So i recently replaced a thermostat in my 1990 firebird formula 305
Now suddenly it now overheats. I realized the fan didnt turn on, but i fixed that by replacing the motor and i know that works now but it still overheats.. my coolant boils in the tank when it got really hot. I feel the fan blowing air towards the engine, but shouldnt it be blowing to the radiator to cool the coolant? I read online that a blown head could be it, i hope it's not

 

Did the engine overheat before the tstat change? If not maybe you put the tstat in backwards. Check to see if upper and lower hose are hot when engine is up to temperature and there is no air pockets in coolant system.

 

The fan should pull air through the rad, same as driving down the road forces it through... works with nature, not against it. Sounds to me like it's working right.

Try a new rad cap.

 

The thermostat is fine. the one that was in there before was stuck open and it never warmed up and i never got any eat. I believe it is just a coincidence that the car started overheating when i put the new t stat in, so it must be something else. today im going to check both the hoses.

 

the hoses do get hot when the car is up at running temp

 

Of course they do.

Put a new rad cap on it.

Kinda humorous how people always jump to the worst possible doom-and-gloom scenario and get their panties all in a wad about it, before trying the simple $5 10-second thing that just is wore out.

Show us some common sense. Put a new rad cap on it. Go on, give it a try, whaddya got to lose besides some nightmares?

 

well i ran the car with out the radiator cap on and coolant start shooting out the radiator. The coolant was all foamy and then when i finally turned off the car the radiator spit a bunch of coolant 2 feet out. The only reason i can think is that there is compressed air getting in the radiator shooting out the coolant.

 

How'd the new cap do?

 

Sounds like an air pocket. Fill the radiator half way until car is up to temp. That should not allow air the system. Then when it gets up to 195 where the tstat opens add coolant and fill slowly. Put cap on and add some to overflow. Run the car and see what happens

 

Pressure test the cap and see if it holds the 15psi rating

 

I dont think the cap has anything to do with it. It could be an air pocket

 

the coolant also foams and bubbles in the reservoir . I dnt think the cap has anything to do with it and for the air pocket I have driven it when I fixed the fan tif there was an air pocket it should've worked its way out already

 

Sounds like perfectly normal behavior for a rad run without a cap on it.

Why on earth did you even do that?

 

to see if there was air bubbles?

 

PUT A NEW RAD CAP ON YOUR CAR.


You are wasting your time posting on the Internet without doing what you have been told to do.


We are going to keep telling you to PUT A NEW RAD CAP ON YOUR CAR until you finally do it. THEN, if there's still a problem (not likely), we can take the next step in figuring it out. BUT NOT UNTIL.


Think back to your high school physics classes, where you learned the principles involved.

 

Look at it this way--
A bad rad cap will not hold pressure as designed for the system, so the temp to overheat is lower than designed. Fluids can take more heat under pressure than not.
A rad cap at 15 or 16 lbs is what, $7 or $8.
The next best most efficient thing to do is go to AutoZone, Oreileys, Etc, get a loaner
" coolong system pressure tester "
Test the rad, test the cap. Yes, test both.
Follow the directions that come with it, or even ask one of them to help you do it.
You will have assurance afterwards either way.
Then
Post the findings.

{ To verify tester works, test a known good system }

 

I'm with them, replace the cap and go from there.

I used to panic when something went wrong...had a rad fan die on an old track car, and thought it was the head..we just need to step back, and start with the cheap, easy stuff first!

 

Made my day!!!!!

 

Well Doc, how'd ya make out??? Don't keep us hanging.

Man I hate that.

 

+1

 

I think he rage quit.

 

Sofaking probably scared him away, being so arrogant...

 

Thats his signature. If he isnt a dick, then he isnt sofa, lol.

But in all honesty, it probably was the cap, he just doesnt want to look like a dumbass.

Especially after this post.

Not picking on you Doc, just use some common sense if you have any...

 

oh willie, I'm rolling. What a way with words!

 

I aim to please

 

Sofa may come off as mean, but he knows his ****. I find it hilarious.

 

^ X2

 

Hey sorry I didnt reply and it wasnt the rad cap I did replace it probably needed it soon anyways it just took 3 thermostats on the third one it finally worked correctly I dont know why the other thermostats didnt work .. shouldve tested it before I put it in