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210 Degrees

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TheEmissary, Jun 22, 2000.

  1. TheEmissary

    TheEmissary Registered Member

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    Right now, with 100+ degree weather, my temp gauge still spikes over 200 degrees with the A/C on. Here's what I have done recently:

    1) static timing: 4 degrees BTDC
    2) 50/50 mix
    3) 89 octane fuel

    After filling up with 89 octane, the surging seemed to quit, but came back again a few days ago. So far, I haven't had any responses from others running a stock 305 with ESC. Instead of 13.2 MPG, I now average 10.5, and this isn't good for my billfold.

    Should I install an auxillary electric fan?

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  2. Burt4x4

    Burt4x4 3/4 ton status

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    Seems kinda hot! I too live in the 100 degre stuff in Central Cal and my 350 w/electric fan stays 185-195 even at a long red light. I would swap out your thermostat for a 180degree one. How long has it been sence you had your radiator rodded out? Also during summer you can run more water than coolent and that helps keep it cooler too. Water disipates heat better thatn coolent. Coolent helps with currosion and freezing from what I understand.
    Good luck

    Rock ON![​IMG] 72 K5 [​IMG] Led Zeppelin
    http://burt4x4.coloradok5.com
     
  3. 8_YOUR_H2

    8_YOUR_H2 1/2 ton status

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    I have noticed my parents late model blazer does the same thing. It never goes below 200deg. It is a vortec and due to the enhanced performance it has a hotter thermostat in it...SO I AM TOLD..I cant say for sure. I changed to a 165 degree thermostat in my wifes daily driver and it stays cool all the time..never goes above..well...165 degrees!! Maby change the thermostat. I had to change it because it stuck CLOSED..weird huh? Any auto parts store has 'em..try that its alot cheaper!!
     
  4. jimmyjack

    jimmyjack 1/2 ton status

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    I had the same prob with my 83 and I stuck in a 165 degree thermostat and its been fine ever since
     
  5. TheEmissary

    TheEmissary Registered Member

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    I recently swapped a high flow thermostat (160 degrees), and even with the A/C off, the water temp would peak at 200, or remain stable at 160. One thing that has been a chronic PITA is running the A/C 100%, and 200 degree boilovers are common. I have had the radiator boiled out last summer, and hoped that this summer, I would have expected a 13 mpg average. Right now, all that I am averaging is 10 mpg out of a 305 with ESC.

    If there are any 1981-86 owners on the list, what's your pet peeve on the ESC system? I have heard that a lot of people threw the ESC distributor away, and swapped in a traditional HEI, due to constant detonation and Chevette-esque power.

    I have replaced the following components:

    vacuum advance
    fuel filters (5)
    engine coolant (used Dex-Cool in place of the traditional green stuff, to deter aluminum corrosion, where an LG4 intake was swapped out last winter)
    remanufactured Quadrajet (the throttle shaft on my original Quadrajet was shot, where I had to purchase a remanufactured carb)

    I have been experiencing constant surging/hesitation, and it seems that flooring the accelerator is something that I have been accustomed to for several years now. The original Quadrajet has went through 5 carb kits, and only once with the remanufactured carb.

    I rather believe in a "fix it once and for all", instead of burnin' a paycheck for auto parts. The last thing that I would do is to liquidate my Blazer for a late model Tahoe, where taking it to the dealer is a usual sight (e.g. I have little knowledge on OBD-II diagnostics).

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  6. TPI86

    TPI86 1/2 ton status

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    I have 1986 that had a 305 ESC and I had the same problem with surging and hesitation. Be sure to check the fuel pump, mine ran fine at lower speeds and as I got to 45-60 the thing would surge like crazy. Another thing to check would be the eccelorator pump, be sure it is dispensing nice steady stream of gas into the carb-you can do this with the air cleaner off-look directly into carb and move the throttle linkage with your hand while watching the accelorator pump work. I am sure glad I put on a TPI system-no more of that SH@*.
     
  7. Russell Keys

    Russell Keys 1/2 ton status

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    Have you checked the radiator cap? It's probally the most overlooked component in the cooling system. I don't think you should have a boilover at 200deg. Because for every pound of pressure added to the system by the cap it increases the boiling point by 3deg. So with a 16lb cap the boiling point should now be at 260deg. Also about that dexcool, a while back when I worked at NAPA we were told that dexcool was only to be used when specified by the manufacturer. I actually had a customer that tried it in his non GM vehicle and it ran quite a bit hotter than with the cheap greeen stuff.Just a thought-Russell
     
  8. TheEmissary

    TheEmissary Registered Member

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    I recently replaced the fuel pump because the old one was leaking at the seam (motor oil seepage). I locked the pushrod when switching fuel pumps (had to pull the AIR pump just to access the bolt hole that connects to the fuel pump pushrod). I have had the pump (manufactured by Federal Mogul) for 2 months now.

    ESC distributors use a 5-pin module, and the "computer box" inside the cab is just a retard module. I wouldn't disconnect the ESC pigtail; the motor died when I done this.

    The last time that I checked the accelerator pump, there are 2 streams right after moving the throttle lever. When I had the carb out of the Blazer a few weeks ago, there was a lot of crud in the fuel bowl, and Holley Replacement Parts didn't bother to put in a plastic baffle (a cylindrical piece that is in place of the APT adjuster).

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  9. coopertwpk

    coopertwpk 1/2 ton status

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    Ok heres some info if you replace your water pump always replace it with a A/C style it pumps slower for better cooling also all smog pump equiped chevys come with 195' thermostats so running 210 is a factory thing do not go below a 180'thermostat gas mileage drops and performance sucks.Also do not have radiators boiled it does not work coring means the ends are removed and a steel set of pins get puched from one side to the other .TBI models check the rear intake manifole inlet they corode really bad and will break off ,ussually you will need a 1/2 easy out to remove it the buy a brass barb to replace the factory clip in.
     
  10. TheEmissary

    TheEmissary Registered Member

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    The radiator has been swapped in 1996, and was boiled out last summer. After boiling, some of the coolant tubes did not flow like the way it used to be, and at the same time, I noticed a lot of scale in the cylinder block.

    I don't know any radiator shop in the Houston, TX area that can "core" or "rod" radiators. I might as well burn $350 for a brand new Modine radiator.

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  11. getsome

    getsome 1/2 ton status

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    My 84 with a 350 and a 180deg thermostat ran hot only at a standstill or stuck in traffic. I was also missing the fan shroud. I picked up a a new one from LMC last week and just installed the top half. It made a world of diffence. I know that you can't test it but did you look into the clutch fan being a problem? It's the only other thing that I can think of that would cause this problem. Let is know what the fix is.

    Getsome
     
  12. TheEmissary

    TheEmissary Registered Member

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    I swapped out the fan clutch with an HD version, commonly found in big-block Suburbans or crewcabs. I had this done last summer, after returning a "stock" fan clutch.

    Everyone knows that there are 3 fan clutches: stock, thermal, and HD. I am using an HD (which is considered the largest in the industry), and haven't had any problems yet.

    Yesterday, I had a couple of boilovers (after switching to a 180 thermostat), and had to open the radiator cap to relieve pressure buildup. The temp peaked at 220 degrees (with the A/C at 100%), and yesterday, I had to make a "pit stop" for water.

    When I refilled with water, I noticed that some of the radiator cooling tubes were clogged, which might be the cause of my constant boilovers @ 210 average. The facility (in Stafford, TX) that boiled my radiator is no longer in business, and due to my use of the Blazer as a work truck, I haven't had time to browse the local Yellow Pages for a reputable radiator/fuel tank shop.

    I might as well limp on refilling with water, and boil my 305 until it burns 100 miles/quart, and let it grenade.

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  13. TheEmissary

    TheEmissary Registered Member

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    The reason that I used Dex-Cool was in part, due to an intake manifold swap.. I recently salvaged an LG4 305 intake, because the stock one on my 305 was corroded around the water ports.

    Zerex, Prestone, Peak et.al. (the green stuff) isn't user-friendly with aluminum, and I have heard of swap meet dealers selling corroded Edelbrock, Offenhauser, Weiand et.al. intakes as low as $5.

    Someone posted (on another thread, a GM dealer employee) that Dex-Cool is worhtless, and shouldn't be used in a GM vehicle. If this indivudual is on the list, e-mail ASAP. I haven't had a problem with Dex-Cool in my mom's 1978 Cutlass Supreme, where her engine didn't boil over.

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  14. DBLAZER

    DBLAZER 1/2 ton status

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    Hey bro, last summer i went throgh the same thing. I replaced everything and could not get the damn thing to run cool, the whole time i was doing all this work, my boss was telling me to swap out the guage, i said naaaaaaa. Well a new raditor, water pump, 3 thermastats later, i replaced the gauge and kaboom! it ran fine!!!!!!
    just check it out!


    89 w/DANA 60-Corp 14 w/5:13s n Detroit's. 4"lift 2" body. NEW AtlassII ordered 5-15-00. 38" sx's -
     
  15. TheEmissary

    TheEmissary Registered Member

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    I just came back home this evening, and noticed that the fan was freewheeling. Still had the 200+ degree boilover, but ended up swapping in a new fan clutch. The inertia damper fan clutch (what could be considered a fan clutch on a 454 dually rig) still had retention, but probably lost a lot of hydraulic fluid.

    After switching fan clutches, I took the Blazer on the highway, and water temp average was 175 degrees F. Didn't run the A/C yet, but hope that it remains below 200. There was a minor surging occuring (due to the possibility of fouled plugs), but reset static timing to 6 degrees BTDC.

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     
  16. 82Jimmy

    82Jimmy 1/2 ton status

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    I want to put a new radiator on. Whats the best brand and most effective?


    Bigger is Better
    Cameron Burnett
    82 Jimmy
     
  17. dumbfounded

    dumbfounded 1/2 ton status

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    Usually overheating is contributed to a bunch of things when a vehicle gets older. Start with the cheap stuff.
    radiator cap
    new coolant with redline's watter wetter (good stuff)
    fan clutch
    sometimes a new temp sensor
    things wear and 200-210 isn't fatal to a motor the tranny on the other hand doesn't like it get a tranny cooler even if it isn't overheating. Mid 80's vettes like mine will run 230-245 in traffic believe it or not and the ZR1's even hotter. That's just how they are from factory. Going below 180 throws an EFI motor off unless a performance chip is in place that requires a 160-165 thermostat. As far as boiling over it shouldn't until about 250-260 if cooling system pressures and coolant/H2O mix is right. Also look at the radiatior. Straighten any bent fins and look for leaves and such. Like I said start with the inexpensive and obvious stuff and things should be OK.

    Wasn't me.............
     
  18. BigBadBowTie

    BigBadBowTie 1/2 ton status

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    <font color=purple>I didn't see anybody mention flushing the cooling system, might very well have build up in the engine somewhere reducing or even stopping flow. Also, any reputable radiator shop can rod out a radiator.</font color=purple>
    [​IMG]

    <font color=purple>Rick
    86 K-5</font color=purple>

    http://www.BigBadBowTie.ColoradoK5.com
     
  19. TheEmissary

    TheEmissary Registered Member

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    Last summer, when I had my radiator boiled (which isn't recommended), I flushed out the entire cooling system, including the two drain holes on the bottom of the cylinder block (SBCs have 2 threaded 1/4" NPT ports), and a lot of scale was present. At the same time, I replaced a freeze plug behind the engine bracket.

    Right now, after running the A/C at 100% capacity, the coolant temp averages around 200, due to a fan clutch swap.

    The Emissary
    1981 K5 Blazer 4 x 4
    305 (LE9)/THM350C/NP208

    Other vehicles:
    1975 Nova
     

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