Anyone please help!!! I have an '89 Pontiac Firebird with a 305 TBI and the damn car won't stop overheating at speeds above 50 mph. I have replaced the thermostat, installed a new high Volume waterpump, new belts, second brand new sets of hoses and new aluminum radiator and nothing! All the hoses to my radiator a seriously collapsing and I am afraid that I am going to burn up my motor like the last one. My old 305 TBI did the same thing and I bought this new '92 Firebird 305 TBI and put it in my car and now IT is doing the same thing, but when the motor was back in the '92 firebird it never overheated! I am lost and about to sell my car, please help. I love this car. Feel free to leave me an e-mail or how ever you can get ahold of me.

 

Is the air dam under the lower radiator mount still installed, on the Z28's you have to have these for good airflow through the radiator at higher speeds I assume its the same on yours

 

Check Air damm components, to make sure all parts are still there.

This is also known as a air deflector. Then there is a black plastic piece, It is called a baffle, that runs down the backside of the front bumber, in-between the bumber and radiator. This forces air through the radiator, so it can't escape around the radiator, or flow back into the backside of the front bumber area. If this is not in place it can create an air vaccum at speeds of 25-45 mph where air is not flowing through the radiator.

The Air deflector scoops up air from beneath the bumber, and pushes it through the radiator. Fans cool at low speeds, 0-40 mph, and the air deflector system does more at high speeds.

I've run my TA at 100 MPH for 2 hours straight in 110 degree heat in Arizona, with a broken radiator fan, and my temperature gauge read 150 degrees, because I had custom made a real good Air deflector (air damm).

If you have not already you could switch to a 160 degree thermostat, isnstead of the standard 185 degrees.

If you don't have dual fans, you could install an aftermarket dual fan system.

Also you can take out the insulation on underside of the hood, you don't need it unless your driving in Arctic weather, and it is a fire hazard.

From my experience of driving in Ariznona for 10 years, is that it's all about getting air to flow through the radiator to cool the system coolant.

Most of this should be in junkyards.

 

Have you had your radiator rodded out?If so, pony up for an all-aluminum rad.

 

I had the same problem with my 87 TA. I took out the ac cooler so the air would go straight to the radiator. I also built my own air damn after the stock one ripped off. I took a piece of sheet metal, cut it to the length of the radiator, put 4 pieces of metal bracing behind it. Made 4 holes into the bottom metal piece that holds the radiator in, bolted it up. Never had a heating problem again. Make sure you put the bracing in behind the sheet metal. And make sure it's strong enough bracing. My first try ripped off after I got the car up to 70 mph. The 2nd one held up to well over 100 mph while I was racing at the track.

 

Can you post some pic of your homemade air dam?

 

The 87 TA was the first car I ever owned. It completely rusted out so I junked it, i think the air damn was thrown away. I can make a quick drawing of it in paint and post it in a few. It's pretty basic and cheap but it worked really well.

 

If your lower hose does not have a wire support it will collapse under high load/rpm's, you need to get a hose with either a built in or formed in wire support, or get a wire support that slides in the hose. The high volume pump makes it twice as important to have support in the lower hose.

 

I uploaded the bmp file to my website. This should work.

http:http://www.angelfire.com/scary/cashm...s/air_damn.bmp

 

Angelfire is blocking direct viewing of those images. Bummer - that sounds like just the ticket i've been looking for to cure my overheating problem as well. I have also found a leaky heater core or bad radiator cap to be a problem as it lets the pressure out of the system and the coolant will boil, reducing its capacity to cool.