GenVibe - Community for Pontiac Vibe Enthusiasts

2005 (base) Vibe about 179,000 miles . Owned it 10 years since 75,000 mile. I,m starting to think the Vibe has a cooling system problem. The a/c not functioning perfectly may only be one symptom. I was sitting with the motor already warmed up. Temp needle was 50%. Couple minutes later needle was 95%. The fan was engaging properly. I replaced coolant a few weeks ago. Perhaps I mixed it not at 50/50. Radiator and thermostat are original. Water pump about 3 years old. No loss of coolant observed.This Vibe always ran about 50% on the temp needle as normal and about 55% when the fan would start.

If heater core or radiator are dirty or clogged with debris would these symptoms be happening???

just ran the vibe in carport . With no a/c on temp needle slowly went up to about 50%. Ran car for 15 minutes and needle remained constant. Turned on a/c . The rad fan did not start. Turned a/c to recirculate and rad fan still did not start. Ran it like that for 10 more minutes and rad fan did not start. and temp did not increase.

is it possible some sensor is occasionally malfuncting and not allowing the rad fan to start.???


And why at a stand still some times temp goes up to 95%???

Drove around awhile. Now the radiator fan works when turned on the a/c.

Sounds like you may have / had an air pocket in the cooling system.
The fan should start to run when the coolant temp reaches the temp sensor threshold.
There is a pressure switch in the A/C system that can go bad and cause the fan to run immediately when the A/C is turned on.

could be. when I replaced the coolant there was no easy way to solve that possible problem.

On my old 98 Chevy Lumina 3.1 litre there was easy to reach valve to do it.

On one of my Vibes, I had air in the heater core after a coolant change, and I was able to burp it out by switching the heater hoses where they hit the firewall, reversing the flow through the heater core. But that was different, my issue was that I was getting no heat out of the HVAC even when the engine was at operating temperature.

BTW= the heater is working perfect.

Today I drove about 5 miles each way to a doctor appointment. Several red stop lights,etc. But I did not try to use the a/c.
The temp needle stayed around 47% the whole time. When I got back home, I put it into "park" and let it idle for about 15 minutes. The temp needle got up to about 75%. Then I turned on the a/c to see if the rad fan would operate. It did not operate Then I turned off the engine. A few minutes later started the Vibe and the temp needle was at 47%.

So the rad fan is definitely screwie.

I bought a Toyota thermostat. brought it to a local shop. they installed it. Also installed a new radiator fan assembly. maybe did a vacuum system method to remove air pockets in the cooling system. I drove the car on a 90 mile round trip today and all went well.

it,s still not over heating. I do notice some weird vibrations while sitting in gear at idle. feels like when a ignition coil is out, but much less severe.

still running nice and cool. a/c working great and rad fan working properly.