Water Pump Dowel?
Thread Starter
Pro
Joined: Dec 2004
Posts: 534
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From: Connecticut
Water Pump Dowel?
I just bought a new AC Declo water pump and in the box was little 3/4" metal dowel. What is it used for? Do I need to use?
Last edited by Grayson; Jan 14, 2007 at 05:34 PM.
Intermediate
Joined: May 2004
Posts: 38
Likes: 0
From: Castro Valley CA
Metal Dowel?
Was it solid? With threads or without?
If it was solid without threads, I have no idea.
A heater hose nipple connects to the passenger side, that's a 3/4" fitting, but hollow with threads on one end and a ridge for the hose to slip over on the other.
There is also a solid plug that goes on top of the pump. The one on the pump I took off a couple weeks ago had 1" outside diameter threads, the one I needed for the new Stewart stage 2 I got was a 3/4" plug.
If it was solid without threads, I have no idea.
A heater hose nipple connects to the passenger side, that's a 3/4" fitting, but hollow with threads on one end and a ridge for the hose to slip over on the other.
There is also a solid plug that goes on top of the pump. The one on the pump I took off a couple weeks ago had 1" outside diameter threads, the one I needed for the new Stewart stage 2 I got was a 3/4" plug.
Intermediate
Joined: May 2004
Posts: 38
Likes: 0
From: Castro Valley CA
wow
ok I have no idea.
I thought it was 3/4" dia.
The Stewart I bought came with a (let's say) 3/16 threaded stud (so its adjustable) about 2 inches long to go through a hole to line up with the cam if you have a need to restrain the cam.
Is there a pocket on the block side of the pump that this would fit into?
To maybe apply pressure to the timing chain cover at the cam? Thats a long shot, but all I can come up with. My stock WP didn't have anything like that when I took it off.
I thought it was 3/4" dia.
The Stewart I bought came with a (let's say) 3/16 threaded stud (so its adjustable) about 2 inches long to go through a hole to line up with the cam if you have a need to restrain the cam.
Is there a pocket on the block side of the pump that this would fit into?
To maybe apply pressure to the timing chain cover at the cam? Thats a long shot, but all I can come up with. My stock WP didn't have anything like that when I took it off.
Thread Starter
Pro
Joined: Dec 2004
Posts: 534
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From: Connecticut
There is a spot right below the right side lower water pump mounting hole. Maybe it is used for alignment to assist with installation?
You can see it here next to the pipe plug.
http://www.ecklers.com/product.asp?p...dept%5Fid=1259
You can see it here next to the pipe plug.
http://www.ecklers.com/product.asp?p...dept%5Fid=1259
Drifting
Joined: Nov 2002
Posts: 1,676
Likes: 197
From: Loveland, CO
I posted a similar thread a few months ago and never got a answer. My pump was from Napa. Nobody seemed to know what it was for, so I just left it in the box. It must have some purpose to be included, but it seem strange that no instructions or person knows what it is for. What a deal.
Ralph.
Ralph.
Intermediate
Joined: May 2004
Posts: 38
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From: Castro Valley CA
Alright, it just occurred to me...
MAYBE it is to align the holes in the gaskets with the holes in the block so that when the sealer you use dries enough to stick to the block, the gasket isn't in the way of the mounting bolts.
I know I ran into a problem with trying to get both sides lined up (without a gasket sliding around on one side or the other and blocking the mounting bolt) with the sealer still wet on the block and the pump.
(The picture of it next to the gasket in the link you posted gave me that idea.)
...and with that, I'm out of ideas.
MAYBE it is to align the holes in the gaskets with the holes in the block so that when the sealer you use dries enough to stick to the block, the gasket isn't in the way of the mounting bolts.
I know I ran into a problem with trying to get both sides lined up (without a gasket sliding around on one side or the other and blocking the mounting bolt) with the sealer still wet on the block and the pump.
(The picture of it next to the gasket in the link you posted gave me that idea.)
...and with that, I'm out of ideas.
Last edited by Jims73SF; Jan 14, 2007 at 08:28 PM.
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Drifting
Joined: Nov 2002
Posts: 1,676
Likes: 197
From: Loveland, CO
Jim, I think you are on a stretch.
When has a manufacturer thought of your ease in mounting a gasket enough to include a dowel to index the mounting?
Somebody out there must know what this dowel if for?
But, Jim, your explaination is as good as anything suggested.
Since it fits in the hole next to the bolt mounting hole, I thought maybe it was a plug to prevent coolant from bypassing the thermostat, but it is not in the right place. I give up.
Ralph.
When has a manufacturer thought of your ease in mounting a gasket enough to include a dowel to index the mounting?
Somebody out there must know what this dowel if for?
But, Jim, your explaination is as good as anything suggested.
Since it fits in the hole next to the bolt mounting hole, I thought maybe it was a plug to prevent coolant from bypassing the thermostat, but it is not in the right place. I give up.
Ralph.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I'm surprised no one has answered this before.
The dowel supplied is to block off the water pump bypass which is on all stock water pumps.
This bypass circulates coolant until the tstat opens, so as not to create engine hotspots and pump cavitation. Some people tap this hole in the block and screw in a brass allen socket pipe plug instead of the dowel.
Some aftemarket high performance pumps do not have bypass flow built into them. This is based on the theory that more flow will occur without the bypass for better high performance cooling.
If you use the dowel, then you must drill a few 3/16" holes in the tstat so that there will be a small amount of flow.
These holes serve 2 purposes, 1 for burping the air out while filling the system and 2-for creating necessary flow until the tstat opens. It also can be argued that the tstat will be more responsive at intitial warmup with the holes.
BTW Jims73SF
Good choice on pump!
The dowel supplied is to block off the water pump bypass which is on all stock water pumps.
This bypass circulates coolant until the tstat opens, so as not to create engine hotspots and pump cavitation. Some people tap this hole in the block and screw in a brass allen socket pipe plug instead of the dowel.
Some aftemarket high performance pumps do not have bypass flow built into them. This is based on the theory that more flow will occur without the bypass for better high performance cooling.
If you use the dowel, then you must drill a few 3/16" holes in the tstat so that there will be a small amount of flow.
These holes serve 2 purposes, 1 for burping the air out while filling the system and 2-for creating necessary flow until the tstat opens. It also can be argued that the tstat will be more responsive at intitial warmup with the holes.
BTW Jims73SF
Good choice on pump!
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
Might be for pulley alignment, here is a Mitsibish pump for sale on e-bay, you can see the hole in the face where the dowel would go
http://cgi.ebay.com/ebaymotors/JDM-4...QQcmdZViewItem
This Water Pump Includes Dowl Pin for Pulley Instalation
Drifting
Joined: Nov 2002
Posts: 1,676
Likes: 197
From: Loveland, CO
Noonie, thanks for the explaination. I am also surprised this subject is so uninformed. You'd think there would be some explaination included in the pump packaging. I consider myself fairly knowledgeable, but certainly ignorant on this subject.
I guess I am still a little dense, but why would someone plug this hole with the dowel. Is it just like you explain that some think cooling flow is better without the hole? It seems dangerous that the dowel is included and no explaination that holes need to be drilled in the thermostat to compensate for the lost flow if dowel is used.
Thanks again, Ralph.
I guess I am still a little dense, but why would someone plug this hole with the dowel. Is it just like you explain that some think cooling flow is better without the hole? It seems dangerous that the dowel is included and no explaination that holes need to be drilled in the thermostat to compensate for the lost flow if dowel is used.
Thanks again, Ralph.
Racer
Joined: Aug 2013
Posts: 480
Likes: 95
From: Georgetown Kentucky
Just thought I'd post a link to what that is essentially what "noonie" above said.
https://www.flowkoolerwaterpumps.com...duct_info.html
Was wonder myself what this metal dowel was for as I'm installing a new water pump and found this post.
https://www.flowkoolerwaterpumps.com...duct_info.html
Was wonder myself what this metal dowel was for as I'm installing a new water pump and found this post.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Permatex makes a RTV specific for: Waterpump & Waterneck gaskets. Small tube, not much for the money, found at AutoZone. Works really, really well for glycol situations.
Last edited by HeadsU.P.; Jan 20, 2018 at 07:27 PM.
