Thread Tools Search this Thread Display Modes
Old 05-11-2008, 07:46 AM   #29
Rivet Master
TomW's Avatar
1967 26' Overlander
Huntsville , Alabama
Join Date: Dec 2003
Posts: 2,930
Images: 2
Guess what I did yesterday?

Last week I got O'Reilly's Auto Parts to order me a new, heavy duty water pump:

Originally Posted by O'Reilly's web site
Limited lifetime warranty

It came in on Friday, and the Store Manager laid it out on the counter beside a regular duty water pump for my inspection. Without taking the backing plate off (did you catch that, Terry ), I couldn't see any difference between the two pumps. I was hoping the super-duper pump would at least have a glitzy paint job.

The manager, who appeared to have turned a few wrenches in his life, could not shed any additional light on the subject and admitted this was the first one of these pumps he had seen. Hoping that the pump might help, I went ahead and bought it.

Here is a picture of the old water pump with the backing plate removed:

There does not appear to be anything wrong with it. The impeller neither loose on the shaft nor rotted away. Several threads from another forum drove me to look at the impellor clearance, which was measured to be [about] 0.070":

Pulling the backing plate off of the super-duper water pump, there was one immediate, noticable difference - a round plate riveted to the impeller:

With my limited knowledge of hydrodynamics, I can see that plate making a difference in the pump's efficiency. Since the plate is there at all AND it is riveted on, I must assume this was the manufacturer's concession for "increased cooling capacity". My reasoning here is that nowadays, manufacturers don't add parts that are not essential to operation or to back up a claim.

Everything on the HD pump I could measure was the same size on the regular pump.

I also flushed the system and went back to green coolant.

Although the Overlander's next trip is still a week-and-a-half away, I will drive the Suburban to work this week to get all the bubbles out of the cooling system and gauge the truck's "unloaded" performance.

Thanks for everyone's help,

TomW is offline   Reply With Quote
Old 05-15-2008, 06:57 PM   #30
1 Rivet Member
1984 27' Airstream 270
Wayne , Ohio
Join Date: Jul 2007
Posts: 8
Check for either plugged tubes inside the radiator, or the cooling fins coming loose from the tubes. The other thing it could be is dirt plugging the fins.

tomjunw is offline   Reply With Quote
Old 05-15-2008, 07:11 PM   #31
Well Preserved

1993 21' Sovereign
Colfax , North Carolina
Join Date: Jun 2003
Posts: 20,362
Tom, the plate on the back of the impeller is to reduce cavitation, and increase coolant flow.
For those who don't know, but do care, cavitation is caused by extremely low pressure allowing water to boil at very low temperatures, hence the bubbles (boiling water). That is one of the reasons submarines travel in very deep water, the higher pressure from the water decreases the tendency to cavitate behind the propeller (boiling water is noisy). The boiling cold water can cause damage to metal parts as well as noise, and cause a loss in efficiency of the device moving the water.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
overlander63 is offline   Reply With Quote
Old 05-22-2008, 04:33 PM   #32
Rivet Master
TomW's Avatar
1967 26' Overlander
Huntsville , Alabama
Join Date: Dec 2003
Posts: 2,930
Images: 2
The time has arrived

Although the Overlander's next trip is still a week-and-a-half away
It's onward ho to Jackson MS with all the replacements/improvements. We're staying at a new Camp Jellystone near the area while attending my Uncle Bill's 70th birthday party (read: family reunion).

Wish us luck,


TomW is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
New water pump-? fresh water tank adonh Water Heaters, Filters & Pumps 24 06-19-2008 07:00 PM
air pump vs water pump kamo Water Heaters, Filters & Pumps 22 02-27-2008 02:01 PM
68 water pump-should the pump cycle? Boondocker Water Heaters, Filters & Pumps 8 08-06-2006 10:11 AM
Bad Bad Things... (a new 454 Engine?) pillageTHENburn Mechanics Corner - Engines, Transmission & More... 24 12-19-2005 12:49 PM
Bad Smog Pump? torin knorr General Motorhome Topics 2 07-03-2003 09:25 AM

Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:19 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.