kozmosis

What are the chances of replacing a water pump, both sensors and having them all be bad? My 97 Camaro SS has been in the shop for the past few weeks after changing the water pump. They ran the car and had no problem. I picked it up and drove 5 miles down to road to the car overheating. Checked all of the obvious things, and then determined the sensors were bad. Took the car again and was running hotter than it should have. Let it cool, driving it back to the shop the low coolant light comes on. Now I am thinking the new water pump is also bad. Anyone else go through this headache?

Injuneer

Has it actually been losing coolant? The low coolant light will often malfunction. But if it's losing coolant, take it back and tell them to fix it.

How did you determine both coolant temp sensors were bad?

Just for reference, what coolant temps are you actually seeing, in degrees?

kozmosis

not sure how he determined they were bad. Currently still running hot, he says the reason is that there is air in the system. He is now bleeding the system. My concern is why air keeps getting into the system, could the water pump be bad and sucking in air? He needs to figure it out but in the meantime I don't have my car to drive. frustrated.

Injuneer

When the LT1 cooling system is filled, the air has to be bled out. There are two bleeder valves for the purpose. Is your mechanic aware of that? Sounds like he has no idea what he is doing.

kozmosis

He did not want to believe it was the new water pump, but it was working properly. It has since been replaced and everything is back to normal.

Injuneer

Do you mean it "wasn't" working properly? Maybe he forgot to install the drive shaft coupling....

nikko

why does my coolant run out of reservoir instead of returning to the radiator. I thought I had it bled right lt1 z28 1996

Injuneer

You need to understand how the reservoir works. When the radiator heats up, the coolant expands and the pressure builds. A spring in the cap opens a valve at 18psi, and the coolant flows into the reservoir. When you shut the engine down, and the coolant cools down in the radiator, it contracts, and creates a vacuum in the radiator. A second spring in the cap opens to relieve the vacuum, and that vacuum pulls replacement coolant out of the reservoir to keep the radiator full to the brim - no air.

If the hose from the overflow nipple under the radiator cap is cracked, or the metal tube that passes under the battery is corroded, no vacuum reaches the reservoir, and you end up sucking air into the radiator. Now you have just undone all the work you put into bleeding the system.

Check the hose and the metal pipe that connects the radiator to the reservoir for cracks or a hole.

Another possible cause of the coolant running out of the reservoir is that the two hoses that connect to the radiator - the overflow hose on the nipple below the cap, and the hose that returns the coolant from the rear of the heads, a few inches below the overflow hose, have been swapped and are connected to the wrong nipples on the radiator.

Finally - third possibility - a blown head gasket will cause violent boiling that blows the coolant out of the radiator, through the reservoir and onto the ground.

nikko

thanks for your response injuneer.at least I have some ting to look for. I'm 62 and this is my first fast car since the sixties so am lost when all this stuff comes into play