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it’s not coming from the carb cooling bypass hose. Could be coming from the intake or exhaust manifold though? I don’t have the intake/exhaust torqued down, but would coolant flow through there? Shouldn’t it just be air and fuel? head gasket maybe? That didn’t appear to be wet, but maybe I missed it. any ideas would help. Thanks!

I'll be swapping my leaking original radiator out for a shiny new Champion 2 row aluminum radiator (EC634) first thing tomorrow and I realized I don't have a drop of extra coolant around. Does anyone know from experience that this radiator will require more coolant than the stock radiator holds? Its odd I can't seem to find that info anywhere. Assuming I don't lose a drop of the almost new coolant while draining/refilling, should I 'make a trip to town' tonight to buy a jug so I'll have enough to finish the job tomorrow?

I just bought some new headers for my 1974 260z, but they run into some transmission coolant lines. Does anyone know if I would be able to bypass these lines? Or what I could do to get around this problem? It's an automatic and I have removed the air conditioning. Any information would be greatly appreciated. The two horizontal lines in the second picture are what I am talking about.

My 78 is getting too hot. I've done a few things to it since it was on the road, so keep in mind that I'm unable to drive it right now, only idle it when backed out of my basement garage. Here's what's been done to it since I drove it a few years ago that relate to the cooling system: -Deleted the coolant bypass line just to tidy up the engine bay. I plugged the thermostat housing and plugged the small coolant line that comes off the heater hose hard line by the #1 spark plug. -Tested the 180* thermostat in boiling water and drilled out the tiny bypass hole in the thermostat just a wee bit after reading about others who had bypassed the coolant line attached to the manifold. -Pulled the radiator out, flushed the not-so-cruddy mixture out of it, then poured in a gallon of water with a measured bit of muratic acid and shook/rotated/flipped/worked the mixture throughout the radiator to hopefully clean the passages. After a few minutes, I emptied, rinsed like mad and stuck it back in the car and filled with coolant/water mix. It's as full as it can get without lifting the front of the car and topping the radiator off. No air pockets, as far as I can tell. I ran the heater a few times to circulate it through the heater core and squeezed the hoses while topping it off. New Sankei radiator cap. -Replaced the aged water pump with a new Asin water pump with the cast propeller, and not the thin blade propeller found in some cheaper aftermarket units. Now, all of that above was done before I realized any overheating problems. I figured most of this was good practice on an old car and it makes me a little less nervous about a long trip with the wife with me if certain parts are replaced. I don't want to swap a water pump in a parking lot somewhere. This car always seems to take quite a while to warm up. (been that way since I bought it 4 years ago from original owner who did not tinker with it at all) Anyway, as it idles and (very) slowly reaches operating temp, the gauge continues to rise. Before I parked it in the basement a few years ago, it would barely get past the middle on the temp gauge in hot weather. Now, idling, it gets to 3/4+ before I shut it off, open the hood and let it cool down. Something I've done has affected it. Today when I shut it off at the 3/4 point, there was a bubbling sound coming from the thermostat housing and the coolant overflow was at the lower level line. I don't think I've ever seen the coolant overflow bottle with any coolant in it since I've had it. I thought I read enough from others who deleted those coolant bypass lines with no problems, but maybe that's causing this to happen. Or, did I unclog something in the radiator with the acid /water flush?

I recently picked up a 240z from an old guy that's had it for decades. It's in really great shape but hasn't been driven in awhile. I changed th oil when I got it home and have put a couple hundred miles on it. I noticed that it's leaking coolant in several places, one spot seems to be coming from where the head and block meet but definitely from a couple of the hoses. I started draining the coolant to flush it and found it to be very milky. I've attached a pic. It's not smoking or overheating so if there is something going on with the head gasket it doesn't appear to be severe yet. Anyone have any ideas of what the issue could be?

Hi. My name is Arnoldo, I'm from south of Mexico. I own a 1977 280z that will be in a future restauration process (as soon as I have enough cash). Recently I noted a leakage in the coolant tubes on the engine block, and in the one in the thermostat housing, so I purchased new ones to replace those. The problem came when I actually tried to replace them: I found that my car had an extra line that came out of the tube on the front of the block and to a part that sits on the upper side of the intake manifold, that has a lot of what I think are vaccum lines to different parts of the car, and another line to the thermostat housing. I didn't found those in the diagram that comes in the FSM (then again, I'm kinda bad reading diagrams), and I don't know what are those line for. The parts that I bought are for that model in particular, but the tube doesn't have this outlet. As Celia Cruz used to say: "My english is not very good looking"... so a picture is better that a thousand words.

Hi all, I bought a 1975 280Z in January and haven't felt like working on it till now mostly cause it is in good running order. A few months ago after taking it out and coming back i notice a growing pool of coolant underneath the transmission. So the search began, I read the service manual I searched the forums and low and behold I found nothing that was useful. Well I finally used my camera and took a picture of the mystery hose that is pissing away all of the coolant in my car. Can anyone tell me what it is where its coming from and what it should be connected to? Thanks

I'm a new owner of a '71 240Z; I've posted on here a couple of times. While the car was in the process of restoration by the previous owner there were periods of long sitting and I am getting everything up to snuff. To help others help me here's what I've done so far: - Rebuilt transmission with new gaskets, bearings, synchronizer rings, and oil seals. Temporarily refilled with synthetic 75W-90 GL-5 (ouch; I know now), now has Red Line MT90. - Replaced clutch friction disc, pressure plate, throwout bearing, and slave cylinder - Replaced distributor cap, rotor, O-ring, breaker points, condenser, and ignition coil with OEM-spec Beck Arnley parts - Replaced plugs and wires with NGK BPR6ES and NGK wires, gapped per FSM specs - Dropped fuel tank and had it boiled at a local radiator shop; replaced fuel filter and am currently running a can of cleaner additive through with premium-grade fuel - Disassembled, cleaned, and rebuilt carburetors with the aid of the ZTherapy rebuild kit and video - Checked dwell, measured at 37 degrees, timed at 5 degrees (second notch from bottom on crank pulley when viewed from passenger side) with electronic multi-function light I'm now driving the car daily to and from work, ~40 miles round-trip. I do my best to keep the engine in the 3000 to 3500 RPM range while driving. The car starts well with the now-functional choke, but the choke/fuel nozzle assembly sticks and I'm planning to re-adjust and calibrate this weekend. I know that I've got an exhaust leak under the hood where the twin pipes meet the manifold; it's missing the flange gasket which I've ordered and will also be installing. The rear hatch also doesn't seal quite right and the original bad gas made quite the odor in the car, so I usually drive with my window down. Although the blower motor/switch don't work the control levers are functional and I can get forced air venting through the ducts into the cabin. This week as I've been driving I've noticed faint white smoke rising from the hood vents (the car has a 280 hood on it.) This morning while making a left turn I also noticed the smoke entering the cabin through the blower vents. I have not noticed smoke from the tail pipe while driving, neither while under load or idling at lights. When I got to work I popped the hood and took a look. I know that I have coolant seepage around the thermostat housing; I'm replacing the thermostat, both its gaskets, and both radiator hoses. I also saw that the frame was wet where the radiator filler neck hose rests near the front driver's side of the engine bay. Finally, there was faint smoke/steam coming from the valve cover breather and where its hose connects to the air cleaner box. Removing the hose cause condensation and puddling of what appears to be oil. I do get some hesitation/lag when starting from standing in first gear. Once it gets past that point the car will accelerate fine up to highway speeds through the other gears. Deceleration, whether in neutral or gear, often includes one or several backfires or pops, I believe from the tail pipe. If you've made it through all of that you now know what I do. I've been doing a lot of reading and searching through the forums, but I still have a few questions: - First and foremost, what should I be looking at for the above circumstances? - What is the "best/proper" way of setting float adjustment? I do believe that I am running too rich. The video shows the float horizontal at .55 in. while I've read on here about holding the lid vertical and tilting while blowing in the fuel inlet to measure. I sent Bruce an e-mail; maybe they've been busy but I haven't heard back. - What are common locations for vacuum leaks? The car has a later N33 intake manifold on it with the corresponding emissions-control balance tube. However, no air pump is installed and there aren't any devices installed on the balance tube. Perhaps related, the vacuum tap on the front carburetor is not there. The hole is not plugged, but the residual broken tap appears to be in place in the carb. Instead, a line runs from the manifold vacuum tap to a three-way join, then a line runs to the distributor advance. Does it make a difference which location vacuum is tapped from? Are there any good images showing definitively what needs to be plugged on the balance tube? - The engine no longer has the coolant line running around the back (firewall end) from the manifold on the driver side to the three-way joint on the passenger side. Instead, the line runs through the manifold and is then capped, with a corresponding cap at the 3-way joint. I am planning to remove the residual line and plug at the thermostat housing instead to eliminate the dead zone; are there any problems with not running coolant through the manifold? The carburetor spacers don't have cut-outs for water flow. As always, all help is much appreciated.

I recently replaced the radiator and added an overflow bottle in my '75 280z. After refilling the system with coolant, I took her for a test run to check for any leaks. The temp gauge was reading good - about 5/8ths...then the gauge dropped to the bottom of its range. I checked the connection on the temp sender and topped off the coolant and took her for another spin. Again the gauge was reading good then stopped working again. I let the system cool again and took off the radiator cap to add more coolant, but the coolant was at the top of the radiator. Would an air bubble in the thermostat housing cause the temp gauge to not register?

1971 240 with SU's/header -- Coolant Water mist sprays out between my intake manifold and head -- Weird. A bit of acceleration and it becomes a little geyser. It is betwwen the number 4 exhaust and intake runners and has actually made a hole in my manifold gasket. Could it be a leak inside the intake manifold? There is a water passage there. Please help!!! Thanks!!!