Ok, so both of my PMP400 pumps are failing. So I'm looking to replace the. But I have a quick question. What is more important? Head pressure or discharge volume? I have currently 3 radiators, and 4 water blocks. But I'm going up to 5 water blocks in the near future. So di I look more to the discharge volume? Or would I want the higher head pressure due to the increased length of the loop? Thanks for the time.

or new with
 $76.99  PMP-500 Pump, G 1/4 BSP   SKU: PMP-500 With CTR-CD1224: $169.99 $134.95 ON SALE ONLY
This week.
 
 $49.99 Pump Fitting & Reservoir Base for PMP-450/S, Rev.2.1   SKU: COV-RP450
 $9.99 Reservoir Top with Fill Port (60mm OD)
$11.99 Reservoir Body, 60x80mm (WxL), 157ml   SKU: BDY-TK080
 

 

Sorry bc, this is what I currently have:
Aplhacool Repack Quad DDC Bay reservoir http://www.performance-pcs.com/hot-alphacool-repack-quad-laing-ddc-dual-5-25-bay-station.html
 
And 2 Koolance PMP 400's http://www.performance-pcs.com/koolance-pmp-400-high-flow-pump.html
 
These are the replacement pumps I was looking at.
 
Max head pressure MCP50X http://www.performance-pcs.com/swiftech-mcp50x-exteme-12-vdc-ddc-pump.html
 
Max Discharge volume MCP35X http://www.performance-pcs.com/swiftech-mcp35x-bk-12-vdc-pump.html
 
I'd like to stay with the DDC family for cost reasons. That way I don't have to buy a new reservoir and all of that. I can simply upgrade and be on my way.

The two pumps I listed will fit the reservoir and would be an increase in performance. And price wise they're not really much more expensive.
 
And I like the reservoir other than the factory face plate was poorly made. Hopefully they have fixed that since. I had Gone Crusing make a new one for me when I got the reservoir. 
 
Speaking of Gone Crusing, I wonder what happened to him. I haven't seen or heard anything from him in a year or two. Which kind of sucks, because he did fantastic work making acrylic cases.  

vsg28
Actually no, the MCP50X isn't a DDC and will only directly fit the Swiftech reservoir. Of course you can use a male-male adapter to hook it up to any reservoir if that's ok.

You are correct. I misread the review I had seen, and then found a thread on Swiftech's forums that clearly stated it was different enough that the DDC tops will not work. Thank you for making me look again vsg. So that pretty much takes care of that.

Well on a positive note I'm pretty sure sure I found most of my problem with my pumps. When I looked at the pump connectors I could see a some browning on the connector from heat. Here's a pic, but it doesn't show the discoloration of the connector as well as in person:
 

 
But on closer inspection the pin retention barbs inside the connector are bent (most likely from someone pulling on the wires to disconnect the connectors in the past) so when the pumps are plugged in the female pins are pushed back into the connector causing an intermittent connection. The intermittent connection probably cause a high resistance problem as the pins moved and lost and regained connection and I'm pretty sure that's where the discoloration came from. One of the pumps is still a little goofy so I'm going to swap to a molex connector that has a stronger more robust pin so this doesn't happen again. Here is the pic of the bent retainer barbs:
 

 
Sorry for the bad pic's all I have is my phone, and it didn't like getting that close to take pics.

bcavnaugh
That is good to know, thanks.
I will check mine that have that type connector to see I if may have the same issue.

Definitely worth a look. Saved me from spending $150+ to replace my pumps.

One is good. The other still fades on and off. So I'm going to replace the connector and see if the problem goes away. It is possible that the pump is damaged or worn inside. But it's easier to replace the end and see if it's ok before tearing down my loop and messing with the pump.