Guest Anonymous Posted January 20, 2001 Share Posted January 20, 2001 Finally got the conversion in.....only to have the 700r4 that was built to crash in the first 50 miles. Drats.. anyway, its cold and my heater is not working. My heater core was stopped up with the 6 cyl last year. You know the symptoms, two water lines goin into the firewall, one hot and one not. Well after flushing out the core, I now have one hot water line going into the heater core and one hot one coming back out but still no heat! What gives? My car is a 78 280z. Any help would be appreciated. Thanks in advance, Kevin @ highpsiguy@aol.com Quote Link to comment Share on other sites More sharing options...
Guest EPS Posted February 5, 2001 Share Posted February 5, 2001 The heater on my 280/350 sounds like yours. I haven't gotten into it much but suspect a door isn't opening since the AC works fine and the fan blows. Well to be honest, I don't have a clue. Would appreciate what you find out. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted February 5, 2001 Share Posted February 5, 2001 I'd suspect it is vacuum related... the doors on the unit actually are vacuum operated and you have a dashpot with about 6 vacuum lines coming into and going out of that unit, which sits right under the heater controls. Mine hasn't worked since I got the car in 1996. Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 5, 2001 Share Posted February 5, 2001 Gentlemen, you are correct. A flap is not moving somewhere. It is, in all likelihood, a vacuum problem. My first recommendation is to replace all of the vacuum lines on your car. Especially the ones that exit the firewall and go to various places under the hood. Another likely culprit may be those two little vac cylinders that reside on the passenger side fender. They control the vacuum based upon the switches in the dash. You can bypass those cylinder and run vacuum lines directly to the appropriate pot under the dash. I always replace the lines on any Z. The problem is that cheap aftermarket vac line splits very easily. Some zip ties used on the line connections will help keep everything sealed up. Craig Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted February 5, 2001 Share Posted February 5, 2001 I don't mean to stir the pot here, but I believe there were a few Z cars that didn't have any vacuum lines controlling the HVAC system. In the two 280's (both '77) and the one 260 (late 74) I've pulled apart, they've all had cable operated heating and cooling systems. It could be that early Z's had vacuum controlled systems, but all that I've ever seen had cable controlled systems. What happened to all my Z's was that the doors all became sealed closed after many years of sitting and not doing anything. Then, when the cable tried to pull these immovable doors, the chinsy cable attachment (a simple 'S' bend in the cable) to the door would pull itself off. I eventually had to re-attach every cable in the heating/cooling system. Everything works great now, but I had to attack every moving part of the HVAC with loads of WD-40. The best way to get this job done is to remove the entire dash. I know that sound like a big job, but it's the only way to really get in there and find out what needs to be fixed. Besides, pulling a dash isn't nearly as big a job as most people make it out to be. Good luck. -Andy Quote Link to comment Share on other sites More sharing options...
TimZ Posted February 5, 2001 Share Posted February 5, 2001 Andy - there was both cable and vacuum control on my 78. Cables control the heater **** and some of the flaps, but there is a vacuum controlled water **** that is in series with the temp control heater **** , that is used to completely shut off the water flow to the core when the a/c is on. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 5, 2001 Share Posted February 5, 2001 OK, you got me I was just trying to keep it brief. Some of the flaps are cable operated but I have always found a vast improvement in my vent system just by replacing the vacuum lines. I don't envy the job that you had, Andrew! Craig Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted February 6, 2001 Share Posted February 6, 2001 ...shoot, aint that bad. Anything's easy after the seventh or eigth time you do it... Of course the first few times were a major p.i.t.a. Also, I can't imagine pulling my dash anymore now that I have a large side bar in place now. That swing-out side bar sounds more and more appealing every day. -Andy Quote Link to comment Share on other sites More sharing options...
Guest EPS Posted February 8, 2001 Share Posted February 8, 2001 What the H is a swing out side bar? Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted February 8, 2001 Share Posted February 8, 2001 courtesy of Scotties web page: [This message has been edited by Andrew Bayley (edited February 08, 2001).] Quote Link to comment Share on other sites More sharing options...
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