Ever had a new Thermostat fail?

[Meridious]

Update: I just could not imagine that the heater core was the issue...I plugged the outlets while the engine was away being rebuilt...but it turns out that the heater core is plugged up as tight as the cork on a champagne bottle.

I have felt around inside the core with a soft plastic probe that wouldn't damage it...and I cannot determine where the stoppage is....but you could not get air, much less water through that sucker...it is completely stopped up.

How difficult is it to change these on the 60 Birds? I just completely overhauled the AC and I believe that the core bolts from under the dash? If I have to take that AC housing off for this...I believe I will just bypass the heater core and do without it completely!




HI everyone,

I just had my original 352 rebuilt. Popped her back under the hood, cranked her up, and VOOM! All was well...well...accept that I found out within about 5 minutes that no water is circulating through the block.

I know that the new water pump is circulating...but nothing is getting to the heater hoses (for example) and as far as I can tell there is zero circulation through the block.

I installed the low-temp thermo (I live in Louisiana...I go for the lower temp) myself, and know it is not upside down, installed improperly, etc.

I even did the old "shadtree" test prior to installing it to ensure that it was not frozen (involves making that spring pop with a small tap with a craft hammer).

I have heard stories about them failing from the factory, but I have restored and rebuilt SOOOO many vehicles through my life...and it has never happened.

So:

Water pump is definately circulating.

Not a drop is getting through the top side of the engine that I can tell...heater hoses high and dry.

Within 10 minutes, the radiator is hopping like a supervolcano ready to blow.

What I DO know for sure is that there is no blowback (Or if there is, it is undetectable without a gauge) into the radiator from the block.

My first step will be to pop off the upper tank and replace the thermo...but I thought I would get some opinions or ideas in case this happens afterward.

Thanks

[simplyconnected]

I have reservations about blaming the thermostat. An air bubble in your block could be the culprit, as well. When we do this at the factory, we completely evacuate the system, then fill. That takes care of any air pockets.

As far as your heater core, I would try phosphoric acid. Seems a shame to change a heater core that doesn't leak.

Phosphoric acid is found in "CLR" (calcium/lime/rust) and "Krudd Kutter - Must for Rust". Both products can be found in Home Depot. The Krudd Kutter is about $8/qt., but works the fastest on rust. CLR is a little higher but may work faster on calcium. Both products wash away with plain water. Both products work better with heat. Pour it in and let it soak until you can recirculate with low pressure (like with a drill pump). Reversing direction a few times dislodges larger chunks.

Hope this helps. - Dave

[ncbird]

Cleaning heater core

I have to agree with Dave on this. What happens is when the heater core is sitting dry (while your engine was out) the crud inside drys and hardens plugging the core. On boats we have heat exchangers instead of radiators and they have to be cleaned regularly. We use a product called Ph-Ospho-RIC or Ospho for short which can be bought at your box improvement stores in the paint dept. We dilute it and run just as Dave suggested. We do use a large pail with the discharge hose in the bottom and the pickup hose suspended in solution to keep from flushing the crud back into the exchanger. If you want to do some research just google "how to clean a marine heat exchanger". This mixture can be neutralized with soda and then disposed of. I would make sure you have a pump that can run on its own so it can flush for awhile. Maybe your drill has a switch to keep it on. Flush the core with fresh water and then reconnect to the motor. This is an acid so take the proper precautions with glass's and gloves as well as protecting the finish on the car. We also use Ospho to neutralize rust so if you have any place you need that done you can kill two birds with one stone. I would suspect that as Dave says krud cutter or clr would work also. Grant

[simplyconnected]

Grant, you are THE MAN, and you hit the nail on the head again. Ph-Ospho-RIC is available at Home Depot at HALF the cost of my stuff. I wish I knew about it yesterday when I was there. I would have picked up a gallon (~$13). I have a 'desert cooler' to do on my '55 and you just saved me some money! I've been looking for a product like this for years.

Phosphoric Acid is found in Coke and Pepsi. My dentist uses it before he sets crowns. At the factory, we use it in a process called 'Bonderite'. When the Body Shop sends units to Paint, the Paint Dept., sprays HOT phosphoric acid on the cars, which disolves any rust, and etches all the weld powder, grease, & junk off the metal. Then it leaves a rough, thin, ugly coating on the metal called, 'phosphate'. We never paint on bare metal. That's why factory paint sticks so well and last so long.

Meridious, this stuff will eat its way to your heater core metal, then stop by itself. It doesn't react violently like hydrochloric acid (muriatic acid), but it works more slowly which is exactly what you want.

Grant's bucket suggestion is the best. All the junk will go to the bottom. You might want to use an old nylon to catch the crud as it comes out the discharge hose. If your core is totally blocked, there will be a lot. Your core will work like new when done.

[Meridious]

This is why this forum is so darned good! Great folks come here!

Awesome information! In all my time I have only ever removed a heater core once and I am not looking forward to that prospect.

Maybe now I won't have to, eh?

Thanks a million...I tell you...some of the information here can turn out to be just priceless.

I would not have even made the attempt to clean this sucker...I figured as stopped up as it is, it must be beyond all hope.

NOW I at least have some hope!

[Meridious]

Any ideas on how long this might take to even begin to allow air through? It is still plugged up so tight that 80PSI won't push an electron through...heck...I think it is plugged up so tightly that atoms would not go in one end and out the other.

I've been running the phosphoric since around 1pm yesterday, but since it won't flow through the core, I can only back it out and push it in occasionally. Nothing appears to be dislodging.

I have a system going where I have the phosphorous entering through both inlets, and can swish it around with a drill pump, but there has been no visible matter in the liquid when I change it (I know something is happening because the phosphoric has changed color a bit...but no noticable particles.

I had the bright idea of using air pressure as well, but a constant 80psi didn't budge it.

I'm a patient guy. I can wait a bit...but I have to admit I am losing hope.

[Guest]

Any ideas on how long this might take to even begin to allow air through? It is still plugged up so tight ... I'm a patient guy. I can wait a bit...but I have to admit I am losing hope.

Maybe try to snake it out at least to get some progress to where the acid will have more effect. Try short section of 1/8" or 3/16" wire cable. Run it into one end of the core pipe and twist it in circles to get it to snake around the corners in the core. Clamp on a small vice grips to one end of the cable so you can use the grips as a t-handle to do your circular twisting of the cable. If you are lucky enuff to get it to bend around the core tubing corners, you should be home free.

[tbird430]

Is the heater control valve unbolted from the core? I was just checking because the orginals open and close- controlling the amount of heat.

I was just thinking that an original design control valve might be closed preventing any flow through the heater core...

[simplyconnected]

Is the heater control valve unbolted from the core?...

Excellent suggestion! He might not be using the core by itself.

Go easy on that air hose. The system was only designed for fifteen psi. Be careful what you snake in there, too. We are talking about soft brass that is soldered with lead. Sticking steel wires in will certainly make a hole.

Be patient. If you can warm the liquid, that will help a lot. I would expect the acid will take a while. Once you have some flow it will go faster. Remember, the acid is breaking the lime and calcium down into nothing. I would expect visible chunks after you get flow.

[Meridious]

Reheating it did the trick. Once I heated the solution to about 140 degrees, I suppose that the valve fully opened and I got seepage. Just a few minutes ago the crud started flowing. Now it is flowing almost freely.

No leaking inside, so nothing was "eaten through" during the process.

Looks like I will be in business soon after all. Good thing, too...as 40 degrees is "cold" to us here in Louisiana.

Thanks for all the help.

I will remember next time that the valve "aint opening at all" without some heat involved.

[simplyconnected]

...No leaking inside, so nothing was "eaten through" during the process...

Good job, meridious! Your patience and tenacity paid-off. I wouldn't expect the acid will eat the brass or lead, just the crud.

It's not fun to be cold. I'm tickled you did it, yourself. - Dave