spinedocab

Greetings to all,

I am new here, and have been lurking for a while. You all have a nice forum group here, and I am pleased to become a part of it.

I recently acquired a SR5 4x4 pickup with a 3VZE/5-speed/auto locking hubs. It seems to be a great truck, and I am enjoying it. I don't drive it a lot, but it's great when I do use it.

I am a pretty competent wrench and have been playing with my Saabs, BMW's, Honda's, Audi's, Plymouth mini vans, and others for years.

I have come upon a question about the fan clutch on my truck. Now that it is a little warmer, or maybe coincidentally, I notice that I can hear the fan whining/roaring a lot when I don't think it should be. It always seemed to be pretty locked up on starting the truck, either cold or warm engine but would stop/quiet down after a few seconds. Lately, however, I notice the fan roaring even after driving steadily for quite a while. Temperature gauge appears to stay in the normal region and the motor runs normally with no driveability issues (other than it's normal sort of sluggish power availability). Once in a while I notice a little "surging" in the power delivery, but that may just be an old oxygen sensor.

Anyway, is there a surefire way to test the fan clutch and see if it is bad? This has to be adversely affecting gas mileage, and the sound is annoying.

thank you for any ideas you can give me.
Andrew.

abecedarian

As the ambient temp warms up, the fan clutch will 'lock' a bit more. this is totally normal.
As for testing the fan clutch, if it's warm outside and you grab a fan blade and try to spin the fan, if it moves more than an inch or so once you let go of the fan the clutch may be bad.

spinedocab

thank you for the advice. Here's the thing, though. Yesterday it was about 65 degrees F. I don't think I should hear the fan howling while cruising at a steady state, no load 35-40 miles per hour. If I stopped in traffic after a warm run and I hot-soak a few minutes, I would expect to hear the howl for a few seconds after I start rolling again, but then it should stop as all that nice ambient air comes flowing in the front again. If it howls indefinitely, and not even when it has had a chance to warm up in traffic, it is behaving unlike my other viscous fan clutches. Hence my question.

This fan will be hooked up on a cold start up too, for about 15 seconds. That seems odd to me too, unless it's just the thick viscous coupling spinning the fan until it warms up internally from the friction of the spinning.

Noltz

Hi and Welcome!

Being a mechanical clutch, it's completely dependent on the radiant heat from the engine to engage or disengage. Quite frankly, it's not accurate at all... at least not compared to an electrical fan with a thermostatic switch. Mine does the exact same thing that you're describing; roar on startup that disappears after 10-30 seconds. Not always there in traffic, but sometimes I can hear it whistling away.

There are a number of write-ups on electric fan conversions if it bothers you. That would the the 100% solution. Replacement fan clutches are listing at $70 at rockauto.com via eBay if you think it might just be the clutch assembly.

Good luck!

PS: The link for the clutch: Click Here!!