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350sb overheating

Discussion in '40- & 55-Series Tech' started by Huge Cruiser, Dec 3, 2003.

  1. Huge Cruiser

    Huge Cruiser

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    Hello All!!

    I am having problems with my truck overheating. I had a 195 T-stat in it and it was going well over 220 so i put in a 160 and it still gets hot but only when I am idling in traffic. I put a 350 sb in and have the yota rad in it. Do I need a bigger Rad or what?????? Any help would be much appreciated!!!
    Thanks in advance!!
     
  2. hammerhead

    hammerhead

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    Where is your sending unit? Is it in the intake manifold or in the head? If your sender is in the head it will read 20 to 30 degrees hotter than it would in the manifold. Lots of people run the stock rad with SBC 350. Is your timing right? If it is retarded or advanced to far it could cause you to run hot.
     
  3. Huge Cruiser

    Huge Cruiser

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    Thanks for the reply, my timing is set correctly, and I am running an Auto Meter mechanical temp gauge, off the head. Should I move It to The manifold???
     
  4. Huge Cruiser

    Huge Cruiser

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    I am also having problems with my alternator. It has a built in reg, but it has three terminals on top, I would like to know which ones to hook up to what wires!!
     
  5. hammerhead

    hammerhead

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    Petey runs the stock rad w/SBC. With 2 guages the one in the head reads 220ish most of the time while the one in the mani runs 190. I run mine (also mech) in the head and it reads in the 210 - 220 range also. Brook runs his in the mani at 185 - 190. Mine doesn't boil over till it is much hotter and that only happened when I had distributor issues.

    My alternator has 2 blade terms on top and the main power stud on back. I'm not sure what you've got.
     
  6. Rice

    Rice SILVER Star

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    Problem 1: If running warm in traffic and not the open road you could benefit from pulling more air through the radiator.

    1. Are you using a shroud?
    2. Are you trying to pull air with an electric fan or mechanical?
    3. Is it a clutch fan and is clutch working properly?
    4. Has radiator been boiled out and cleaned?

    Problem 2: Alternator. Be careful ... unless the tech section on this board was updated it is incorrect and will ruin your alternator. Big "BATT" terminal goes to batt using heavy guage wire. Split off from there and run a wire to Terminal #2. This is the sensing connector. It will run this way but will not energize the field and start charging until about 3000 RPM. To energize the field from start up you also need to connect the idiot light (Terminal #1). Run a switched 12 volt source (The RUN side of your ignition switch will work) in series through a warning light (MUST be there ... otherwise there will be too much current going to the field) and then to Terminal #1.
     
  7. woody

    woody unhelpful spotter Staff Member Admin

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    clutch fan and now many blades??
    shroud or no shroud?

    Those are your two most likely culprits....I had minor overheat issues, and never ran a shroud...upgraded to a custom 5-row radiator and a Flowkooler water pump and mine has had zero problems since.

    (BTW: Rice, PM me on which link is incorrect...I'll either fix or delete it...)
     
  8. fsusteve

    fsusteve

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    If all else fails try a hi flow water pump.
     
  9. fj40mayo

    fj40mayo

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    I was having these problems on mine. I had a clutch fan and then went to an electric. It worked ok unless it was a hot day. I went to the Taurus elec. fan with built in shroud and haven't had any more problems - at least not with keeping cool.
     
  10. dinkleberry

    dinkleberry

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    I had the same problem. Had no shroud and the fan was about 6 inches away from the rad. Switched to an electric and a 160 thermostat and it's fixed.

    If your still heating up at cruising speeds (on flat ground) then your rad is inefficient.

    Depending on your SB and your local weather, you may need a bigger rad and a high volume pump.
     
  11. Landpimp

    Landpimp

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    and I got mine to run much cooler by swaping the small fan for a 17" Flex fan, new t-stat(160deg I think)

    warning.....I don't know crap about SBC's :D
     
  12. Rice

    Rice SILVER Star

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    If you are using a regular steel blade fan bolted directly to the water pump I'd suggest switching to GM Part # 405442. This is a high pitch 4 blade fan that pulls a ton of air. For severe heating I don't recomment electric but rather a high pitch fan with a heavy duty RV style Thermal clutch. As we mentioned be sure you run a shroud and get the fan a couple inches from the radiator if it isn't already.

    Below is the correct way to wire your alternator. Notice that Wire #2 just goes to the +12V side which is why it can just be pigtailed to the BATT wire.
     
  13. DJSH

    DJSH

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    Rice, et al-

    I am trying to hook up a GM alternator using the stock wiring from my FJ60 and am a little lost. The GM has three wires, red (S) - dk brown (L) - light brown with white stripe (F). From the Cruiser, two white into one connected to back of GM Alt - black w/ yellow stripe (not connected to alt, but powered and seems to run back to charcoal canister) - yellow with white stripe connected to (L).

    I show a charge in the ammeter from the (L) connection I think, but I don't know what the black w/ yellow stripe goes, do I connect it to (F)? :doh:

    Also, does anyone have a diagram of how to hook up the charcoal canister correctly with a 350 conversion?

    One last question, how do I hook up the reverse lights, they didn't make it back together after the conversion.

    Thanks for any insight.

    Dave
    '87 FJ60
    '97 FZJ80
     
  14. Eskimo

    Eskimo SILVER Star

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    Guys... let's think about this. A thermostat only controls when the water starts going through the radiator. if he's already running over 200*, a cooler thermostat WILL NOT HELP.

    I have a 4-core rad, and was still running hot even after inner fender mods, spacing the hood, all kinds of stuff. Would run ok at low RPM's, but overheat on long pulls or highway. (oh, black magic fan)

    Bought a new (not reman'd) waterpump from Napa, and haven't had a lick of trouble since.I won't even get into the high-flow pump debate, but typically, it's not the "high flow" part that fixes the problem, it's getting a new water pump that really fixed it.
     
  15. jnau99

    jnau99

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    I also had a crap load of problems with heat. I run a howe allum. rad and now a high flow pump (which didnt change anything). It would run fine at low rpm but didnt like long hills and stuff the that extent. I finaly put in a oil cooler and now the hottest it gets is 180 climing big hills.
     
  16. dinkleberry

    dinkleberry

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    [quote author=Eskimo link=board=1;threadid=8340;start=msg80606#msg80606 date=1072470444]
    Guys... let's think about this. A thermostat only controls when the water starts going through the radiator. if he's already running over 200*, a cooler thermostat WILL NOT HELP.
    [/quote]

    A lower thermostat will help to a degree. The motor still gets hotter than the thermostat opening temp. The hotter the block gets the harder it's gonna be to cool it. If you start cooling at 180 or 160 the chances of an overheat are less.

    I agree that if your motor is running well above the thermostat temp than your not getting cooling in the rad. Which could be caused by a bad water pump, fan, rad, shroud, or thermostat.

    A $2 thermostat is the cheapest place to start.