oil leak under thermostat housing HELP!

[hosser37]

i just installed a t3t4 hybrid with tubular header and when i started the car i noticed oil leaking from under the thermostat housing... i pulled the housing off and started the car again and determined that it was coming from between the head and the block. i pulled cyl. 1 spark plug... no fluids on the plug. it only leaks when running. its been sitting in the cold for a month now and hasnt been started in that time period either, but the last time it was ran there was no leak, why the sudden change? does it have to do with the temperature or my new turbo?

im new to this site so your help is more than appreciated, help this poor kid from having to stand out in the cold!!

thanks guys- Bill

2g 1995 gsx

 

[rstray]

could be the valve cover seal. there is alittle half circle rubber piece that tends to fail...