Cooling system trouble

[mckeig]

Hi all. It's my 1980 giving me problems.
I replaced the heater valve and core last week, the valve being the last thing to go wrong before I put it on non-op and parked it two years ago.

I removed the radiator and flushed it.
I drained the engine block. I put on new hoses all around, and a belt since I was in there.
I filled the system per the instructions on the forum. (Jacked up front, filled and burped as specified)
After running a few minutes, the temp would steadily increase, and as it rose to 210, 220, I shut it off.
Let it sit, tried burping again. Restarted. Same results: Cold lower hose, cold lower radiator, no fan, hot upper hoses and hot heater core hoses. Airlock?

I wondered if the thermostat just wasn't opening, so I ordered a replacement and put it on today. I have it in the correct orientation, and I drilled the small hole in the edge to help with air release.
So far, the results are the same as before. I have done four sessions of fill-burp-run-test over the last 6 hours. Every time the temp just keeps creeping up and the fan never comes on. I can't seem to find any more air in the system. The lower hose is not ice cold, but it's not warm by any means. The bottom of the radiator does feel cold, while the top is very hot.

I tested the fan and it runs fine. I wouldn't think the thermo switch could activate given the radiator is very cool where the switch is. I then ran a jumper ground wire to the fan plug to see if the temp would level out if the fan were running. Nope. Still climbs right up like before even with fan on full time.

My theories at this point: Water is not moving through the system as it should, meaning water pump may be bad? (Anyone know the direction of flow through the water pump?) New thermostat is bad and not opening? (I'll test in hot water to see.) There is still some air somewhere that I haven't found? I should mention it ran fine and never had any cooling problems before parking two years ago. Could the pump go bad sitting that long?

The last couple times I have been watching at the radiator filler neck, with the cap off. It slowly rises while the engine is running, but I don't see it moving across the radiator like is mentioned on the forum, when (or if) the t-stat opens. I put a funnel in there so it could rise into the funnel rather than overflow. No bubbles or gasses. I slowly squeezed all the hoses to see if I could find any more air. I couldn't. It rose until the funnel was almost full. After I shut off, as the engine cooled the fluid went back down to to the level it was in the radiator.

Any ideas? It is getting frustrating at this point. I will replace the water pump if I have to, but want to rule out other things first.

Thanks!

[mckeig]

Just tested the original t-stat (one I took out) and it opened right where it was supposed to. I think that rules out the t-stat being the problem.

As far as water pump, all the cars I've owned and worked on have visible failure. Weep hole leaks, bearings sound bad, etc. Would a pump be bad with no outward appearances?

[131]

Did you have good flow through the radiator after you flushed it?

[mckeig]

Did you have good flow through the radiator after you flushed it?

With a garden hose in the top, it flowed freely out the bottom. That was the extent of the test.
I did get a lot of sediment out of the bottom before it was done.

[So Cal Mark]

sounds like you have air in the system

[mckeig]

sounds like you have air in the system

I'm not sure where else to look for air. I'm considering draining and starting over. Maybe give the block a flush to make sure the passageways are clear? I've spent a lot of time burping hoses until I see/hear no air, and filling the hose to the little jacket on the air intake last, since it's the highest point.

[mckeig]

By the way, Mark, the new stainless heater pipe I got from you fit great. I was quickly mutilating the old one in an attempt to bend it.

[bradartigue]

Unplug wire that pegs the needle; use only the wire that does the sweep on the thermostat. Warm up on the motor and watch it; sometimes a bad sender on the overheat line can cause false readings.

Do you have the heater core open when flushing that system? If not then all the air from that guy is going into your head as you circulate.

[azruss]

When i restored my car after sitting, I took the cooling system apart and found balls of green silicone looking stuff in the system. a couple were large enough to seriously limit flow. when you filled with coolant, you should see a drop in the coolant level in the radiator when the thermostat opens. I would double check the stat orientation.
The water pump flows out of the coolant T to the top of the radiator and to the top of the stat. The stat valve should be in the lower radiator hose. when it opens, the coolant flows into the water pump. If the stat is staying cold and not opening, you still have air in the system.

[mckeig]

Unplug wire that pegs the needle; use only the wire that does the sweep on the thermostat. Warm up on the motor and watch it; sometimes a bad sender on the overheat line can cause false readings.

Do you have the heater core open when flushing that system? If not then all the air from that guy is going into your head as you circulate.

I will look into the wire. On page 10 of your wiring diagrams, it shows engine overheat switch [01125] gray/black. Is that the one to unplug?

The heater core was open when I flushed, but I did notice I had it closed today when I refilled after replacing the t-stat. I opened it when I started burping. Maybe I trapped air? I think I would have to drain again, then make sure it's all open, then follow the procedure again. That is a good plan, thanks.

[mckeig]

When i restored my car after sitting, I took the cooling system apart and found balls of green silicone looking stuff in the system. a couple were large enough to seriously limit flow. when you filled with coolant, you should see a drop in the coolant level in the radiator when the thermostat opens. I would double check the stat orientation.
The water pump flows out of the coolant T to the top of the radiator and to the top of the stat. The stat valve should be in the lower radiator hose. when it opens, the coolant flows into the water pump. If the stat is staying cold and not opening, you still have air in the system.

Good to know the flow. I have the t-stat facing the lower hose, which is the closed outlet. The machined outlet was labeled "to water pump" with an arrow. The last one went to the upper hose. Since I've now tested my old one and found it to be good, I may swap it back in when I drain it.

I didn't notice the water level dropping, or cycling at all. I'm leaning towards air in the system and the t-stat not opening.

Thanks

[76was124]

Wild guess, which I am not sure is even technically correct, but if you had the heater core inlet and outlet swapped and the heater valve closed could that cause an overheat? Regardless, if you follow Brad's advise and open the heater valve, unless there's a check valve, you would see a difference.

[bradartigue]

Unplug wire that pegs the needle; use only the wire that does the sweep on the thermostat. Warm up on the motor and watch it; sometimes a bad sender on the overheat line can cause false readings.

Do you have the heater core open when flushing that system? If not then all the air from that guy is going into your head as you circulate.

I will look into the wire. On page 10 of your wiring diagrams, it shows engine overheat switch [01125] gray/black. Is that the one to unplug?

The heater core was open when I flushed, but I did notice I had it closed today when I refilled after replacing the t-stat. I opened it when I started burping. Maybe I trapped air? I think I would have to drain again, then make sure it's all open, then follow the procedure again. That is a good plan, thanks.

Yes, the overheat switch as you described.

[vdesigner99]

Check the radiator cap I had the same problems on my 84 after replacing all kinds of stuff.
Replaced the cap and probs went away.

see:
http://www.fiatspider.com/f08/viewtopic ... a&start=15

Good luck

Victor

[wizard124]

As the engine is warming up, rev it to move the water through the system.