Danged problems

[Sentinel]

OK 2 probs
1. Had the car running today and as it warmed up overflow filled up and began to overflow, so went throught the refill process, once it warmed up again, overflow tank filled up, but didn't retract back into rad once cooled. Any thoughts, Non Vented rad cap?

2. took it for a spin around the block and heard 2 clunks, then once I pulled into the driveway (shut off and in gear) the clunking noise kept up sounded like something was still spinning(tranny area, clutch, its a new one?) Then took for another spin and no more noise, still drives ok.

[chris]

i think it's the rims. he.he

[Kevin]

Here is a quote from the Fiero online service guide, I used this method when I replaced my hoses last year. The cap should be vented as it makes use of the overflow (maybe it has gone), the one on the back is not vented for sure. I posted a link as well on the bottom for the cooling section.  Good luck, Kevin

Bleeding the cooling system
Here's what I do to purge air from the coolant system.

The trick is to take the thermostat out and leave it out until you are sure the _all_ of the air is purged from the system.

Park on level ground.

Remove both the radiator cap, the thermostat cap, and the thermostat.
Slowly begin pouring your 50/50 mix of coolant into the thermostat opening, carefully watching the radiator opening.
When coolant begins comming out the radiator opening, re-install and tighten the radiator cap, top off the coolant in the thermostat opening, re-install and tighten the thermostat cap.
Start the engine for ~30 seconds then kill the engine.
Remove the thermoststat cap and top the coolant off. Loosen the radiator cap and wiggle it until coolant begins to come out, retighten the cap, top off the coolant in the thermostat opening and re-install the thermostat cap.
Repeat steps 4 & 5 until you are satisfied that _all_ of the air is out of the system. You might want to make a short run to the beer store with the thermostat out, LET THE ENGINE COOL, then repeat steps 4 & 5 again.
Re-install the thermostat.
NOTE: Fiero owners should bleed the coolant system _anytime_ the coolant reservoir runs dry. i.e. system has sucked air into the radiator.

From: Terry Loveless

http://www.geocities.com/motorcity/garage/5007/fiero_osg/cooling-system.html#bleed

[dguy]

Had the car running today and as it warmed up overflow filled up and began to overflow, so went throught the refill process, once it warmed up again, overflow tank filled up, but didn't retract back into rad once cooled. Any thoughts, Non Vented rad cap?

I would definitely go through the burping process that Tinker mentioned.

Also, assuming that you started her cold, and the coolant started flowing into the bottle before the temperature gauge got even close to the normal operating range for your car, the first thing I would check is the radiator cap.  Assuming that the rest of your cooling system is functioning properly, there's no way that it should be venting coolant this early in the game.

[FieroBUZZ]

Change the cap.  It's not expensive.  It should be NON vented.

[34FieroGT]

The stant part# for the cap you want is 10230.  The stant application guide lists a non-vented cap for the Fiero, but they lie.    The part# quoted above is actually for a blazer 4.3 (I think...), but it works.  I put one on my Fiero this spring and have noticed quite a difference with the cooling.

   tyler...

[dguy]

Change the cap.  It's not expensive.  It should be NON vented.

Why a non-vented cap, Gary?  To be honest I have yet to have anyone sufficiently explain the benefits of a closed cooling system to such an extent that I actually want to replace my vented cap with a sealed one.

In my own little world, I still believe that it's better to vent any excess pressure from the system in a controlled manner and in a known location, rather than allow it to find its own way out of the system through your favorite hose or gasket.

Ideally the need for this would never happen in the first place, but there's always that one time exception...

[Fieroflyer]

Basically the newer 2.8's and 3.1's have a different location for the water pump, it sits higher up on the block causing a problem where the water pump is one of the highest things in the system (stupid design) it is prone to air locks. Water pumps can not pump air so GM added a vent off the top of the thermostat housing that bled off into the overflow allowing any air in the system to escape. On the Fiero the overflow is in the front too far away so I added a rear overflow to allow venting and tied it into the heater hose to allow for any fluid to be able to return to the system.
Before I did this I had the odd ocassion where an air lock would occur usually because the back end of the car sat higher than the front causing any air in the system to collect at the water pump. The repair for this was to have the rear of the car lower than the front and open the vent on top off the thermostat housing to vent the air.
Since adding the rear overflow the problem went away and I drove trouble free for quite some time.
The problem now may be the rad cap spewing into the overflow when it shouldn't causing massive amounts of air into the system. Possibly the thermostat not opening and causing an over heat which in turn causes the rad to spew into the overflow and once again air gets into the system. Which if this is the case the cause of the noise problem might be air traveling through the coolant tubes. This if enough air could be very noisy.
Reccomend thermostat change which is a tight job and bleeding the system as before with the rear of the car lower than the front so air is forced into the rad and safely out the rad cap. Because of water pump design reccomend trying if possible to park so front is higher than rear and see if this helps.
Seeing as I built this car I will come to Ottawa at my first oppertunity and see if there is something I can do to help. Hoping 3800's do not also have this problem. Dan  

[FieroBUZZ]

Dan, I see the 3800 GP guys have a bleeder at the top of the thermostat housing.  None of our antics, just open it and let the air out.

[fiero308]

did you hear the clunks AFTER you stopped and shut if off?
It could be steam and water in some of the higher passageways of the heads etc.
I think the fiero has to have the cooling system burped at the engine - you have to find the physically HIGHEST point (that is where air will go) and open that until water (coolant) comes out.
and maybe do it a few time as 'bits' of air might move around a bit.
If you had trouble filling it then I suspect air pockets  and steam and water forming then condensing and that is your clunks.  Also VERY dangerous.  An improperly cooled motor grenades really nicely........  breaks rods, cams, pistons, cast iron, steel, it ALL goes............
Just be really careful and meticulous about getting ALL of the air out.  If you aren't sure, DON"T drive it!!!!!!!
good luck!!!!

[Sentinel]

Yes it was after it was stopped and shut off, made the  overheating mistake once before, won't make it again.

Dan thanks I'll be doing that next, gonna have to get the Grand Am manual to figure out where the thermostat is(up againt the firewall I'm, assuming), luckily my driveway is slanted so it should work well./ Thanks biys will let you know.