Is this the right water pump for an L31 Vortec with Vintage AC?
 

I had purchased a water pump and installed on my 66 C10 but it looks like I bought the wrong one. It only had 1 heater hose port and before I bought this one I was hoping someone might know.

The search was for a 1997 C1500

https://shop.advanceautoparts.com/p/...711/11936594-P

If that link is the correct one this time, do the metal stems need to stay put, or can/should I replace them with barbs to get the bypass hose to the intake connected properly?

Ill attach a pic of what I have now and the vintage air instructions

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

No.
The second vintage air picture (enlarged) shows a hose returning to the water pump.
The water pump in your link has press-in hose nipples that are incorrect for your install. I mean you can make it work, it would look like hail but...

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

I searched for a 1997 C1500 with a 5.7L, what should I be searching?

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Your not using serpentine belt system are you?
And did you ask Vintage Air if the system you purchased was for a "long" water pump?
They could also help with a water pump.
I see you have Vortec Heads that's why I asked about the serpentine belts.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

My 94 has the same pump. One hole in the top like yours.
My return line from the heater goes into a fitting(nipple) on the rad. Right below the cap.

What are you gonna use for a rad?

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Ahhh, that "may" be what the blown up pic shows. If he has a 64-66...

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

The radiator is the same one I had before just been rodded and reconditioned. That port though under the cap on mine was for the overflow. There was a small hose that ran down the side of the radiator. Is that an option to run the return? The diagram did show a line going in that direction but I assumed it was the water pump it was targeting.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

I thought the hose was pointing to the pump as well. I didnt realize that pump was press on...so glad I didnt order it :D


Ive got v style pulleys. I put a question to vintage airs tech line, still waiting on a water pump reply.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

You can’t use the overflow line. Too small. And you’ll need it for it’s intended purpose.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Just got off the phone with vintage air and they weren't sure which water pump to suggest or other option but they will call me back he said. He also said no can do on the overflow tube connection.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Do you know that some people don’t use a bypass on the intake like you have set up.
They rely on the normal heater hose routing to serve as a bypass.
Intake to bottom of heater core, top of core back to water pump is normal.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

A suggestion from Vintage Air was to use a water neck riser like this

https://www.summitracing.com/parts/v...BoC4XMQAvD_BwE


The bypass was something he questioned also. He said mostly big blocks need it but not small blocks.

There is a member named sweetk30 on the site that had mentioned needing the bypass to solve some issues he was having...here are the comments

"dont forget L31 vortec has no bypass hole port in the block so you need to do a bypass hose like a bbc uses . or you can get bubbling / girggling / coolant smell as it pushes up in to the over flow tank .

and the port might be in the block to the water jacket area but the head surface to head hole is not there . this is why you need a bypass hose . the true vortec L31 installs from gm the water pump has a hose and the intake has the spot for it "

And here is a link to the thread where it came up. My first attempt at getting the water pump and intake sorted out.

I sure hope this gets cleared up soon so I can get this stuff installed.

https://67-72chevytrucks.com/vboard/...d.php?t=811209

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Water neck riser does no good. You already have a spot for your heater hose.
You need a spot to hook up a return line to.
Either on the water pump or on the rad. Your down flow rad doesn’t help with that. Return should be on outlet of rad which is the bottom tank on yours. I’m not sure if you’d get adequate flow down to the bottom.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Just go to your local auto parts store and get a long pump for a SBC. I believe they started using long pumps in the early 70's on all chevy small blocks. My 70 has a short pump but has the heater return fitting and also I used the top fitting for the coolant bypass. Yes all vortec heads need some sort of bypass.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

I spoke with Edelbrock and what the tech said was that if the block has the bypass port/hole on the passenger side directly under the mount hole for the pump (which mine does), and if the pump has a hole on the same spot then that is all the bypass thats needed on a small block thats running old school v style pulleys. I need to just double check if that hole in the water pump mount continues through the pump to allow for the flow.

This is the pump I put on and remember the hole but didnt check if it went completely through and didnt dead end somewhere.

https://shop.advanceautoparts.com/p/...m=water%20pump

So if it all checks out then he said just run the heater return line to the top of the pump and cap the port on the manifold.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

The issue is that even if your block has the bypass hole and the water pump does too, the Vortec heads do not have the corresponding hole drilled in them. All GM trucks with a small block or big block, 1972 and earlier originally came with short water pumps. There are atleast 3 variations of the long water pump used 1973-1987. Then in 1988 or so when the serpentine accessory drive was introduced, then you had a reverse rotation long water pump. Then the '96-'02 L30/L31 Vortec engines had yet another variation of the long water pump.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Here’s the kicker!
Your pump may have the hole.
The hole and passage may be there in the block.
But there likely isn’t any hole and passage in the head.
If there is no hole you can pull the head off and drill it out.
To see if the passage is open from the pump to the coolant passage in the head (use a wire snaked thru) you might need to remove the intake.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Wow this is tough. I know I wont be drilling holes in my new engine so whats the best thing to do here guys?

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Find a pump with two bungs on it.
Another kicker might be pulley set up with vintage air.
Does it need a short or long pump?
Which is on it now?

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

If all you can find is a short pump with two openings like this one

https://www.speedwaymotors.com/Short...um,106965.html

You can use some spacers like this


https://www.speedwaymotors.com/Weian...sh,145573.html

Instant long pump.

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

The pump I bought I thought was the long style pump. It measures nearly 7 inches tall from mounting surface to the top of the pulley mount.

https://shop.advanceautoparts.com/p/...m=water%20pump

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

looks identical to the one I had before which I needed for the power steering conversion years back

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Would the water pump rotation matter for the engine I bought?

https://www.summitracing.com/parts/NAL-12681432

If not then should I just start searching Rockauto for c10 to c1500 trucks from 1973 to 2002 and see if I can find a long style pump with 2 ports in it, not unlike the one I started this thread question with? I wasnt sure if the long style press on fitting stems in that one could be removed and hopefully get some NPT barb fittings to replace it. Maybe Rocknrod was saying that the fittings are pressed into the pup and have no threading?

https://shop.advanceautoparts.com/p/...711/11936594-P

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Another thought from both Edelbrock and Vintage Air was to drill holes in the thermostat to solve the air pocket/overheating issue rather than going through all this. Bad idea?

Re: Is this the right water pump for an L31 Vortec with Vintage AC?
 

Easier to just remove the bypass you have, plug the intake hole and use that spot on the pump for your heater hose return.
Run It like that.
If you read a bunch of threads on other forums you’ll see half the people out there run it just like that and have no problems.

Some thermostats come already drilled.
You don’t need to do that.