Also, how do I check them and how do I clean them up? I am running rich.

 

Second question: Is the engine coolant bottle on the left at the front supposed to spew coolant all over the floor when you top it up (from somewhere about halfway down the bottle), or does mine have a crack or hole, i.e. is it supposed to be sealed? There doesn't seem to be any cooling problem and no coolant seems to be lost. PS - one other thing, the dipstick in the coolant bottle has suddenly started developing a black smudge at the bottom. I thought about possible blown gasket but that doesn't seem to be the case and there is no engine warning light.

 

Thanks.

Also, how do I check them and how do I clean them up? I am running rich.

 

Second question: Is the engine coolant bottle on the left at the front supposed to spew coolant all over the floor when you top it up (from somewhere about halfway down the bottle), or does mine have a crack or hole, i.e. is it supposed to be sealed? There doesn't seem to be any cooling problem and no coolant seems to be lost. PS - one other thing, the dipstick in the coolant bottle has suddenly started developing a black smudge at the bottom. I thought about possible blown gasket but that doesn't seem to be the case and there is no engine warning light.

 

Thanks.

Engine by numbers

http://www.300zx.co.uk/forums/showthread.php?t=26120

 

A: You can't. Test and replace if necessary.

 

B: That's an expansion bottle, not a coolant reservoir.

Edited November 12, 200817 yr by Graham S

the bottle your talking about it the coolant overflow tank, not a conventional expansion tank, when its full it will dump coolant usually visible from the nearside front bumper at the bottom. You dont fill the cooling system from that bottle, do it directly via the radiator. If you peel back the left side arch liner you'll see the bottle and the level lines on it, that dip stick is rubbish. if you want to empty it to within the lines dissconnect the tube going to the cap and feed it down the front of the rad towards the road surface and let gravity take it course. If the bottle is filling up and your getting coolant dump, check the cooling system pipework for any leakage no matter how small and maybe think about a new rad cap.

How can you test them?

 

all you need is a safety pin. Once you find the connectors - both are three pin connectors, with black, black/red, and white wires. Passenger side is near the rear of the passenger side plenum chamber, and driver's side is on the side of the engine, just in front of the master cylinder.

 

Check that the connectors are clean and free of corrosion first. Be careful undoing the connectors, as the rubber seal can drop out into the engine bay, never to be seen again.

 

Warm the car up, and with the car at hot idle and with the connectors all plugged in, insert the open safety pin into the end of the connector along the red wire, making sure that it makes contact with the red wire inside the connector. Connect the voltmeter (low volts range, eg 20 V) with red probe to the safety pin and black to earth. You should see 12 volts DC. Note the engine should be above 2,000rpm while performing the test.

 

Then plug the safety pin into the white wire, making sure that it makes contact with the white wire inside the connector. Connect the voltmeter (low volts range, eg 2 volts) with red probe to the safety pin and black to earth. A good 02 sensor when warm should show the voltage moving between around 0.3 volts DC and around 0.7 volts DC - this is the ECU cycling the oxygen content (via varying the fuel content) to keep the ratio correct. At higher revs, the upper voltage increases from memory, but it always cycles, except possibly at WOT (which I recommend that you DON'T do while parked in the driveway! ).

 

If the voltage reading doesn't cycle, then it's probable that the 02 sensor or cable/connector is stuffed. I'm not sure about the Zed, but some/most 02 sensors take a while to heat up, so until the engine and exhaust are hot enough, the ecu usually operates in 'open loop', which means that the voltage won't vary. Thus, you have to do the test when the engine is hot, eg after a 10 minute drive

 

courtesy of aus300zx

You can test them using ConZult or Datscan. You tell by the readings the sensors give whether they our out of spec or not.

Thanks for these helpful replies.

ive been putting water in the expansion tank!!!

The main reason why the expansion tank leaks is because it is made up of two parts (the tank and a filler neck) which are only loosly slotted into each other. If the coolant level in the expansion tank gets too high it usually leaks past the joint where the tank meets the filler neck.

 

If your radiator is filled up and the engine is cold there should be about 600ml of coolant in the expansion tank. Any more and you're likely to see it leaking out once the engine is hot at the end of a run. Any less and you could potentially end up with an airlock in the system as the radiator tries to suck up more coolant into the system and only gets air.

 

HTH

 

Dan

Thanks for these helpful replies.

 

owning a zed in 'maritzburg, stone throw away from durbs - you are certainly living the life! Lucky sod!! :bow:

tracking post

Put a volt meter on them and see how the read they should fluctuate every couple seconds or so, i cant remember.

owning a zed in 'maritzburg, stone throw away from durbs - you are certainly living the life! Lucky sod!! :bow:

 

Nice to hear from you! I've got a Zimbo 1 cent piece if you want it. You can buy yourself something nice :-)

 

Must say, I am really enjoying barrelling down to Durbs and back every day in the Z. Nice how everyone gets out of the way.

Nice to hear from you! I've got a Zimbo 1 cent piece if you want it. You can buy yourself something nice :-)

 

Must say, I am really enjoying barrelling down to Durbs and back every day in the Z. Nice how everyone gets out of the way.

 

You know what..... I'd trade you a years membership on here if you posted that to me!! It may be worthless moneywise but anything from back home is a memory in itself :nana2:

so just to recap, only put water in the radiator,

 

and not the container on the left?

You shouldnt really need to keep putting water in the exp/overflow tank, check the level in the bottle so its between the marks, and fill from the rad, squeeze the top hose if its silicon periodically to help expell air from the system. Sorry dont mean to be pedantic but you should be using antifreeze mix, especially through the winter. Once all levels are how they should be, if the overflow tank is filling up and dumping coolant then you would have to suspect most likely air in the system.

Getting back to the O2 sensors, I have now checked my connectors with the safety pin method (which works quite well, was impressed).

 

I get the necessary cycling on the left connector but on the right connector I get a sustained .16 (or .22 at another time) V reading. Not .04 to .07 cycling like the other one.

 

Does this mean the sensor or connector is cooked?

not necessarily, it could be a fault with an injector on the right hand bank.

Put a screwdriver on the top of the injector and listen through the handle, you should hear a distinct clicking. Next measure the resistance across the terminals, should be between 10-14ohms. Let the car sit for half an hour then whip the plugs out and inspect them, if the plugs wet or has a strong smell of fuel then it could well be leaking. Try running some injector cleaner through next time you fill up, although its not really recommended for old injectors, can cause problems.

How would I check for injector problems? Would it be quickest to take it to Nissan and get them to put Consult on it?