Engine overheating?

Yes, I checked voltage at the fan relay. All relays have +supply to them. I found out that the cooling fan relay 1 is clicking relay, but fan is not coming on, that would indicate the temp sensor and computer is working. I need more wiring diagrams. Thanks

I have it working now and automatically responding. I found two things (not very common) that was keeping it from working. First I saw there was no ground at right cooling fan black wire. I think there should be ground there all the time. Second I found that there was a bad relay at cooling fan relay 1, bad contacts. Diagrams really helped.

I understand that the ground for the fan relay is completed by the -trigger ouput from PCM. I was talking about "5 BLK 1050" big thick black wire down by the right fan. It didn't have cotinuity to ground, so I tapped in and put a ground wire. Its responding automatically and shutting off. Just curious why that one big thick black wire was not grounded, its not like it went through a relay, I looked at the diagram. I followed that big BLK wire to the bottom of dist box and did not have cotinuety there ether.

Yes the ground goes through one of the relays

Engine Cooling problem
2002 Chevy Venture 4 cyl Two Wheel Drive Automatic

Van will redline when driving around town, but wont blow hot air through vents. If I speed up very rapidly the temp goes down and starts to blow hot air. None of this happens when driving on the highway. Checked for coolant in the oil(NONE Present) and no visible leaks. Any help would be MUCH APPRECIATED Thanks

Yes the fan starts up when the temp increases and then shuts down when temp gauge returns to normal.

Ok Thanks for your Help! I will check it out

My temperature guage goes way up (3/4) when idling or in stop and go traffice. It remains normail (3/8) on the freeway. Is this normail or do I have problem?

Pam Freis

Sounds like a problem to me. I have the same year venture as you do. My Temp rarely goes past the 1/2 mark and I live in Phoenix. I would check a few things right off the bat.

1. Have you changed your coolent recently? What mixture % is it? Parts store sell testers cheap to test your coolent.

2. Check the 2 fans that are attached to the radiator to make sure their running. I'm thinking if the fan's are not working properly, you would see the overheating issue idle/parked/stopped. But when driving on the freeway their may be enough airflow from your speed to keep the engine cool.

I would start their. A bad thermostat possible as well, but I would expect that to make the eninge overheat after a few minutes of driving and not cool back down unless it's sticking.