any one got any idea why a zed would dump loads of water out the expansion tank , then temp guage right up , then after she cooled down a bit and refilled with water , she runs fine again ?? has happened twice in 6 months but no pipes leaking and as soon as refilled ,temp guage goes back to norm and she runs as sweet as ever !! ???? im very confused

Don't know about on a ZX but when my old Mk3 Soop did this it was a blown head gasket :cry:

 

Hope it's not the same for a ZX...... :shock:

 

Richard

Sticking thermostat?

Worth checking the rad cap, often poor seating can cause a pressure drop, higher water temp and cause these symptoms, if the rubber seal is perished or damaged may require changing.

 

One other thing to check is the neck where the rad cap fits, this often wears and as you tighten the cap it gets loser at the point you stop turning where the plastic has worn, try tighten in the cap down a bit less and it often sits down tighter.

 

Jeff TT

cool il check the rad out , pretty sure its not the head gasket as when engine was fired back up, the temp went back to normal and drives fine , if it was head gasket it would have overheated again right away

if it was head gasket it would have overheated again right away

 

spot on , not sure it would be the rad cap as it would happen more frequently than twice in 6 months and also the stick you were giving it on the way there would certainly have presented that problem

 

Ryan

spot on , not sure it would be the rad cap as it would happen more frequently than twice in 6 months and also the stick you were giving it on the way there would certainly have presented that problem

 

If the rad cap sealing is a problem due to faulty cap seal or radiator neck then often it is caused when the sadly all to infrequent checking of the coolant level is done, after the cap does may not reseal correctly, twice in 6 months may be just that.

 

Jeff TT

If the rad cap sealing is a problem due to faulty cap seal or radiator neck then often it is caused when the sadly all to infrequent checking of the coolant level is done, after the cap does may not reseal correctly, twice in 6 months may be just that.

 

Jeff TT

Jeff the car did near on 200 miles of pretty enthusiastic driving before dumping the water , do you not think that it would have shown that problem a little earlier in the day???

 

Ryan

Quoted by Ryan.

Jeff the car did near on 200 miles of pretty enthusiastic driving before dumping the water , do you not think that it would have shown that problem a little earlier in the day???

 

 

Enthusiastic driving will often show up weaknesses in any cooling system, however high speed ( if that what it was ) also brings about lots of cool air through the radiator etc, this can be just enough to keep the system stable, but as is often the case slowing down or getting caught in traffic is when the lower intake air will tip the balance and hence an overheat.

 

Of course answering any technical questions with limited information of the exact symptoms before and after or during can only be based on the "most likely cause" and a suggestion on what to check.

 

Always an exception but have seen the radiator neck and rad cap problem cause this type of overheat/ water problem many times, however it is always good practise to check water levels often, more so now than when zeds were new, but rad cap sealing is becoming a bigger issue now due to the wear on the radiator neck, also the old yellow sticker rad caps ( Nissan ) still seem to still be in evidence which means if you have one of these fitted chances are it could be up to 10 years old if not more.

 

Jeff TT

any one got any idea why a zed would dump loads of water out the expansion tank , then temp guage right up , then after she cooled down a bit and refilled with water , she runs fine again ?? has happened twice in 6 months but no pipes leaking and as soon as refilled ,temp guage goes back to norm and she runs as sweet as ever !! ???? im very confused

 

Likewise....Got to meet...pulled up and my temp gauge maxed out.

Toped it up with Baggins Volvic water(Generously Donated Thanks)http://www.300zx.co.uk/forums/attachment.php?attachmentid=8509 .....and it was fine again.

First time its ever maxed out on the temp gauge but have had to fill it up with about 2Litres of water every couple of weeks l8ly :shock:

 

I have an old yellow sticker rad cap so could be suspect but after further investigation with help from krsmayo it looks like its actually coming from a rear pipe...just behind the plenum.

 

Check out the piccys below

 

Its either coming from the jubilee clip end or the manufactured rubber join on the rubber pipe.I have tightend the jubilee clip but will need time to see if it has worked.

I have a suspision that it may be seeping from the manufactured rubber pipe join.

 

The top of the pipe is easily accesable but cant c where the other end goes.

 

Any one know if its possible to replace this pipe easily or do u have to dismantle the top end to get to it???

 

Anyway....im carrying round 5L of water now to fill up before and after journeys. :xxx:

BlackMagic.

 

Looks like your luck is in, the hose is one of the ones that serves the heater matrix, quite straight forward to change and not to dear either (£10 ish) check around that area though lots of smaller pipes that can cause problems but many still accessible from above although hand scrappers.

 

Jeff TT

BlackMagic.

 

Looks like your luck is in, the hose is one of the ones that serves the heater matrix, quite straight forward to change and not to dear either (£10 ish) check around that area though lots of smaller pipes that can cause problems but many still accessible from above although hand scrappers.

 

Jeff TT

 

Ok....cheerZ :D ......Will have to get it sorted next weekend.

 

Think i'll get a new rad cap as well just to totally eliminate it.

however high speed ( if that what it was ) also brings about lots of cool air through the radiator etc, this can be just enough to keep the system stable,

Jeff TT

 

Not quite right Jeff If you have ever ran a car at 70 miles an hour the temp should sit at about 75 degrees, at 90 this goes to 80 degrees at 120 miles an hour this will go up to 90 degrees and so on , just because you go faster it does not mean your car will be running cooler , the rest of your points are valid though

 

Ryan

quoted by Ryan Not quite right Jeff If you have ever ran a car at 70 miles an hour the temp should sit at about 75 degrees, at 90 this goes to 80 degrees at 120 miles an hour this will go up to 90 degrees and so on , just because you go faster it does not mean your car will be running cooler

 

Ryan your missing the point slightly.

 

Yes higher engine output (speed ) will produce more heat, that`s basic physics,the point I was trying to make was when there is a problem with the cooling system it effects the boiling temperature of the water due to lower system pressure, basic physics again. However at higher speeds and more air cooling there is a chance the system stays within a knife edge of stability until something changes ie: accepted slowing down will reduce output heat but the cooling effect of the ram air into the radiator is reduced in bigger proportion and can become critical to a point where an overheat will occur.

 

 

 

Jeff TT

any one got any idea why a zed would dump loads of water out the expansion tank , then temp guage right up , then after she cooled down a bit and refilled with water , she runs fine again ?? has happened twice in 6 months but no pipes leaking and as soon as refilled ,temp guage goes back to norm and she runs as sweet as ever !! ???? im very confused

 

I had this in the past and went through all the same Questions and none of the answers worked until I had the rad Recored then bingo sorted. The sh1t and bits of flash build up in the core elliments over the years and its worse for cars that are more weeknd motors and if you don't flush it once a year it compacts so much it wount flush. If your car is Auto its even more critical because your Rad inco-operates you oil cooler so a good enthusiastic bit of driving can reach critical mass for the poorly old Rad and it spits it dummy out.

 

Anyway hope its just the heater pipe if not There's something else for ya to look at. Oh yes by the way if you kept your engine bay a bit cleaner you'd spot these things before the do any damage. You could grow spuds in there mate. Get it cleaned :nono: :slap: :rofl:

Oh yes by the way if you kept your engine bay a bit cleaner you'd spot these things before the do any damage. You could grow spuds in there mate. Get it cleaned :nono: :slap: :rofl:

 

LOL... :D ...CheerZ bud

 

Its not all quite that dirty ...Honest :x: just a bad area... :(

 

Got big plans for this....just need big wallet now. :mad:

Piccy

problem ended up being matrix hoses at rear , One had a pinhole in it and was letting air into the system occasionally. changed hoses and no probs since.

problem ended up being matrix hoses at rear , One had a pinhole in it and was letting air into the system occasionally. changed hoses and no probs since.

I had the top one of the two replaced and that was a pain in the :smash:

Hate to think what its like doing the lower one.

I still have a turbo water pipe to be fixed........ :rolleyes:

I had the top one of the two replaced and that was a pain in the :smash:

Hate to think what its like doing the lower one.

I still have a turbo water pipe to be fixed........ :rolleyes:

 

wasnt too hard tbh mate , just very fidly , u need little girlie hand like chunk to get in there really.