Editing Forums/Z31P/z31-repairs-forums engine-mechanical/Another coolant leak…

{{ForumImport
|op_user=waynedwops42
|op_date=2019-08-21 19:04:09
|post_count=5
|archive_url=/Z31performance_archive/forum/z31-repairs-forums/engine-mechanical/544204-another-coolant-leak.html
}}

'''waynedwops42:''' <small>(2019-08-21 19:04:09)</small>

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.

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'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'm going to find a pressure tester to know for sure but I'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't seen any white smoke or milky coolant yet but anything is possible. I'm hoping it'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?

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'''Wilsonthesphere:''' <small>(2019-08-21 20:44:59)</small>

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.

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'''waynedwops42:''' <small>(2019-08-22 02:24:53)</small>

Thanks for the suggestion, using a compressor I found that the coolant is leaking from a throttle body hose.

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'''waynedwops42:''' <small>(2019-08-23 03:14:45)</small>

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 wouldnât idle, unplugged the O2 sensor and it idles fine. Great....

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'''FrozenZ:''' <small>(2019-08-25 16:31:58)</small>

worth just trying to scrub the connector clean with soap and water and then some contact clear before shelling on a new O2....