My 86 GT has a sticker on the underside of the engine cover that says this car needs a special coolant fill procedure as described in the owner manual. I don't have an owners manual so what is the special procedure? Looks like the engine is higher than the radiator so I assume the coolant needs to be topped off from the engine end.

Click on "Ogre's Cave" at the top of the page. He has a detailed coolant fill procedure on his site under Powertrain > Cooling > Coolant Fill.

The issue is the radiator cap isn't the highest point in the system, so if you fill from the radiator, you'll get air trapped in the system and likely overheat. You do need to fill from the thermostat housing at the engine, but you also need to burp any air out of the system. It's not hard. His "short version" is good for most flush and fill work, but you may need the long version and to manually bleed the air if you replace the heater core or have a completely dry system.

[This message has been edited by Formula88 (edited 02-23-2012).]

quote Originally posted by Formula88: Click on "Ogre's Cave" at the top of the page. He has a detailed coolant fill procedure on his site under Powertrain > Cooling > Coolant Fill. The issue is the radiator cap isn't the highest point in the system, so if you fill from the radiator, you'll get air trapped in the system and likely overheat. You do need to fill from the thermostat housing at the engine, but you also need to burp any air out of the system. It's not hard. His "short version" is good for most flush and fill work, but you may need the long version and to manually bleed the air if you replace the heater core or have a completely dry system.

Yes but now I've removed the long fill version... Info for heater is still there but if the plumping is good and you install Tstat then Heater will burp itself.

Alot of us install the Tstat after filling... Works ok for a top off but that trap air in heater loop section till Tstat is installed.

Lube the Tstat seal with Silicon oil/grease. Brake grease and dielectric works.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

The "special fill procedure" basically means top it off at the engine (i.e. the thermostat housing). In most cases, you don't even need to touch the radiator cap.

Some people like to use a complicated "burping" procedure. But in my experience, it's largely unnecessary. I have drained and filled the cooling system in my Fiero several times (engine/tranny swaps, cradle refurbishing, etc), and have never needed to mess with the radiator cap.

Why not just jack the front of the car up to make the radiator higher?

Because it would trap even more air in the radiator with the front end higher. If you are going to burp it then it's not a big deal. It's just unnecessary (i.e. more) work.

I've never had a need to raise the rear when filling the system. I did burp it with the t-stat out. Never brave enough to just fill it from the rear and run the engine to extract the air.

For the OP, download the '86 Service Manual here: http://www.fieronews.net/fu...nloads.php?cat_id=13

[This message has been edited by Hudini (edited 02-24-2012).]

The problem is that the system spans the length of the car and has three high spots: engine end, heater core, and radiator. No matter which is highest, nor where you fill, there will still be at least one relatively large air pocket. You can fill at the engine side with the radiator cap off (per the typical methods found on here) but that leaves air at the heater core; thus, the burping procedure.

My preferred solution is to install one of those inline "T" fittings from an auto parts store in the front trunk on one heater core line. This enables one to fill from the engine side, vent the air at all three high spots, and fill the whole system in one step. In addition, I don't trust the plastic caps provided with those tees (I tightened one too much and split it out), so I got a brass one from the hardware store. After I replaced the plastic cap with the brass one, I've had no issues for years with this system. But, if you need to keep it 100% stock, you need to follow some procedure to get the air out at all three high spots.

Tom

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1988 Fiero GT
Custom Corvette / MR2 electro-hydraulic power steering
17" rims covering up 11.25" rotors with Cadillac Calipers & drop spindles

I have a slight incline in front of my house. I park nose down, then fill at the engine until the radiator is full. Cap it off. Start engine and finish fill at the rear with the thermostat out. When the system is full, and before the coolant gets hot and starts to expand add the thermostat, and its cap. Make sure the overflow tank is full. Go for a 10 min ride. Good to go.

At times the 4.9 swaps are hard to burp. This slight incline was the ticket with my swap. Over heating was never a problem.

I always add a 1/8" hole to all my thermostats for an escape path for air.