So, here's my story I bought my second car from Arizona and brought it to California where I live. It's an 1988 iroc-z 5.0L(manual). I was beyond psyched to drive my second car after just selling my hand-me-down P.O.S civic. My father being overcautious wanted me to put a license plate on the front which i thought would stop airflow by about 40% (being stupid i found out my radiator sits behind my grill so it really didn't matter --just looks horrible). But even without it it still overheated. I'm not entirely mechno-savvy (i wish) but I took the car to a mechanic my dad suggested and have gone since 3times with no sure fix yet. I mean I know a mechanics job isn't easy but in most things three strikes and your out. He has replaced fans both actually, the thermostat, etc. My car runs like a dream but as soon as I stop(traffic,parking even jump-starting) my car turns into a volcano of FML~ I really wish someone would have an idea as to whats going on with her lol the only other thing I could mention that might help off the top of my head is shes got an abnormal amount of electronics lights,screens,ps2, alarm system and my battery is about needed to be replaced although i don't think it has anything to do with it cuz I've been meaning to pull it all out anyway just thought I'd add that.

Any input would be appreciated, I wish I knew so I could know how to fix it later down the road but that's learning huh...

 

This could be a lot of things. You can do some checks yourself though. First, if your temp gauge works, check that fan comes on at the proper temperature. If it doesn't you can temporarily wire it in so it is always on when the car is running til you get it fixed. Second. Check the water flow. Hold onto the top hose and see if you can feel water flowing through it once car reaches warmer temperatures. If not, change thermostat. I would also change hoses if they appear old or worn. An old hose will tend to collapse on itself when it gets hot. Third, have the cooling system flushed. If there is a clog or buildup in the engine or heads, this will flush most of it out when done right and help water flow. Fourth, check the mixture in the radiator. You can get a cheap gauge at an auto parts. Read the forums on here, there is plenty of mention of the proper mixtures. Last, these cars are notorious for overheating in traffic on hot days because of the poor air flow through the radiator. There are lots of ways to help this, again search forums. Personally I installed an aluminum radiator because of the high temps here in Miami and I like to run the A/C in heavy traffic. Another thing that can hurt the flow is the Heater Core. You can try to bypass it if necessary. Hope one of these suggestions works for you. These are just the basics, but it is usually an easy and not too expensive job to fix an overheating car.

 

an easy way to see if the fan isn't kicking on is simply turn on your air conditioner. if the problem "goes away", then you know it's fan related.

 

Is it actually boiling over? And are you measuring the temps with a method unrelated to the temp guage in the dash, which may, or may not, be an indication of the actual state of nature at the end of the sender?

If it's boiling over, replace the radiator cap first. It'll run like $3 and should be routinely replaced anyway. If it continues to boil over, pressure test the system.

If the fans are running while it boils over (after a successful pressure test) make sure there's no trash buildup restricting airflow. Pull the plastic rad hold down piece out and tilt the radiator back. Clean out all the trash that's likely between the AC condenser and the radiator.

Make sure you've got a good tune up. A poor running motor will generate more heat. If you haven't replaced the O2 do it now, along with the plugs/cap/rotor.

 

Good point with the fans. As long as it kicks on with the AC that should work.

 

You haven't said yet if it's actually "overheating"; all you've talked about is "boiling over", which IS NOT a definitive sign of "overheating".

Try a new radiator cap first.

Your fans should turn on at about 235° and turn off at about 215°. In other wwords, in the factory's opinion, the engine DOES NOT EVEN NEED COOLING AT ALL until the temp reaches 235°. But of course, "water boils at 212°", right? So how can that possibly work? Well, the answer is, water DOES NOT boil at 212°: rather, pure water at atmospheric pressure boils at 212°. But coolant (50-50 anti-freeze and water) at cooling system pressure (15 psi above atmospheric, more or less) boils at about 265 - 270°. So before getting all worked up about "overheating" just because your car boils over, make sure (a) you have the right amount of antifreeze in it (at least 30% but no more than 50%), and (b) your radiator cap is good, so that it holds pressure.

 

Airflow does have a small part but Trans AM/Firebird models do not have a grill at all.

Things I would start with:
Visually check the Air Dam is in place. It's a black piece of plastic that should be mounted under the radiator support on the bottom side of the car. It deflects air upwards towards the radiator. A car will usually boil the coolant tank at high speeds without one.

Check that both fans are working properly. Do they turn on when the motor gets hot? They are controlled by a temperature switch that can go bad or the fan relay could have went bad.

Do the fans blow air the correct direction? They should be pulling air through the radiator. Being DC current it's possible to get the power and ground wires flipped and the motors could be trying to push air back through the radiator which would fight the air flowing through the radiator at speed.

 

Ok to kind of up-to date things the temp gauge fried((stopped working)) the first time it overheated I believe that's when the mechanic replaced the thermostat and a fan that blew. I got it back and the car ran find and then I noticed the temperature go from about midpoint to dangerous levels and I parked the car it boiled over (same-day). Took it to the mechanic again replaced a fan and Radiator cap. Then I was at a car show in the sun a buddy of mines car wouldn't start so I tried to help him jump his 1955GMC and my car boiled over again... Another individual he knew had similar problems and suggested wiring the fans to the ignition, and or upgrading parts such as a 3core radiator or a better alternator which I have yet to due until I find a real answer to my problem. The mechanic used a heat gun on the engine core and it ran fine and even kicked in right on time with the 2nd fan when he showed me, and I'm not one to dogg my car so idk... I checked the hoses they seem to be doing their job I'm just stumped...

 

From what you've posted I'm inferring that 1) it's boiling over but we're not sure that it's actually overheating when it's boiling over and 2) the fans are functioning correctly.

The system is either 1) not maintaining sufficient pressure OR 2) actually overheating - while the fans are running.

Inspect your radiator cap, even though it was supposedly replaced. Ensure its new, the correct one and installed completely-pushed down and turned all the way. Then pressure test the system.

Inspect your radiator and AC condenser coils. Ensure trash is not blocking airflow. Remove the radiator hold down panel and check between the two.

Wiring fans to ignition won't help. It's already boiling over with them running, right? Turning them on sooner won't magically improve their cooling efficiency.

You also don't need upgraded parts. The factory parts work fine when in good condition. A radiator with heavy scale will lose some efficiency and as fins get bent/damaged heat transfer suffers but your rad would have to be in pretty bad shape to cause all of your troubles.

If it's overheating parked at idle the problem is NOT your air dam. Fan speed direction won't matter much either...but it IS fairly easy to check.

If there's any sign that the water pump has recently been replaced you may want to verify that the correct rotation pump was re-installed. The pump for a serp system spins opposite the older v-belt pump.

 

My is to "burp" the cooling system. I had a 79 T/A with a 400 pontiac that was extremely sensitive to air pockets in the system. The method I used was to put the front of the car on wheel ramps (this makes the filler neck of the radiator the highest point in the system) then removed the radiator cap SLOWLY (I always began with a cold engine). Next is to get the most powerful fan you have and put it in front of the car aiming it at the radiator and turn it to the high setting. Now start the car and get it warm to open the thermostat. If need be you could rev it but do not rev it more than 2000rpm, remember there is no load on the engine in neutral. once the thermostat opens you should see air bubbles coming to the surface. As the bubbles escape the coolant level will go down and you will want to add 50/50 as this happens. I suggest small plastic water bottles, much easier than a gallon jug.

 

Gonna mention this since no one else seems to have yet. I would check your motor oil and see if it's like a milky brown color. If it is, then you have a blown head gasket, which will cause the symptoms you're describing. If the oil is okay, then use a pressure tester on the system to see if you're able to hold pressure. If not, then you have a leak that needs to be sealed up because it's preventing the cooling system from doing its job properly. If the system pressure tests good, check the lower air dam to see if it's missing or missing chunks. Also blow some air through the condenser and radiator fins to get any crud out that may be impeding airflow. If none of those things fix your problem, then I'm stumped too, since you said you've already changed the cap, thermostat and checked the hoses.