Hi all,

I just got a 1991 Firebird Formula with a 5.0L V8 305 TBI Engine. It is automatic.

The main issue with the car (for now) is that it overheats. It failed inspection from the previous owner because of this. I am a woman, so my knowledge of cars is not extensive (although I am not knocking the female mechanics out there in any way... more power to ya, ladies! I wish I had your knowledge and skill set). My dad is very good with cars, any cars, so he is researching info about this Firebird and I decided I should help. He just got a Chilton repair manual yesterday.

Thus, I have a few questions/comments here that I hope you can all help me with:

1. How hot is this car supposed to run, usually? The woman who previously owned it said anywhere from 200-220 is normal.
2. The car overheats when it is idling or in a lot of stop and go traffic.
3. It doesn't overheat or it cools down when the AC is on or when it's cruising down the road without frequent stopping.
4. It has a new thermostat.
5. When you turn off the car and put your head near the hood, you can hear it boiling. That can't be good.
6. Smells like gas... more than it should... if it should at all.

So far, that is what I can remember off the top of my head as I post this. Doing it on my break at work... so I don't have all the information I wrote down readily available. I suspect it is the fan/ fan relay....

The car is in otherwise very good condition. It just needs some tlc, and it needs to be driven and made happy again. Ever since I was 15, I always said I wanted a Firebird. I am about to be 25 now, and I finally own one. I know that fixing it up is going to cost some money and that it will take time, but it is well worth it.

Thanks again for any help you can provide!!

 

being a woman doesnt mean you cant or shouldn't learn about cars. I have plenty of lady friends who are better with cars than I am :-) that being said, first thing I would do is find out if there are any leaks. if not get the cooling system flushed and go from there. that runs around 60$ in my area but prices can vary.

 

The first thing I would consider is a new radiator cap. An old cap could have a weaker spring in it. The spring is to maintain pressure in the system. Liquids boil at a higher temperature when they are under pressure. 220 or slightly above that is fairly normal range. Welcome to the forum! The only thing guys have on you is strength and the ability to squeeze under their 3rd gen without being impeded by their chest.

 

Ok, what you have told us is it overheats while sitting idling for awhile and no other time.
That means you have a airflow through the radiator problem at idle. Which means, the 1st cooling fan/ slow speed fan isn't working.
1st, do you have 1 cooling fan or 2? If you have 2, replace the dr side fan motor or the fix the reason it isn't getting power to turn on, fuse, relay or ?
If you have 1 fan, you need to find out Y it isn't turning on during idle.

 

It sounds like the temp sensor that controls the fan when it gets warm may be bad. The fan comes on automatically with AC on, but not when it gets warm. (While I'm thinking of it, make sure you have the plastic air deflector under the radiator to get the air through it while cruising down the road. ) The fan should come on around 220 degrees, or shortly before. Make sure the radiator fins aren't all bent over and restricting air flow also.

 

If the car's been overheating, change the oil. Overheating isn't good for the oil life.

 

thanks for the replies so far!!! I am going to print this out and give dad what we've collected here so far... he said thanks!

i turned the firebird on today because my buddy came over to see it, and the hairs on my neck stood up. I NEED to DRIVE it!!!

thank you so much for the info. I will post back again tomorrow after he has checked some of these suggestions.

 

my mom had an 87 trans am that she and her boyfriend modified for racing. she knows her way around cars pretty well, so you are absolutely right.

i know my way around paint brushes and canvas lol. a different kind of "art."

 

i know all about impediments. lol.

thanks for the welcome! :-)

 

there she is needs tlc, but I am super excited.

 

Hey all,

It's been a while. I've been busy teaching :-) end of the year and substitutes are needed.

So, the fan does not engage at 222 degrees like it's supposed to.

Dad did a radiator flush, and he's going to do another one.

He's also going to install that Total Fan Control system. Said it's a genius idea! :-)

So that's a quick update there :-)

We were polishing it up today. It's looking gooooood!!!

 

UPDATE:

we replaced the relays, and it is still overheating. the fan only kicks on when you turn on the air conditioner. otherwise, it will not. can't seem to figure this out.

 

If u can't get it working by replacing fan switch or coolant sensor in passenger side head then just wire it straight to a interior switch n turn it on whenever u need to

91' bird 305 TBI T-5, trick flow 175 cc heads, 4.10 gears, lots of suspension upgrades......... 24mpg @ 2300rpm hwy 65mph ........ 8.63@ 85mph 1/8th on street tires... 8.000's soon

 

I gotta tell him to check the coolant sensor. i think he overlooked that. he is going to do the Total Fan Control system though. the one talked about in these threads.

we're both getting irritated with this lol

 

I paid 3k for my 91 bird about 7 years ago .. Km 25 now and prooly have around 10-11k$ in it total including the 3k I paid for it .. All I got left to do now is paint ,some minor interior work , and the T56 trans and aluminum driveshaft I want and it will b done ! Which islta really NEVER " done "

91' bird 305 TBI T-5, trick flow 175 cc heads, 4.10 gears, lots of suspension upgrades......... 24mpg @ 2300rpm hwy 65mph ........ 8.63@ 85mph 1/8th on street tires... 8.000's soon

 

I'll be 25 in November lol

I just want it fixed up... little by little. Next thing will be a cold air intake. Luckily my brother works with cars so he can help me and can paint it for me.

This overheating issue is really, really getting to me though.

 

could it be a bad fan switch? the fan switch and fan relay are two different things, correct?

 

Follow the wiring from the fan to the passenger side cylinder head that's your fan switch / coolant sensor for the fan ...

I don't really remember the factory fan setup as I've been using the ebl flash for tunning and my fan is controlled by the ebl

91' bird 305 TBI T-5, trick flow 175 cc heads, 4.10 gears, lots of suspension upgrades......... 24mpg @ 2300rpm hwy 65mph ........ 8.63@ 85mph 1/8th on street tires... 8.000's soon

 

I'll b 26 end of next month .. July 28th to b exact ... For a CAI on TBI u can check out my setup I custom made .. It wasn't exactly cheap but no body makes a good CAI for our TBI cars and mine works better than any pre-made aftermarket setup IMO .... I made a thread awhile back detailing exactly how to build it and where to get parts/prices etc.... I think its titled custom TBI CAI or something like that











91' bird 305 TBI T-5, trick flow 175 cc heads, 4.10 gears, lots of suspension upgrades......... 24mpg @ 2300rpm hwy 65mph ........ 8.63@ 85mph 1/8th on street tires... 8.000's soon

 

ooooh thank you so much that will be a BIG help for sure.

 

Bad fan switch. That was the whole problem. Finally, we can get this thing inspected. I may not be a mechanic, but I can do some darn good research lol.

 

Lol this day and age all u need to b a decent mechanic is a little common sense and do good research ...

And about the canvas and paint brush thing .. U should take that hobby/skill to the next level and apply it to cars! Mabey start out learning to airbrush and go from there ... A steady hand can make big $ pin striping ,air brushing , and painting cars

91' bird 305 TBI T-5, trick flow 175 cc heads, 4.10 gears, lots of suspension upgrades......... 24mpg @ 2300rpm hwy 65mph ........ 8.63@ 85mph 1/8th on street tires... 8.000's soon

 

My brother does airbrushing on cars, motorcycles, helmets, toilet seats lol, just about anything. He's awesome. Look up Armando Medina... Or Google the Predator Bike. That's a big project he worked on with some people from a place called Pitstop Motorosport. He's really talented.

I was jumping up and down in the parking lot when the fan turned on. The neighbor probably thought I was crazy lol.