Yesterday I was on my way to Virginia from NYC. On the way out of NYC I was forced to sit in heavy traffic for a long time until we finally got out of the city. It was about a 90 degree day and of course we had the A/C on. The temperature crept above 210 and at about 220 or so I turned off the A/C, but it kept on going up to about 230 or so. I put the thing in neutral and revved the motor to about 1500-2000 rpms to get the clutch fan spinning faster. That worked, and I got it down to about 200 or so that way. By the time it started creeping up again, traffic cleared. On the rest of the drive it was running pretty well, at about 200 or so with the A/C, only creeping up to 215 or so once or twice under heavy acceleration. At any rate, this is unacceptable, especially with the huge sums of towing I have coming up. I was going to try starting out by replacing the fan clutch which may be on its way out and then possibly adding an electric fan in front of the condenser to come on when the temp hit 210, and change the thermostats. Any other suggestions? Call me spoiled but I think modern trucks like ours should be able to sit in traffic with the A/C on full blast on a hot day, and I'm sure they did from the factory.


I should also add that I put a Heath Boost controller on the truck and that by itself made a big difference in normal operating temps on my daily commute to work (now runs 5-10 degrees cooler).


Any other suggestions would be appreciated. Thanks!Edited by: tdupuis

Kennedy fan clutch! Get one.

The fan clutch is an item but also make sure your raditor and A/C condensor is clean, if you don't have good air flow it make a big difference with these trucks. Also if you have a '97 with the dual thermostaats you can bolt on a Duramax fan, might have to trim the fan shroud a bit.

I second both Ronnie Joe & 16gaSxS. I had the dual thermostat setup put in my '93, along with the Kennedy fan clutch. At the same time, the radiator was replaced. It was pretty corroded and clogged after 10 years. Your radiator should be checked. Your water pump may also be on the way out. Worth checking while you're in there.


With all these repairs / upgrades, mine runs a steady 160-170; a little higher in hot weather or when towing. These trucks have a lot of heat to get rid of.

Kennedy's asking $300 for the clutch and fan. Is it me or is that pricey.
My truck gets up to 200 every time I'm in line at the bank with the a/c on.
For $300 I'll research what others are asking.

I wonder if this setup would help?http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7908787447&catego ry=33600

I put a inch of washers on the bolts between the hood and its mounting brackets.
the difference isn't visable but the truck has been running at 180 on the cool side with a/c on and going 65-70 mph.
When I sit it has been going up to 200 still but it least it cools off quick. Edited by: quantum mechanic

check heathdiesel.com they have options if you want to use your fan or replace the fan and clutch.

My 1998 K2500 has 143,000 miles. When crusing anywhere over 35mph it runs just under 180 (no AC) or just above 180 (AC). If I get in traffic here in No. Virginia on a 90F day it will climb to 210 (AC)(straight up on guage I believe). Once I get moving again it will pretty much return to around 180. I had it idling for a while on a very hot and humid day with AC on and it got WAY hot, maybe around 230-240. Once I ran it around a little I got it down to 210 before parking it and shutting down. Is this normal? I figured a big rig like this should stay cool no matter what, it holds almost 7 gallons of coolant. I will be blowing compressed air through the fins tonight but I'd like to make it run cooler - heat is the enemy, how will a PMD ever last with these underhood temps is beyond me!

BobT here again. I forgot to mention Dexcool is within 50k and water pump/radiator are original . .

Gm got us good with the cap on the overflow tank.
It's hard to see how bad it is inside now.
I think your fan clutch might be bad. mine is and it gets hot sitting with the a/c on.

Thanks QM. I will run it at idle next time i get a chance, AC on and drink a beer or three and wait. hood open shouldn't matter, i'll see when/if the fan clutch kicks in. offhand WHAT temp is it supposed to kick on?

190-195 deg. I think. I heard mine come on and off alot before and now, nothing?

I have yet to check fan clutch operation, have vehicle partially dissasembled to do PMD relocate mod and install guages. Stealing yet another pic from QM, this is what the fan on my 1998 Suburban looks like - is this correct? I though GM went to a different fan after 1997 . .





http://dieselplace.com/forum/uploads/D9Z_fanclutch.jpg

Bob,





Your blade and clutch are similar but different.


My clutch is built by Borg Warner to OEM specs EXCEPT the cut in temp has been reduced by 15°f. This is a special part number built especially for me. I cannot buy millions at a time like GM, and was damn lucky to get them to even consider this project, but the result is an admittedly expensive clutch that WORKS. There is no other clutch for this application built to any spec other than OEM to the best of my knowledge.

So,
how could I "theroreticly" modify mine to come on at 180 deg.
could it be as simple as modifing the therastatic coil?

i have heard that you can pull out the silicone and rebend the coil but i would play with it and a heat source and some way of measuring it's temp. so you bend it the right way and can calibrate it even if crudely. beats the bucks for a clutch

You probably could, BUT you'll never know where you are at.


When built, the clutch is put into a tempered water solution to move the coil to simulate a specific temperature, then the internal porting is "clocked" so that all are set to precisely the same temp.





Some have successfully fooled with the spring, but for precise, calibrated, RELIABLE results:








http://www.dieselplace.com/forum/uploads/Crate_of_fan_clutches.jpg

'Kennedy', thanks! Quick question: IF my radiator is healthy and IF I must replace a faulty fan clutch (with OE or OE recalibrated), is the 6-blade fan on my '98 truck going to be good enough to keep it cool or should I be looking for a newer 9-blade model?

Check between the radiator and a/c condenser. You will be suprised at what will buildup in there. I had the same problem several yaers ago and and the tank seams were also leaking. When I removed the radiator for repair 25 to 30% of the area was clogged.

'Kennedy', thanks! Quick question: IF my radiator is healthy and IF I must replace a faulty fan clutch (with OE or OE recalibrated), is the 6-blade fan on my '98 truck going to be good enough to keep it cool or should I be looking for a newer 9-blade model?








Your OE blade is the 9 wing steel 20" unit. My clutch will bolt right in.

Bob,





Your blade and clutch are similar but different.


My clutch is built by Borg Warner to OEM specs EXCEPT the cut in temp has been reduced by 15°f. This is a special part number built especially for me. I cannot buy millions at a time like GM, and was damn lucky to get them to even consider this project, but the result is an admittedly expensive clutch that WORKS. There is no other clutch for this application built to any spec other than OEM to the best of my knowledge.





Correct me if I'm wrong but if your clutch kicks in at 180 instead of 195 then it seems like it wiould be on all the time. Sure does make some noise and take power away when my kicks in now. I have a 95 3/4 4x4 and I would like it to stay cooler. I am looking at the 1997 upgrade to 130GPM water pump and dual t-stats. Would I still need your new fan clutch with the dual T-stat system in place. How bout my fan, does it need upgrading to?


Thanks

I went ahead and pulled the thermastatic coil end out and clipped about 1/4"" off.
Then bent it 1/4" further up the coil and reset it in silicon.

I'll let ya'll know if it worked.

ps.. the coil was full of grease and grime again. It was about 2-3 months ago that I cleaned it.

Thermostatic clutches sense AIR temp. In order to get the clutch in, you must have coolant temps that are much higher. This is all influenced by ambient temps, radiator efficiency, and additional heat sources like AC condenser, coolers etc.





Fan and clutch would need to be matched.





Noise and power loss are a small price to pay for lonegevity. Simple tradeoff that makes sense...

John;


I love the photo of all those clutches.....http://www.dieselplace.com/forum/smileys/Clap.gif


Now how did you get Borg Warner to build these babies for ya? Did you marry a Borg Warner Excutives daughter or something? Just wondering! http://www.dieselplace.com/forum/smileys/Approve.gif


Sorry you won't be in Missoula this weekend.... hope your Labor Day even is a hit!

Getting the prototype(s) was easy. One is here, and the other on Jim (Chris) Bigley's truck. The engineer was great to work with. He was on the team that worked with GM on the development of the OE unit. FWIW, the "kill temp" that GM uses which is the COOLANT temp at which the clutch must ABSOLUTELY be fully engaged is 230°f!





As for blade selection below is the reply I got when discussing the 21" Dmax blade. I believe that the differences at different static psi is because the plastic blade "flattens out" somewhat under load:





John,
There is no clear winner across the board.
With proper fan tip clearance to the shroud (.75" is normal for GM) the 15992650 is probably a little better at idle and low vehicle speeds, and the 15010202 is probably marginally better at speeds with more ram air. But, remember our previous discussions. It is a mortal sin to put an alternative fan on a fan drive after initial development. A fan drive is developed for a specific fan, and if a different fan is introduced a new fan drive should be developed. The fan drive that BorgWarner released for you was developed for a 15992650 fan. The C/K Diesel fan drive is not appropriate for the GMT800 (15010202) fan. The GMT800 Diesel fan drive is not appropriate for the C/K (15992650) fan.



Jim






It took me almost 2 years of begging and prying to get them to build these along with FULL prepayment in advance with a 6-8 week lead time...

QM -


You went the wrong way - the bi-metal coil lengthens as it heats up, turnng the gate to redirect the viscous fluid.


Procedure would have been to flatten the original bend, re-form new bend closer to end, 'staging' the gate in higher temp positon.


Pull one from another clutch, start from there.

I checked temperatures all around the engine in a climate chamber under various ambient temperatures, and discovered that items in front of the radiator contribute to the the rise: large driving lamps=10 degrees C.; bullbar=5; GMC emblem=5.

Today, I ran it for a hour on the freeway for over an hour and then let it idle for 30 min. while the A/C was on hogh .
I was surprised to see it never got over 195 deg.
It was 97 deg out side felt like 103 with the heat insex.
I was also resisting the MAP signal over 20K ohms, no intercooling yet.
I'll let you know if it gives me trouble.

Did a test today. Ran around, took my daughter to a park, came home and decided to test:


- again, I INSIST I have a big mongo 6-blade fan, but NOT the large fan clutch in the photo in my earlier message above


- when I got back temp was dead-on 185 with AC on


- OA Temp (No. VA) was 81F in the shade.I parked it running in the sun AC on med-hi, rear AC on med.


- for 35 minutes I ran it, moving it up and down my driveway on 3 ocasions to see if I could add heat from trans.


- Highest I could get was 1 tick past 210. I distinctly heard the fan kick on and off a few times at around that temp(i wish to correct my previous posting, temp may have been 2 ticks or so past 210 so shy of the 235 tick.)


- At this point I concluded the heat rise was too insignificant to get me too hot in traffic


- I then drove down my rural road at a relaxed pace for 3 miles in about 6.5 minutes and she just cooled right on down to 185.


I may install one of the modded 20" 9 blade fans (cut down 21" DMax fan) to get more air, but for now thats about it . ..

Now try letting it sit till it's that hot and pull something heavy in traffic.
you'll see the tempature guage stay on 235 deg.

Has anybody tried any of the electric fans on one of these? I've been considering it for a while now. Wouldnt that put less drag on the belt drive system (granted a little more on the alternator) and alleviate some of the power loss from going to a 'cooler' clutch? Aren't at least some of them adjustable temp and obviously all of them can be manually overridden too. And you could also make sure the fan is off while your on the highway so you get no additional drag and turn it on when you have the A/C on. Edited by: Texas Diesel Guy

I don't know if I have room - my Suburban has 2 air-oil heat exchangers in front of the condenser. I bet QM above is right about my truck going to 235+F if i pull a heavy load in traffic in hot weather - I just know if I get in 1/2 hr jam I'll turn around and take another route. I am going to start by getting a new clutch and put in a 9-blade fan (factory 6.5 like I SHOULD have in my truck (dammit) http://dieselplace.com/forum/smileys/Angry.gifor a modded DMax 20"). I still don't know why the dang coolant temp gets away like thathttp://dieselplace.com/forum/smileys/Confused.gif - I used my '98 Trooper for towing stuff in hot temps and NEVER got the gauge past 1/2 (probably 220F by then)

Has anybody tried any of the electric fans on one of these? I've been considering it for a while now. Wouldnt that put less drag on the belt drive system (granted a little more on the alternator) and alleviate some of the power loss from going to a 'cooler' clutch? Aren't at least some of them adjustable temp and obviously all of them can be manually overridden too. And you could also make sure the fan is off while your on the highway so you get no additional drag and turn it on when you have the A/C on.





Aside from the fact that the electric fan setup is incapable of keeping up, there's no such thing as a free lunch. The power has to come from somewhere, and that somewhere is the alternator. The CS130 alternator isn't bad if used at a minimal duty cycle, but I'd rather not trust it to keep up with the additional load of 40+ amps on a regular basis.

Did a test today. Ran around, took my daughter to a park, came home and decided to test:


- again, I INSIST I have a big mongo 6-blade fan, but NOT the large fan clutch in the photo in my earlier message above


- when I got back temp was dead-on 185 with AC on


- OA Temp (No. VA) was 81F in the shade.I parked it running in the sun AC on med-hi, rear AC on med.


- for 35 minutes I ran it, moving it up and down my driveway on 3 ocasions to see if I could add heat from trans.


- Highest I could get was 1 tick past 210. I distinctly heard the fan kick on and off a few times at around that temp(i wish to correct my previous posting, temp may have been 2 ticks or so past 210 so shy of the 235 tick.)


- At this point I concluded the heat rise was too insignificant to get me too hot in traffic


- I then drove down my rural road at a relaxed pace for 3 miles in about 6.5 minutes and she just cooled right on down to 185.


I may install one of the modded 20" 9 blade fans (cut down 21" DMax fan) to get more air, but for now thats about it . ..








Bobt,





Not sure who swapped yours out, but it should have a 20" steel blade.





Either way, the clutch that you likely have carries the same OE cut in temp calibration. Cut in can occur GRADUALLY, so if the fan can move enough air while partially engaged, it will seldom need to fully engage. I've had numerous comments that with my clutch, the AC performance dramatically improved.





Now for the blade idea, you can choose to believe me or not, but as I stated earlier, the 21" blade is MARGINALLY better when it has more help. This is at 21" Can you guess what happens when you trim it to 20????





20" steel 9 wing is my suggestion. What you use for clutch (OE or mine) does not make any difference to me. I know what works (and didn't) for me... Edited by: Kennedy

I disagree


2800 CFM and only 13Amps draw doesn't sound that bad to me


http://www.partsamerica.com/PartDetails.asp?SourceArea=&SourcePage=SEARCHRESUL TS&MfrCode=FLE&MfrPartNumber=150&CategoryCode=600 3


neither does dual fans and still under 20a.


http://www.partsamerica.com/PartDetails.asp?SourceArea=&SourcePage=SEARCHRESUL TS&MfrCode=FLE&MfrPartNumber=210&CategoryCode=600 3

You can buy performance parts for your alternator for higher amp ratings and continuous amp draw, they don't cost much.

Go for it! Let us know how it works...

http://www.jacksongalleries.com/alex/jeep/taurusfan/

Supposedly ford taurus fans are great.. draw a lot of amps.. but also move a TON of air.. same fans as lincoln mark VIII

I might try this myself shortly.

-- WheatKing

just wanted to say something to Mr.Kennedy, didnt mean to step on your toes, maybe your right, your fan clutches are probably better, I was just asking about the electrics. I really don't think mine would be the best test vehicle anyway, runs too cool and too good. Maybe someone with overheating problems will try it though.


did I mention FAAAAAST???Edited by: Texas Diesel Guy

Here's a pic of my fan/clutch setup in my 1998 K2500. 6-blade.





http://www.dieselplace.com/forum/uploads/F28_Dscn1119.jpg

Good Day!

I vaguely remember reading that the stock engine-driven fans move in the neighborhood of 10,000 CFM. (Yes, this depends on rpm, vehicle speed, etc.) If this is so, even two electric fans aren't close. Worth thinking about…

As JK says, go for it, just be careful. Until you've pulled a lot of miles in the mountains with a serious trailer, you won't be sure an electric fan setup equals the engine-driven fan & JK's clutch.

Blessings!

Brian JohnsonEdited by: moondoggie

TDG,


Many have tried electrics. IF the alternator holds up, they still don't pull enough air to keep cool, especially under load.





BobT,





Looks like SOMEONE has been goofing with your rig. Can you even rotate the blade with engine off? Looks like a solid hub.





So basically, if a guy wants a std replacement clutch, I'v added the Hayden line. Less $$, but std calibration. For some it will work fine, so long as the cooling system isn't being pushed too hard...

Here's a pic of my fan/clutch setup in my 1998 K2500. 6-blade.





http://www.dieselplace.com/forum/uploads/F28_Dscn1119.jpg





That doesn't happen to have any wires coming out of it does it? If it was an electric clutch, it could be run off actual coolant temperature.

That sure looks like the Flex-a-Lite flexible fan setup, with at least one spacer - no clutch - and adaptor to the threaded screw-on waterpump hub.


Show-and-tell scores again!

Ha ha ha !! I just have to laugh at this predicament. Yup, show-and-tell is KING ! JKennedy, I CANNOT move fan with engine turned off. I knew something was fishy, I have had cars with mechanical fan clutches before. 'whatnot', no wire no clutch. GMCTD, you are probably right about the fan. I got this truck from an original owner, great guy, very technically adept, prior GMC truck repairman and service tech/trainer.


Anyhoo: 1) the fan is not loud in the least and you can't tell it's doing anything at idle at least - is the ratio the same? 2) Do these fans work? if they are supposed to I still have a cooling temperature control problem 3) the continuous drag must affect efficiency to some extent

I'm guessing by the looks of it, the hub has 4 through bolts?? Or does it thread on?





Originally, I was thinking that was the OE 6 winger, but the bolt pattern is too large on that unit, so GMCTD is likely right that it is a Flex fan. That's why it is quiet. Flex fans move little air when loaded and take little power, but of course can't keep up with the load either.





I've also seen the blades break off...

Here is a pic of the Flex-A-Lite fan I removed from my engine. It answers the mail for road-going, non-towing applications. I noticed its inability to aid in cooling my rig, when, already at 210F coolant temp, I was forced to maneuver in 4-lo for traction on a steep offroad grade in 95F high humidity and my temps got up to almost 235F. It’ll be on ebay soon.
http://www.dieselplace.com/forum/uploads/Flex_fan.jpg
Here is a pic of the intake silencer pipe and its proximity to the 20” DMax fan blade I installed with the new OE clutch. You can see where I raised the silencer a bit with a rubber mount I had lying around to gain clearance. Before I did this the clearance was less than .125”
http://www.dieselplace.com/forum/uploads/Intake_Silencer.jpg

CLUTCH: I did a little grinding and moved the clutch spring CCW by about .11”. Now I haven’t seen the coolant gauge needle more than one tick below 185, but its only been driven totally unloaded in cool 75F temps.

Question: I have a couple inches of debris accumulation between my radiator and my condenser, but it’s a tight fit and I could not vacuum it out. In addition, when I blew compressed air through the radiator fins, a lot of dust and dirt came out. What has anybody done, without removing the radiator, to get it and the condenser good and clean? Simple green and lots of water? Thanks!

SO BOB


Which Fan and clutch did you end up using. Your mention 20" DMAX fan but I thought they were 21" and cause some clearance problems. Don't mean to nicpik but I am looking to start working on my cooling system upgrades to and looking for real world advice.

Usual procedure, BOBT, is to remove the radiator to clean that between-cores debris.


It is the quickest cure for overheating\warm-running '88-up GMC\Chev Diesel trucks.

BobT,


This is what helped me tremendously:


http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=006575

bowtie, the clutch is OEM Borg Warner from a dealer. Duramax fan from ebay was machined down to 20" for better fit-up, very nice. gmtd, thanks. I will try a different way first until I have to remove radiator for another repair. spindrift, thanks but I cannot access that link as I'm not subscribed.

Bob,


The following is a copy of my original post:


Now that the wallet has all but dried up for any new, significant mods, I've been looking for a few R&M items to sink my teeth into. Yeah, I know, should have been the other way around.

A while back, I looked at HowieE's web site, saw that scuzzy radiator of his and figured that was something I would take a look at. But when I did, my radiator and coolers looked good so I scratched that job off the list.

Fast forward a couple of months to this weekend. Here in NJ, it seems as though its been raining for 40 days and 40 nights. This afternoon I went outside and I could see my breath! It's June 6th and the thermometer read an astoundingly cool 56*. Gotta' move south. Anyway, I had run out of things to do so I figured I'd take a crack at cleaning the radiator.

Howie was kind enough to lend me his Master Blaster (aka "Hydro-Air Washer") which he modified to include a long copper spray wand. I bought some Greased Lightning Orange Blast at Pep Boys and I was ready. First, I warmed the engine to operating temperature, removed the fan shroud and loosened all of the brackets so that I could get the wand down and between the radiator and coolers, applied the Orange Blast, and waited.

My first attempt at using the Master Blaster was rather comical since the combination of water pressure and air pressure nearly ripped the thing out of my hand. I knew I wasn't going to be effective by myself so I enlisted the aid of my son to work the handle while I directed the wand.

Then the fun began. Since I couldn't see what, if any combination of dirt, bugs, leaves and other matter was coming out the front, I was relying on my son for a status report. It didn't take too long before the look on his face told the story. Almost immediately he said, "Dad, it's really dirty!" I was thinking to myself, "C'mon, how dirty could it be. It didn't look dirty." So we switched places.

What can I say. The amount of absolute crap that was flushed out was absolutely unbelievable and the "water" was just about black. I almost felt guilty for not digging a big whole to bury all of the carcasses that had piled up on my grille, bumper and the ground. Fortunately, none of the PETA folks witnessed what had happened.

I'm now the newest member of the Hydro-Air Washer Fan Club. The whole process made a believer out of me.

For those of you planning to haul heavy loads this summer, if you haven't already taken a crack at it, think about cleaning those radiators and coolers. You just might be glad you did.

And thanks again to Howie for lending his Master Blaster to me. This gizzmo is very cool.

bowtie, the clutch is OEM Borg Warner from a dealer. Duramax fan from ebay was machined down to 20" for better fit-up, very nice. gmtd, thanks. I will try a different way first until I have to remove radiator for another repair. spindrift, thanks but I cannot access that link as I'm not subscribed.





So now, in all likelihood, you have a 20" plastic blade that pulls less air in all cases than the 20" steel blade...

Thanks spindrift! very good. what water pressure is used, or is it an air/water blast using 120psi shop air? do you flush the radiator first then follow up at condenser?

We have warm water at the hose connection in combination with shop air. Yes, I worked from engine compartment and out to coolers.

JKennedy, yup, very nice agressive plastic fan. I bet once I clean my heat exchanges a bit it'll work well as my engine will remain lighly modded and I will not pull more than 10,000 lbs for the most part. Guilty of hauling the family and dog and motorcycles/utility trailer with wood. BUT 1) I am prepared to alter clutch spring position in case fan runs too much and 2) I have a STOCK 20" steel 9-blade fan as backup. Then the DMax fan goes back on ebay ! Ain't life grand! Thanks !

BobT


So how is it working so far. Notice any difference temp wise.Are you happy with your setup

JKennedy Looking at your web site I found this:



<TABLE>
<T>
<TR>
<TD>Pre 1997 models used a 6 blade 20" steel fan with a very large pilot and 6 mounting bolts. 1997 and later used a 9 blade 20" steel fan with a much smaller pilot and 4 bolts. The new clutches will be of the 1997 and later style so if you do not have a small pilot, 4 bolt, 9 blade fan, you will need one. I also have these available. Either 20" steel vs. 21" plastic blade will work fine. The clutch has been designed/tested with the 20 steel blade which will fit with absolute certainty and no clearance issues. The 21 Dmax blade will bolt on, but may require shroud modification. This blade has NOT been tested with this clutch calibration. I personally run the 21" blade on my '96 with no shroud modifications and no contact. Your results may vary... </TD></TR>
<TR>
<TD>
Does this mean that you are running the same plastic fan as well. How is it working for you ?</TD></TR></T></TABLE>

bowtie, I don't know yet. Truck is at the airport in VA and I'm here in AZ wishing I could test it out here! My fan has had 1/2" concentrically removed, which I like for fitup purposes. Not sure the full 21" would fit in my old rig. I will report how it does but I can say it is a beautiful fan that GM (or Isuzu, more likely) designed.

JKennedy Looking at your web site I found this:



<TABLE><T>
<T>
<TR>
<TD>Pre 1997 models used a 6 blade 20" steel fan with a very large pilot and 6 mounting bolts. 1997 and later used a 9 blade 20" steel fan with a much smaller pilot and 4 bolts. The new clutches will be of the 1997 and later style so if you do not have a small pilot, 4 bolt, 9 blade fan, you will need one. I also have these available. Either 20" steel vs. 21" plastic blade will work fine. The clutch has been designed/tested with the 20 steel blade which will fit with absolute certainty and no clearance issues. The 21 Dmax blade will bolt on, but may require shroud modification. This blade has NOT been tested with this clutch calibration. I personally run the 21" blade on my '96 with no shroud modifications and no contact. Your results may vary... </TD></TR>
<TR>
<TD>
Does this mean that you are running the same plastic fan as well. How is it working for you ?</TD></TR></T></T></TABLE>








I'm back to the 20" steel unit. That needs to be updated on my site. I also found that the 21" Dmax blade was not really 21". I had sent it out for testing, and the vendor trimmed it to 20" to make things equal when evaluating against his 20" unit and did not tell me. I had a hard time getting it back in time for a trip, and hastily installed w/o inspection...