Loud fan type noise when accelerating? Fan clutch?thermostat?
 

Hi i Recently just fixed my Land rover discovery 2 2001 and when i started it up it seemed like the viscious fan was spinning faster then usual? maybe i havnt driven it in awhile but when i accelerate i get a lous noise that sounds like a high pitched wind sound. Maybe its the fan clutch or possibly i need a new thermostat? Please let me know what you think it may be.


Thanks

i figure maybe i have to much water and my coolant levels arent right. possibly i need a new thermostat since my car over heated last week and may have dmamaged the one i have?

No, the thermostat will not be damaged, but the engine sure can be. Let us start at the top.

1. With truck cold, engine off, spin fan by hand. It should feel like butter in there, and when you release it should only go a 1/4 turn. If it stops at once , fan clutch is "frozen" and that is waht is making high air sound.

2. With truck warming up, hold plastic bag near grille. It should suck toward grille, not blow away. Recent work on truck can change serpantine belt route, or reverse fan blades, or reverse power wiring to electric fan(s).

3. Once warmed up, turn off truck. Spin fan and release. If it continues past 1 revolution (free wheels) the clutch is also bad because silicone fluid inside has been lost thru a bad seal.

4. Bad fan clutch will make truck overheat at idle and slow speed. At highway speed, overheat is more likely from low coolant, clogged radiator, sticking thermostat, water pump turning backwards because belt on wrong. If coolant is going somewhere, it can be leak on ground, leak on manifolds (burns off while driving), leak into oil (makes it milky), leak into cylinders (makes white smoke out the back).

5. A fan clutch is a cheap fix, as is a thermostat or radiator flush. There does need to be some air for expansion space in the coolant reserve container. Coolant, oil, power steering fluids are weekly check under the hood items.

6. A stuck (frozen) fan will make a loud noise when revved up, because it is moving a lot of air. Normal fans make loud noise for less than a minute, spread the silicone fluid around inside, de-couple (clutch) to about 20% power transfer when warmed up. If getting hot will come back at 70-90% power. You can also have a belt that is making noise, or water pump bearings, or other things turned by the belt.

7. If you have a sound like water rushing under the dash that is bubbles in the heater core. You can purge that. It can also be exhaust gas in the coolant from ahead gasket. There is a $50 chemical test for that.

Did anythings Savannah Buzz wrote work for you? Or did you come across the problem or solution?

Thanks!

Have not heard. But what sort of issue are you having?

It was a frozen fan clutch I replaced it and now it sounds fine thanks savvanah

You mentioned your t/stat, if it is over 60,000 miles you should change it along with the coolant pressure cap since they both fail with time because of the Dexcool.

Savannah Buzz, Thanks for the reply. It is pretty much the exact same problem as Thatdudeuno1. Loud fan/airy noise when accelerating. Only difference is mine is a '98 Disco. I am going to go through some of the steps that you posted today. Ill let you know what I find out.

Thanks again!

You can check for fan noise while parked, just rev up engine slightly. Most clutch units have loss of fluid, and eventually freewheel, loss of cooling (but they are quiet about it). Some fail by sticking in the fully coupled position, increased fan noise that does not go away in a few minutes. Have even seen one at the junk yard where previous owner had put a bead of RTV all the way around, so a free wheeling one would be converted to a 100% coupled one. OK in an emergency, but not a long term solution. Note that bad fan clutches are known to secretly hold hands with the water pump and jump off the cliff together. Be sure to look for any pulley wobble when truck at idle.

So the fan doesn't free spin at all, its pretty much seized up. It can be moved but not easy. I have one on order now. Is this a drivable problem, seeing is I must go into work today, and I live 30 miles away?