necrotosin Posted September 12, 2011 Share Posted September 12, 2011 I have a 73 240z and im having overheating problems still. Changed the radiator, water pump, fan clutch, hoses, whole nine yards. It overheats even with the thermostat out at idle. I have no clue what else I can do to make it stay at a constant temperature. Anyone have suggestions? I had a post like this couple weeks ago and someone deleted it, can you please not delete it this time, really need some help here. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted September 12, 2011 Share Posted September 12, 2011 Is it really overheating or does a gauge show its running hot?. If it is overheating. How fast does it overheat after it is started up?. Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 12, 2011 Share Posted September 12, 2011 (edited) Your other thread didn't get deleted, it got moved, to the Tool Shed - http://forums.hybridz.org/index.php/topic/102031-overheating-getting-frustrated/ If your engine cools off when you're moving, and heats up when you stop, then you most likely have a problem with air flow through the radiator. The radiator is where the water flowing through the engine loses it heats, radiating it away to the air passing by. No air flow, no cooling. Edited September 12, 2011 by NewZed Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 12, 2011 Author Share Posted September 12, 2011 With the thermostat out and running, it heats up in about 10-15 min. I dony have a fan shroud on the car either. Could this help direct the air flow it needs when sitting at idle? Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted September 12, 2011 Share Posted September 12, 2011 Yes a fan shroud would definitely help. Did you re route any of the coolant lines on the side of the block? Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 12, 2011 Author Share Posted September 12, 2011 Havent re routed any cooling lines. Only replaced parts. The car didnt have a shroud when I got it. Did the 240z originally have one back then? Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 13, 2011 Share Posted September 13, 2011 Have you driven the car? Quote Link to comment Share on other sites More sharing options...
z240 Posted September 13, 2011 Share Posted September 13, 2011 When replacing the water pump, you may have missed corrosion/cavetating damage on the front cover. Without a proper clearance between the pump vanes and the cover, pumping efficiency is lost. Causes for the cavitation have been discussed here, worth seeing if the root causes apply to your engine. Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 13, 2011 Author Share Posted September 13, 2011 Everything was cleaned out when I took the water pump out. Put on the new and it definitly was flowing better than before. I watched the water flow through the radiator with the cap off. Flowed much better. But what bugs me is theres no fan shroud.. Is it going to help it cool at a stand still with a shroud on it? Also should I run a colder thermostat? I had a 195° one in it. Think I should throw in a 160° or 170°? I'm also going to change the sensor right below the thermostat housing to see if I get a better reading Quote Link to comment Share on other sites More sharing options...
pleadingbark Posted September 13, 2011 Share Posted September 13, 2011 Try a 160 degree, my car was doing the same thing, overheating like crazy, I replaced literally everything in the cooling system, 3 core radiator etc. Ended up being because I didnt have a thermostat in there and there was a HUGE air pocket in there. Cooling system was being too efficient and circulating the air before it could cool it down. I know this is a stupid question but is the fan blade on maybe backwards on the fan clutch? After I put the thermostat in mine and bled it, no more over heating. You can also grab a digital temp gun from harbor freight for about 30$. Quote Link to comment Share on other sites More sharing options...
Leon Posted September 13, 2011 Share Posted September 13, 2011 195 degree thermostat? It's not winter, use a 180 degree, unless you're in a very hot climate in which case use the 160. I run an ebay 2 row radiator with no fan shroud and a 180 degree thermostat. Cools great. Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 15, 2011 Author Share Posted September 15, 2011 Is it really overheating or does a gauge show its running hot?. If it is overheating. How fast does it overheat after it is started up?. I have reason to believe its the gauge now. I put a new sensor in it and it does the same thing. It jumps to 260° right when I put it in drive. Once I throw it back to park it goes back down Quote Link to comment Share on other sites More sharing options...
NewZed Posted September 15, 2011 Share Posted September 15, 2011 I have reason to believe its the gauge now. I put a new sensor in it and it does the same thing. It jumps to 260° right when I put it in drive. Once I throw it back to park it goes back down This is why your first thread got Tool Shed'ed. The whole thing is good for a laugh though. Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 15, 2011 Author Share Posted September 15, 2011 Stuff happens I suppose, thanks for the "help" Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 16, 2011 Author Share Posted September 16, 2011 What is the difference between a mechanical and electrical gauge? And which one should I use on my z for the most accurate reading? Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 17, 2011 Share Posted September 17, 2011 What is the difference between a mechanical and electrical gauge? And which one should I use on my z for the most accurate reading? A mechanical water temp. gauge uses a small sensor filled with a fluid that is connected to the meter with a small copper tube. The sensor is installed on the engine such that part of it is submerged in the coolant. As the coolant heats and cools the fluid expands and contracts changing the pressure in the tubing. The meter in the dash is essentially a Bourdon pressure gauge and responds to the pressure changes within the sensor. The system is calibrated to read directly in degrees Fahrenheit or Celsius. An electric temp. gauge uses a thermocouple sensor to detect the coolant temp. The sensor is submerged in the coolant. A thermocouple is device that generates a small voltage in response to heat. As the temp. changes the voltage output varies. The meter in the dash is a sensitive milliammeter connected to the thermocouple and responds to the changes in the voltage output from the thermocouple. Both can have good accuracy or poor accuracy depending on the quality and design. The advantage of mechanical gauges is they work without electricity. This is needed in vehicles with magneto ignition and no battery or other source of electrical power. They will provide a reading when the vehicle is off which is sometimes useful. The advantage of electric gauges is better isolation of the measured medium and the cabin of the vehicle. This is especially useful for fuel pressure gauges since routing a fuel line into the cabin is a very bad idea. It is also an advantage in vehicles with a great distance between the engine and the instrument panel, such as a rear engine vehicle. Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 18, 2011 Author Share Posted September 18, 2011 Installed a mechanical one and it works great but it is going to 220° at idle. Im letting it idle for 15-20 minutes. I know it should run pretty hot but is it suppose to be that hot? Quote Link to comment Share on other sites More sharing options...
Miles Posted September 18, 2011 Share Posted September 18, 2011 You might try ClassicZ as they deal more with stock Z cars. http://www.classiczcars.com/forums/forumdisplay.php?2-240z-260z-280z-Forums Quote Link to comment Share on other sites More sharing options...
beermanpete Posted September 18, 2011 Share Posted September 18, 2011 Installed a mechanical one and it works great but it is going to 220° at idle. Im letting it idle for 15-20 minutes. I know it should run pretty hot but is it suppose to be that hot? 220° is too hot for just idling. A fan shroud would likely help IF air-flow through the radiator is the problem. What is the temp while driving the car? Quote Link to comment Share on other sites More sharing options...
necrotosin Posted September 18, 2011 Author Share Posted September 18, 2011 Not sure yet, going to button it up today and take it for a spin Quote Link to comment Share on other sites More sharing options...
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