2003 impala overheating problem

[bobbyboy-g]

HEY GUYS, hope someone can help me with this issue...a few months ago i had overheating problems with my 2003 impala back then trans fluid was getting into radiator, i replaced radiator, flushed out the cooling system, added new coolant,changed trans filter etc.. and all was well until this weekend...i was driving home and the red temp warning light came on...car starts to overheat, car goes into limp mode, i get the car home and since it was a weekend i replace the water pump, thermostat, rad cap, hoses, bleed the system, drive the car a couple of miles to test it, then park it and let it run for about 20 minutes, the temp gauge stays at about 175 so i think everything is "cool" well on my way to work monday about 8 miles away the temp light comes on and limp mode starts to kick in, but i am now at work, no leaks anywhere just the overheated hissing sound and the overflow bubbling...so i let it sit the whole day, i top it off with coolant and start for home, about 4 miles later the temp light comes on car starts to go limp, i pull over for about 30 minutes then i start to drive again and then again the same thing a few miles later...i let the car sit for about 3 hours after i got home, then i go check things out, i start the car and have it on for about 45 minutes, the temp stays at 175, no overheating or anything...okay i figure just one of those things..well today i go to work and the exact same thing happens again, right down the same exact locations...i was just outside with the car for about 1 hour with the A/C on and the temp did not even reach the mid way point 200....the fans do come on with no problems..there are no leaks at the heater core either,a friend mentioned bypassing the heater core to see if that might be the problem but i would prefer some input from the forum since it has been helpful in the past.. my car is a 2003 impala 3.4 engine....does anyone have any idea what might be wrong.....

[adamace1]

Are you sure it is overheating? Could it just be a bad temp sensor?

[richtazz]

Are you actually losing coolant? It sounds as if you have the infamous intake gasket leak these cars with your engine are known for. It will allow coolant in the oil, as well as air into the cooling system. This will cause an air bubble to continue to re-occur no matter how many times you bleed it.

[bobbyboy-g]

hey adamace1..yes i am very sure the car is overheating....hey richtazz, i checked the oil and it does not seem to have any foreign substance and the coolant is not mixed with anything...as far as coolant loss it does seem to lose some but i am not sure if its because the overheating thing is causing it to...today it did not overheat after driving it about 6 miles, but the needle got up to about 230...real close to the 260 max...crazy thing is i let it sit for about 2 hours after driving it, then go turn it on, and let it idle in the driveway for about 45 minutes, the needle barely reached the halfway point (200)....why would this be....would i have to bleed it again maybe....and if it has a gasket leak would it only show up when i drive the car... if the heater core has a restriction would this cause this problem, and could i disconnect or bypass the heatercore and connect one of the hoses directly to each end of the outlets on the block to check it or would this cause any major problems....i hope these are not to many questions....i would appreciate any help...thanks

[crazy Jim]

Seems it only gets hot while running down the road, I wonder if something is blocking the airflow up front ocassionally? Also are the fans running when it is overheating, although while driving down the road the fans should not be that big of an issue. Secondly, I would bleed the system again and if it still gets hot I would them begin to suspect that the new WP or T'stat are no good.

[bobbyboy-g]

HEY CRAZY JIM, that is correct,it only seems to overheat when i drive it....today i took it to work and the needle was about to hit red when it got there, same thing on the way back home..it was something like this once it got past 200 the mid way point...needle hits 220 then comes back down to about 195...needle hits 230 then comes back down to 200....needles hits 240 then comes down to about 220....last it goes up to about 250 then it comes down to about 240, at that time i was driving into my driveway, do the fans go on and off or are they suppose to stay on all the time...i am asking because it seems like if the fans go on and cool it a little but then probably cut off and temp rises again..i am not sure if they cut off because i am driving at that time..i am just guessing here...thanks for your reply...

[crazy Jim]

The fans should be on anytime the temp is over 220. Your description matches exactly what mine did when the water pump started going bad. Unfortunately this desc also matches exactly with a poorly operating T'stat. Since you have recently replaced these items I would first ensure there is no air in the system and then fall back to maybe a faulty WP/T'stat...

Several years ago I peiced together an '84 Camaro that had been involved in a serious head on collision. I basically started from scratch and was unfamiliar with what parts were needed to complete the front end. When I drove the car it would get hot(220+) but when I came to a stop it would cool back down (180-190), weird. Well after much experimantion I determined an airdam underneath the radiator would correct the situation. A bit more research and I found out that I was missing a factory peice that mounted directly below the radiator. This peice acted to create a low pressure area behind the radiator thus "pulling" more air through the radiator. Cooling from then on was never an issue.

[richtazz]

Heating up as quick as it does, there has to be an air pocket in the cooling system or a sticking t-stat.

[bobbyboy-g]

hey guys, thanks for replying, okay here here is the latest of this continuing saga, car was driven about 5 miles today and it was acting the same temp up then temp down when it started to reach about 250 i got off the car and opened the hood and only one fan was on...i let it cool off, topped it off with coolant and drove home, when i got home i opened the hood and noticed that the one fan that was working would turn on and then turn off, during this time the needle moved a little backward then forward as when i was driving, but now it was really getting close to overheating. so i turned it off...i replaced a burned out 25 amp fan fuse and the other fan came on, but then the fuse blew out, i put in another one but it also blew out, so i am guessing it is probably the fans...would the fans not working correctly cause it to lose coolant ? thanks

[richtazz]

It would if it's overheating. The coolant will get pushed to the overflow bottle, and may be getting forced out the overflow. I still don't believe teh fans are the problem while driving, unless you sit at a lot of stoplights on your commute. The air flowing through the radiator as you drive should be enough to keep it cool (except on days where the temp exceeds 85F or so. Before you go crazy, replace the t-stat and re-bleed the cooling system and see what happens. Also check the ends of the intake where it meets the heads and block for coolant leakage. You may have one of the rare instances of intake gasket failure where the coolant leaks outside, not inside the engine. Also check the quick connect hose fittings going to the heater core for signs of leakage. A cooling system pressue test may help narrow down where your leak is if the t-stat/bleeding doesn't fix it.

[bobbyboy-g]

HEY GUYS, well looks like the leak finally showed up....we bled the system, filled it up, and let it idle for about 30 minutes, then as the temp started to rise, i looked under the car and saw coolant coming out of the back middle of the engine,at two different places but maybe because it ran down the frame and split into two...not sure though cause we could actually see where it came from, from the topside i cant see where it is leaking from either...more investigating will be down tommorow under daylight..any suggestions as to where it might be coming from...thanks

[bobbyboy-g]

hey guys, i have another question, water started coming out of the area around the water pump, causing the water to hit the belts and spray everywhere, i replaced the water pump and it was fine for 3 days, i got another water pump put in, 4 days later the leak shows up again at the same place...i can see it leaking from underneath the pulley, soon as i turn off car it gushes to the floor...(needless to say car overheats) could this be the dreaded intake gasket i heard so much about or could it be 2 bad water pumps..please help...thanks in advance...

[crazy Jim]

sound like WP, when I replaced mine scraping the old gasket off was the hardest part of the job. Did you make sure the sealing surface was clean?

[bobbyboy-g]

hey crazy jim, thanks for the quick reply, yes everything appeared to be clean...is that normal for the water to gush out of that weep hole after turning the car off, is there any other thing around that area that could leak water, do these cars have freeze plugs near that area...2003 impala 3.4 engine...i will try and get the water pump exchanged at the auto parts store...thanks in advance..bobbyboy-g

[crazy Jim]

not normal unless you mean to ask "is it normal for a bad WP to leak out of the weep hole" then yes it is normal...