i was out earlier in the zed and when i got home i was allowing the turbos to cool down and i noticed my temp gauge almost at the top , the highest ive ever seen? what is causing this, i checked the water tank and the dip stick is wet so im guessing there is water in there, the dipstick is it supposed to have a brown coloured dirt on it,, doesnt seem normal to me??

 

Im now worried head gasket may have gone.

 

can anyone clear this up for me.

 

btw i was only out for an hour and i wasnt thraping it everywhere

i think your confusing the expansion tank dipstick with the engines Mikey.The expansion tank dipsticks tend to get brown and stained.

Are you sure you havent got an air lock.

Jack up the front of the vehicle as high as possible, remove rad cap, and bleed screw fill little bit at a time, keep heater on hot / max and full pelt.

Keep doing till all air blows hot into car and you cant get anymore in, (starts filling expansion tank)

Turn replace cap a bleed screw, turn if off, lower down to normal and let it cool. Then check water when cold.

If water is on oil dipstick, get a compression test done.

There should be minimal amount of water in expansion tank when cold, as engine fills it up when hot, then draws it back when cooling down.

thanks guys, yes it is like a stain on the water dip stick so this has put some doubts to rest, i will try what you just said stu if i can get my head round it and see what happens

Thats the overflow bottle. You need to check the water level in the radiator, via the radiator cap.

 

Im afraid the VG does'nt like getting hot, unless your lucky, you may now be looking at a possible headgasket failure. If water is low, top it up, check for leaks, check the level after taking it for a drive. Its probably worth having a Compression test done on it too. Testers can be purchased from somewhere like Halfords, or it should be relatively cheap for a garage to do the test for you.

Edited August 19, 200916 yr by Yowser

so the radiator cap comes off then how do i know if its too low or not?? is there markers to show me? or will it be obvious.. oh and whats the 'vg'

sorry to butt in.

 

Jonny, do as Stu has said.

 

with the engine cold take the rad cap of a check level your should see the coolant at the top/neck of the rad.

 

'vg' is refering to the 300zx engine code 'VG30DETT'

i see, ok ill do this tonight, so if its below the the neck of the rad then i should top it up i guess.

 

worst case scenario can anyone tell me how much its likley to cost to have the head gasket done and wether it will last??

Ive had mine over heat in the past with the temp off the scale, it tends to shoot up when the water drops low, i've switched the engine off as soon as i noticed, fixed the pipes and all was fine, doesnt use oil or water, no gunk in the oil either, maybe i was just lucky.

 

As the others have said top the water up to the level of the rad neck, go for a steady drive to get up to temp, park up switch off and look for any signs of leaks/hissing.

Ive had mine over heat in the past with the temp off the scale, it tends to shoot up when the water drops low, i've switched the engine off as soon as i noticed, fixed the pipes and all was fine, doesnt use oil or water, no gunk in the oil either, maybe i was just lucky.

 

As the others have said top the water up to the level of the rad neck, go for a steady drive to get up to temp, park up switch off and look for any signs of leaks/hissing.

 

thanks, im hoping for the best... its never happened before, and its the first time ive seen the temp that high, as i try to keep an eye on it.

The engine can take a few overheats if you catch quick enough and switch of and let it cool down but if you try to force cool the engine i.e. put cool water into a overheat engine this is where you can cause the damage.

i see, ok ill do this tonight, so if its below the the neck of the rad then i should top it up i guess.

 

worst case scenario can anyone tell me how much its likley to cost to have the head gasket done and wether it will last??

 

im afraid its over a grand for a head gasket but it will last once done as long as you dont you a cheap gasket.

yassa - your scaring me..... my car has only done 75 odd thousand miles, im gonna have to resort to praying.. and then hope this isnt the case lol :D

You might have a leak somewhere. You should keep a close eye on it in case the leak only begins when it is hot and under pressure. Such leaks are typical of small cracks in rubber hoses. They hold up till a certain pressure then let go. You can never see them with a cold engine. Nor does leaving it on tickover often let it get hot enough to fully pressurise. Feeling for a hard top hose when its hot can prove this. If the top hose is still soft after a drive then the cooling system pressure is bleeding away. Also check the radiator cap as a bad seal there can also cause this and reduce the boiling point.

If it was your stock temp gauge that was near the top im sure you would of heard the water hissing or seen it bubbling/forcing itself out of the rad pipes, unless your water is very low!

thats the thing, there was no hissing so water could be low, but water doesnt just dissapear right?? so does that mean it could be a leak or again points to head gasket lol ??

will obv check water level after work tho to confirm

thats the thing, there was no hissing so water could be low, but water doesnt just dissapear right?? so does that mean it could be a leak or again points to head gasket lol ??

 

Check the oil cap for mayo/white gunk and do a compression test or as willieO suggested if its low on water as it gets hot it expands and could be forcing its way out of a small split in one of your pipes.

ok so ill drive home and see how hot it gets and the ill check the pipes for a leak when its hot... , hopefully thats all it is then it will explain the no hissing steam etc due to no water in the rad , due to the leak .... hopefully... then i know its not the hg. :-)

Also i've had it were steam was escaping but no leaking water and over time enough water is lost through steam that when it reaches a low it will over heat, its probably a small pin hole that will get worse over time and eventually lead to a split.

 

Main points to look at are the 2 small pipes on the end of the metal pips slap bang in the middle of the engine, these are hard to see as the cam sprocket covers hide them,

2 pipes at the back that go through the bulk head for the heater located back middle.

 

The top and bottom rad hoses are also prone, the other pipes such as under the plenum and turbo water pipes are not visible from the top of the engine and are difficult to see.

 

This will give you some ideas of were to look for signs anyway. Good luck tracking it down.

Also i've had it were steam was escaping but no leaking water and over time enough water is lost through steam that when it reaches a low it will over heat, its probably a small pin hole that will get worse over time and eventually lead to a split.

 

Main points to look at are the 2 small pipes on the end of the metal pips slap bang in the middle of the engine, these are hard to see as the cam sprocket covers hide them,

2 pipes at the back that go through the bulk head for the heater located back middle.

 

The top and bottom rad hoses are also prone, the other pipes such as under the plenum and turbo water pipes are not visible from the top of the engine and are difficult to see.

 

This will give you some ideas of were to look for signs anyway. Good luck tracking it down.

 

thanks for the advice

ok fellas i have ben home from work and the temp stayed around the middle of the scale like it is normally, let it cool right down have checked oil , the dipstick and there is no mayo so thats gd news... then checked the radiator took the cap off and notices an orangy stainy colour simialer to that in the dipstick off the water expansion tank... is that normal also, but there was no water, i was told water should be up to the neck of the rad??? also couldnt notice any steam coming from anywhere after i drove home. so whats my next move? shall i fill the radiator up to the rim??

Well there will be some water in it but you cant see round the neck bend too well, follow sussex stu's guide to filling the rad on 1st page, at least if you an fill it to the neck you can see if its losing any water next time you check, the brown stain is just rusty water stains i would have thought.