything is working 100%.

A/c runs 44-45 so that seems plenty cold, that's about as cold as your fridge. It was about the first thing I checked on it. Now I have the 4 fan speeds it's really nice, plus the engine running at temp (it didn't have a thermostat in it before), and heater core seems quite a bit better, let's say, based on that last test, about 2/3 of the way towards being in spec, and probably plenty warm to work ok in real life.

 

[RonD]

Also try putting selector on PANEL or FLOOR not panel/floor, that will turn OFF the AC compressor, which is always on in any other setting beside OFF, but fan goes off when setting OFF is selected

AC is on to dry the air in that cab, the heater can easily over power AC, but it does cool the air a bit

 

[James Morse]

Thanks RonD, I was running the tests on Panel only, so that's right, I might get a different reading with a/c involved, didn't try that yet. Fastpakr was telling me about that offline, before.

What causes the valve in the engine bay to open/close?

I get what you're saying, once that valve is open, the only control for the amount of heat is the blend door.

Yes, now that I think about it, if a/c cools ambient air (say 80F more or less, yesterday), to 45 (if -not- using Floor or Panel), then the heater has a bigger change to make to the air so likely it would be a little less hot than otherwise. In fact, it would basically duplicate doing a test without a/c involved if the ambient air were 45, which is a more realistic situation. Then there are of course situations where ambient air is, say, 0, can't really know what will happen then until I run into that situation.

I didn't leave the vinegar solution in the core very long. Vinegar will dissolve iron, and I don't know if this could eventually eat through part of the core, in which case, if the core leaks, I imagine there'd be a strong antifreeze smell coming through the heater vents, you'd know it right away. What I'm saying is it might not be a bad idea, depending on what you say, to do another flush to the core. With the nice hose clamp removal tool and the hoses, it's really very easy. I suspect that the core was mostly blocked and so while some hot water was getting through, I think for the most part it was clogged, the stuff that came out in the start of the flush just barely dribbled out and was really thick and gooey. Maybe now there is some or most of it freed up but some could maybe still be blocked.

I have to think whoever had it never used the heat because with no thermostat in it you wouldn't get much heat regardless of condition of heater core. The truck hardly ever got even 10% into the normal temp range. I'm hoping now that it runs normal temp (I put 195 thermostat in it) I might get a little better mileage, too. It looks like I was getting about 13mpg but that's all in town driving plus a lot of idling during working on it, plus figuring based on a couple fills isn't really enough info to tell.

 

[RonD]

This is the vacuum diagram for Ranger Vents: https://www.ford-trucks.com/forums/attachment.php?attachmentid=517&stc=1

Look on the right, the WHITE vacuum hose, it controls fresh air vent AND heater by-pass valve in engine bay, the GRAY hose

It has Vacuum in OFF and MAX AC settings
So by-pass valve has vacuum and is closed in OFF and MAX AC


Flushing gets any larger debris out of core
CLR or Vinegar are acidic(ph2.5), they help loosen corrosion, but it needs to sit for 15-20min before being flushed out
No, it won't hurt the core or any other parts of cooling system to do this

New Coolant is a base, ph9-10, so this would eliminate any worries about remaining vinegar or CLR after cleaning and flushing, it Neutralizes any remaining acid

The anti-corrosives in coolant can ONLY protect bare metal parts, so once corrosion starts that metal can no longer be protected, the new coolant slows down the corrosion but can't stop it once its started, its like painting over Rust

Corrosion started in the first place by not changing coolant when it was do, 2 years for silicate base, 5 years for others
No such thing as "lifetime coolant", well I guess its determined by what "lifetime" means, i.e. 5 year warranty.....Lifetime is over sucker, lol

 

[James Morse]

Thanks RonD this helps me a lot. Great diagram and explanation.

I suspect flush of system had not been done for some time. When I poured off the drained (old) antifreeze, there was a lot of rust-colored sediment settled to the bottom of the bucket.

Finally did undiluted hot vinegar and left it in a while. Not a lot more crud came out so looks like I got a lot of it in the previous attempts. Temp now hits 135, up from 130 before the last cleaning, and was 100 before I did the routine, so substantially better. I'm calling it done.

Thanks for all the help.