Cooling problem

I am stumped on this one! 1995 Lumina 3.1 and it is overheating. It now has a new radiator, water pump and thermostat. It will run at idle without overheating and temp guage goes to about 2/3 and stops. As soon as I get out on the road and drive a mile or so it goes up to the red. When I stop it the overflow is full of fluid. I have been driving this thing every day for the past few months with no problem. I even flushed the system using a flushing mix until it ran clear and readded new coolant. The heater works fine and am not getting any condensation through the vents so I do not think it is the heater core either. I even put it on the computer and the only code that comes up is the MAP sensor. I don't think that it is the one of the gaskets on top because there is no water in the oil. I did find out that only one fan is working so I am going to fix that today but that is not the root of this problem. All help greatly appreciated!:eek7:

I would check the radiator for cold spots using a non-contact infra-red thermometer.

Definitly take a temp reading,guage may be off. Is it actually boiling over? With all the work you did involving draining the system could be air bound. See if you get air out of bleeders. Another thing to check is tranny. rad. cools fluid so if it's running hot..

Check and be sure all the hoses are plump and not collapsed and make sure you put the thermostat in the correct direction (and see if its the correct one).where did you get the thermostat and the radiator and did you put it in? because the temp gauge should only get up about halfway. anymore and you have a problem. this seems like the thermostat isnt opening properly.

If water is pushing into the overflow tank CHECK THE RADIATOR CAP to see if it is holding pressure. I have seen bad caps do this several times.

I dont know much about cars,but maybe you didnt bleed the air out after you did all that work,,,might be pressure built up,you know??

Ok, so I bypassed the fans so that they both work and they are on all of the time when the car is running so I know that is not the problem because it is still doing some crazy stuff. I work approximately 14 miles from home. When I leave the house I will drive approximately 5 miles it will go up to about half way on the guage and then cool back down to about 1/3. I will drive another 7 or so miles and then it wants to shoot up towards the red. I will stop and the overflow resevoir will be full. If I wait 10 minutes the fluid will slowly go back into the radiator and it will cool back down but it will continue on this viscious cycle. I have used both bleeders several times to let air out of the system and as many times as it has boiled over into the overflow it should have been bled by now. If I can just figure out how to make the fluid stay in the system I will be ok. I have had many vehicles and fixed many cooling problems before but I have never seen one do this after replacing the entire cooling system. Any more thoughts?

Ok, so I bypassed the fans so that they both work and they are on all of the time when the car is running so I know that is not the problem because it is still doing some crazy stuff. I work approximately 14 miles from home. When I leave the house I will drive approximately 5 miles it will go up to about half way on the guage and then cool back down to about 1/3. I will drive another 7 or so miles and then it wants to shoot up towards the red. I will stop and the overflow resevoir will be full. If I wait 10 minutes the fluid will slowly go back into the radiator and it will cool back down but it will continue on this viscious cycle. I have used both bleeders several times to let air out of the system and as many times as it has boiled over into the overflow it should have been bled by now. If I can just figure out how to make the fluid stay in the system I will be ok. I have had many vehicles and fixed many cooling problems before but I have never seen one do this after replacing the entire cooling system. Any more thoughts?

Gee,thats terrible. Maybe the head is blown. :frown:

What Can Make an Engine Overheat?

Overheating is caused by anything that leads to a loss of coolant, prevents the cooling system from getting rid of heat, or causes excess heat in the engine itself:

Coolant leaks (water pump, radiator, heater core, hoses, freeze plugs, head gasket, engine internal).
Weak radiator cap (does not hold rated pressure and allows coolant to boil over). Pressure test the cap to check it out.

Cooling system clogged (deposits built up in radiator or in the engine due to maintenance neglect or use of hard water). Use a cleaner, then reverse flush system to clean it out. A badly clogged radiator may need to be rodded out or replaced.
Thermostat stuck shut (replace).
Inoperative electric cooling fan (check fan motor, relay and temperature switch for correct operation).
Bad fan clutch (replace if slipping, leaking or loose).
Missing fan shroud (reduces cooling efficiency of fan).
Slipping fan belt (tighten or replace).
Too low or too high a concentration of antifreeze (should be 50/50 for best cooling).
Bad water pump (impeller eroded or loose - replace pump).
Collapsed radiator hose (check lower hose).
Debris in the radiator (remove bugs & dirt).
Late ignition timing (reset to specs).
Restricted exhaust system (check intake vacuum readings and inspect converter, muffler & pipes).
Radiator and/or fan undersized for application (increase cooling power by installing larger radiator and/or auxiliary cooling fan).

Ok so after changing everything with the exception of the heater core it was still overheating sperratically so I decided to do something drastic. I actually removed the thermostat made a gasket and replaced the housing. I drove it for 3 days and it never went above 1/4 on the temp guage and then the gremlin returned. I left work got a couple of miles down the road and it started again. I noticed that when it gets hot the top radiator hose is really tight and not allowing me to push water through the system. Once again I thought that it may be a bubble in the system so I attempted to burp it but got no air. If I did not know any better I would think that one of the head or intake gaskets may be bad but no fluid is leaving the system, it just evacuates into the overflow. I will stop give it a couple of minutes to allow the overflow to push fluid back into the system and it goes back to a cool range until it decides to do it again which could be immediately or a couple of days. Dangdest thing I have ever seen! Any other ideas appreciated. :screwy:

Get it tested for head gasket leaks, there are several techniques to do this, testing for exh gases in the cooling system is one,. If the hoses become hard/pressurized shortly after start up, that is almost always a hd gskt issue.

Ok so after changing everything with the exception of the heater core it was still overheating sperratically so I decided to do something drastic. I actually removed the thermostat made a gasket and replaced the housing. I drove it for 3 days and it never went above 1/4 on the temp guage and then the gremlin returned. I left work got a couple of miles down the road and it started again. I noticed that when it gets hot the top radiator hose is really tight and not allowing me to push water through the system. Once again I thought that it may be a bubble in the system so I attempted to burp it but got no air. If I did not know any better I would think that one of the head or intake gaskets may be bad but no fluid is leaving the system, it just evacuates into the overflow. I will stop give it a couple of minutes to allow the overflow to push fluid back into the system and it goes back to a cool range until it decides to do it again which could be immediately or a couple of days. Dangdest thing I have ever seen! Any other ideas appreciated. :screwy:
I wouldnt believe that MAX dude. If it was a head gasket,it would bubble up in the radiator,you would see it. There is a green bottle at autozone called head sealer,omg,that stuff is great. Held up my car for year til I got money to buy this one. You may have to use two bottles,and let it get hot for like 15minutes, cause it is just water you use with it,you would have to check that often. Its a pain,but at least you would have a car that ran. Once again. Mine drove for me for a year!! Sorry dont think I can help you out anymore,but good luck on whatever you do or whatever it is. Trisha

Well I finally went ahead and tore down the engine on Saturday and when I took off the valve covers there was some fluid in the oil but not much. When I got down to the lower intake manifold gasket the back one was ok but the front one came out in pieces. I went ahead and cleaned everything up and started to put it back together when I realized it would be silly to do that when the head gaskets are only one small step away. So I will be reassembling it this weekend and post back with the outcome.

Well I finally went ahead and tore down the engine on Saturday and when I took off the valve covers there was some fluid in the oil but not much. When I got down to the lower intake manifold gasket the back one was ok but the front one came out in pieces. I went ahead and cleaned everything up and started to put it back together when I realized it would be silly to do that when the head gaskets are only one small step away. So I will be reassembling it this weekend and post back with the outcome.
Wow what a job you have started, good luck with it, I hope you find your problem,Trisha

Since you have it down to the heads, it wouldn't hurt to check the deck warp and probably even the valvetrain condition. Since you're already there, you might as well.

Just be extra sure you don't drop noogies into the coolant or oil passages. No sense in blocking that spiffy new rad of yours.