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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #1 ·
Good evening cummins forum. I apologize in advance if this has been covered. I’ve searched the forum and didn’t see this covered much in the 2nd gen section. I’m about to replace the water pump on my truck due to leaking. Seams like it sprung a leak over night. How do I properly purge the air completely out of the cooling system to avoid cavitation and over heating? I read about a plug somewhere on the head, you remove the plug, fill radiator and coolant reservoir till coolant comes out of plug hole? I’m not sure how to purge/burp the air from the system. Any help would be greatly appreciated.
 

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You have it correct. The pipe plug is near the thermostat housing, make sure it is loose enough for air to escape. When coolant shows, tighten and fill the radiator full and bottle. After a couple of hot overnight shutdowns, the radiator will top itself off out of the bottle.
 

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Also if you raise the front of the truck up some it will help.
 

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Drill a 1/16" hole in the t-stat, install an motor on. Self bleeding and does not effect warm up times enough to worry about.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #5 ·
You have it correct. The pipe plug is near the thermostat housing, make sure it is loose enough for air to escape. When coolant shows, tighten and fill the radiator full and bottle. After a couple of hot overnight shutdowns, the radiator will top itself off out of the bottle.
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I’d imagine this is the plug? Is this NPT? So I’d remove plug, fill radiator and reservoir till coolant comes out the hole, replace plug, continue filling till radiator and reservoir is topped off? In theory from there I’d have no air/cavitation in the cooling system?
Thank you
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #6 ·
Drill a 1/16" hole in the t-stat, install an motor on. Self bleeding and does not effect warm up times enough to worry about.
Rather than drilling a hole in the T-stat couldn’t I remove the coolant temp sensor and fill till coolant comes from that hole?
Sorry if this is t the brights question.
thank you.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #7 ·
Also if you raise the front of the truck up some it will help.
I’ll be doing this in a drive way with I slight incline. Not sure if the jack and stands I have access to will safely bare the weight of the truck. I’m trying to avoid getting the truck towed to where all my tools are. Long-ish drive to go pick up my tools and come back to work on the truck.
 

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Rather than drilling a hole in the T-stat couldn’t I remove the coolant temp sensor and fill till coolant comes from that hole?
Sorry if this is t the brights question.
thank you.
Sure, but then you have broken the seal there and are at risk for a leak.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #9 ·

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #10 ·
That makes sense. Thank you
Sure, but then you have broken the seal there and are at risk for a leak.
Sure, but then you have broken the seal there and are at risk for a leak.
Just pulled the belt off the water pump. Doesn’t appear to have any play. Looks like the pump is leaking at the bottom. Coolant is building up bellow it on the casting of the block. To my understanding there is a weep hole at the bottom of pump? Can’t find an inspection mirror. About to buy one right now to check.
 

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Yes there is a weep hole underneath. That's where mine leaked. The inner seal leaks and then thru the bearings and out the hole. Yours may have just started so bearings have no play yet. The pump seals with an oring to the block. Make sure that's all clean.
In your pic you have the tstat housing off so that could be your way to bleed air out

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #12 ·
Yes there is a weep hole underneath. That's where mine leaked. The inner seal leaks and then thru the bearings and out the hole. Yours may have just started so bearings have no play yet. The pump seals with an oring to the block. Make sure that's all clean.
In your pic you have the tstat housing off so that could be your way to bleed air out

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That was a picture I found online. It was too dark this morning to take a picture of my particular truck. I currently have my t-stat installed.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #13 ·
What do guys think about gates water pumps?
any good bad or ugly about them? Local Napa has GMB pumps in stock. Never heard of the brand. According to Genos garage gates pumps are very similar to the Cummins OEM pumps. Any thoughts?
thank you all
 

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What do guys think about gates water pumps?
any good bad or ugly about them? Local Napa has GMB pumps in stock. Never heard of the brand. According to Genos garage gates pumps are very similar to the Cummins OEM pumps. Any thoughts?
thank you all
My last one on my 3rd gen engine lasted approx 2 yrs. Oringinal had 10 yrs on it and was still working ok, swapped it as a preventive measure. Current one is oem cummins and installed since 2016, guessing 300k on it at the time. 485k on it now.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #15 ·
My last one on my 3rd gen engine lasted approx 2 yrs. Oringinal had 10 yrs on it and was still working ok, swapped it as a preventive measure. Current one is oem cummins and installed since 2016, guessing 300k on it at the time. 485k on it now.
Would you recommend the gates? I’m usually uptight about running only genuine Cummins/Mopar parts on the truck. For the price difference I figured I’d ask.
thank you?
 

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I've never had to do anything special to burp the cooling system after replacement. Having the truck slightly front high is good but other than that just have the heater on full blast and once the coolant stops lowering top it off and put on the cap.
 
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2000 Ram 2500 24v SLT Laramie 4x4, 47re automatic
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I just put a new Gates water pump on two weeks ago.
If a product is good enough for sale on Genos, I trust it to be fine.
The pump that failed was also a Gates that I put on 10 plus years ago.

I noticed a tiny bit of coolant on ground a number of weeks ago, didn’t even look why, ignored it for the time being (idiot).
The pump failed rather catastrophic.

Did a 550 mile drive in the truck, parked it, next morning jumped in and took off and made it 15 miles.
Check gauges light came on, zero amps on gauge, pulled over popped hood.
Rad fluid everywhere, pump bearing so toast the belt slipped to the side and cut it.
Cut edge of belt whipping around, wrapped around fan, slashed a big gash into the hood liner.
Rad fluid soaked the alternator, grounded it out?, zero amps on gauge.
Cut belt piece off, unwrapped it from fan and got the truck back home quick as I could just as it was starting to overheat.

Replaced bits with a Gates pump 43526 & Gates belt and tensioner kit 90K38157A w/ air conditioning from Rock Auto.
Only did RockAuto instead of Genos due to quicker shipping to Canada.
Figured alternator would be toast too, but I blew it out with air and seems OK for now.

Did nothing about air purging, just rolled around in the snow and bolted the bits on, filled Rad and reservoir to cold level & ran it till hot.
Sat overnight, topped it off to cold level and all has been fine since.
 

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It is not that hard. You can also warm it up with the cap off and slowly fill until completely full, a little rpm speed up will help, put cap on when full and fill reservoir 1/2-3/4.
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #19 ·
I just put a new Gates water pump on two weeks ago.
If a product is good enough for sale on Genos, I trust it to be fine.
The pump that failed was also a Gates that I put on 10 plus years ago.

I noticed a tiny bit of coolant on ground a number of weeks ago, didn’t even look why, ignored it for the time being (idiot).
The pump failed rather catastrophic.

Did a 550 mile drive in the truck, parked it, next morning jumped in and took off and made it 15 miles.
Check gauges light came on, zero amps on gauge, pulled over popped hood.
Rad fluid everywhere, pump bearing so toast the belt slipped to the side and cut it.
Cut edge of belt whipping around, wrapped around fan, slashed a big gash into the hood liner.
Rad fluid soaked the alternator, grounded it out?, zero amps on gauge.
Cut belt piece off, unwrapped it from fan and got the truck back home quick as I could just as it was starting to overheat.

Replaced bits with a Gates pump 43526 & Gates belt and tensioner kit 90K38157A w/ air conditioning from Rock Auto.
Only did RockAuto instead of Genos due to quicker shipping to Canada.
Figured alternator would be toast too, but I blew it out with air and seems OK for now.

Did nothing about air purging, just rolled around in the snow and bolted the bits on, filled Rad and reservoir to cold level & ran it till hot.
Sat overnight, topped it off to cold level and all has been fine since.
I’ll be ordering the gates pump today from rock auto as well due to the shipping. It’s also cheaper than what genos sells it for! It’s hard pill to swallow buying the Cummins pump that is 6 times the price of the gates. I checked several local shops yesterday and none of them carry a gates pump.

Thank you
 

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2002 2nd gen Cummins 4x4 2500, 4” MBRP exhaust, 5spd swap, FASS 150, edge juice , S&B intake
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Discussion Starter · #20 ·
It is not that hard. You can also warm it up with the cap off and slowly fill until completely full, a little rpm speed up will help, put cap on when full and fill reservoir 1/2-3/4.
I’ll give this method a try. I’ve been more concerned lately about getting things done correctly the first time. My truck is currently my only form of transportation. I take my 4 year old boy to school and pick him up daily. I’d really hate to be stranded on the side of the road with him due to overheating.
Thank you
 
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