Another coolant leak…


  • Another coolant leak…

    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?
    '85 2+0 Turbo

  • #2
    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.
    Own:
    1986 Z31 2+0 Turbo GLL ---- spearco IC ,3" exhaust, Poly everything with solid subframe and diff mounts, HX35/40 Holset Turbo, CLSD, Nistune with 1220cc FIC injectors on E85.
    1993 Jeep Cherokee 4X4
    Owned:
    1995 Z32 2+0 NA Black
    1985 Z31 2+0 turbo Black
    1986 Z31 2+0 NA Red
    1988 Z31 2+2 NA Auto
    1988 Z31 2+0 Turbo White ---- Stripped for all of its goodies.
    1984 Z31 2+0 turbo Brown
    1985 Z31 2+0 NA Black
    2003 Nissan frontier D22 supercharded vg33e 4x4

  • #3
    Thanks for the suggestion, using a compressor I found that the coolant is leaking from a throttle body hose.
    '85 2+0 Turbo

  • #4
    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....
    '85 2+0 Turbo

  • #5
    worth just trying to scrub the connector clean with soap and water and then some contact clear before shelling on a new O2....