I’m trying to fix the water leak problem on the crossover at the top of the water pump. I was able to get a new O ring. It leaks when I’m filling the radiator without even having any pressure. I got a new seal from the local auto parts shop that is for this year and model. I’ve tried putting a washer that fits in the top of the water pump to put pressure.
The car is a 63 Coupe De Ville but it has a 64 429. If the previous owner used the crossover from the original motor, which from I’ve researched was a 390, would the crossover work. I have a machinist looking at it and trying figure it out.
Any info would be much appreciated.

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Comment by Matt H on July 25, 2018 at 1:10am

Thanks Jason 

Comment by Jason Edge on July 24, 2018 at 5:20pm

The cylinder head water outlet pipe (cross over pipe, water intake, or whatever you like to call it, is the same 1963 to 1964 although there are two types - with ac and without. Either way, alignment into water pump cavity is the same. I have had 5 driver cars and installed them a half dozen time and never had one leak.
Two things I have done:
First: As previously noted make sure the male nipple is not corroded. If badly corroded it will leak... period.  I have coated them and built them up with JB Weld on a previous driver car before installing. Seemed to have worked as it did not leak.
Second: Put new O-ring into water pump cavity first. When you mount the cylinder head water outlet pipe to the heads, the male nipple will push down and seat inside the ring. The gut instinct is the slide the O-ring on the nipple first. It will just slide up the nipple when outlet pipe is installed.

I have never used more than one O-ring but do not see where it would hurt as long as they are pushed in to the cavity first. I have also never used Permatex or other sealants.  The job of the O-ring is to sell between the nipple on the outlet pipe and the top water pump cavity and if you have such a gap that they will not fill the void and need to use some type of sealant I would instead build the nipple up.

Comment by Matt H on July 24, 2018 at 5:13pm

Thanks Russ

Comment by Russ Austin on July 24, 2018 at 4:51pm

The step on top does not seat into the water pump.

Comment by Matt H on July 24, 2018 at 3:52pm

Thanks but we aren’t even to that point of it over heating. The water flows past the O ring when I’m just filling it without it being under pressure. 

Comment by Tony and Ginny 429 on July 24, 2018 at 12:53pm
The problem with bad WPs coming out of the box and the engine running hot was a problem that was happening about 8 months a year ago
You sB fine unless the WP is a fairly new installation due to that timing

The pumps impeller was in the wrong location and had to be moved for those WPs to work correctly ?

The info on the subject is in the library on this site (Use search engine )

Comment by Tony and Ginny 429 on July 24, 2018 at 12:43pm
Go to Old Air products --on line only
You should find the 20/80 valve you need there new

When i called and spoke to the OAP they told me they no longer had that valve but i did find it on line on there website
I had purchased one on ebay for 30 dollars more than OAP and returned it due to the large diff in price
My purchase was just two - three months ago

Comment by Matt H on July 23, 2018 at 11:29pm
Forget the first statement. Mid type.
Comment by Matt H on July 23, 2018 at 11:28pm
Thank you. It does have putting. I tried putting kB weld around it. A machinist has it now and will put a new nipple in it. I tried the permetex and did not work. The water pump was replaced before I bought the car but not sure where or what brand. The machinist was wondering if the step on top is to seat in the water pump since it’s .950 and the hole in the wearer pump is 1.000”
Comment by Tony and Ginny 429 on July 23, 2018 at 9:50pm
Did you recently replace the water pump ?
If so what brand did you use and when was it purchased and from who

In the recent past there have been issues with WP running hot out of the box after being installed

I use two washers on the cross over and Permatex on them
It never leaks again when done that way
Do use a sealer in the coolant per the manual --always



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