https://dev.z31library.com/index.php?action=history&feed=atom&title=Forums%2FZ31P%2Fz31-repairs-forums_engine-mechanical%2FAnother_coolant_leak%E2%80%A6 2026-08-15T16:52:29Z Revision history for this page on the wiki MediaWiki 1.43.8 https://dev.z31library.com/index.php?title=Forums/Z31P/z31-repairs-forums_engine-mechanical/Another_coolant_leak%E2%80%A6&diff=6226&oldid=prev 2026-05-15T05:17:59Z

<p>Forum archive import (z31performance)</p> <p><b>New page</b></p><div>{{ForumImport<br /> |op_user=waynedwops42<br /> |op_date=2019-08-21 19:04:09<br /> |post_count=5<br /> |archive_url=/Z31performance_archive/forum/z31-repairs-forums/engine-mechanical/544204-another-coolant-leak.html<br /> }}<br /> <br /> &#039;&#039;&#039;waynedwops42:&#039;&#039;&#039; &lt;small&gt;(2019-08-21 19:04:09)&lt;/small&gt;<br /> <br /> Just finished refreshing my engine recently. New oil pan seal, rear main seal and all gaskets except for the passenger side head gasket. After finding and replacing a leak in the hard line that runs under the lower intake mainfold I thought I was done. At idle there are no leaks and the engine sounds almost quiet.<br /> <br /> After running it through some more tests I decided to maintain about 4000 rpm for about five seconds, and suddenly a huge column of steam shot up from the engine and the driveway got soaked in coolant. I had someone hold the car at about 4000 rpm again while I watched for the leak, and god help me it looks like there is coolant coming out from the valve cover. At idle there is no evidence of a leak, though. I can&#039;t tell for sure because of all the steam but there is coolant pooling on top of the driver side exhaust manifold after these tests. I&#039;m going to find a pressure tester to know for sure but I&#039;m having doubts as to whether or not I can get the cooling system to leak the way it did with a handheld pressure tester. Haven&#039;t seen any white smoke or milky coolant yet but anything is possible. I&#039;m hoping it&#039;s a loose throttle body coolant hose but they all seem tight, and I know there are no coolant lines besides the turbo below the valve cover… Any ideas?<br /> <br /> ----<br /> &#039;&#039;&#039;Wilsonthesphere:&#039;&#039;&#039; &lt;small&gt;(2019-08-21 20:44:59)&lt;/small&gt;<br /> <br /> There is coolant lines in the engine valley which could cause it. I was able to find coolant like by connecting the air compressor to the radiator reservoir tanks overflow tube. Dont shoot with 100psi it would blow up. try giving it 15-20 psi should help you find the leak.<br /> <br /> ----<br /> &#039;&#039;&#039;waynedwops42:&#039;&#039;&#039; &lt;small&gt;(2019-08-22 02:24:53)&lt;/small&gt;<br /> <br /> Thanks for the suggestion, using a compressor I found that the coolant is leaking from a throttle body hose.<br /> <br /> ----<br /> &#039;&#039;&#039;waynedwops42:&#039;&#039;&#039; &lt;small&gt;(2019-08-23 03:14:45)&lt;/small&gt;<br /> <br /> As a follow up, seems like I toasted my O2 sensor from letting coolant soak in the connector overnight. Started the car up and it wouldn’t idle, unplugged the O2 sensor and it idles fine. Great....<br /> <br /> ----<br /> &#039;&#039;&#039;FrozenZ:&#039;&#039;&#039; &lt;small&gt;(2019-08-25 16:31:58)&lt;/small&gt;<br /> <br /> worth just trying to scrub the connector clean with soap and water and then some contact clear before shelling on a new O2....</div>

z31p_Waynedwops42