GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 6 of 6
  1. #1

    Default Is a bigger better radiator needed after the engine being bored out?

    So I am doing my very first engine rebuild, so still learning. That being said, I was told that after having the engine bored out to .040 that a better radiator was needed. He said something about high volume but I wasn't sure. Any help would be greatly appreciated.
    1985 GMC Suburban Sierra Classic (K1500) Chevy 350 5.7l
    3 inch lift with 33 inch tires

  2. #2
    TRPLXL2's Avatar
    Join Date
    Jan 2009
    Norwalk, Ohio
    Blog Entries


    I don't know much about old trucks so forgive me, but do you still have the mechanical fan setup? If so I would consider going to pull a part, grab a set of dual electric fans out of something, and use that and it would cool it just fine. I used a set of f body fans in my v8 swap, and they work beautifully with the stock radiator. I spent all but $100.00 for the setup, including relays and all. It runs off of the ECM coolant temp, just like factory.

  3. #3


    I'm with Amy, a decent fan system and make sure the rest of the cooling system is flowing properly.
    You might change to a slightly lower temp thermostat to fine tune the system but as it stands your factory cooling system in good shape is enough to handle boring out the engine.
    It's not going to run appreciably hotter than it did before being bored out.

  4. #4
    Jr. Engineer
    Join Date
    Aug 2010
    eas' bum fuk, maine


    i suggest you try it the way it its now before doing anything (just plan on having to get a nother radiator just incase). cruising down the road at 35+ miles an hour, the electric cooling fans arnt doing squat, you could completly remove them and still not overheat as long as yoru moving. the problem yoru going to have is when your sitting still. if you find you need more cooling then you could try adding an additional fan to what you have, or a completlly new fan such as an efan upgrade like suggestd.
    "i dont think you got the picture. i got a beautiful picture. this baby happens to have an extra turn of speed, which is the only thing i care about. you dont understnad what happens do you? they make cars. they make 'em exactly the same way. one or two of 'em turn out to be something special. nobody knows why. i know why. i may be kiddin' myself, but i think i can make somethin' out of that sad little bucket of bolts." ~ Tennessee Steinmetz

  5. #5


    A simple over-bore is not going to generate any more heat than the original motor; however, if you increase the compression, bump up the cam, advance the timing, etc (all things that will increase the engine heat), you must get rid of the additional heat.

    The stock rad and fan and pump will handle the heat of a rebuilt engine, it will not handle the heat if the performance is increased over stock.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  6. #6


    X3 - a freshened engine won't create that much more heat, but you should check that your current cooling system is in order. All the junk that the "old" engine spewed out, before the need for a rebuild, ran through that radiator. I would flush the system and check for leaks, just cuz.

    The fan swap that Amy mentioned is a pretty popular project. I think they use the Taurus fans...

    Good luck,

    1999 Chevy K2500 Suburban 350
    K&N, reworked cai, Thrush cat-backs
    Vinyl, cranks, floor shift, and rear air!

Similar Threads

  1. Engine oil in radiator
    By Treadnmud in forum Chevy Suburban Forum (GMC Yukon XL)
    Replies: 1
    Last: 02-20-2012, 08:39 AM
  2. Bigger alternator needed for towing?
    By nos351wcm in forum GM Electrical Tech
    Replies: 9
    Last: 05-05-2011, 04:16 PM
  3. Help needed! 93 Sub. engine 350 replacement
    By 1500Gst in forum Chevy Suburban Forum (GMC Yukon XL)
    Replies: 2
    Last: 02-26-2009, 02:18 PM
  4. 5.7L engine trouble - opinions needed!
    By hihoslva in forum GM Powertrain
    Replies: 5
    Last: 08-11-2008, 01:54 AM
  5. Room for bigger engine.
    By Jake in forum The Coffee Shop ~ Chit Chat
    Replies: 1
    Last: 07-05-2006, 03:15 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts