Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Over heated on the trail again... need measurement from WP to Rad.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KRAZIE87K5, Jul 10, 2002.

  1. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

    Joined:
    Feb 23, 2001
    Posts:
    3,369
    Likes Received:
    0
    Location:
    Chicago, IL
    I over heated on the local trails again the other day. /forums/images/icons/mad.gif I've looked into the parts to get a regular belt driven fan (from the water pump), but I don't think the 454 and the 4 core radiator are going to play well together! /forums/images/icons/tongue.gif

    Can someone give me the depth of their fan and clutch assembly? Thanks!

    -Dan
     
  2. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Do you use V belts? If so, I've got a standard rotation 7-blade big block cooling fan, with the mongo heavy duty fan clutch. $55 would get it to your door. /forums/images/icons/cool.gif It won't work though if you're running the serpentine belt with the reverse rotation water pump. /forums/images/icons/frown.gif
     
  3. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I just measured it. It's 3.5 inches from the back of the fan mount to the front edge of the fan clutch. /forums/images/icons/cool.gif
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    Get an electric fan if you're serious about off roading.
     
  5. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

    Joined:
    Feb 23, 2001
    Posts:
    3,369
    Likes Received:
    0
    Location:
    Chicago, IL
    Serious about offroad? Get an electric? I've got a 2200CFM 16" fan w/thermostat, and it doesn't have a ice cube's chance in hell of keeping my engine cool when offroading...

    If you are "serious about offroading" I'll sell you my setup for $65, $75 w/shipping.

    -Dan
     
  6. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

    Joined:
    Feb 23, 2001
    Posts:
    3,369
    Likes Received:
    0
    Location:
    Chicago, IL
    Harry... Lemme work on the wife... we're heading to FL soon, and I need to keep all the money nearby until we get back. I'll let you know ASAP...

    -Dan
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Stock F-body setup pulls 5000CFM plus, *thats* where the problem is, not that its electric. Electric will always work better at low engine speeds compared to a clutch or flex fan, given same CFm rating.
     
  8. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    No problem. I can't use it 'cause I need one that rotates the other way. /forums/images/icons/frown.gif
     
  9. TopOff

    TopOff 1/2 ton status

    Joined:
    Jan 16, 2002
    Posts:
    1,760
    Likes Received:
    0
    Location:
    Folsom, ca
    What condition is your radiator in? (I presume 4 core).

    Are you sure the thermostat is opening all the way? (drill a 3/16" hole in it)

    Hoses in good shape? (didn't swell and block fluid)

    What shape is the fluid in? (Is it half water, half coolant)

    You have a 16" electric fan now? (I think you need atleast two 14" electrics).

    What condition is the pump in? (A corroded pump, bad impellers, will not flow enough water at slow speeds)

    Good luck.
     
  10. Waxer

    Waxer 1/2 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    1,857
    Likes Received:
    0
    Location:
    Long Beach, CA.
    </font><blockquote><font class="small">In reply to:</font><hr />
    Electric will always work better at low engine speeds compared to a clutch or flex fan, given same CFm rating.

    [/ QUOTE ]

    That just isn't the case with my setup. I ran a Permacool 16" Elec before and overheated like a son of a bitch on the trail. This was 1500-2500 rpm rock crawling with a lot of climbing. Now after I put the stock setup back on with a new fan clutch, new shroud from LMC truck, along with the existing 4 Core radiator my cooling issues are GONE. At idle the stock setup is pulling TONS MORE AIR than the Permacool fan did when it was on full blast.

    I have not been able to find it yet, but I'd like to know just how much air a PROPER stock setup pulls.

    BTW, like your Mr. T pic /forums/images/icons/smile.gif
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    No, that *is* the case, its just that your electric fan simply doesn't move enough air. I have yet to see any published CFM ratings of a stock clutch fan, but I *know* what a Camaro dual fan setup runs, and I can see no way whatsoever that a stock clutch fan, at 700-1000RPM (typical idle/crawl speed in my case) flows the 5000CFM of the STOCK Camaro setup. (I see you are talking above that range, but don't forget, that stock fan had to be designed with an RPM variation compromise)

    Whats your electric rated at? Half of that? GM considered 5000CFM enough for a 5.7 liter engine, with AC. If GM did it, you can be assured they didn't OVER do the cooling setup, so that means (likely), 5000CFM is adequate to cool that vehicle setup (relatively light car, poor grille opening, AC) in the hottest temperatures you can expect, in the worst traffic possible, anywhere in this country. (and cut the second fan on at 232*!) It may not mean it will cool a 454 in a 6000lb truck climbing rocks in New Mexico in 100 weather with AC on, but in any case, GM didn't see 2500CFM being suitable even in a smaller all around vehicle, much less a truck.

    All I'm saying is, given the *same* CFM (as in total output at a given RPM, which I can guarantee isn't the same electric vs clutch fan), it doesn't matter what drives the fan, the cooling WOULD be the same. The difference is at what speed each fan puts out the *most* CFM, and when each fan does so, in the case of the clutch fan, you also have to add in at what RPM it puts out the most CFM, which isn't an issue with an electric fan. When its on, its already flowing the max it can. (unless its a 2 speed fan of course)
     
  12. Waxer

    Waxer 1/2 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    1,857
    Likes Received:
    0
    Location:
    Long Beach, CA.
    You're right, its all about how many rpms you are doing at a given time. When climbing over rocks my rpms are anywhere from 1500 to 2500, sometimes higher. It just depends on the situation. I've got a 6.55:1 first on my tranny and that along with the 3.73's and 33" tires makes for some high rpms while basically going nowhere.

    I have to add that when I had overheating problems I was running a th350 back then and that would add to the heat as well.

    The CFM rating on my permacool was 2950 for the 16" fan. Did not come with a shroud, was an open fan. I literally feel the difference between the two at the grill. My shirt gets sucked in now when before I would have to put my hands inside the grill to feel the sucking.
     
  13. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I've got electric fans on my K5 and they've always done the job for me. But when I look at new trucks, I notice that they still come with large fans, driven by the engine via a temperature sensitive clutch. Apparently GM thinks that the engine driven fans are the best way to cool an engine that is working hard to drag around a large truck and its cargo. /forums/images/icons/cool.gif
     
  14. Waxer

    Waxer 1/2 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    1,857
    Likes Received:
    0
    Location:
    Long Beach, CA.
    That is correct. Anytime you look at a stock HD Truck, they all have engine driven fans and its that way for a reason. Although Camaros or other "cars" can cool fine with the elec fans that come with them stock, they just don't cut it on Fullsize Trucks. Sure on the street they cool fine but start putting some strain on the motor at low speeds and you'll see which works better. My experiences show engine driven fans to work best for what I do.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Guaranteed its because they aren't as limited with space, and its half as expensive : )
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Factory electric fans as I've seen them for V8 GM's, ALL have shrouding of some sort. Bery thin, but effective, since the blades aren't nearly as "deep".


    If a fan can flow X CFM at X RPM, it will flow X CFM at X RPM, and the vehicle could care less how the fan is actually driven, the results will be the same. Until someone posts stock CFM fan numbers at X RPM, this won't be resolved.
     
  17. Waxer

    Waxer 1/2 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    1,857
    Likes Received:
    0
    Location:
    Long Beach, CA.
    well its not ONLY about the CFM, its also about vehicle weight, gearing, tires, etc...

    Most of us push the envelope with oversized tires, stock gearing, added weight of camping gear, roll cages, armor, etc... So X cfm that cools a light car on the street fine is not guaranteed to work on a 6k pound truck with oversized tires climbing obstacles with no other air flow than whats provided by the fan.
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    You are missing what I'm saying.

    Say the stock truck clutch fan pulls 4000CFM at 1500RPM. (Now realize, I'm just throwing these numbers out as an example!)

    Say you put two fans on that same vehicle, that combined, pull 5000CFM. No matter what, the electric fans will cool better. I don't *think* anyone doubts that. (if you do, explain how air moving faster through a radiator, can possibly cool less efficiently given these two examplessince the radiator, water pump, and engine are all the same for either fan setup)

    What the doubt is, is how much does the stock clutch fan flow, and at what RPM is it moving the most air. Because we KNOW what electrc fans run CFM wise, we just need to figure out what the clutch fan runs.
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,982
    Likes Received:
    191
    Location:
    Roy WA
    Good point here though, I believe the tranny adds a lot of temp to the coolant, especially with no auxiallary cooler.

    I have no problems keeping my 350 cool in any situation, including 90 degrees with stop and go traffic, running similar (3.42/SM465/K5) specs. I'm running a 2 core (old and corroded lol) with the stock clutch fan. The 2 core is setup for the tranny cooler, which if you think about it, reduces coolant capacity, if not by much.
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    All an engine driven fan does is throw water all over it. If you don't believe me, come on down in a few weeks, Dan, I'll show you how to put that K5 to use.

    If you're not a REALLY good driver though, you might want bigger tires. /forums/images/icons/wink.gif
     

Share This Page