Im feeling very very defeated, Cooling system ?

[georgeramos]

I cannot seem to keep air out of my cooling system. i rebuilt the entire system about 1 1/2 years ago including recoring the rad, new t stat, water pump, hoses and added a flush T at the heater hose to burp the system. i thought I was burping it correctly and the car HAS run normally before but now its overheating and the bottom of the radiator is absolutely cool to the touch. I opened the flush T and the rad cap (while it was cool of course) and the following occurred.

There was no liquid showing at the T but the Rad was filled to capacity. When i added water to the T it simply overflowed the rad. I kept adding until it was overflowing at both ends. Drove it, overheating.

I came across the post about how some cars have an "extra" internal t-stat so I guess I will start taking things apart to see if thats the case here.

Any other advice before I start digging into that? i probably wont get to it til next weekkend as Im tired of messing around with this f...ing car today.

Thanks

[81SPIDERMATT]

when the radiator is full cap it and then add to the tee .do you have the brass screw on the coolant tee.. did you fill that also??.. also make sure the heat is on so that valve is open .... some have drilled a small weep hole in the thermostat to let out air ... make sure overflow tank has fluid and those hoses are in good shape .. check all the hoses clamps and make sure they are tight ... jiggle shake and squeeze the hoses as you fill and you know the thermostat is working ??? right??? .... air can be frustrating and for some unknown reason doing the same thing over and over it took me 4 times before it was right .... f****ng air ...

if you have a plenum heater fill that spot too

[georgeramos]

Hi Matt, thanks for the reply, I dont think i have the brass screw, not sure what you mean. my car is a 71 if that makes a difference. Also, in terms of the heater being "on' do you simply turn the switch to the on position? or is it a matter of sliding the lever to the "heat" position? or both? Does the car need to be running as you do this so the heater is actually on?

[garion]

I have a slight modified way of filing the system..

I leave the bottom of the external T stat t off (the hose going to the rad). The hose is connected to the rad.. Then I fill the rad, until you get water/coolant out that hose.. Then I connect the Tstat up, finish filling the rad, till it comes out the top rad hose.. Close that up, then fill from the new coolant tee.. I've had pretty good success with that.

[81SPIDERMATT]

Hi Matt, thanks for the reply, I dont think i have the brass screw, not sure what you mean. my car is a 71 if that makes a difference. Also, in terms of the heater being "on' do you simply turn the switch to the on position? or is it a matter of sliding the lever to the "heat" position? or both? Does the car need to be running as you do this so the heater is actually on?

don't know if the coolant tee exists on your car .or the plenum heater either .. as for the heat ..slide the lever for heat ... that opens up the valve to heater core and the core to the rest of the system ...

[bradartigue]

You're chasing too small of an issue, if the radiator bottom is cold and the top is hot then you're not circulating anything. This isn't due to some air in the head - that problem results in wacky gauge readings not genuine overheating.

This is messy work so drain your coolant and don't start doing any of it until the block is cold:

This is a very simple system and I'm thinking you have either a thermostat that is incorrectly installed or a bad water pump.

Absolutely make sure you don't have an in-head thermostat. No car made after about 1969 should have one. The stock setup is an external thermostat ONLY. To be sure, unscrew the four bolts holding the coolant port onto the head. This is the thing that eventually goes in between your cam wheels. If there is one in there, get it out. (Plenty of people can insert here the virtues of the in-head thermostat, but you cannot run both).

Make sure your thermostat is oriented correctly; otherwise you'll get the results you are describing. Here is a video of it: http://www.youtube.com/watch?v=-BqyZ3_rWEQ = thank you IAP.

With the radiator drain open, fill your radiator with a hose. Don't worry about coolant. Water should come right out of the drain. If not, you have a blocked radiator. Then, with the radiator drain closed, water should some out of the lower radiator hose. If not, you have a blocked radiator. Both of these scenarios are pretty unlikely but easy enough to check.

Fill the system with clean water (no coolant), unhook the hose to the radiator top, crank the motor (you don't need to start it). Water should flow from the disconnected hose. If not, you may have a bad water pump.

[georgeramos]

Thanks Brad, that gives me a clear procedure to follow. I will post the results when I do it.

Thanks all!

[toplessexpat]

George - Brad's approach is logical and clear. I'd be tempted to focus in on the water pump as the source of your woes (once you've eliminated the radiator blockages etc.). Is the pulley firmly attached to the front (eg no "wobble"), when you unbolt it, is it nice and clean with a good gasket.... Etc

I understand that some water pumps can cause cavitation - not so much part of your problem, but if you replace the WP - check it doesn't.

A

[majicwrench]

Like was said, double tripple check thermostat installation.

Water pumps don't often fail in such a way as to cause overheating, but might as well check flow.

When was the last time this vehicle worked well w/o overheating??

I dont understand all the complex confusing ways to fill these cooling system. Mine (72) fills nicely w/o a coolant T or anything else.

[georgeramos]

That's whats confusing. I rebuilt this system within 1000 miles ago and it worked perfectly from that point til about a month ago. First symptom was fan not kicking on so i assumed thermal switch or air bubble. I burped it and it SEEMED to be ok. Then again yesterday it started getting hotter than usual. Let me claify it did not get into the red. If i was moving it would hover at about 200 to 215 estimated. If stopped maybe 230 to 240 until moving again. At one point when it was at 230 or so i pulled over and the radiator felt cool at the bottom tank. Once driving it went back to 200 to 215. Even seemed to dip back to 190 at one point as if the thermostat suddenly opened all at once.

When i rebuilt the system that included freshly recored rad, new water pump, thermostat which i was VERY careful in orienting following images and words from a factory manual, new thermal switch, new fan relay and also did new belts at that time. Also added the t at the heater hose. I was really careful and methodical.

[focodave]

Here's an easy way I have found to do it:


Make sure the radiator cap is on tight and that everything else is capped.
Attach this garden hose stub to the coolant "T" that many of us have plumbed in to our heater hose.
Simply fill the system through the funnel.
At some point the funnel will become full and will not drain.
Let it set like that (with funnel full) for a few minutes until you see all of the air bubbles burp their way out of the system.
Since the level of coolant in the funnel is the highest point in the whole setup, the air will completely bubble out on its own after a few minutes and will be displaced with a portion of the coolant that is in the funnel.
Simply remove any remaining standing coolant out of the funnel (I use a turkey baster to suck it out of the funnel to prevent a huge mess in my engine compartment) and remove the stub/funnel, replace the coolant "T" cap and you are good to go.

[4uall]

for what its worth, this might help I had the internal t stat issue

http://wwwe.fiatspider.com/f08/viewtopi ... verheating

[majicwrench]

IF it worked in the recent past obviously something has changed. Put Tstat in a pan of boiling water and see if it opens.
If it opens, check water pump flow as above.

[Exit98]

George,

Are you sure its actually overheating?

Are the sensors in the head ok. By gauge was erratic till I cleaned up the spades and replaced the old frayed wires.

[georgeramos]

OK, I havent driven the car since yesterday and when I removed the cap from the T in the heater hose coolant spills out. there is pressure in the system still. Does this point to any specific issue? Thermostat?

Thanks