red_rocket_z

Guys car is overheating, goes straight to redline within 3-4 mins. Took it to a garadge and they checked all sensors and relays and all are working. They finally discovered the fans were not working at all, so they fixed the fans.Guess what....it is still overheating! Guys said that they dont think its the thermostat because when it does get to red line it does gradually drop a little bit. They told me they have no idea what it is and to come pick it up. What in the world could it be? Could a bad catalytic converter have anything to do with it? I am trying to avoid taking it to the Chevy dealership and getting blasted with there high labor costs. Car is 97 z28...mods throttle body, pulleys, lingenfelter cold air intake, 4:10 gear, huest shifter, air foil, msd 6al ignition box, and 175 shot nitrous.

joeSS97

I would replace the T-stat.It doesnt cost much.Also could be the water pump drive gear.See how it flows when the stat opens.Make sure to bleed all the air out of the system.If that doesnt help,more than likely your radiator is plugged up.

TSheaZ28

My 97 is doing the same thing. I finally got around to looking at it today, and I had it on the stands while running, and the fans never came on, and the car was at redline for temp. It was also dripping a little coolant down the spark plug wires. Could it be the t-stat or is the water pump froze? Thanks for any help!

transAMdriv3r

water pump failure, air in the system

birdman1

I think these radiators suck, and they plug up easily, and roddingtghem does not fix it for the long term. I put a brand new one in mine 2 years ago, made it a very happy car again.

this is assuming it's not the water pump, thermostat, etc, per all the previously suggested causes.

red_rocket_z

TSheaZ28, let me know what you find out. If the radiator is stopped up that wont keep the fans from coming on will it?

tiznodd

The fans are not the problem. There is no way it could get that hot that quick unless water isn't moving or there is air in the system.

Eric_96Z

Same thing happened to me, the radiator was plugged some a$$^%&* put green antifreeze in with the orange and i guess that made it plug, anyway it barely warped a head and didnt blow out the head gasket but it would get hot in about 3 mins...

Blackbirdws6zzz

It could be a thermo but if it was stuck open, it would still flwo thru, if it was shut, the upper hose would be hot and the lower hose wwould not be. I'm afraid it might be your water pump, either the drive shaft is broek and your proppeller isn't spinning and circulating coolant. Hence It just sits in one place and gets hotter and hotter. Thats why it over heats so quickly. Thats my vote. Try and do the opti at the same time, if you do it yourself just be very careful. and try to suck the coolant out the top of the waterpump and get out as much as you can before you pull it off. You'll have to rip the IGnition off, AIR pump, And then you'll get the 6 bolts for teh water pump. Good luck man.

CALL911

If you are CERTAIN, its not your fans, and probably not the thermostat, I would begin by flushing and re-filling the cooling sysem, to also include the block. (just pull out the knock sensor underneath the motor) Also make sure all the air is out of the system once you have filled it up, and drive it for a bit. If you have more than 50k on the stock water pump, I would reccomend changing it out as well, and if you got the money, as previously stated, I would also do the opti swap. If you get a new water pump it will come with a new thermostat, however I reccomend a 160 instead of the stock one. You can also purchase a fan switch for not too much money to automaticly turn on your fans early. As for the radiators, they are good radiators. If you don't put the orange coolant in them, and keep them clog free with regular maintenance, they should last a long time and easily cool a heavily modified F-body. One last thing you can do to help out under the hood temps is to bypass the throttle body coolant line. Start with the simple easy stuff here, and continue on if it still doesn't cool off. If you do everything I mentioned here, you are pretty much garunteed a cooler running car.

TSheaZ28

Well, I just finished ripping the waterpump out. That was the problem from what I can tell. When I pulled it off, the bearings for the impeller were shot. It would bearly turn inside. I got A LOT of coolant everywhere. Will the opti have to be replaced cause I did get coolant on it? If it does, this car is gonna suck me dry for the next couple weeks Anyways, thanks for the help guys.

CALL911

Opti's are pretty fragile when it comes to moisture. At this point, you can dry things up the best you can on the opti, and try to put it back together. However, if the car misses, or stumbles, you will have to rip everything back apart and put a new opti in anyways. If it has been a while since the opti change (40k +), and you have the money now, I would just save yourself the near hassle and change it while everything is apart. Good luck.

TSheaZ28

Ok, so I'm trying to tear the opti out. Do you need a puller to remove the crankshaft pulley/balancer? I got the 3 bolts out, but I can't get it to come loose. Also, will it hurt the car to sit for a little while without the waterpump on. I might as well change the opti while I have the car ripped apart, but I don't have the money right now. The car has almost 69k on it, and I don't thin any of these things were ever changed before.

CALL911

It won't hurt your car at all to sit there without the waterpump off for a while. Just as long as no critters or anything crawl into your block. As for the crank pulley, I have managed to get it off just by using a hammer, and sometimes a crowbar. And then there were other times I needed the puller to remove it. I think you can rent one pretty much for free at autozone.

TSheaZ28

Thanks Call911. As much as it frustrates me to spend money, I actually liked tearing the car apart. I think once I get the waterpump changed and the opti changed, I'll be happy that I did it all myself. This is the first big repair I have ever done to any vehicle. I just hope I remember where all the bolts go.