Topic: cooling system help

[evannice]

You may want to try bleeding with the car at a pretty steep angle so the air in the horizontal tubes comes out.
[/quote]

That sounds like a good tip, Jim, will do.  Also sounds like your garage is a lot of fun!

Eric

[evannice]

Well that was a PITA to get the heater core out, but it sure needed to be done.  There is corrosion and seeping around the heater valve, and a large collection of lovely Minnesota Fall foliage and mouse nesting material.  The air intake flap is rusted solid.  And you can see where the air bleed fitting twisted right off.  I'll take it over to the radiator shop that helped me with the leaking header tank.  And I pulled the front radiator as well.  Figure I might as well take that in now while the system is apart, rather than put it all back together and discover the radiator needs servicing.

Eric, San Diego

[evannice]

Hi Gil,

Latest update: put it all back together with newly cleaned out radiator and repaired heater core and BMW thermostat and it overheated much faster.  The front radiator does not get warm at all now.  I am thinking the old stuck open t-stat was at least allowing some thermosiphon effect, and I am turning my attention to the water pump.

Hope your project is progressing well!

Eric, San Diego

[evannice]

Hi Gil,

Pulled the new BMW t-stat out and put the old Fiat Abarth stuck open t-stat back in, problem solved.  I just drove it around quite a bit in hot weather including sitting idling in traffic.  Warms up a little slowly as you would expect form a stuck open t-stat, then stays in the 1/3 to 1/2 operating range.  Heater works very well, front radiator fan comes on and the green dash light comes on as designed.  Virtually no coolant came out the overflow hose.

I'm going to boil the BMW t-stat and see if it opens, but I have to wait until my wife is not around the kitchen.

In retrospect, I think my car's cooling system problems were:  radiator cap not sealing and wrong PSI, faulty temp switch in front radiator, unable to bleed the heater due to corroded fitting.

Hope your project is comeing along well!

Eric, San diego

[zippyfiat]

Hi Eric, it's good to here that you have pretty much solved your cooling problem and that you can now drive the car without worrying.  It sounds like if you figure out the BMW thermostat, it wil all be fine?

BTW, it's funny how women have such an odd perspective about car parts inside the house!  I am not allowed to even hide new parts in boxes anywhere!  Arghhh...

I just bought a set of 4 Abarth hubcap emblems.  They are the type that are discs with studs on the back.  I think they are similar to the ones on the original Abarth hubcaps.  Now I need to find the correct style of hubcaps to use.  I think the correct ones are early or late 600 ones that are more bowl/dish shaped??  I cannot seem to retrieve the photos of the hubcaps you sent me on our PC.  Can you possibly post them here or email them to me?  You'd need to email via this forum to use my new email address.

Gil

[evannice]

Hi Gil,

Hope you got the hubcap photos.

I got the kitchen to myself this afternoon and boiled up that BMW T-stat.  It took a good 10 minutes at full boil to get it to open, and then it did not close again when back to room temp.  I'm no expert but that seems like a crappy T-stat.  I will stick with the original-looking stuck open one, the car seems very happy with it.

Eric, San Diego

[Pantdino]

Hi, Eric,
Certainly a stuck-open thermostat is better than a stuck-closed one!
As long as the car doesn't spend too much time at temps below 180 deg F it should be fine, from what I have read

Jim

[evannice]

Okay, I kept chasing this problem, having a correct T-stat fabricated, having the overflow tank neck modified to seal properly with a 13 PSI Stant cap, much improvement but the car would still not circulate water at idle and would overheat if allowed to sit in traffic. 

I eventually replaced the water pump, and that fixed it . The pump on the car was a relatively modern GMB style with the bent sheet metal vanes on the impeller. The one that works is the older style with the cast disc impeller with straight flat vanes radiating outwards. It appears to me that the GMB works well CW but not well enough CCW, and that the earlier disc style is omnidirectional. I have been told by those that made their own reverse-124 in 850 cars back in the day that they did not run into this problem. I bet they were using the omnidirectional pumps.

Now it is quick and easy to bleed air out of the system, it warms up faster, the heater works quicker and is noticeably hotter, the radiator fan comes on when the car is pushed hard and stays on for a long time. I just put 100 miles on the car today with fairly high freeway speeds followed by periods of idling in traffic. The temp gauge stays between 1/3 and 1/2 operating range and stays there no matter what.

[Paul vander Heyden]

How about a self bleeding system.  If you have a front radiator, There should be a petcock on one of the top tanks.  If you were to remove this petcock and replace it with a small diameter line screwed in where the petcock was and the other end terminated on the expansion tank (above the fluid level) then whenever the car ran it would automatically route any air back to the air cavity in the expansion tank (with some small amount of fluid as well of course). 

Never a bleeding problem again !!

Good luck

Paul