ok so here is my problem, recently when i drive my cari start hearing this weird noise. i pulled over to see what it was and opened the hood. my coolant tank was bubbling over like crazy and lots of hot steam was coming out of it. the hose that runs from it to the radiators looked like it was pushing massive amounts of hot air into tank. why is this? any help greatly appreciated. i wanna get it taken care of quick, i love my 3rdgen as im sure everyone does.

 

Blown head gasket maybe, right between the coolant lines and the cylinder, the pistons are pushing air into the system and overheating it. Thats what I can come up with, any other info or input form others.

 

COULD BE VERY MINOR AS WELL. IE....STUCK THERMOSTAT, BAD RADIATOR CAP(BUT NO LIKELY), FANS NOT COMING ON (EVEN THOUGH IT'S COLD OUT YOU NEED YOUR FANS), OR YOUR BELT IS EITHER OFF OR SLIPPING. YOU ARE HAVING AN OVERHEATING PROBLEM IS WHAT'S HAPPENING. MORE THAN LIKELY IT IS THE THERMOSTAT. HAVE YOU HAD THE CAR SERVICED LATELY?

 

I agree with topradman, its probably something minor. Check your thermostat first.

 

Sorry I should have specified the easier items first, I forget sometimes that Im not the one in charge, Army mechanic thing. But yes check the easier stuff first. My bad.

 

thanks for the quick replys everyone. the thermostat huh? where is it located? how do i check it?

 

Follow the top rad. hose to the top of the engine. Under that housing is your Thermosat. My engine is easier to see it though. Which engine do you have?

 

not sure exactly what engine i have, just know its the 305 v8.

 

What year is it. Does it have a round air cleaner on top of the engine. It doesnt really matter. My point is, if its TBI or Carb, the thermostat is eaiser to see. Not sure about TPI. Never worked on one before. Just follow the Top radiator hose to the top of the engine. It goes straight into the thermostat housing. I would suggest getting a Haynes or chiltons manual if you have never done this before. It would be a big help.

 

yea ive got a carb. so im guessing mine would be right about the spot yours is in. so do i take this part apart? what am i looking for once i do take it apart? happy new year to everyone

 

The engine in the pic should be the same as yours, which is an LG4. I have the thermostat housing already off in this picture. Get a haynes or chiltons manual and follow the directions in the book. Or do a search on this site. Someone may have already given detailed instructions.

 

The coolant is boiling out of the radiator into the overflow tank. Probably NOT the thermostat as I can't imagine any t-stat failure causing overheating AT the radiator. A stuck t-stat may cause the motor to overheat by restricting coolant flow but that's obviously not your problem.

Let's not pull the t-stat just yet.

The coolant is boiling over because either: 1) the engine is overheating or 2) the coolant is not being kept under enough pressure. A bad radiator cap can cause #2 as it allows the coolant to boil over at a lower temp.

What did your temp guage show when this happened?

Do you have mechanical or electric fan at the radiator? Was the fan running when this happened? What year/model engine? (you need to know this).

 

The way I understand it is, if the thermostat is staying closed, the engine gets hot and too much pressure will build up and it will over flow into the overflow tank. Thats what happened on my 88 about 10 years ago and a few other vehicles I have had over the years. But, I just assumed the engine was over heating. Its a carbed engine so I figured its an LG4 which I think came with a clutch fan. Not sure on that though.

 

wish i had seen this before i replaced the stat. well i did replace the stat and she is still doing the same thing . whats next? she runs for like 15 mins before hitting the 260 area mark. also im not sure what type of fan she is and what engine im still new to this so im not very knowledgable about this stuff. i know she is a rs camaro 305 v8 5.0l

 

Is your fan attached to the front of the engine (clutch fan) or is attached to the radiator and have wires plugged into it. But make sure your not low on antifreeze first. With the engine cold take off the radiator cap. It should be filled to the top. If its not, leave the cap off, start the car and turn the heat on. Then fill the radiator. Keep it running for a few minutes. The level will keep dropping if its low. Just keep topping it off.

 

seems to be attached to the radiator. after switching the stat i filled the anifrezze up and followed the steps u described here but still no luck but still over heating.

 

RS would be an '88 or later model with TBI and electric fan.

Is the fan turning when it overheats?

 

it was dark when i looked at it so i could be wrong, but it didnt look like it was turning at all.

 

WOW! ALOT OF OF EVERYTHING BUT..... THIS If you heard a noise which i think some people didn't consider. Was it a whinning noise or belt smoking????? it could be that you're water pump went out. take the belt off which is easy to put back on and try to turn the pump you're self WHEN COOL. and if there is any restriction trying to move it the bearings went out on the water pump time to place a new one. GOOD SUGESTION TO ON THE THERMOSTAT. TRY THAT BEFORE TEARING ANY MORE. and it wouldn't be a blown head gasket trust me i would know if you saw a **** load of smoke yea now. if its leaking check you're oil to see if has a white milky substance or when u pull the dipstick it has alot of bubbles and smells real sweet. and if it doesn't check what color is you're antifreeze. if it is milky substance kinda hard to see it would be a leaking head gasket. BUT more likely i point my finger on the water pump.
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It would be a lot of white smoke coming out if you blew the head gasket.

 

the white smoke happened to be smoke coming out of the coolant overflow tank and the noise the the bubbling noise of the radiator shooting the coolant into the tank

 

Is the water pump leaking? Usually when gm pumps go bad they leak. Also you could just need a cooling system flush.

 

well im not exactly sure of what the device looks like but i cant see anything leaking. what about the flush? how do i do that?

 

Whoa guys, let's start with the basics here.

Assuming you haven't played with any wires and nothing's become disconnected...

The fan should come on before it overheats provided the radiator cap is good. You can pressure test the system which will also test the cap or you can purchase a new one for $3-5.

If it still overheats with a new cap and the fan doesn't come on, it's a fan issue.

If it overheats with the fan running it's something else in the system, either restricting air flow through the radiator (sometimes trash gets sucked up and will block airflow) or restricting water flow (water pump, etc.).

When the water pump is bad it will usually leak coolant from the weep hole on the bottom of the pulley snout. Don't replace the water pump until you know it's bad.

Don't throw parts at it yet other than a new cap. The price of a new cap is cheaper than the diagnostics to determine it's bad.

 

thanks sounds like good advice. ill change the cap next. do u happen to have a pic of the engine that shows where the water pump would leak if it was bad?

 

No pic. The weep hole is on the bottom side of the snout that sticks out with the pulley attached. Hard to see the hole with it mounted but you can usually see a drop or two of coolant round about there if it's leaking.

 

dang see i dont know wut any of this stuff is im so new to working on this car. i did do what u said tho. i ran out and bought a new cap and im going to put that on as soon as i get off work. im still here now. i really think it may be the fan. any idea how much that would be to fix?

 

My guess would be fan as well, but the radiator cap should be confirmed and it doesn't hurt to replace.

If the fan isn't running when it overheats again, it's most likely the motor but could be wiring/relay/sender/fusible link/etc. Still some diagnostics to do before we start replacing any other parts.

 

ok ill replace the cap tonight after work and then take her around the block and see what happens. is any of that stuff that has to do with the fan expensive? i dont really have a lot of money right now but love my 3rdgen and i dont want her to be inoperable

 

Okay understanding on the water pump. But you don't always have to rely on that b/c if you take the belt off and you turn the water pump and if its grinding or feeling a grind sorry to say but the bearings in the water pump are bad. Yes do the cheap things first like cap and if the fan isn't work try to hook a live wire to it and ground it to see if it will turn if it turns then its a relay switch/fuse/ or whatever. Trust me 9/10 times its usually the water pump minus if the cooling system been ****ed with with wires to the fan and if the coolant is a brownish color it needs flushed. but if its a green good looking color its fine. well depending on the color of coolant i use the green but i guess there is red out???? idk but i stick with what i know works. Honest just take the belt off OR if you don't start it in you're drive way and if you don't see the water pump move then its at fault. the water pump is located in front of the engine right where the fan is. You will see a pulley in the middle and thats where the water pump is it kinda looks like a 3 prong starfish i guess lol. hard to describe something like that w/o a pic.

 

Is it overheating at highway speeds or stop and go traffic, driving around town, or both. If its doing at highway speeds I doubt the fan is the problem. The outside air will keep it cool when moving at higher speeds. But in city/town driving theres not much air movement and then the engine gets hotter and the fans kick on. Try this, start the engine and turn the AC on. Assuming you have an electric fan, it should come on. That will tell you if the fan is good but not the switch.
Something else I just thought of. How cold is it where your at, and do you have the right mixture of coolant?

 

well i live mostly in a urban area so i dont see too much highway travel. yea it is really cold here. 26 to be exact

 

Did you try turning the AC on to see if the fan kicked on? If it did take the car for a drive and turn your ac on and see if it gets hot.

 

alright check this out. this morning i was planing to take my car up to the shop so they could find out what was going on. so on the way out i decided to take one last peak under the hood.i opened the hood and started the engine. almost right away i see steam coming up from my engine. this shocked me because i always thought the steam was coming from coolant overflow tank but it was actually rising up from the engine itself. so i looked closer, there was green fluid all around my left engine head. COOLANT! so i traced the line to a weird looking device. pic is called "download". so i switched that for cheap but in the process a long skinny cord running to the top of that device broke. u can see where it goes in on pic called "download2". all in all i thought the problem was fix but its not. she still overheats.

 

Heater diverter valve is bad. It prevents hot water from cycling through the heater core when the A/C is on. You can replace it with a new one from AZ for around $30, or take it out altogether with either a plastic hose splice or a new heater hose (long enough to replace both pieces) for less than $10. If you don't install a replacement valve you may lose a little AC efficiency but you probably won't notice the diff.

The vacuum line attached to the top of the valve should come from the firewall area. It needs to be reconnected or capped (if you don't replace the valve) to prevent a vacuum leak.

And it could have been that your rad cap was bad and that not enough pressure was building up in the system before you replaced it to notice the diverter valve leak. Long shot maybe.

 

Fill your radiator back up. Did you check your fan yet? Turn on your AC, the fan should come on if the motor is good. Another thing, just because coolant looks ok, doesnt rule out the possibility of needing a system flush. Rust can build up inside the block preventing the coolant to flow. You can do it yourself its easy to do. Problem is its too cold outside, unless you have a heated garage. But I wouldn't do that until you have ruled everything else out. If you decide to do it though, get a haynes manual, it will have instructions on how do it.

 

thanks guys for all the help. ill def get that vacuum line replaced soon. i finally just took her up to the shop and its her water pump and radiator that bad. doesn't surprise me too much i guess. the owner before me left my car sitting in a ditch for 6 months without touching it so things gotta be replaced. the shop wanted 600 dollars to replace the stuff but luckily i have a friend that works at advanced auto parts. 150 dollars is all i need to get the stuff fixed. doing Saturday, so i hope to back on the road with u guys soon. thanks agian for everyones help. i appreciate it a lot

 

thats good u found out what happened. I posted earlier. i thought it was the water pump the way u were describing it grateful it is now fixed.