SD22 FAN clutch

[philip]

Short story / experience about the fan clutch on my '82 720 pickup

For a long time before I got this truck and for the miles I have put on it, the fan belt (crank/alternator/water pump) has required frequent adjustment and twice replacement in 30k miles. Each time there were chunks missing from the inner side of the belt.

Maybe it's my ears ... but for awhile, I began noticing the fan howl would continue LONG after the engine was fully warmed up on cool days. You'd expect continued running at engine speed on hotter days especially with the A/C running.

So I decided one day back about Nov '05 to replace the thermal / viscous drive clutch. Unfortunately, the new fan clutch continued running at engine speed until I had traveled several miles at Interstate speeds. Hmmm. So I called Hayden who had been purchased by some Texas outfit. The new company tech desk told me how to test the clutch ... which I did ... finding the new clutch failed (would not release). I exchanged it for another of the same brand. SAME THING. It appears Hayden is installing a fluid with too much viscosity which keeps the fan engaged far more than required for these small diesels ... even with A/C.

Out of the box, both my old clutch and BOTH new clutches had a LOT of resistance to being turned by hand. I found a used clutch on eBay for an SD22 and bought it cheap ... gambling on what I would get. This used clutch has considerably LESS resistance to being turned by hand. Unfortunately, there is no brand name on it.

In the meantime while I was waiting for this used clutch to arrive, I figured I would try driving around with NO CLUTCH / FAN at all. After all, diesels throw off considerably less heat than gasoline engines when idling and it is (what passes for) winter here in SoCal.

What all that in mind, I put put everthing back together WITHOUT a fan. Found out some interesting things. With the engine at operating temperature and left to idle, it takes 15-20 minutes for the coolant temperature to reach 212 degrees. Even then, I can drop 10 degrees in about 3-5 minutes by turning the heater ON full hot with fan on high setting. Or if I park with the grille into the prevailing breeze, I've idled for 25 minutes. Hmmm!

It's been nearly two months and I still have no fan installed. Fuel mileage at Interstate speeds has increased about 1.5 mpg! No doubt this setup is less stress on the fan belt too.

-Philip

[goglio704]

Two words: 'lectric fan. Probably wouldn't take much of one either.

Or if I park with the grille into the prevailing breeze, I've idled for 25 minutes. Hmmm! Idea

A weather vane hood ornament might be helpful.

Kidding aside thanks for the post. It goes to confirm the theory that there may not be that much heat these motors need to shed. Are you going to continue the experiment into warm weather?

[glenlloyd]

And that was where I was headed in the questioning..warm weather. I can't imagine that it would be easy to survive without a fan in warm weather, but if one can actually get an additional 1.5 mpg by switching from a belt driven fan to electric, now that might not be a bad idea.

I've been trying to get there on my Dodge van for years, but never have quite gotten it done. I should have done it when I had to change water pump a year ago but never did.

Steve A

[philip]

snip
A weather vane hood ornament might be helpful.

Kidding aside thanks for the post. It goes to confirm the theory that there may not be that much heat these motors need to shed. Are you going to continue the experiment into warm weather?

Weather vane? I've been using the political method ... wet index finger in the air.

At idle diesels don't generate much heat.

Try this: Start the engine cold. Set the idle about the same as if the engine were fully warmed. Now ... keep touching the exhaust pipe just below the header pipe flange. It's remarkable how long the engine has to run for this "touch point" to become too hot to check. Ok... for you smarter guys, check this with an infrared heat gun.

[philip]

And that was where I was headed in the questioning..warm weather. I can't imagine that it would be easy to survive without a fan in warm weather, but if one can actually get an additional 1.5 mpg by switching from a belt driven fan to electric, now that might not be a bad idea.

I've been trying to get there on my Dodge van for years, but never have quite gotten it done. I should have done it when I had to change water pump a year ago but never did.

Steve A

About two weeks ago, we had a heat spell of several days (had a couple of major brush fires too!). Temperatures were in the low 80's. Only difference is that it took about 10 minutes to reach 212 degress (red arrow).

Also, the 1.5 mpg gain was on 33 mpg base mileage with the engine fan running locked all the time. That would be a 6% increase.

[asavage]

I'm a big fan of electric radiator cooling fans. Here's some background:

[concatenation of two posts I wrote last year for thedieselstop.com]

Post 1:
I used to own an '83 G30 (Chev 1T van) w/6.2l diesel (160 HP) that our family bought new. At 102k, I bought it from the family and I immediately yanked the huge fan shround and OEM fan setup -- in the Chev van, you can't do anything under the hood with that fan shroud in there, you have to remove it even to change belts.

I put in three approx 14" 'yard fans -- that's how wide the G30 diesel radiator is -- and connected them up with a pretty elaborate control system, including custom-engraved backlit translucent LED-lighted monitors in the cab, override for manual fan ON/OFF/Auto, "fans are on because of coolant temp", "fans are on because A/C high side has reached 175 PSI", etc etc. I drove this rig with this configuration for 78k miles and six years, and for what I used it for, it was adequate, but only just.

I live in the Pacific NorthWet, and it was great not having to hear the OEM fan every startup and down the block, and the power increase was noticeable, it would accel from a stop better -- not a lot, but it wasn't my imagination, either. And towing wasn't a problem, not even in the summer.

But when I'd drive down to SoCal, it was pretty marginal, I'm talking like 90° weather and up it would keep up in non-tow conditions, but there were a couple of instances when I would have liked more airflow. I'm pretty certain that I would not have been able to tow in that heat, and I can recall going up Grapevine foot on the floor, 65 MPH and having the fans kick on -- that's bad, because elec fans can't contribute at highways speeds, but the OEM fan can. In that situation, I could not dump heat as fast as I was creating it.

Granted, I was using junkyard fans from Gawd knows what -- one would burn out every year or so, and I'd solder in a spare I'd keep laying around -- but I'm not convinced that newer fans would have given much better results.

For reference, total current draw with all fans on was approx 24A. When the 30A fuse would blow, it meant one of the three fans had died

Post 2:

The first car I converted to an electric fan was a 1960 Hillman Husky (the one shown in my avatar these days, actually, in about 1981), and it was a JC Whitney kit. I added a mid-60's GM A/C relay to reduce the load on the thermostatic switch.

That fan wouldn't turn on all winter, from October to April, unless the coolant got low or I idled it for half an hour. I drove that car several years, and it was consistent. The Husky had a solid fan OEM, and they had a reputation for cracking and denting the hood -- or going right through it!

The noise reduction was substantial with the electric fan (Husky had 4.78:1 gearing and a 4" stroke 1390cc engine, so you can see why removing the mechanical fan would quiet it down: it was really spinning at 70 MPH!).

When that car went gunnysack (broke a ring drag racing a Celica on the way to school), I pulled those electric fan parts off and put them on a couple more cars over the years. The fan died after a while, but I kept using the bulb-style adjustable thermostat, and sold it with the Chev G30 diesel van in 2000.

OTOH, I owned an '80 Audi 5000S for a couple of years with the radiator off to one side in the engine compartment, and Audi used a cardboard duct system to direct grille air to the tiny radiator. The thermo-fanswitch died on I-5 and it would overheat at 60 MPH. Yes, the fan was absolutely needed even at that speed. I rigged a manual switch to get me home, then replaced the thermo switch (and sold the car shortly thereafter).

I had a '60 Ford F100 (with the unibody bed) w/223 Six and three-speed, and I similary took off the mechanical fan (but did not install anything in its place) and drove it all winter as a commuter car with no fan. Never got hot, picked up almost a whole MPG. Sold the truck in the spring, handed the new owner the fan and told him he'd better think about installing it

The G30 has huge frontal area and similarly huge radiator, but diesels can generate a lot of heat when under load (but not when loafing). I was surprised to find that cooling airflow was marginal with three electric fans, but I suppose that the radiator's efficiency may have dropped over the years -- certainly it had a top tank seam leak the last five years I owned it, and I drove it year-round in an unpressurized condition, ie the pressure relief lever in the up position. It never gave me any trouble. I should have fixed it, but :shrug:

[asavage]

I've got a nice swap-meet 16" fan & thermostat hanging on a wall in a garage on Whidbey Island, but haven't had a chance to install it on any of my four vehicles yet. Someday . . .

Other add-on projects stacked up:

* Water injection on the Aerostar. Needs tank fabbed, that's all, have all other parts: pump, switches, dual vacuum sensors, dual solenoids.

* Bypass oil filter on the Aerostar and '82 Wagon. Have two MotorGuard 30 units just waiting to be plumbed. Been sitting for over 18 mos.

* Prelubers. I have two of them too, with control modules, electric ones.

And like that. So much stuff to do, so little time. I need to retire again! Or win lotto (but I know that the lottery is a tax on people who are bad at math).

[philip]

And that was where I was headed in the questioning..warm weather. I can't imagine that it would be easy to survive without a fan in warm weather, but if one can actually get an additional 1.5 mpg by switching from a belt driven fan to electric, now that might not be a bad idea. snip

Steve A

Sunday ... had a 300 lb delivery to Bakersfield. Going north on I-5 to the Grapevine has a couple hard pulls and certainly, the return southbound leg going up the Grapevine grade is a long hard pull.

At the toughest stretches, 4th gear at 48-50 mph on the floor. With ambient temperature of 72 degrees, the coolant temperature meter moved to the straight up position (just short of actual mid scale). So under this condition, no overheat danger. Figure too, I have A/C which means the A/C condensor slows air flow through the radiator a little.

[asavage]

Going north on I-5 to the Grapevine has a couple hard pulls and certainly, the return southbound leg going up the Grapevine grade is a long hard pull.

At the toughest stretches, 4th gear at 48-50 mph on the floor.

I know that stretch, and 50 MPH is doing pretty well for the little SD22. I was miffed in '94 that my G30 would only do 65 with the A/C ON going south up to Grapevine. No A/C = 70 MPH: 5 MPH difference. That 6.2l was a 160 HP engine. You've got that SD22 tuned like a ricer Next thing, you'll have neon on the undercarriage and a camera in your cell phone . . . AHAHAHAHAHA!

[davehoos]

I'm a mechanic working as an A/C specialist. We get lots of cars in with electric fans fitted & most stuggle.

Ambient temps range 10-45 celcius averages with high humidity. The diesel fans are overkill, but on long climbs towing you notice problems. High altitude is here is under 1000 meters. Not like the rockies!

Air ducting is critcal to most cars as most cars get there air from the high pressure area below the bumper. At certian speeds some cars dam the air in front and all the good stuff goes over head.

We see problems with high a/c pressures destroying compressor clutches. Toyota & Nissan commercials rarely use electric booster fans. They depend on the radiator heating up to work the viscus fan. The a/c alone will not generate the 70 cel air heat to lock up the fan. The models with electric booster fans often just keep the visco from kicking in.

I had a ford truck [350] come in, ex tow vehicle. It overheated on slight grades. The owner asked us to put the condensor on the side. After telling him it would make no difference, we removed it and he drove the truck for a week. The vehicle was fitted with electric fans (4X14[12]?) bolted to a cowl. They can't draw air from each other and 2 large fans in front. These work out to be the the largest air flow. They switched the fans with the sensor on the top hose. The front 2 fans operated with the a/c pressure switch.

We told him to buy the original cowl and refit the fan. The cowl was not fitted due to the bigger radiator. The water returning to the engine was too cold and the thermostat was having a hard time. Suprise it now works.

[philip]

I'm a mechanic working as an A/C specialist. We (my shop?) get lots of cars in with electric fans fitted most struggle. 10-45 celcius averages here with high humidity.

But for a couple of longitudinal exceptions, transverse front wheel drive cars DO have an electric fan or two, "hello." 10-45 C (50-113 F) would be a mitigating factor to the overall lower altitude in your area.

Diesel fans are overkill, but on long climbs towing you notice problems. High altitude here is under 1000 meters. Not like the Rockies. SNIP

What "problems" could you be witnessing with your Rear Wheel Drive diesel customers when 1000 meters (3,200 feet) is the highest altitude your customers encounter?

[davehoos]

What "problems" could you be witnessing with your Rear Wheel Drive diesel customers when 1000 meters (3,200 feet) is the highest altitude your customers encounter?

Toyota has fitted altitude compensators to its products and the other brands followed. Japanese import engines often have compensation built in to the injector pump. For whatever reason they didnt have these new there is a noticable improvement.

Over heated SD engines is normal. They are sold here in decent numbers in 4 and 6 cyl in 2006. It easy to replace with the later motors or the LD20. Split radiator tanks, cracked heads, seized pistons etc. A few years ago an aftermarket head appeared to solve the water passage cracks. General servicing has little to do with it. I worked my first 10 years in new car dealerships servicing low mileage vehicles.

Commercial vehicles tend to be driven in to the workshop and expire. The Urvan is much more sensitive to raised heat levels as you can guess trapped in the engine compartment under the seat.

We have here an Expressway condition between Newcastle and Sydney. 70 mph for 100 miles. The road crosses 2 rivers too. These are long easy grades with parking for dieing cars at the top. After newcastle traveling westward you cross the dividing range. The crest is approximately 6-700 meters in altitude. The road is near level ground for the next 1000+miles.

I have driven in the USA on route 66-LA return, Chicago to New Orleans to San Fransisco via Galveston and Denver in early winter and spring. Also travelled california/nevada 4 times. In Australia we simply don't have the long haul mountains like the Rockies. Australia is more like the mid western states. New Zealand has vehicle punisher roads, normally slow running areas with long straights between 2000 ft climbs.

But for a couple of longitudinal exceptions, transverse front wheel drive cars DO have an electric fan or two,, Dave

Most front drive vehicle depend on air flow from the ducting and the shape of the nose. Most turn off at given speeds or run at low speed to make certian that the electronic bits dont overheat. Around here BULL BARS/ROO BARS (extra lights) are fitted to large numbers of car/trucks. At low speed there there is normally no illeffect, but over 50 mph you watch the temp rise. Most simpley complain that the a/c is no longer cold. Most temp gauges dont work. In the dealership we had modified gauge and sender units to put the needle in any position to keep the owner happy. The sender is often in a postion that changes little, IE near the thermostat.

Specs change, but as a rule. Electric fans flow air around 35/50 mph. More than that they restrict air flow.same aplies to the mechanical fan, most Nissans here use a cowling. Without the cowl, air circulates around the blade. Look at newer vehicles designed for high speed you see extraction ducts under the car and flaps on the fan cowl. Air banks up in the radiator and gains velocity.

European cars have some high tech designs. Fans from VW/Audi are some of the best. The aftermarket fan assembley we use on a/c condensors have a rated 2-4 K hour life span. 14 to 16 inch curved blade fan will just cope with Nissan diesel. It will rarely come on and when the temp rises you back off. This should be a saving on long term running costs.

To replace the mechanical fan with an electric, it would need to be aprox 3500 watts. This is equal to 300 amps. Most are 120-280 watts. Most mechanical fans use 3 horspower to work. Common here to reposition a/c condensor and add extra radiators to slow moving vehicles.

[philip]

Philip asks: "What cooling "problems" could you be witnessing with your Rear Wheel Drive diesel customers when 1000 meters (3,200 feet) is the highest altitude your customers encounter?

Dave replies: Ttoyota has fitted altitude compensators to its products and the other brands followed.japanese import engines often have compensation built in to the injector pump.for whatever reason they didnt have these new there is a noticable improvement in the tune of

Dave, altitude compensators have NOTHING to do whatsoever with viscous or electric fan clutch operation.

Over heated SD engines is normal.they are sold here in decent numbers in 4 and 6 cyl..in 2006 it easy to replace with the later motors or the LD20.

You are factually in error. SD engines do NOT run overheated as a normal condition. Furthermore, SD22 and SD25 engines have not been installed in any pickup here in the US since 1985 or 1986. They are not part of the recent engine inventory for vehicles in Australia either.

SNIP

Specs change,but as a rule,elictric fans flow air around 35/50 mph

Factually in error. You would need at least 5hp to generate that much wind. Never EVER have I witnessed such gale force wind from an electric car fan. If you found one producing a 20 mph wind, you would have found the exceptionally powerful unit.

snip

To replace the mechanical fan with an electric,it would need to be aprox 3500 watts.this is equal to 300 amps,most are 120-280 watts.most mechanical fans use 3 horspower to work. SNIP .

Which gets us back to choosing and sizing a fan for an engine that produces less heat than a gasoline engine when loads are light.

[davehoos]

At the begining of the thread you commented on the fan locking up much longer than the few minutes it should take for the fluid to move from the turbine chamber into the storage area and then freewheel. This is a common complaint.

If the bearing is not siezed, you may unbolt the 2 halves of the hub and check the fluid quantity and quality. Check the bimetal strip use a heat gun. At around 70 cel the flap valve will open then close at around half that. In some nissan hubs the valve is open when cold and shuts off as it moves past the port in the plate.

Fan speed. I refered to the road speed of the vehicle. You said the electric fan will blow 20 mph max. OK, what happens is the electric fan chokes up the area of the radiator core. I've seen quotes of 35/mph road speed stopping more air flow. A manometer is good for diognosis. A Queensland radiator company manufactures a radiator that is very hard to draw air through. The idea is that you get max heat transfer.

[philip]

SNIP

If the bearing is not siezed,you unbolt the 2 halves of the hub and check the fluid quantity and quality

The OEM Nissan part that failed to disengage could be disassembled. The two replacement aftermarket clutches were hermetically sealed. The slightly used clutch I found on eBay is also hermetically sealed but is from a different manufacturer and luckily, has much less drag. However, I have found that I need NO clutch driven fan at all ... at least during these southern California winter months.

As you said the SD22 over here would be rare.the 3 bearing crank shafts,cooling system problems small intake manifold and the final nail is the cheep cost of a later model replacement engines. SNIP

David, you find me an SD22 with a crankshaft failure due to metalurical or fatigue failure. The 3 main lower end is plenty beefy for a naturally aspirated engine rated at only 65 hp. Have you noticed the SD33 six cylinder engine (NA & Turbo) have only FOUR mains?

These SD four cylinder engines do not have any propensity to run hot or for chronic overheating when they have the correct thermostat design (there is another thread addressing that issue) and a properly sized radiator in good condition with adequate air flow through it.

The engine's limited breathing ability is one of the things that keeps these engines from breaking. This applies to ALL SD four cylinder engines. But you are entitled to your opinion.

Fan speed. I refered to the road speed of the vehicle. You said the electric fan will blow 20 mphmax. OK, what happens is the electric fan chokes up the area of the radiator core. Ive seen quotes of 35/mph road speed stopping more air flow. A manometer is good for diognosis. A Queensland radiator company manufactures a radiator that is very hard to draw air through. The idea is that you get max heat transfer.

I said that if you found an electric fan that could produce a 20 mph breeze, that particular fan would be the exception meaning .... most electric fan produce LESS.

A manometer is for measuring pressure of gases and vapors, particularly if water is the medium in the manaometer. This is not the tool you use for measuring wind speed. You would use an anemometer.

Your radiator manufacturer in Queensland is simply marketing a three or four row radiator. Fact of the matter is the forwardmost row does the most cooling because it gets the coolest air. The last row does less cooling because the air flowing past the final row has been heated by the rows in front of it. To market such a dense core radiator as a positive thing speaks to the dim view they hold of their customer base.