georgiaz Posted December 10, 2003 Share Posted December 10, 2003 The heater on my 280 only blows cold air. The defroster blows very slightly warmer air. I have done several searches on heaters and heater hoses, but can't seem to find a similar problem. The heater core is not getting hot. Could it be that I have the heater hoses routed backwards? The hose from the water pump is connected to the top tube on the firewall. I know this has been discussed before, but I don't remember how the hoses should be routed. I found references to the hoses for newer model 350s, but I'm not sure if the ones referenced have the reversed flow water pumps. Mine does not. I know the problem may be with one of the heater valves, but I thought I would see if it was something not so hard to get to. Quote Link to comment Share on other sites More sharing options...
Guest Joe17 Posted December 10, 2003 Share Posted December 10, 2003 i dont know how much help i will be, but if your heater core isnt getting hot when the heater is on then you probly ahve a bad valve or maybe even a bad linkage. i highly doubt the hoses are set up wrong. i know its a hard place to get to but try to look under the dash and look around to see if all of your linkages are connected. next take a look at the valves and if all else fails. take a look at the hoses. a 280z manual would be very helpful in a situation like this. i will go take a look at mine and check out the troubleshooting and get back to you tomorrow. - Jo Quote Link to comment Share on other sites More sharing options...
preith Posted December 10, 2003 Share Posted December 10, 2003 On my '77 I had a similar problem. I removed all the AC, and sure enough the heater wouldn't work. There is a vacuum operated valve right a the firewall which would shut off the heat when the AC was turned on. This would fail-safe to closed when without vacuum. Quote Link to comment Share on other sites More sharing options...
Georgia Flash Posted December 10, 2003 Share Posted December 10, 2003 Daryl, I am having problems with my newest Z's heater also. I suspect mine may be the heater valve. I have had one of these go bad in a ZX I once had and it spewed hot water and anti freeze all over the passenger side floorboard. Victoria British sells these things so take you a long week end and get that bugger out before someone riding with ya gets fried feet. Quote Link to comment Share on other sites More sharing options...
innerware Posted December 10, 2003 Share Posted December 10, 2003 it could easilly enough be that there is air trapped in your heater core. Not allowing proper flow of fluid. Like in an old water radiator in a house. The more air the less heat. Or you could have a vacuum leak and it isn't adjusting properly. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted December 10, 2003 Share Posted December 10, 2003 Another common problem, similar to the air in the core, is that you don't have the cooling system full. If the fluid gets even a little bit low on my explorer, it seems that none of it ever reaches the heater core. Just a thought, should be easy to check. Quote Link to comment Share on other sites More sharing options...
georgiaz Posted December 12, 2003 Author Share Posted December 12, 2003 Thanks for the suggestions guys. Prieth, I pull the A/C off of this one so the valve you mentioned could be the problem. I assume you are talking about a valve under the dash right? I am going to have to pull the blower motor out so I can get back under there to see what is going on. Joe, I would appreciate hearing what you find in the manual. Georgia Flash, long time no see my friend. We need to get together again so I can show you the finished product. Maybe I can drive it up there some time. Quote Link to comment Share on other sites More sharing options...
Georgia Flash Posted December 15, 2003 Share Posted December 15, 2003 Yes it would be nice to see the finished product live and in person Then maybe I could get another look at the wiring in the engine compartment. Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted December 19, 2003 Share Posted December 19, 2003 I took my 280Z to a radiator/heater/AC shop and had them lube/adjust the heater controls and pressure test the system. I also had them REPLACE all the vacuum lines since they were splitting all over . YOU could do this if you have a vacuum line drawing ( I didn't). No vacuum at the valve= no defrost-vent-heat. Either way, I found out it takes a couple minutes for the air to get hot, even with a warm egine. Probably while the heater core fills up & gets hot. Good money spent, IMO. Does anybody have a solution for eliminating the vacuum cannister on a '78 280Z with EFI? I dunno if the dashpot and other vacuum stuff affects the engine operation. Quote Link to comment Share on other sites More sharing options...
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