I have a 2003 Impala 3.4 and it is overheating. I had the radiator changed out last summer and the hoses. I put on a new radiator cap, thermostat and waterpump the other day. It is fine while it is idle, but when I drive the the gauge starts going toward the red line. Please help....I don't know what to do.

Is the fan running when it gets hot? Also, have you checked to make sure there's no obstruction in and around the radiator? For example, my mom lives on a road that Tyson Foods uses to transport live chickens. Every other year her truck will start to overheat. We have to pull the radiator out and clean chicken feathers out from between the radiator and AC condenser. The fluff makes it through the condenser, but can't get through the radiator. Also, check that the radiator hose that the water pump draws from isn't collapsing when the throttle is applied. If it is, a hose with a spring will fix this issue. Hope some of this helps.

Did the overheating start before or after you did the radiator cap, thermostat and waterpump the other day? What parts did you use AC delco factory or house brand, etc? My Impala had a new to me style thermostat where the gasket went around the edge, not a surface gasket like I'm used to and it also had a bypass hole in the thermostat. Did your new parts match exactly the ones that came out? I have the gauage reads about 180 but the computer is seeing dead on 208 degrees.

TJ

the overheating started before I put the new parts on. the fan is also running when it gets hot. I'll have to check with my brother about what parts he used, he changed everything out for me. I'll have him to check to make sure there is no obstruction and to also check the hose. I did put some coolant in one day that wasn't Dexcool, I hope I didn't mess anything up. I was told by someone else that it may be a gasket. I'll have it towed to a shop this weekend to have it looked it.

3.4's have several cooling system related issues.
The lower intake design is terrible,and susceptible to leaking.
They also must be purged of all air through the air bleeds before coolant will circulate correctly.
If it has overheated then there is a good chance the head gasket has went if it got too hot or has been continuously overheated.
If fans work,air is purged and your losing coolant then you need to do a cooling system pressure test while engine is hot and cold.
Also do a block test to check for hydrocarbons in the cooling system.
If it were me and fans worked I would go directly to block test personally.

Good call on the purging of air from the cooling system. When I did the LIM gaskets I had a hell of a time purging all the air and I did "get hot" but didnt over heat. I shut down before that point. Air pockets will definately do it. As playtoy mentioned that 3.4 and 3.8 for that matter share the same crappy LIM gaskets as our L31's do. However if those LIM's go on the 3.4 you can dump coolant in the crank case and spin your bearings before you can get the motor shut off.

If you did over heat to the point you had steam coming from your hood or the temp gauage was pegged there is a high chance you did damage gasket material. You didnt mention the mileage, but if you have over 100K and have not done LIM gaskets on that motor and want to keep it, do not drive it another inch without replacing them. If your brother did the WP then he can do LIM (not to be confused with the UIM gasket there are two). It took me a day and it was the first one I had ever done. Just go slow and be patient so you dont break little plastic clips or vacuum hoses!

Another thing, you mentioned mixing coolant. As long as the coolant you added was the "orange stuff" you should be "ok". If you mixed green or any other color even clear you could have a problem. Dexcool will gell with the other kinds and block coolant passages.

Dexcool has a lot of detractors. I personally like it when used in the proper system. It can only be used in a closed system, which your 3.4 is (no radiator cap or "surge tank"/ vented overflow tank). The key to dexcool is to keep it out of contact with the air. Prolonged contact with air will cause it to turn corrosive and start eating gaskets and anything aluminum. As long as you separate air from dexcool you have the best protection money can buy! Its just not "user friendly".

TJ

98Blackss wrote:

Dexcool has a lot of detractors. I personally like it when used in the proper system. It can only be used in a closed system, which your 3.4 is (no radiator cap or "surge tank"/ vented overflow tank). The key to dexcool is to keep it out of contact with the air. Prolonged contact with air will cause it to turn corrosive and start eating gaskets and anything aluminum. As long as you separate air from dexcool you have the best protection money can buy! Its just not "user friendly".

TJ

Agreed.

I have a lot of experience on the old 3.1 in the Grand Ams, so am very familar with the LIM setup on those engines (not good memories there). DEFINITELY get the metal Fel-Pro problem solvers.

Dexcool. Bleah. Why use an antifreeze that gels when something goes wrong when you can use one that doesn't? I use the yellow stuff which is the non-Dexcool 5 year stuff. Works just as well, doesn't gel when it sees air.

I remember hearing in a Ford class that EPA was going to require all manufacurers to switch to Dexcool formulated antifreeze.
That was at least a year or more ago,and i've not heard anything furthur about it.