Rear mounted radiator? - Pirate4x4.Com : 4x4 and Off-Road Forum

7.62FMJ · 03-14-2010, 11:17 PM

I will be working on my truck soon now that the weather is in my favor, and due to my design, there is no room for a radiator under the hood. My main question is how does the extra 'load' on the water pump effect it? Will the length of hose from front of engine to rear of cab, and the raised radiator put too much strain on a stock water pump? Engine is a 400 w/ stock water pump...

Blown74Ford · 03-14-2010, 11:23 PM

stock water pump will work fine.

Ibuildembig · 03-15-2010, 07:11 AM

Agreed...have done several crawlers now with the radiator in the back. Have yet to have an issue with water pumps...but bleeding the air out of it when you first fire it up sometimes sucks.

cslimfu · 03-15-2010, 11:58 AM

Drilling a 1/16'' hole in the Tstat helps the filling and burping.

Ibuildembig · 03-15-2010, 12:43 PM

I tried that, and without a T-stat at all....best way I found to do it was weld a nut to the highest point in the return tube in the engine compartment, screw in a petcock and force it out that way.

wheelin66bronco · 03-15-2010, 01:40 PM

My water pump has been fine for 5+ years running a rear radiator, like said the only biznatch is burping the system.

mustange70 · 03-15-2010, 05:35 PM

stock pump is more than fine, if you're going to be seeing constant high rpm i do suggest slowing everything down with a smaller crank pulley, the factory pumps tend to move to much volume at the high rpms and as such the rad won't remove enough heat, and the result is a slow overheating condition. I did this on my race preped 400 and the thing doesn't get a hair over 180 when ticklin the 7k redline in the mud bogs.

7.62FMJ · 03-16-2010, 01:48 AM

Quote:

Originally Posted by Ibuildembig

I tried that, and without a T-stat at all....best way I found to do it was weld a nut to the highest point in the return tube in the engine compartment, screw in a petcock and force it out that way.

Can you explain this a little further? I'm not quite sure I understand what you are describing. Any pics handy?

Ibuildembig · 03-16-2010, 09:47 AM

I can take some pics today.....basically your gonna have some sort of tube attaching to the water neck and turning around to go back to the radiator right? All I did was make that tube bend up higher than the engine before it turned down and went under the body and back to the radiator. At the crown of the bend you drill a hole on the top side of it. Then get a petcock ( I used one for an air compressor), a nut that it will screw into, and some good pipe dope. Weld the nut over the hole, screw in the petcock and your done. Then open it up all the way, stick a garden hose in the radiator and force the water through the system with the engine running...as soon as you see water pissing out of the petcock hole, your almost done. Close it off and run it for awhile, every once in awhile open it up and let the steam out.

7.62FMJ · 03-17-2010, 02:15 AM

Thanks a lot! I've got a pretty clear picture in my head now!

03-14-2010, 11:17 PM	#1 (permalink)
7.62FMJ Coke dealer... Join Date: Feb 2006 Member # 66780 Location: Roanoke, VA Posts: 1,804	Rear mounted radiator? I will be working on my truck soon now that the weather is in my favor, and due to my design, there is no room for a radiator under the hood. My main question is how does the extra 'load' on the water pump effect it? Will the length of hose from front of engine to rear of cab, and the raised radiator put too much strain on a stock water pump? Engine is a 400 w/ stock water pump... __________________ Awwww Piss!

03-14-2010, 11:23 PM	#2 (permalink)
Blown74Ford Registered User Join Date: Jan 2009 Member # 128152 Location: Klamath falls, Oregon Posts: 38	stock water pump will work fine. __________________ '74 ford,tube frame,rear eng,blown BBF,C-6,Profab, GM 2.5 ton front ,F106 rear, F/R lockers

03-15-2010, 07:11 AM	#3 (permalink)
Ibuildembig Wheeler Join Date: Jan 2004 Member # 26504 Location: Fruitland MO Posts: 370	Agreed...have done several crawlers now with the radiator in the back. Have yet to have an issue with water pumps...but bleeding the air out of it when you first fire it up sometimes sucks. __________________ If you have a mullet and play video games, your not tellin me shit 68 F350 CC project 72 F350 CC for parts 79 F150 with tons on coils 88 F350 truggy 90 F350 beater truck 96 F250 CC DD

03-15-2010, 11:58 AM	#4 (permalink)
cslimfu GREEN BASTARD!!! Join Date: Nov 2008 Member # 123458 Location: amity, oregon Posts: 1,594	Drilling a 1/16'' hole in the Tstat helps the filling and burping. __________________ It's a hell of a thing, killing a man. You take away all he's got, and all he's ever going to have.

03-15-2010, 12:43 PM	#5 (permalink)
Ibuildembig Wheeler Join Date: Jan 2004 Member # 26504 Location: Fruitland MO Posts: 370	I tried that, and without a T-stat at all....best way I found to do it was weld a nut to the highest point in the return tube in the engine compartment, screw in a petcock and force it out that way. __________________ If you have a mullet and play video games, your not tellin me shit 68 F350 CC project 72 F350 CC for parts 79 F150 with tons on coils 88 F350 truggy 90 F350 beater truck 96 F250 CC DD Last edited by Ibuildembig; 03-15-2010 at 12:43 PM.

03-15-2010, 05:35 PM	#7 (permalink)
mustange70 Registered User Join Date: Jan 2005 Member # 41097 Location: Calgary Posts: 2,109	stock pump is more than fine, if you're going to be seeing constant high rpm i do suggest slowing everything down with a smaller crank pulley, the factory pumps tend to move to much volume at the high rpms and as such the rad won't remove enough heat, and the result is a slow overheating condition. I did this on my race preped 400 and the thing doesn't get a hair over 180 when ticklin the 7k redline in the mud bogs. __________________ 90' C350 AKA 4 door 1 ton Bronco 96' Ranger: kings, EMF parts, 800hp SBF

03-16-2010, 09:47 AM	#9 (permalink)
Ibuildembig Wheeler Join Date: Jan 2004 Member # 26504 Location: Fruitland MO Posts: 370	I can take some pics today.....basically your gonna have some sort of tube attaching to the water neck and turning around to go back to the radiator right? All I did was make that tube bend up higher than the engine before it turned down and went under the body and back to the radiator. At the crown of the bend you drill a hole on the top side of it. Then get a petcock ( I used one for an air compressor), a nut that it will screw into, and some good pipe dope. Weld the nut over the hole, screw in the petcock and your done. Then open it up all the way, stick a garden hose in the radiator and force the water through the system with the engine running...as soon as you see water pissing out of the petcock hole, your almost done. Close it off and run it for awhile, every once in awhile open it up and let the steam out. __________________ If you have a mullet and play video games, your not tellin me shit 68 F350 CC project 72 F350 CC for parts 79 F150 with tons on coils 88 F350 truggy 90 F350 beater truck 96 F250 CC DD

03-17-2010, 02:15 AM	#10 (permalink)
7.62FMJ Coke dealer... Join Date: Feb 2006 Member # 66780 Location: Roanoke, VA Posts: 1,804	Thanks a lot! I've got a pretty clear picture in my head now! __________________ Awwww Piss!

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