Have 1 more for you guys

max57

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Dec 12, 2014
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OK , I will put a new AC Delco plastic impeller Pump in it and think I will tap the rear plate behind the head with 1'' adjustable releif and plumb to thermostat housing similar to coker6365. Maybe try to leave electric too if not to restrictive, for idle cool down. Anybody know about what pressure to relief at while thermostats are closed??
Coker6365 did you relieve any of the impeller or just weld the gear.
 

coker6365

Coker6303's ***** Daddy
Dec 4, 2011
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OK , I will put a new AC Delco plastic impeller Pump in it and think I will tap the rear plate behind the head with 1'' adjustable releif and plumb to thermostat housing similar to coker6365. Maybe try to leave electric too if not to restrictive, for idle cool down. Anybody know about what pressure to relief at while thermostats are closed??
Coker6365 did you relieve any of the impeller or just weld the gear.
Plastic impeller sononly the drive gear is welded. Fins are factory length, no cutting.

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max57

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Dec 12, 2014
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Can not seem to find a pump with plastic impeller. All I see is ac delco ACDelco 252-898 . Metal impeller . Also anyone know about what psi I should relief the pump ?? what size 3/4''hose
 
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coker6365

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Dec 4, 2011
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Can not seem to find a pump with plastic impeller. All I see is ac delco ACDelco 252-898 . Metal impeller . Also anyone know about what psi I should relief the pump ?? what size 3/4''hose
What year pickup? Plastic impeller was 06-up.

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max57

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Dec 12, 2014
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What thermostats are they?
Low temp Mishimoto stat, seem to open 160 & rides about 170.
What year pickup? Plastic impeller was 06-up.
LBZ 2006 , which takes the ACDelco 252-898 (Metal empleller)
Found some good threads on this and water comes up through oil cooler to block then heads , so only relief is the bypass tube back to water pump, Heater core when on, and little 1/8'' holes in stats while thermostats are closed.
Now I am thinking maybe a relief off the back plate on block or off the top heater hose near the stats and sending it to the plug in back of the thermostst housing or to lower hose which could be the (return) heater hose.
Im leaning to putting a Tee in Heater hose near thermostats , put a adjustable relief with 30psi and dump to opposite heater hose that routes back to lower Radiator hose. as that way I will keep more water going through the block & heads even while it is Dumping. Rather than relief out the rear of block or oil cooler feed line like Socals . They Socal says Block & Heads do not flow enough , but others are relieving by using therostats and hholes drilled in them so i would think it can flow enough. Any input would be great , for or against.
 
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Bdsankey

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Low temp Mishimoto stat, seem to open 160 & rides about 170.
What year pickup? Plastic impeller was 06-up.
LBZ 2006 , which takes the ACDelco 252-898 (Metal empleller)
Found some good threads on this and water comes up through oil cooler to block then heads , so only relief is the bypass tube back to water pump, Heater core when on, and little 1/8'' holes in stats while thermostats are closed.
Now I am thinking maybe a relief off the back plate on block or off the top heater hose near the stats and sending it to the plug in back of the thermostst housing or to lower hose which could be the (return) heater hose.
Im leaning to putting a Tee in Heater hose near thermostats , put a adjustable relief with 30psi and dump to opposite heater hose that routes back to lower Radiator hose. as that way I will keep more water going through the block & heads even while it is Dumping. Rather than relief out the rear of block or oil cooler feed line like Socals . They Socal says Block & Heads do not flow enough , but others are relieving by using therostats and hholes drilled in them so i would think it can flow enough. Any input would be great , for or against.


If you look at the pressure testing Banks has done the issue is the heads and coolant bridge. The oil cooler they saw less than 2psi of resistance across it. The SoCal kit is very well made and extremely easy to install based upon talking to Gabe/Lorenzo and Richard. You can do it yourself but I think you may end up finding it is easier/faster/about the same cost to buy the SoCal kit.
 
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JoshH

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LBZ 2006 , which takes the ACDelco 252-898 (Metal empleller)
Found some good threads on this and water comes up through oil cooler to block then heads , so only relief is the bypass tube back to water pump, Heater core when on, and little 1/8'' holes in stats while thermostats are closed.
Now I am thinking maybe a relief off the back plate on block or off the top heater hose near the stats and sending it to the plug in back of the thermostst housing or to lower hose which could be the (return) heater hose.
Im leaning to putting a Tee in Heater hose near thermostats , put a adjustable relief with 30psi and dump to opposite heater hose that routes back to lower Radiator hose. as that way I will keep more water going through the block & heads even while it is Dumping. Rather than relief out the rear of block or oil cooler feed line like Socals . They Socal says Block & Heads do not flow enough , but others are relieving by using therostats and hholes drilled in them so i would think it can flow enough. Any input would be great , for or against.
That water pump you listed is the biggest POS ever. Do not use it. You need to get an OE pump from GM, or I believe the AC Delco p/n 251748 is the same. AC Delco Professional parts are Chinese garbage though.

The heater core has coolant flow at all times, doesn't matter if it is on or off unless you plumbed in a valve with your conversion. If so, that could be part of your problem.
 

max57

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Upstate, NY
Bdankey, you could be right. maybe the heads and bridge are restricting the flow,. I have not heard Banks testing.
I guess if Socals is proven to work and it is the heads and bridge restricting, I would be better to do the back plate which should be easy to tap and put a relief in there. Not sure if I have room for the fitting on Socals kit, looks like it points outward from block would be very tight . better if it pointed down the side of block.
 

Bdsankey

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Bdankey, you could be right. maybe the heads and bridge are restricting the flow,. I have not heard Banks testing.
I guess if Socals is proven to work and it is the heads and bridge restricting, I would be better to do the back plate which should be easy to tap and put a relief in there. Not sure if I have room for the fitting on Socals kit, looks like it points outward from block would be very tight . better if it pointed down the side of block.

It is in this episode: https://www.youtube.com/watch?v=L2KAGiu2Yrk


Unless you've got some crazy piping or configuration you should have no problems fitting the SoCal kit with AN or JIC lines. It points towards the steering shaft/steering box at say the 7 o'clock position if you were looking at the water pump housing from the rear of the vehicle.
 

max57

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it i s the same pump just comes with the housing. It is the one that came apart the first time out last fall.
(Yes the LBZ water pump (ACDelco 252-898) is currently in stock. The LBZ water pump with housing (251-748) is also in stock.)
 

max57

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That was great Video. I listened to Gale close as he is doing a L5P Duramax, which the thermostast housing itself was the restriction. He said the Earlier model Duramaxs Housings flowed a lot better. I can not seen to find anything on Earlier models though. But L5p model was tested in and out of oil cooler that flowed 100 gals minute @2400 rpm that was really ramping up fast till his flow meter stopped . He seen 50psi@2500rpm , 60psi@3000, 70psi@3500 . with only 2lbs pressure drop going through cooler , Also said that Edelbrock make a higher flowing head like early model duramax for l5p. So im guessing these LBZ's flows pretty good coolant.
Cummins relief is at 30psi, looks like L5p is safe to least 70psi . How much different is the water pump from L5p to lbz? How much PSI can a LBZ pump take ( i guess 70-80psi is safe) How much does it need keep flash heat away from heads ? Guess we are going to find out.
 

max57

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Dec 12, 2014
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Josh, I just noticed you mentioned the Heater core, my heater core turns off at the inlet hose.(Vintage air). I was just thinking I removed the EGR cooler and was wondering if trucks heat is always on! All restrictions. Thanks
 

max57

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Dec 12, 2014
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Upstate, NY
Did a little test while waiting for new water pump. Put a gauge in the outlet Heater hose next to thermostats. Thermostats Closed. Electric Pump on. 0 psi . if I pinch off heater outlet 2psi. Lesson learned electric Stewarts EMP E389A flows 55 gpm is not enough flow for duramax and pump has very low head pressure. Will try the new Mecanical pump to compare pressure soon.
Thanks for the help guys, I think we are getting somewhere !
 

JoshH

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it i s the same pump just comes with the housing. It is the one that came apart the first time out last fall.
(Yes the LBZ water pump (ACDelco 252-898) is currently in stock. The LBZ water pump with housing (251-748) is also in stock.)

They do offer the water pump you say you bought with the housing, but the part number I listed is the OEM version with the plastic impeller and the housing also. It is not just a cast impeller pump with a housing. It is also made in Japan instead of China like the cast impeller pump. It is a much higher quality pump.