Hi there.

i own a 2004 Venture. I have been experiencing problems with both cooling fans.

Here is the story, the other night, i noticed that the temp reached the redzone, then the engine started to belt out steam. As it turns out, the lower heater hose plastic 3-way valve broke. So i had it fixed.

At first i did not know why the hose broke but now i think its because of the fans.

What is happening is that when the engine first starts, i turn on the A/C, and as expected the low-speed fans switch on, then after a few seconds, both fans switches to HIGH Speed. The normal HIGH SPEED that i am used to.....very loud and strong. Then while the engine runs, as time passes, the supposed "HIGH SPEED" loses RPM....significantly. I know that its not the LOW Speed because i know the feel and noise of the LOW SPEED.....so basically, the fans "switch" to high speed, but it never reaches the normal RPM and noise. Then at times, one of the fans would stop working while the other is on high speed.

This started perhaps the other night which is reason why i blew a hose.

Here is the historical replacements i made BEFORE this all happened

Replaced the MAIN ENGINE ELECTRICAL HARNESS
Replaced the FUSE BOX
Replaced the Fan ELETRICAL HARNESS
Repaired both Cooling fans by replacing the carbon brushes since it the carbon brushes were previously worn out.

So basically the whole electrical system in the engine was replaced, including the radiator dan harness plus the fuse box.

All the relays are fine, no fuses busted.

I hope someone can enlighten me why my fans are loosing RPM as the engine runs longer, and sometimes one fan fails.

Thanks in advance.

 

I have a 2005 Silverado cooling fans are coming on after truck is parked have any suggestions

 

Try the Silverado section, might be an issue someone else has had.

Sounds like you have a short, or something in the fuse box under the hood maybe. Check the relays, and fuses there first, look for corrosion, melted plastic, loose contacts, etc.