<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div dir="ltr">I had the same issue on my 67 1600. Problem was not anything to do with radiator or cap. (I run stock cap). Problem was head gasket. Exhaust gas getting into the coolant and over pressurizing the system, pumping the coolant out of the overflow tank and eventually overheating. I had my head cleaned up, used a hi quality gasket and sprayed everything with copper coat before reassembly. Problem solved and car has never overheated or run hot since.</div><div dir="ltr">Good Luck.</div><div dir="ltr">Roy H.<br></div><div><span></span></div><br> <div id="yui_3_16_0_1_1428334357143_25163" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1428334357143_25162" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_1_1428334357143_25161" dir="ltr"> <hr size="1"> <font id="yui_3_16_0_1_1428334357143_25160" face="Arial" size="2"> <b><span style="font-weight:bold;">From:</span></b> Graeme S. via Datsun-roadsters <datsun-roadsters@autox.team.net><br> <b><span style="font-weight: bold;">To:</span></b> datsun-roadsters@autox.team.net <br> <b><span style="font-weight: bold;">Sent:</span></b> Friday, April 3, 2015 5:03 PM<br> <b id="yui_3_16_0_1_1428334357143_25159"><span id="yui_3_16_0_1_1428334357143_25158" style="font-weight: bold;">Subject:</span></b> Re: [Roadsters] 1500 Radiator Cap.<br> </font> </div> <div id="yui_3_16_0_1_1428334357143_25165" class="y_msg_container"><br><div id="yiv2028746839"><div id="yui_3_16_0_1_1428334357143_25164">
Been through this recently.<br clear="none">
My cooling system and engine are all fully reconditioned and I have
no overheating problem, BUT, it was belching coolant just the same.<br clear="none">
Now, bear in mind the early cars were designed for a low pressure
7psi[50kpa], non-recovery type system.<br clear="none">
The cap is not easily converted to a high pressure13psi[90kpa], you
have to swap the neck of the radiator to get the new cap to work
properly.<br clear="none">
Low pressure cap uses a long neck, high pressure cap uses a short
neck.<br clear="none">
All the research I did showed that there is no long neck high
pressure cap :(<br clear="none">
My Radiator Shop advised to retain the low pressure system because
that was what it is designed for: what the weak link is I know not!<br clear="none">
Anyhoo, I decided to fit a blanking cap to the radiator and plumbed
in a pressurised aluminium recovery tank from the radiator overflow
connection, using a low pressure long neck recovery cap [7psi], on
the tank.<br clear="none">
Works a treat and if you didn't look between the front cross member
and the radiator core, you would never know :)<br clear="none">
The system can burp all it wants but it is able to syphon it back in
to the radiator.<br clear="none">
I posted some pics. on the 311s.org site, have a look here: -<br clear="none">
<a rel="nofollow" shape="rect" class="yiv2028746839moz-txt-link-freetext" target="_blank" href="http://www.311s.org/phpBB3/viewtopic.php?f=3&t=23012&hilit=recovery+tank">http://www.311s.org/phpBB3/viewtopic.php?f=3&t=23012&hilit=recovery+tank</a><br clear="none">
The final version is at the end of the posts.<br clear="none">
<br clear="none">
<pre class="yiv2028746839moz-signature">Regards,
Graeme S.
nissanman.shutterfly.com</pre>
<div class="qtdSeparateBR"><br><br></div><div class="yiv2028746839yqt0969977704" id="yiv2028746839yqt66309"><div class="yiv2028746839moz-cite-prefix">On 4/04/2015 09:07, Charles Hubbard via
Datsun-roadsters wrote:<br clear="none">
</div>
<blockquote type="cite">
<div style="FONT-FAMILY:Arial;COLOR:rgb(0, 0, 0);FONT-SIZE:12px;">
<div> My 1964 SPL310 (1500) has run hot since day one. It has a
fairly pristine 3-row radiator core. I live in the Dallas
Texas, area, and it gets pretty hot around here. The stock
idiot gauge steadily pegs on the highway at about 65 mph. I
put an after market gauge in which showed the temperature
close to 290 deg. Slowing down to 55 MPH brings the
temperature down but it still runs at 275deg. After running
around town and turning the motor off, it often blows most of
the coolant from the upper tank through the overflow tube. It
often vapor locks after it gets turned off. I took my
radiator to the local old school radiator guru today. He did a
flow test and it was fine. However, he noticed that my cap
was pretty week. He thinks my stock cap may only be a 3-4lb
cap and suggested that I purchase a 12 lb cap. . He's
thinking that that my roadster may be continuously be losing
coolant when it gets pressurised and allows air into the
system, which makes the car run even hotter. A tighter cap
would hold coolant better and help the cooling. The
temperature would stay lower, even under more pressure. The
stock radiator caps are not exactly growing on trees, so
getting a 12 lb cap to give it a try may not be obtainable.
The radiator shop says they can put a new cap assembly o the
unit, but I hate doing that before I even know if it will
solve my issue. Does anyone know a source for a 12lb cap that
will fit a 1500 radiator? Feedback from those in the know
would be appreciated.</div>
<div><br clear="none">
</div>
<div>.<span style="font-family:Arial;font-size:12px;">Charlie
Hubbard</span></div>
<span>
</span><div style="FONT-FAMILY:Arial;COLOR:rgb(0, 0, 0);FONT-SIZE:12px;">Flower Mound, TX<br clear="none">
<a rel="nofollow" shape="rect" class="yiv2028746839moz-txt-link-abbreviated" ymailto="mailto:cehubbard@verizon.net" target="_blank" href="mailto:cehubbard@verizon.net">cehubbard@verizon.net</a></div>
</div>
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