lonnie77

Do you get a blast of heat ever time you accelerated? Then after checking vacuum lines even those under the intake, find nothing wrong and think what the heck? Try looking here...

https://rennlist.com/forums/members/...-img-4911a.jpg

https://rennlist.com/forums/members/...9-img-4915.jpg

https://rennlist.com/forums/members/...0-img-4914.jpg

I had fixed this two years ago and forgot about it.

risaac928

Thanks gonna run out to the garage and take a look at mine

BIMMERMIKE

Help me understand the "heat" part. I'm also trying to chase a vacumm leak with no success!

joejoe

Ahhh the dreaded plastic 'y' for evap system. Found a leak that had evaded me for years (actually Porken found it) Mine was the vacuum to the computer. It was disconnected at the engine bay firewall (came off rubber bit) and was right next to it. Ken found it when checking for vacuum (none) at computer inside car and located disconnect in engine bay. Very difficult to see if not looking for it specifically.

SteveG

IIRC Nicole (hookedoncars) sells a metal "Y" replacement.

Landseer

Like bimmermike, I'm chasing one also on 85 USA.

Sounds like a whistle when coming off idle and accelerating slightly.

lonnie77

The heater control valve will open and allow water into the heater core if there is a loss of vacuum. You will feel heat from the vents and console.
The cruise control on the opposite side is another place to check and the contol valves under the console can stick open. Pick a vacuum line and use a mityvac or trace it in both directions. Then there are vacuum hose under the intake and going through fender wells.