1995 Impreza WRX overheating and strange idle

[DaddyTurbo v1]

Just wondered if anyone could help,my car has boiled the water in it's header tank twice recently although the temp guage is reading fine the whole time. I left it running on the spot and it wont boil up and fans kick in fine. it happened 1st when i'd come off motorway and then a week later doing 20mph uphill behind a truck,i'm really stumped!!! also from a cold start it will idle up and down between 100rpm - 1200rpm until it warms up. finally,my blow off valve hisses the whole time,even just on idle. any help or suggestions would be GREAT!!!!! Thanks

[Lrchorne]

My 95 wagon never used to idle properly when cold ad sometimes when very hot also. Has yours ever taken a lot of starter motor turns to fire up? Up to 30 secs or so?
My rad sprung a leak also but when overheating the guage did tell me so am as confused as you there. L

[DaddyTurbo v1]

cheers mate,it is a strange one! never had trouble on the start up other than it drops the revs so low when its on idle sometimes it cuts out. i am really stumped!!!!!

[Rotary Madness]

The idle problem sounds like your dump vlave is fked. When i got my second impreza, the guy i bought it off had a really chavvy thing on, made a huge whooshing noise. Anyways vent to atmosphere DV's can leak, especially when older, and it cuases all sorts of boost problems, as well as idle problems.
What i did was bin the peice of crap, and fitted a blanking kit, so it runs with no DV, and its no perfect! The stock DV is also very good, as it recirulates the air back into the airbox, so the MAF isnt confusing things.

[DaddyTurbo v1]

thanks Rotary,that would help but for one thing. the idle problem was there before the blow off valve was fitted. confused?? welcome to my world! lol any other thoughts mate??