Replacement Engine -- Loud Air Noise

Replacement engine is in and complete except for coolant. I wanted to hear it run before I dumped water in.

It starts and runs surprisingly good, but after a few seconds it makes a noise that sounds like something more along the lines of air going through a tube at high speed. Hard to describe. doesn't sound like a belt slipping and all pulleys appear to be working.

I feel like the noise is coming from the accessory area/ fan area.

Any thoughts? Could there be air flowing in the hoses/radiator?

How should the fan clutch work? the blades spin. I guess that is expected?

Start it without fan belt on the crank, there is no water in it so water pump doesn't matter.

And see if you can locate the noise, with no fan engine bay will be very very quiet
If no noise then it is an accessory making the noise.


Fan clutch should be semi-locked after sitting cold for a hour or so, so hard to turn
After start up you will hear a "fan noise" for maybe 5 seconds and then the clutch will unlock, shut off engine and fan should spin easily.

Fan clutch works from RADIATOR HEAT, not engine heat
On the front of the clutch is a bi-metal spring, as the center of the radiator heats up that spring heats up and moves a valve inside, this causes the fan to spin closer to water pump speed, so starts to lock, the warmer it gets the more it locks

belt off... no noise

THANKS!!!! without the belt it runs nice and quiet.

I guess that if there is an accessory issue, it hopefully won't stop me from getting this engine up to operating temps. I can always swap out what is having issues later. was worried about some strange vacuum/intake leak

I think I am going to put the belt back on and fill the radiator with fluid tomorrow and go through a flush.. weather permitting

You can always leave the fan clutch off for warm up with water or coolant

The fan is needed for air flow thru the radiator when stopped, but if you are just going to check for leaks it won't over heat

Blades Spin On Cold Engine

The fan blades do rotate pretty easily on a cold engine. There is some resistance. Feels like a gel inside. When the motor was running the fan was spinning. From your description of the clutch being locked on a cold engine, it sounds like mine has issues.

Fan clutches can be tricky, on the truck I have now, the fan clutch was so tight that the engine wouldn't warm up, after a two almost three week battle with friends and me trying to break it loose I took it to a garage and he took it off with an air hammer & changed it for me it's been good ever since. If you were to get the extreme duty fan clutch like we put on my other truck, you will pretty much always have fan noise when it gets warm out. I liked it, felt like I was driving Jeep in the old TV series MASH my

I was checking out clutches and saw "heavy duty". Does that just mean that it is more likely to come on regardless of radator temp?

No, it works the same, might last longer

When the fan clutch is cold after sitting overnight the fluid inside is thick, so on start up it is the same as it is locked/engaged, but after being turn at 1,000rpms for a few seconds the fluid heats up and thins out, so it can flow easier and fan is now unlocked, until the radiator starts to heat up

The fan sucks horse power and MPG so you want it disengaged for the most part.
While driving the air flow thru the radiator is more than the fan could provide, its only when you are stopped or driving very slow that you want the fan to be fully engaged, which happens as radiator heats up when air flow slows down as you come to a stop

Electric radiator fans are better but more expensive than the fan clutch setup for car makers.
In transverse mounted engines(FWD cars) they have to use electric fans

Smoke on Startup

i removed the fan and clutch and the noise persisted. I think it was coming from the accessory area by the alternator. I put the fan and clutch back on and filled with distilled water.

I started up the Ranger and let it run... I noticed that there was A LOT of exhaust smoke... White smoke billowing out of the tailpipe. My first thought was S$&#.. this truck must have a bad head/intake gasket. I even sent a text to a guy who has done towing for me telling him he may get a call to take away the ranger.

I did remember months ago before I took the motor from the explorer, I repaired a bad freeze plug so I could fill with water and had it running for a while with no smoke.

Now the smoke was bad for a while. I decided to continue... take the ranger out for a ride and drain the water and put in antifreeze.

Overall the truck idled well, and even ran OK. I was able to get it to 55 on a stretch of road, but didn't push it. I think the smoke subsided quite a bit. It was dark last night, so I couldn't be sure it was cleared.

Is there any way the initial clouds of smoke could make sense? I did fire it up a few times and let it run for a minute or less prior to the longer smoke filled run. No smoke those times.... also the coolant passages were dry.

Oh.. one final note.. the initial accessory noises that I heard seem to have subsided.

Why did you swap engines?
Maybe old engine dumped some coolant into exhaust system
New engine heated up exhaust and was vaporizing the old coolant
Long shot but could happen


Simple, and FREE, test for a cylinder leak(blown head gasket or cracked head) is the Glove test

Cold engine
Remove rad cap
Remove over flow hose and plug that port; gum, putty, vacuum cap, ?? whatever
Lower coolant level in rad 2", more is fine but at least 2" down

Disable startup, unplug 4 wire connector on coil pack or pull Fuel Pump fuse or relay

Put a latex Glove over rad cap opening and seal it with zap strap or rubber band; OR you can use a balloon OR even a condom in place of the glove

Crank engine over and watch the Glove
If it bounces you have a cylinder leak
If it doesn't bounce then you don't
100% accurate test, unlike chemical tests, lol.

You may get a initial "bounce" when water pump starts to circulate coolant, but it won't repeat, leaking cylinder will be a repetitive bounce while engine cranks, each time leaking cylinder is on its compression stroke, a bounce, no mistaking it

If it does bounces then remove 1 spark plug at a time and crank engine over
When glove stops bouncing the last spark plug removed was from the leaking cylinder, put spark plug back in to confirm

You don't have to do this last part, if Glove bounces both heads need to come off to be tested and surfaced in any case, but some people like to know which cylinder has the leak so it can be examined more closely



Alternator bearing noise can come and go, but plan on it going, for good, sooner than later


How/why glove test works
Each cylinder in any engine has at least 140psi on its compression stroke, a blown head gasket or cracked head MEANS a cylinder has a leak into the cooling system, that's the definition of these problems, and why it causes over heating.

So the cooling system pressure will change each time the leaking cylinder is on its compression stroke, Glove bounces.
Even the smallest leak will show up, so compression tests are OK but not definitive for this, and chemical tests can show false positives from coolant contamination from other sources, which is why Shops like/love doing the chemical tests

You can have more than one cylinder with a leak, glove will bounce less, its noticeable, so keep taking out spark plugs to ID the 2nd or 3rd leaking cylinders.........if you want, as said once you know there is a leak doesn't really matter which cylinder, all need to be resealed and heads tested for leaks

That's great information. I will have to give it a shot with the glove.

I bought the ranger not running. Seller said low compression. It would turn and maybe randomly fire. When I started to disassemble, I found both heads had cracks between valves. I don't know enough to be able to tell if the head gaskets also failed.

if the radiator test passes and the smoke subsides, I am planning on monitoring the coolant level and see if I lose any. I guess there are other avenues for loss, like intake manifold gasket, but I am hoping to not work backwards if I can avoid it.

I believe it passed the glove test. The radiator was down 4 or 5 inches. I left it as is. I removed the reserve tube and plugged it and put a rubber glove over the filler with a rubber band good and tight.

I turned the engine over several times and the glove didn't move at all.

I put everthing back to normal and started the truck. Ran pretty nice as before. Accessory drive noise is still there when cold. No exhuast smoke at first, then there was a good amount and then it started to subside all within the few minutes I had it idling in the driveway. I guess this may be normal. I am used to toyota and honda motors.

picture of exhaust

That kinda looks normal to me... considering the temps... and the fact that water vapor is always present in the exhaust stream. It should lessen when the engine gets to operating temp. I just remote started my truck... it's -10 right now. She's steaming pretty good.

The test I always used in place of the glove test... is to put my pressure tester on the radiator... give it a pump to get the needle off 0... start the engine and watch the pressure gauge. If you have a combustion leak into the cooling system... it will start to climb almost instantly. I've always used this test... well... because I have a radiator pressure tester.

Edit... you can always get your face into the exhaust and give it a good smell. If there is anti freeze in there... you will smell it.

Wow. -10. I hope thats celsius. Either way its cold. 30 F this morning when I started the truck. I will take your advice and give the exhaust a sniff. I am sure I did before, but wasn't thinking about strange odors.

At least now I am only digging down to an intake manifold. Not something I want to do but for me a full day or weekend task. I am probably going to put that off unless I have some clear indication that I am burning or losing coolant.