trwebb26 Posted January 15, 2006 Share Posted January 15, 2006 I want to remove the heater from my 78' 280z. This includes the blower, air lines, wiring, controls, etc. It doesn't have A/C so I don't have to worry about that. My question is about the two heater hoses running from the front-right side of the engine. I will not need them anymore. Assuming I'm not using water for anything else (I'm not using an IAC or TB with water running through it) - do I just plug up both of the holes... or do I have to connect the outlet to the inlet using some heater hose? What size metric pipe plug will I need? Thanks Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted January 15, 2006 Share Posted January 15, 2006 You can just plug. Or just loop back bypassing the heater core. Quote Link to comment Share on other sites More sharing options...
GHtokyo Posted January 15, 2006 Share Posted January 15, 2006 Hi, I kinda have the same question. My car had a bypassed heater core when I bought it. I just got done replacing the heater hoses inside the car. (Core was actually good I think) I don't recall the size of the fittings However. This is a pic of my current setup. I bet I could just plug this line going to/from the thermostat because I'm not using the TB coolant passage. Can someone confirm this? Also, does it matter which line goes to the inlet and outlet of the heater system. for example, could the lines on the firewall switched and have normal heater operation? I don't recall the size of the fittings either. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted January 15, 2006 Share Posted January 15, 2006 Plug them. Do not loop! The heater core is in parallel with the radiator. Replacing the heater core with a loop of hose means that you be bypassing your radiator and returning a good portion of the heated water back to the engine. I can’t think of how many people I have seen make this mistake. Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 16, 2006 Share Posted January 16, 2006 Is this really true? I've always run my engines with a piece of hose between the radiator inlet, and the fitting at the rear of the head. I never have problems with over heating, even on my race car that never gets over the T-stat temp (180) even after 20 minute track sessions in 90+ deg heat. I'm running a 2 core 240Z radiator in it, and the engine makes around 165HP at the wheels. I always thought that this would always bring coolant directly from the radiator to the head, bypassing the block. Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted January 16, 2006 Share Posted January 16, 2006 i never once had a problem either. ran my Z for over a year in houston heat with the hose between them and boosting sometimes over 18psi... never once a problem and im running a reg 280Z rad. mike Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted January 17, 2006 Author Share Posted January 17, 2006 Well... now I'm confused. Can anyone agree on whether or not plugging the holes is ok??? Still no word on what size plugs I should use. Thanks guys. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted January 17, 2006 Share Posted January 17, 2006 I tried plugging the outlet at the front and the elbow at the back of the head once on my ITS car, and it would run hot. I think it most likely was causing some cavitation in the pump, or a hot spot in the head that wasn't receiving a good flow of coolant. I put a hose from the front outlet to the rear of the head and that solved the problem. It may not look as nice, but that would be the way I would suggest. Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted January 17, 2006 Share Posted January 17, 2006 Plug them. Do not loop! I can’t think of how many people I have seen make this mistake. You can plug the lines, and it realy doesn't matter if you loop it or not. I would preffer to loop it so that all the coolant is in motion. Yes the coolant is already warm by the time it mixes with the "cool" water from the rad, but if your system is working properly it won't make a difference. In fact if the engine starts running warm, that means that you have a problem developing in your cooling system. Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted January 17, 2006 Share Posted January 17, 2006 hose from front to back on my Z... rock steady @ 160-170. Quote Link to comment Share on other sites More sharing options...
AdrianZ Posted January 17, 2006 Share Posted January 17, 2006 I did the loop too. was thinking about running a sold metal pipe down the sie of the motor even. if anything my car runs cooler. I got pictures too. I'll load them up when i find where i put them Quote Link to comment Share on other sites More sharing options...
bradz240 Posted January 17, 2006 Share Posted January 17, 2006 I used a 1/2" pipe plug in the back of the block in place of the splitter and a 3/8" pipe plug in the hose at the front. Quote Link to comment Share on other sites More sharing options...
kcelectronics Posted January 17, 2006 Share Posted January 17, 2006 Plug or Not really makes little difference! The heater tap effectively blocks the flow, or if you run with the heater ON then it is adding a small cooling effect to the radiator, and as already been mentioned if you plug the 2 outlets and the engine runs hot you have other issues. I have done both so really it is your choice! On one hand it adds 1 more place for a water leak but it is a quick fix. Or you can plug them if you want a cleaner look. Chuckie:twisted: Quote Link to comment Share on other sites More sharing options...
preith Posted January 17, 2006 Share Posted January 17, 2006 An old timer who's been preparing raced Zcars for over 20 years specifically told me to loop it. This helps it run cooler. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted January 18, 2006 Share Posted January 18, 2006 Never had any problems! Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted January 18, 2006 Share Posted January 18, 2006 In answer to your question, both hoses to the heater core are 5/8" ID. I just had to loop mine until my new heater core gets here. I hate running with my windows frogged up here in rainy Southern Oregon. Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted January 18, 2006 Author Share Posted January 18, 2006 Ok... Let me throw another wrench in the works. The Haynes manual says to turn the heater on when you are draining the water from the engine. This means that there is a valve inside the heater controls that blocks off the flow to the back of the head when the heater is off. So when the heater is off - there isn't any water flowing through that hose to the back of the head anyways. By looping it you are adding extra cooling to the head (good), but taking away from the amount of cold water available to cool the block (bad). There is a very strong argument for looping it or not looping, but I'm enjoying the discussion. Waddaya think now? Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted January 20, 2006 Author Share Posted January 20, 2006 Bump!!! Quote Link to comment Share on other sites More sharing options...
AdrianZ Posted January 20, 2006 Share Posted January 20, 2006 Never had any problems! how did you get the rear one to poitn forward? mine points to my firewall so i have this huge looping thing that rest against my batterie Quote Link to comment Share on other sites More sharing options...
TimZ Posted January 20, 2006 Share Posted January 20, 2006 By looping it you are adding extra cooling to the head (good), but taking away from the amount of cold water available to cool the block (bad). I guess I'm not seeing this... If you add the hose "loop", you aren't routing extra cold water anywhere - you are bypassing coolant from the point where it enters the head right back to the pump inlet. Quote Link to comment Share on other sites More sharing options...
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