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Hi Guys...I am in the process of installing the coolant hoses. I understand that the return line from the radiator is the larger tube and that attaches to the upper outlet of the Water Pump. Now, a couple people have been using the stock upper rad hose for this connection, but this hose won't fit over the larger tube and I see by their pics that they have actually used the smaller of the tubes for the return line. Does it really matter which tube is used for the return line? Any cooling issues by installing this way?

Thanks for your help,

Brian
 

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Supply return are also reverse on the engine. It feeds the heads first not the block so the whole set up seems odd. There is a post somewhere with part numbers for rubber hoses for the engine end. HTH, Cheers Richard.
 

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Brian,

Does not matter for cooling since the tubes are so long. The only issue would be getting the hoses/adapters for the engine side of the tubes to match the diameter of the engine outlet/inlet to the tube. On the radiator side, most use the supplied stainless steel tuding which has adapters to match either size.

Make sense?

Henry

And make sure you put the tubes in early as once the steering rack is in, it is very difficult to get them in,
 

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Discussion Starter #6
Thanks guys, I appreciate the help.

One more question about flow that I need confirmed. The coolant leaves the motor from thermostat housing and enters the upper rad inlet. Is this correct?

Thanks again for your help.

Brian
 

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Thanks guys, I appreciate the help.

One more question about flow that I need confirmed. The coolant leaves the motor from thermostat housing and enters the upper rad inlet. Is this correct?

Thanks again for your help.

Brian
I think that is backwards. Not running the stock water pump and haven't even started my LS3 yet, but IIRC, Shane, or Richard, or someone else said that the upper water pump fitting is the one that is hot, meaning that the flow is OUT the upper, and IN the thermostat housing. It is on the forum somewhere, so a search should turn up the answer.
 

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I can confirm that. I drew arrows on things after I worked it out so I wouldn't forget! The line to the thermostat (bottom one) gets hot last.
 

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I can confirm that. I drew arrows on things after I worked it out so I wouldn't forget! The line to the thermostat (bottom one) gets hot last.

So just to not confuse things, the upper fitting on the water pump, the one WITHOUT the thermostat in it, is the OUTLET. Is that correct, eeeny?
 

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So just to not confuse things, the upper fitting on the water pump, the one WITHOUT the thermostat in it, is the OUTLET. Is that correct, eeeny?
yep, the water goes in at the thermostat (lower) and out the top.

I think for the heater ports, the larger one flows TO the heater core.
 

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I'll probably get slammed for this, but I think cooling system on the GTM is a bit of a disaster:

1) trapped air stays in the heads ... PDG @ 25Hr overheated due to this, right?
2) reservoir is not the highest point in the system
3) even if it was, the water flows down then up again to get to the res, like a P trap in a bog (toilet).
4) On my car at least, the thermostat never opens if the car is just idling:
a) the heads heat up first
b) this turns on the fans
c) by the time water gets back to the engine, it's cool, so the thermostat stays closed
d) no enough water flows thru thermostat, and back to a) again

Giving it some revs clears this "deadlock" and it's ok after that, AFAIK.

I'll probably add a 2nd reservoir tank high in the engine compartment that feeds the 2 head air bleed ports.
 

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Yep - that's what I'm doing as well - a "header" tank for the engine steam vents, along with the front tank. I think Crash had a dissertation on this a while back. It's hard to believe the thermostat in the COLD flow - it'd be neat to find out what the GM geeks had in mind here!?!?!?!?! Best regards, Ted Wright #261
 

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Discussion Starter #15
Dave

The insulation I am using is from Smock & Schonthaler (814) 456-4222

#RHT138X050 1 3/8 X 1/2 HT Armaflex-B
#RHT158X034 1 5/8 X 3/4 HT Armaflex-B

I believe they come in 6' lengths and are rated to 300 F. They are also not sliced on the side and slip over the cooling tubes.

This product was discussed on the forum some time ago, but based on all the options, I thought this stuff would be the best.

Brian
 

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One word of caution on using both a tank in the engine compartment, AND the 'Vette reservoir in front. If you fill the tank in the engine compartment with coolant, and put a typical rad cap on it, here's what can happen. Let's say that when the engine warms up and creates pressure and the pressure vents out the 'Vette reservoir, like it's supposed to. Now when it cools down, the engine bay tank cap allows air in to fill the neg pressure like it's supposed to. About 3 cycles of this and you're going to have an empty engine bay tank, the engine is going to be full of air, and you're going to be spewing coolant out the 'Vette tank. The only way to prevent this is to put a sealed cap (both pressure and vac) on the engine bay tank. Once you've done that, you've effectively made the engine bay tank worthless as nothing can get in or out anymore.
 

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Shane - Good thoughts. Now, some s'posin' - Case 1 - s'pose I put a pressure only cap on the engine tank? Air out, no air in, right? or, Case 2 - s'pose I put a pressure-vacuum cap on the engine tank with an overflow tank(vent tube submerged, of course). Air and water out, water in. Will they work - which is better? Best regards, Ted Wright #261
 

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One word of caution on using both a tank in the engine compartment, AND the 'Vette reservoir in front. If you fill the tank in the engine compartment with coolant, and put a typical rad cap on it, here's what can happen. Let's say that when the engine warms up and creates pressure and the pressure vents out the 'Vette reservoir, like it's supposed to. Now when it cools down, the engine bay tank cap allows air in to fill the neg pressure like it's supposed to. About 3 cycles of this and you're going to have an empty engine bay tank, the engine is going to be full of air, and you're going to be spewing coolant out the 'Vette tank. The only way to prevent this is to put a sealed cap (both pressure and vac) on the engine bay tank. Once you've done that, you've effectively made the engine bay tank worthless as nothing can get in or out anymore.
yep, I was thinking the same thing after I write it .. needs more thought ;-)
 

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It's hard to believe the thermostat in the COLD flow - it'd be neat to find out what the GM geeks had in mind here!?!?!?!?! Best regards, Ted Wright #261
The thermostat never fully closes off, as the plate has slits in it. Plus the heater bypasses the thermo if it is on:

 
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