well its been 30mins since i did the block test kit and guess what?

 

 

it stayed blue

 

this is the kit i got

 

http://www.uktools.com/block-tester-p-12508.html

 

Tests in seconds for:

Cracked Blocks

Leaky Gaskets

Cracked Heads

Warped Heads

When Fluid Turns From BLUE TO YELLOW Combustion Leak is Present.

 

well its still blue...

 

so what on earth is causing my overheating issue.

 

The car has only ever reached 127degrees once. all my testing I've never let the car get higher than 105 as I've shut the engine down once it approaches 100c

 

So im now stumped

 

But im glad its not a blown head gasket.

maybe a long shot but could faulty intercooler cause overheating

 

All the intercooler does is cool the intake air as it gets hot as it goes through the turbo housing, simply brings down intake temps, For the intercooler to not cool enough would mean it had a hole in it/split/leak... then the engine would run like a sack of potatoes.

ah ok never had a turbo before but i thought the intercooler cooled the exhaust gases/my bad

ive had 5 300zx's, this isnt the first one ive done a coolant change on lol, or changed the water pump or thermostat for that matter.

 

Last zed never had any of these issues after id changed water pump and thermostat.

 

Well i figure you are no fool when it comes to 300zx's never assumed otherwise, but everybody makes mistakes.

 

Like the guy who fixed my first Z from the club here, oh yeah mate ill fix it ive done it 10 times before.... does plenum pull, fixes the water leak, then put the windscreen squirter hose onto the balance pipe and snapped 4 rods...

 

Is fixed really the correct term?

Well i figure you are no fool when it comes to 300zx's never assumed otherwise, but everybody makes mistakes.

 

Like the guy who fixed my first Z from the club here, oh yeah mate ill fix it ive done it 10 times before.... does plenum pull, fixes the water leak, then put the windscreen squirter hose onto the balance pipe and snapped 4 rods...

 

Is fixed really the correct term?

 

your ok, did all my own work on the zeds ive owned and a few on other members cars as well.

 

But this problem eludes me.

 

Unless its still a blocked rad issue, think its off to the shop tomorrow to get some food coloring and stick that in my rad, see if it comes out of the heater matrix hose at the back.

your ok, did all my own work on the zeds ive owned and a few on other members cars as well.

 

But this problem eludes me.

 

Unless its still a blocked rad issue, think its off to the shop tomorrow to get some food coloring and stick that in my rad, see if it comes out of the heater matrix hose at the back.

 

Sounds like a solid plan to go with.

 

I guess see how that goes, there really isn't many other possibilities left.

 

All be worth it when it's right though.

Sounds like a solid plan to go with.

 

I guess see how that goes, there really isn't many other possibilities left.

 

All be worth it when it's right though.

 

running out of options to be honest lol its either that, or radiators blocked again.

arent the tubs water cooled on a zed? any chance some of that crud that was in the rad has blocked a turbo gallery slowing the flow around the engine and causing the tub to get hotter and therefore the water? just throwing some ideas out there coz it looks like your running out of places to look!!

arent the tubs water cooled on a zed? any chance some of that crud that was in the rad has blocked a turbo gallery slowing the flow around the engine and causing the tub to get hotter and therefore the water? just throwing some ideas out there coz it looks like your running out of places to look!!

 

doubt that would cause over heating as the turbos are a secondary water system feed off the same part of the cooling system as the heater matrix.

water pipe colapsing under pressure and acting like a valve?

water pipe colapsing under pressure and acting like a valve?

 

not yet, going to give the block test one more go tomorrow before removing the thermostat completely and giving the radiator a good flush through, something is stopping it cooling how it should.

water pipe colapsing under pressure and acting like a valve?

 

thats what i was aiming at

ian seems the trouble started at the water bypass but dont know enough to know if a water bypass would cause this much overheating issues

is there any way that when you did the bypass something solid like a nut or bolt or washer or something could have gotten into the cooling system and be blocking it? ive never done a bypass so i dont know what the chances really are of this happening but anythings worth a shot?

its nothing to do with something like that. it most likely is airlock somewhere or a major blockage.

 

bypass pipes have been changed twice and no way to get foreign objects in there and if i did and the blockage was at the turbos all it would do is cook the turbos until something failed on them.

 

the blockage (if in deed it is) will most likely be the heater matrix thus not letting me get air out of the system, or a air lock that isnt bleeding.

 

only other thing would be the radiator blocked again. ive pretty much replaced everything cept the heater matrix and the engine its self.

well i geus all you have to do then is bypass the heater matrix and see if it makes a difference

meant to say as well

iv got a working heater core if thats the problem you can have it coz its one ov the many parts i have thats are taking up spece

meant to say as well

iv got a working heater core if thats the problem you can have it coz its one ov the many parts i have thats are taking up spece

 

well i get no heating so i think i might have to take you up on that bud. not sure yet though.

well itshere if you need it

this is rubbish i need to resub to edit

its just the core no pipes but it works

ok long shot time you say the engine was rebuilt if the head gaskets were patern parts

they might not have the correct opening for the water ways over time they have become blocked or restricted this could efect the way the air gets out or not in this case

or just don't circulate this is a very long shot

I reckon it's as simple as a rad blockage or an air lock mate. I've had some cracking air locks over the years, taken me forever to bleed out and find, but 9/10 an overheating issue, when you've replaced the stat, pump, pipes, flushed it and flushed it again, is just a blocked rad. If there's been a load of silt in your engine before and it's now infected two rads, there isn't much you can do about it :(

 

I've still got the standard manual rad if you need it just to figure out the problem, I just can't get to you for a while, as I just bought Davezx's Alfa and need to do an oil change and check everything out tomorrow.

ok long shot time you say the engine was rebuilt if the head gaskets were patern parts

they might not have the correct opening for the water ways over time they have become blocked or restricted this could efect the way the air gets out or not in this case

or just don't circulate this is a very long shot

 

id consider this if it wasnt for the fact it all started when the thermostat failed. was running fine before then.

 

think i need to get a hose at it some how and see if i can get what ever is in there shifted. i just dont know how im going to get a hose to it.....

could you connect the hose to the water bypass pipe ?

I would remove the rad and flush it. then remove the thermostat and double check it, then flush the engine from the top hose so it runs out the lower hose, then reverse the flow. also i would remove the water plugs either side of the block, think it was 2 square ended plugs and flush the block again see how much comes out of the block itself that way. also i would disconnect the matrix and flush that and flush through the pipes from the matrix. I'm wondering if the pipe below the lower plenum from the heater matrix could be blocked, and another thing has anyone used radweld or gasket sealent when assembling the engine.

 

After all that you might have a cooked mouse in one of the pipes blocking it lol.

 

Good luck mate and will be watching this with interest.

I would remove the rad and flush it. then remove the thermostat and double check it, then flush the engine from the top hose so it runs out the lower hose, then reverse the flow. also i would remove the water plugs either side of the block, think it was 2 square ended plugs and flush the block again see how much comes out of the block itself that way. also i would disconnect the matrix and flush that and flush through the pipes from the matrix. I'm wondering if the pipe below the lower plenum from the heater matrix could be blocked, and another thing has anyone used radweld or gasket sealent when assembling the engine.

 

After all that you might have a cooked mouse in one of the pipes blocking it lol.

 

Good luck mate and will be watching this with interest.

 

i would, but my biggest problem is i live in a first floor flat so cant get a hose pipe down to the car :( ive been using the lower radiator hose attached to the top intake pipe and having to pour water in through that to get it too flush. but to say its not very effective is an understatement. doubt its shifting anything, but had to give it ago.

 

and the car wouldn't make it any where to get it close enough to a hose pipe, really cant wait till i fecking move.

Maybe thats the problem. Maybe your not flushing it through with a strong enough force to dislodge the crap build up?