Hi my
name is Scott, and I have a question about my 2000 Chevy Crapalier. Well I started hearing the dreaded water pump sounds, as well as seeing some antifreeze coming out the weep hole. I preceded to change it and everything went well until a few days later when I noticed the temp gauge starting to get higher and higher. I panicked got the car home in time opened the hood and noticed the coolant was still full, and everything was running smoothy. No loss of coolant, nothing coming out of the overflow, no funky smell, and the car was running great. So I talked my neighbors friend and he said to change the coolant temperature sensor. So I did, and noticed the same problem. Well after trying these things I decided maybe it needs a good cleaning and flushing. Right now I am running super cleaner through the system. I still noticed the problem after running the cleaner for like thirty minutes, so I wiggled the pigtail connector wires that went to the coolant temp sensor, and immediately seen the gauge start to drop. So I replaced the connector, and here is were the question comes in. After changing the connector I started the car, and waited for it get up to temp, and the fan turned on earlier than it usually does, and car temp guage is maintaing a temp cooler then I have ever seen, and the, fan will not shut off after it gets cool, it runs the whole time, until I shut the car off. After I shut the car down, I start it back up and the fan is not running and will not until it reaches temp again, and then cools the car down and simply stays on. Any ideas on what might be causing this. Thanks in advance

 

Have you properly bled the cooling system of air? This can cause blockages and spikes and overheating.

Does the fan turn on with the AC?

 

Yes i have bled the system via the bleed screw, didnt hear or see much when doing this though. I am not sure of the exact temp the fan comes on at. I do know the middle mark is 195, and the fan comes on when it gets one mark past that. It cools to a little under the halfway mark and stays there with the fan running, and not turning off. It used to turn on on the second mark and cool down to the 195 mark and shut off. I was wondering if running straight water with the prestone super cleaner in it might cause some differences in temp. Also has mostly been done sitting and idleing. Anyways thanks for the quick reply.

 

Leave the bleed screw open when filling. You should see some leak out when full and out of air. If you have 2 bleeder screw lines, do the lower line first, then close it, then continue to the upper line and close that when it leaks.



Another alternative is to CRACK it open when the car is running. I would only devise doing this when the car is warming up, and hasn't built full pressure. It will come out as hot steam otherwise.

My preferred method is to use a cooling system pressure tester, add some pressure, and open the bleeder screw and close it when fluid comes out.

 

Thanks for all the information,. I did it exactly like you instructed and the car seems to be doing great. I do however have another question. Just yesterday I noticed a small leak coming from the upper inlet cooling pipe where it inserts into the side near the valve cover. A few months ago I purchased a upper inlet coolant pipe. When it arrived the o-ring was missing, so I called them and they said they did not have a replacement, so I was left guessing on the size. I have now developed a leak from the o-ring area, and cannot find what size the o-ring is anywhere. I was hoping maybe someone reading this would know or have a guide to know. Thanks in advance.

 

Try taking the inlet cooling pipe with you to the auto store or hardware store to match an o-ring to it.

 

Yeah I thought about doing that but the thickness of the o-ring would be the concern. I have a ton of ring that would fit around it, but if it is not the right thickness it will not seal right. Thanks for idea though I will have to eye it again I guess. Go up one thickness or something.