Cooling Fan CFM?

[JamesTWood]

Hi guys. I've been looking at this forum for years due to all the useful information on it, but I finally found an issue that I wasn't able to solve based on someone else's post.

My 2005 base model Vibe's cooling fan broke on me. The fan came off of the motor and I was unable to reattach it. Instead of spending $270 on an OEM fan and shroud I got the after-market Hayden based upon the recommendation of the local O'Reily store. It attaches directly to the radiator and seems to be working correctly. It's rated at about 650 CFM of airflow.

Unfortunately the car is still overheating on warm days in stop-and-go traffic. It doesn't overheat at idle, it doesn't overheat above 35 MPH, and if it's overheating and I turn on the heater the heat will drop down to normal (after a bit).

This tells me that the coolant is running through the radiator (and into the heater core) correctly, the thermostat is working correctly, and the water pump is working correctly.

My hunch right now is that the aftermarket fan can't push enough air, but I can't confirm that because I don't know the CFM rating for the OEM fan. I know it's a Denso, but that's about it. All the sites I've checked don't tell me the airflow rating.

Does anyone know the airflow rating for the OEM cooling fan on the 2005 1.8L 2WD Vibe?

[M1MECHANIC]

It sounds like your thermostat needs to be replaced. Had same problem with honda prelude. The heater pulls the water off befor the thermostat and that is why the temp. drops when you turn it on. At 35mph there is enough air pushing through to cool the engine and radiator so it won't overheat but will run warmer then usual. Stop and go traffic relies on the thermostat opening up to let water flow for cooling. I would try replacing the therstat first, even if it's new. I went through 2 that were bad once in one replacement. If you want to check if first, then pull the thermostat out boil some water, then put the thermostat in the boiling water. It should open, best if you check the temp of the water as most are rated at around 180 deg. unless you upgrade to the 220 deg. But all that aside as a mechanic I would say replace thermostat. Hope this helps.

[JamesTWood]

I suspected the thermostat too, but I used the cheap method of feeling the temperature of the intake and output hoses from the radiator. There is no difference in the temperatures that would suggest the thermostat is not working correctly. Also I flushed the radiator after installing the new fan and it flushed out normally. It also doesn't heat up unusually quickly and it's able to remain cool at idle speeds.

While I'm not 100% certain, I am about 98% sure that it is not the thermostat.

[Chiadog]

Check the fan to be sure it is turning in the correct direction. Sounds like you only overheat when the forward speed of the vehicle matches and cancels out the reversed fan!

[JamesTWood]

I did have to reverse the fan blades and wiring to make sure it spins the correct direction. At idle the fan is pulling air through the radiator and A/C condenser toward the back of the vehicle. The fan is spinning the same way the air blows when the car is moving.

[JohnO]

The motor is probably designed to turn in one direction. Reversing it would reduce the power it can produce and thus the air flow. The same for the fan blades. They are designed to turn one way. Running it backwards will reduce the air flow.

[JamesTWood]

That may be the case, but the instructions that came with the fan indicate that it is reversible.

I am strongly suspicious that the fan isn't producing enough airflow, but I don't know the best way to test it and/or compare it to what it should be.

[Chiadog]

My 2005 base model Vibe's cooling fan broke on me. The fan came off of the motor and I was unable to reattach it. Instead of spending $270 on an OEM fan and shroud I got the after-market Hayden based upon the recommendation of the local O'Reily store.

A used oem fan from a junkyard should cost less than $25. My local yard sells them for $10. I assume your oem motor and shroud are still usable?
If that doesn't work for you, get a laser temperature sensor gun from Harbor Freight and scan the entire radiator for cold spots indicating a plugged radiator. Generally speaking, if the two radiator hoses (in vs out) are the same temperature with the fan running - the radiator is plugged and short-circuiting.
Another crude check is to evaluate the amount of heat coming off the radiator when the cooling fan kicks on while idling in PARK - should feel a significant blast of hot air and the fan should cycle OFF in a minute or less. Did you check the radiator and AC condenser for dirt/debris?
good luck,
chiadog

[WinstonWolf]

I had my fan replaced because the original was buzzing horribly. I too notice that the CFM is down on whatever fan they put in as a replacement. Hasn't been a huge issue yet, but I'm hoping it won't be killing me in July/August.