Cooling System Bleeding Procedure

[Torxx]

Can someone please give me the shorthand version of how to properly bleed the cooling system. I am going crazy over my '79 spider running hot at idle. I wont bore you with details, but I need to make sure I get the system bled properly so I can move on to the next possible cause.

I read a tech bulletin from IAP that basically says, raise car, fill top hose that leads to t-stat til coolant flows out of tee, replace hose, run til hot, lower car and top off radiator, replace cap. sounds easy . will that work?

Is there a better way? The long drown out instructions I saw posted on the site was hard to follow.

help please

[So Cal Mark]

once you have filled the radiator, remove one of the small water hoses to the choke. Hold the hose as high as it will go and finish filling the system through that hose. Once coolant starts to come out of the radiator neck, replace the cap and top off the system thru the choke hose. When it's full coolant will come out of the choke nipple without air bubbles.

Or, install a Prestone flush tee from Autozone n the heater hose next to the dist and fill the system there

[Torxx]

O.K., do Ineed to raise the front end? Does it matter which of the two hoses that I use (that go to the carb Choke)?

Let me make sure I have it right. 1. Fill radiator to top 2. fill water hose to carb til coolant flows out of rad. 3. Cap Rad 4. continue filling water hose til coolant flows out of nipple on carb choke 5. replace water hose on nipple 6. drive happily

thanks for the help

[rlux4]

Torxx, I could not get my system to fill properly at all until I drilled a small hole in the valve part of the stat. After I "discovered" this it was pointed out that back in 1985 IAP had this suggestion on the page that shows how to bleed the system. Here's a picture of my stat:

The problem is, none of the bleed procedures address the issue of the coolant coming out the bottom of the radiator and up the hose to the stat. There is nowhere for the air to go that is trapped there, it is stopped by the closed stat. In my case, the stat never would open because it had air on the downhill side to dispel the heated coolant on the top side of it, or the 1-2 inches of air would not allow the coolant to be drawn up into the flow going to the water pump from the block.
I also put a "T" in the heater hose as Mark suggested, it allows you to fill the system at the highest point without raising the front of the car. There's a whole discussion on this here: http://www.fiatspider.com/f08/viewtopic.php?f=9&t=3788
Good luck,
Ron

[rlux4]

The "T" goes in the highest heater hose, the one from the head. As here:

Ron

[So Cal Mark]

do not raise the car, just finish filling thru the choke hose. Air in the block will be pushed out through the choke nipple. It doesn't matter which hose you remove, but disconnecting the longer of the two will let you hold the hose higher for filling.
I'm assuming your idle temp is so high due to the cooling fan not operating. If the fan is cycling, then you have a different problem

[mbouse]

the trouble with the stock design is that the radiator cap is not the highest point in the cooling system; the underside of the head is the highest point. water likes to "seek its own level" and forcing the air pockets out of the head can become a chore.

if you'd like, send me an email and i will share with you Jenny Obert's written procedure. additionally....

i recommend that you buy a coolant flush kit (prestone sells one for about $6). the T-fitting should be installed in the center of the hose that connects the engine head (between #3 and #4 spark plug) to the heater core pipe protruding from the firewall. this then becomes the highest point in the cooling system and is SUPER EASILY used to fill the system w/out any air bubbles. you need no longer jack the car up, remove choke hoses, or suffer inefficient coolant flow do to bubbles of air. i have a picture of this installation that i could email you.

email to:
mbouse at chartermi dot net

[Torxx]

Mark, I have been perplexed by this issue. The fan comes on but not until the gauge reads 220 +/-. We used a point and shoot thermometer and the radiator appears to be operating evenly, temp wise. The fan will cool the car back down, but it will rise back up before kicking the fan on. If bleeding doesn't work, I'm thinking of replacing the head sensor on top of the engine (which has been replaced not that long ago) or the next thought is the radiator which was just serviced, and they claim that they check flow as a standard procedure.

[mbouse]

in my limited experience, if the fan is kicking on and off, there is coolant flow thru the radiator.

which, in my small amount of experience, says that it is not air pockets that are causing your issues. burping promotes coolant flow by removing air pockets, the air pockets prevents coolant flow.

if you have fan on/off, you most likely have good flow, if you have flow further burping is not the solution.

[rlux4]

Mike, I infer from your post, post my post, that the picture I posted of the "T" in the heater hose is not a good one for illustration purposes. Do I infer correctly? Or do I, in fact, infer incorrectly?
It could be that because I know what I'm looking at, it is clear to me, but may not be the case with someone else.
Enlighten me, brother. Do I need a better picture for future use?
Thank you,
Ron (who likes a little alliteration)

[So Cal Mark]

heating at idle but not at speed is not a flow issue, it's air flow related, but your problem sounds like a sending unit/gauge problem. If the real temp at the top of the radiator is 195 when the fan comes on, your gauge is giving you a false reading.

[mbouse]

what i was inferring was I have a picture of the installation, but it is not from my car. in fact, i have no clue who's car it is. I can state that in an individual email as i send them out... but i hesitate to post openly a picture of another person's car.

it's a simple install, i just keep forgetting to take a picture of it on my car.



and, i apologize that i speed read past your post, not seeing the correct picture... i am sorry that i inferred incorrectly anything .. took me a while to understand your inferrence to my inferring incorrectly.

inferred an apology. mega-oops!

[rlux4]

Perfect MIke! You took that in exactly the right spirit. What a guy.
Plus, I like your sense of humor, it's a lot like mine. (So be careful, mine gets me in trouble sometimes.)
Ron

[mbouse]

spirits? did someone say spirits? i've had spirits before, something like al-key-hawl, only lots better

not good for those days when you need to get something important accomplished, however. important=anything greater than holding down the nearest lawn chair.

[Torxx]

Thanks for the offer mike. I have the tech guide you referred to. Marks procedure was very easy to do. Thanks Mark. Unfortunately for me I still have the same issue. I need to get my hands on another laser temp gauge, and check the temp on the top of the engine to see if matches what the gauge reads. I can't believe I didn't do that when I had in my hands a few weeks ago.

It's the sensor near the firewall that controls the gauge, right?