2003 zr2 over heats when towing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**truckdude239** · 10-18-2011, 05:33 PM

our o3 ar2 with 4.3 over heats only when towing, New radiator water pump t-stat new intake gaskets, oil coolerlines, belt and tenisor, only over heats when towing, towing a 6x12 foot tailor rated for 3500 ounds

gchemist · 10-18-2011, 08:30 PM

Add and external tranny oil cooler. Remember the tranny and engine lines go int the radiator too. Are you still running Dexcool? I upgraded the mechanical fan on my Jimmy. A 4.0 explorer fan does a better job of cooling. I like the upgrade. Even my A/C works better!!

**truckdude239** · 10-18-2011, 08:58 PM

green stuff new fan clutch its my room mates truck and doesn't want to add a bigger cooler i told him that before but he maintains that it use not to over heat pulling so it shouldn't now, i think that the gm radiator design in those trucks are stupid, engine oil trans and coolant cooled in one. basic i think the trans is getting 2 hot for the radiator to cool, and shor tof a bigger cooler on the front its not going to get better

gchemist · 10-19-2011, 12:03 AM

There is an larger aftermarket radiator available. If he didn't replace the original radiator when Dexcool was removed, he probably has a partially clogged radiator.

Send him this link on upgrading to a V-8 Vette radiator.
http://www.jagsthatrun.com/Pages/Par...-Radiator.html

ProStreet68SB · 10-19-2011, 08:16 PM

Are you towing on O/D?

**truckdude239** · 10-20-2011, 07:26 AM

nope no o/d

68C15 · 10-20-2011, 02:20 PM

what is the cam retard offset at? (think dist. timing)

bighaas79 · 10-20-2011, 06:46 PM

Factory or aftermarket radiator. There are alot of cheap aftermarket radiators out that don't flow like the factory ones did. There are aftermarket radiators that work fine but I say you got a radiator that just isn't cutting it. Everybody likes to save a buck but most of the time if you get too cheap it ends up costing you more in the long run.

10-18-2011, 05:33 PM	#1
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,230	2003 zr2 over heats when towing our o3 ar2 with 4.3 over heats only when towing, New radiator water pump t-stat new intake gaskets, oil coolerlines, belt and tenisor, only over heats when towing, towing a 6x12 foot tailor rated for 3500 ounds __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

10-18-2011, 08:30 PM	#2
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: 2003 zr2 over heats when towing Add and external tranny oil cooler. Remember the tranny and engine lines go int the radiator too. Are you still running Dexcool? I upgraded the mechanical fan on my Jimmy. A 4.0 explorer fan does a better job of cooling. I like the upgrade. Even my A/C works better!! __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

10-18-2011, 08:58 PM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,230	Re: 2003 zr2 over heats when towing green stuff new fan clutch its my room mates truck and doesn't want to add a bigger cooler i told him that before but he maintains that it use not to over heat pulling so it shouldn't now, i think that the gm radiator design in those trucks are stupid, engine oil trans and coolant cooled in one. basic i think the trans is getting 2 hot for the radiator to cool, and shor tof a bigger cooler on the front its not going to get better __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

10-19-2011, 12:03 AM	#4
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: 2003 zr2 over heats when towing There is an larger aftermarket radiator available. If he didn't replace the original radiator when Dexcool was removed, he probably has a partially clogged radiator. Send him this link on upgrading to a V-8 Vette radiator. http://www.jagsthatrun.com/Pages/Par...-Radiator.html __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

10-19-2011, 08:16 PM	#5
ProStreet68SB The Engine Whisperer Join Date: Sep 2006 Location: Ohio Posts: 770	Re: 2003 zr2 over heats when towing Are you towing on O/D?

10-20-2011, 07:26 AM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,230	Re: 2003 zr2 over heats when towing nope no o/d __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

10-20-2011, 02:20 PM	#7
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: 2003 zr2 over heats when towing what is the cam retard offset at? (think dist. timing) __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

10-20-2011, 06:46 PM	#8
bighaas79 Registered User Join Date: Nov 2008 Location: manly iowa Posts: 390	Re: 2003 zr2 over heats when towing Factory or aftermarket radiator. There are alot of cheap aftermarket radiators out that don't flow like the factory ones did. There are aftermarket radiators that work fine but I say you got a radiator that just isn't cutting it. Everybody likes to save a buck but most of the time if you get too cheap it ends up costing you more in the long run.



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