Fan Envy

[redshift96]

Okay, after reading everyone's posts about installing the 21" Dmax fan, and how it yields TOO MUCH cooling... I have to admit I'm a little green.

Wondering what the best setup would be for an older body style truck. I'm assuming it's waaaay too much work to adapt the later-model serpentine accy's (A/C, P/S, etc) to work with the older truck. And I'm guessing you can't just put serp pulleys on the older accy units and expect it all to work. So a serp drive is out, right?

So that means we're using standard rotation.... which means the best we can do water pump-wise is the slightly higher output unit from Peninsular? And in turn the best fan available for that pump is going to be the 9-blade 20" from what... '92 or so?

Do I have all this right? Is there a better (cooler) way that doesn't require all kindsa McGuyvering of the accessories and A/C lines to work?

Is there anyone who could just cast a mirror image of that damn Dmax fan so us old school std rotation types could get in on the action?

Hmmm...

 

[Acesneights1]

You can upgrade the clutch to a Hayden severe duty. Don't need to do as much to a 6.2 in an OBS application as they were not really prone to overheating problems due to better airflow and much larger radiator. Pretty hard tooverheat a 6.2 really gotta try. Atleast that has been my expeireince and I have owned alot of them. You did not specify which truck you are referring to in your sig but the serp belt conversion is well worth the trouble if you can find the parts. The V belt setups don't work right since Gates discountinued the 8 series belts years ago.

 

[iamdave0887]

the Gates belt i bought for my alternator for my blazer sits nice and high in the pulleys. You can even sit a little bit of the belt above the pulley, so it does have a nice bite.

I'll get the number off the belt later but i believe it starts with a 7 and is the "XL" series, or something like that.

 

[Missy Good Wench]

The serp drive setup from a NBS truck with its brackets and such, either a 6.2 or 6.5 will bolt right on and work fine.

92 -95 stuff has the Alternator on the LH side of the engine and the 97 and later is on the RH side.

There are a few simple mods that have to be done.

The water pump must be changed to the one used with the serp drive.
The AC pump if from a 92-95 truck will need to be connected using the hose harness from a 91 Burb with a 350 engine (Will connect to your existing hard lines and hook right up.
The plug on the alternator wiring must be changed to the new style type that works with the later alternator.

Use the 6.2/6.5 serp drive fan and clutch or the Dmax fan.

This is an easy swap and is well worth while.
Really cleans up the underhood area with less long hoses and the extra belts and stuff.


Have fun

Missy

 

[randomid25]

I've never seen more than 210* with my 6.2 turbo. It actually ran a little bit hotter before the turbo. I think this is due to the old coolant and probably scale buildup before. While i had the truck apart, i flushed the cooling system and refilled my system with new coolant/distilled water at a 50/50 ratio.

 

[redshift96]

Well, THAT's great news... !

The serp drive setup from a NBS truck with its brackets and such, either a 6.2 or 6.5 will bolt right on and work fine.

92 -95 stuff has the Alternator on the LH side of the engine and the 97 and later is on the RH side.

There are a few simple mods that have to be done.

The water pump must be changed to the one used with the serp drive.
The AC pump if from a 92-95 truck will need to be connected using the hose harness from a 91 Burb with a 350 engine (Will connect to your existing hard lines and hook right up.
The plug on the alternator wiring must be changed to the new style type that works with the later alternator.

Use the 6.2/6.5 serp drive fan and clutch or the Dmax fan.

Whoa... I'm so glad I asked. And THANK YOU SO MUCH for the breakdown, MissyGW.

I'd be overjoyed to be able to use a hi-flow water pump let alone the Dmax fan.

Sooo... if I get all the brackets and peripherals from a '97 thru... 2001? then the alt is on the pass side, A/C is on the right, just like the OBS? And can I use the 97+ A/C pump? Or would I need to replace it with a 92-95 unit and use the 350 hoses if everything else is coming off a 97+?

I guess the bottom line question I'm trying to get at is this: Does it make the most sense (least work, best result) to put everything on the motor the way it would be on the 97 (excepting the A/C pump perhaps), and adapt connections as req'd? Or to keep the original OBS layout, and only use the parts from the serp setup as needed to accommodate the belt/pulleys?

Power steering pump from the NBS goes in the same place as OBS? So the pulley is the only diff? Or do I have to give up the divorced reservoir and use the all in one style that's a pain to reach?

Thanks for the feedback on the older motors' running temps too, guys. In this case, it will be a 6.5TD w/DB2 going into the '85 Sub, so while I may benefit from the radiator, I'll prob have to subtract some cooling points for the integral coolers and marginal 6-blade fan. The fan clutch upgrade is a given.

The last (NA) Sub seemed to run pretty close to the edge, but that was going by the dash gauge. Hard to say for sure, but it made me very nervous when towing, especially up hills. Gauge would wander up around 220 - 230 at times. Never boiled over, but sure didn't make it easy to relax and enjoy the scenery.

 

[Missy Good Wench]

The easiest system is to use the early one. 92-95 6.2/6.5

The wires will need to be moved for the alternator is all.

The power steering is just right and will hook up.

Use the AC lines from a 350 powered truck of same body style (OBS)
The little pancake AC pump fits nice on the 6.2 just like the 6.5 trucks and the hoses mentioned will fit perfectly as the 6.2 is slightly wider and so the hoses are plenty long enough to reach where they need to.

The later parts will work too but you end up messing around modifying the AC lines to fit.

Best deal is to scrap the old oil cooler lines and run fresh ones to a remote oil to air cooler out front.

Keep us posted

Missy

Use the Hiflow pump and the late style crossover. NOTE you will have to modify the throttle cable bracket a tad to use the dual stat crossover.

If your running hot its likely due to a radiator thats plugged up inside the cores.

Toss it and get a fresh Visteon radiator.

The cross flow radiators plug up and silt in over time and it is not worth screwing around with an old unit.

My 95 DaHooooley was getting hot and so I replaced the radiator when I did the engine.

Well worth the $270 for the new one.
Stay away from the cheap epoxied core ones, they will fail and there is no fixing them.

 

[WarWagon]

The newer body style has radiator airflow issues. Your older body style does not. Your best cash is spend on fixing your problem with the current setup. Be it a bad fan clutch or plugged radiator.

I would not recommend the bigger fan as you don't need it and it will just waste power and fuel.

 

[redshift96]

Yeah but...

The newer body style has radiator airflow issues. Your older body style does not. Your best cash is spend on fixing your problem with the current setup. Be it a bad fan clutch or plugged radiator.

I would not recommend the bigger fan as you don't need it and it will just waste power and fuel.

Good to know... but I have to make a decision on a new water pump for this motor very soon, and I'm trying to decide which way to go. If I upgrade to the reverse rotation serp stuff, I might as well use the best pieces I can, right? (HO pump, Dmax or 20" fan) Esp since I tend to do my towing on trips that will definitely put the test to my cooling system. (Long grades in midsummer, loads of people and gear, 4k - 6k lbs trailer, etc).

So if I stay with the std rotation v-belt system, and use the 110gpm Peninsular pump and SD fan clutch, is there a better fan to use than my lame old 6 blade?

Planning to give the new engine it's inaugural run through Death Valley, Flagstaff, and up through the Colorado Rockies to Wyoming, then back over again to Utah and finally over the Sierras. The first leg will have 5 people plus gear in the Sub, and this will be smack in the hottest part of the summer.

Man, I've got just under three weeks to get this together and ready to roll. It's going to be a race, in both money and time.

PS: Would the bigger plastic fan really suck much more power than the old stocker when the fan clutch isn't engaged?

 

[WarWagon]

"best fan available for that pump is going to be the 9-blade 20" from what... '92 or so? "

I can't answer if this is a standard rotation fan or not. If so that upgrade can't hurt more than taking more power to run.

We have run our NA 1988 diesel 4x4 suburban up and down the Rockies. Better MPG than a 350 but smoked and was passed by about everything. We did not spare it and never had a temp issue. (Well until the block heater fell out at 65 MPH and a head cracked from lack of coolant.)

With the time race on I would stay as stock as you can and looking for trouble spots. You have identified a water pump issue on 6.5's , but, for balancing the flow between banks not an issue of enough flow. This may not apply to standard rotation pumps.

This link explains fan clutches. The clutch will always spin at 20-30% of shaft speed when unlocked. So a bigger fan takes more power and MPG. You may not notice. A plastic fan has less inertia than a steel fan. You may feel the difference in downshifts as a lighter fan gets up to speed quicker.

http://www.haydenauto.com/Featured Products-Fan Clutches and Fan Blades/Content.aspx

In any case fan clutches loose 200 RPM per year are are considered junk at 5 years. So maybe a combo of an old original fan clutch and a externally dirty radiator/cooler/condenser and internally plugged radiator could be causing you to run hot.

The fan clutch mod is recommended and has had some good results for the new body style on the 6 blade fans.

Again the NBS has airflow issues. Bigger and thicker radiator doesn't help us. A bigger fan with more blades does. In your case you should have enough airflow to keep you cool without a fan upgrade, but, everything needs to work.

If you have time going to the newer serp belt drive would be worth it just to be able to change the belt quickly.

 

[Acesneights1]

I bought the Hayden SD clutch for my burb just because it was cheap compared to the 6.5TD one and I figured the one on the truck was probably original. Go figure the SD clutch for the 6.2 is like 40$ for the 6.5TD 140$. What a ripoff.

 

[turbovanman]

I am going dual 16" fans with a thermostat set to 210. Its a Flexlite unit that has a probe that goes into the rad and you can adjust the temp. #31147

My stock clutch fan starting to howl at higher rpm and wouldn't release, tried a good used one, same, bought a new Hayden, better but still coming on, so bought some Proform fans on Ebay for $70 shipped, the controller is $40 from Flexlite, so some simple fabbing and I'll have the best of both worlds. My mpg dropped 3 mpg and it doesn't like to rev.

 

[Acesneights1]

Non serp 6.2's AFAIK are all standard rot.

 

[Franko914]

Have you considered replacing the engine-driven fan with a dual-electric-fan setup? You can wire them to turn on at the same time or sequentially (by using separate thermostatic switches set to different threshold temp settings). A few after market kits available, or DIY. Happy to post a link for did-it-myself if interested.

Regards,
Franko

 

[turbovanman]

Installed 2 16" fans today and a Flexlite adjustable controller. Took a few hours but wanted it done correctly. Those fans can suck, you can stick a piece of cardboard on the grill and it won't move, :thumbsup:

I haven't driven it yet, just got finished, I didn't splice into the a/c system yet, it should work without that but if not, I'll just hook into the compressor on power and put that onto the controller so when I turn the a/c on, the fans come on.

 

[Acesneights1]

Franko, Your thread on your conversion was on the old site. How did your fan setup workout for you ?

 

[turbovanman]

Wow, what a night and day difference, its quieter, smoother and best of all, MORE power. It doesn't struggle so hard now to go up hills, revs up much faster and higher and runs a bit cooler. I highly recommend this, :thumbsup:

 

[davo727]

Sounds good vanman! Does that deal have an indicator light in the cab showing if the fans are on or off?

 

[turbovanman]

Sounds good vanman! Does that deal have an indicator light in the cab showing if the fans are on or off?

No, not really needed. I drove it home then set the temp so they go on just over 1/2 on the gauge, which is a bit over where it runs regularly. I could put a light but then more wiring etc, bah. :thumbsup:

Plus in town, I keep an eye on the gauge anyways.

 

[redshift96]

Looking forward to hearing how well this holds temp under heavy towing load/mountains/hot weather/etc.

I recall reading that some here feel that the electric fans can't keep up with the thermal load under stress.