Good news:

 

Went to Santa Pod today to test times with the new intake - got best time yet of 14.204s @ 100.91mph - woohoo! :D

 

Bad news:

 

Had a water leak straight after my only run, which slowed when the car cooled down. Looked like the hose going through the firewall to the heater matrix had a fine pinhole puncture. So when the time came to go I set off cautiously, but 2 miles down the road steam everywhere and water all over the road :mad: Luckily I did manage to pull over and cut the engine before *all* the water flowed out, the remaining water came out while engine off.

 

Phoned the AA who arrived in 20 mins :) and found the offending hose, now with 1 inch long split in it. He didn't have any replacement hoses, with 90deg bend in so patched the hole up temporarily and filled the rad up with water (I questioned about the lack of coolant but he said it was fine to get home).

 

Anyway, car started fine no steam, set off again and a mile down the road the temp gauge is at max :( . No more leaking water so I don't know whats going on :confused: . Pulled over immediately.

 

The upshot of which is that the poor zed went back to Daventry on the back of a flatbed truck and is now waiting in a garage in Dav to be mended/diagnosed.

 

Anyone shed any light on the overheating? My thoughts are that the refilling of the water system has created airpockets, so I've asked the garage to flush the cooling system completely and change the mended hose. Would airpockets cause high temp readings? The car starts ok, which I only did to get on and off the truck.

 

Good news was pretty shitty compared to the bad news eh!

 

Thanks for your help

 

Pete

A number of issues to think about:

 

i) If the sensor is sitting in an air or vapour pocket then the temperature should appear lower since heat transfer coefficient for gases is less that liquids, thus bigger resistance between fluid and the sensor. This is the reason when a complete dry system can show a lower temperature. Ouch!!!!

 

ii) If you have a severely air locked system then you will get all sorts of temperature problems due to maldistrubution of the coolant. Some coolant paths will get mainly water whereas others can get mainly air.

 

iii) If the radiator icontains lot of air then again bad heat transfer coefficient between contents of radiator and air. Thus the coolant will not get as cool. I'll keep my fingers crossed that this is the case.

 

Same thing happened to me about a year ago. Fortunately just as I was pulling into my driveway. AA fixed by wrapping self amalgamating tape around the hole then topping up radiator which was virtually still at the top. BUT, in my case this was the good news. When they opened up the radiator they swa saomething akin to a chocolate milkshake. I had been driving around with a cracked cyclinder head without even noticing it

:( :(

Thanks for the reply mate, hopefully the garage will tell me iit is (iii), though its this bit that scares me:

 

Originally posted by Posidrive

When they opened up the radiator they swa something akin to a chocolate milkshake. I had been driving around with a cracked cylinder head without even noticing it

:( :(

 

I noticed brown sludgy stuff on the coolant dipstick while I was looking for the leak :( A bloke with me commented that it smelt like rad-weld :confused: . Could this be the same thing you had? What was the remedy? Costs etc?

 

Cheers

 

Pete

My car kept over heating due to air in the system, with mine it wasnt realy a case of fill and go, more like fill, run a bit, add loads more water, run a bit, add more etc until full. You never know there might be more air in there.

Oh and that's obviously filling through the rad cap not through the dipstick place like someone i knew did! :p

It is often forgotten how much air actually is disolved in the water itself, this will release when superheated as in a pressurized cooling system.

 

When topping any amount of water loss in a zed be sure to have the heater temp on 40 so as to ensure the heaster matrix circuit is open and also that the water going in contains oxygen so check the water level again later, in fact always top up with at least a 50% water antifreeze mix.

 

Jeff TT

Hope it turns out alright for ya pete, but you should know them red zeds are not as strong as the black ones:D

 

Buy the way did Adam improve on his time or was it a bad day all round.

 

P.S you can change the time on your avatar now;)

Thanks keith, twas a good day wasn't it - apart from the trip home :rolleyes:

 

Didn't see him run again after I kicked his ass (Sorry Adam :) ) :D :D Think hes got a fuelling prob cos he's got WAY more BHP than me. Or maybe red is weaker but faster...

 

LOL I will change my avatar!

 

Still v concerned about the light brown sticky stuff on the coolant dipstick after seaching on the forum :( Hopefully I'll find out when the "pros" look at it tomorrow.

 

Pete

I'm not sure that you really want to here this. Mine was an oil/water mixture probably more oil than water. So you're probably OK on that front although the about 1 month earlier when I checked the water there was a small amount sludgy deposit areound the radiator cap. Put uyou finger in the water and if it feels oily then start sweating. I'd lost all water twice in the previous 60k miles so it was sort of inevitable that I would have head problems eventually. Cost 2k+ to fix. 1.5 k for the basic head gaskets job, 600 for the recommended valve regrind plus 200 for a reconditioned head. I know that perhaps I should have bought a ne head but theres only so much that I'm willing to spend of a car that has done 170k miles. This was all done be SE so they did a very good job but took ages to do it. The local guy that does most of my work would have charged 50% more!!!

£1.5k for headgasket replacement??? :eek: I'm reviewing my prices!!! :D

I take it that you mean I was charged too much? This did include the evil VAT. At the time I was pretty happy. Just before I got the car just under 6 years ago the previous owner had two new heads when the coolant was lost. Best part of £5000 on the invoices for the job done by Nissan. It was a company car so I suppose fleet managers don't care about the cost.

Erm yeah thats what I meant lol

 

So what times did everyone get then???

:mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad:

sorry, what I meant to say was

:mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad:

possibly a little

:confused: :confused: :confused: :confused: :confused: :confused: :confused:

and a touch

:eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek:

but mainly

:mad: :mad: :mad: :mad: :mad: :mad: :rolleyes:

I recon youve Blown head gaskets and damaged heads, it happens all to quickly, hope for your sake you havent but since ive been there done that lol, expect the worst, as then if its not that bad its a relife, rather than convincing yourself you havent done anything, What the AA guy did is a no no bigtime.

 

So what were your times ADAMR? i mean you have some serious power there no?

Should have had a decent trap speed at least?

The car is going for a rolling road set up on Wednesday - fuelling's still f**ked and the cars got no top end. 60' times are the same as last year when I ran 13.545@107mph (2.32 secs) but after I get to the top of 2nd its all over:(

 

Boost pressure seems fine at 1.35-1.4 bar, and when I'm driving on the motorway its torquey as f**k - quarter to half throtle in fifth and it flies - way faster than it was before, but on full throttle , theres flat spots, massive popping when you back off the gas etc etc

 

ho hum 8.5k lighter and over a second slower:rolleyes:

 

oh and if you wanna laugh while I'm getting the thick end of it thats fine, so long as when its running right I get oral to completion;) :D

Ok got the car back from garage, they've flushed the coolant and changed oil and filter like I asked. But not changed the duff hose, muppets, "...it's an import, parts are hard to get...3 or 4 weeks..." ITS A BLOODY 8 INCH PIECE OF HOSE!!, I'd have got it from Halfords if the car had been driveable :rolleyes: :mad: Some people!

 

I asked about the brown cack in the expansion tank, the guy said it could be the start of headgasket failure :( :mad: :( He priced the job up at £1200, 25-30 hours engine out :confused: .

 

Hoping for a bit more advice on this: There's never been any sign of water down in the oil, only this possibly oily brown stuff on the expansion tank dipstick, which is still there after flushing. (Suppose the stuff in the expansion tank will stay there despite flushing ?)

 

I told him I'm not handing over loads of money when he wasn't really sure. Asked about how to test if the gasket's going, he said they might be able to take a look through an endoscope down the spark plug recesses :confused: is this possible cos I'd rather know thats the problem before authorising any work anywhere?

 

Plus they hadn't had a 300zx in before.

 

One good thing is that the overheating was due to airbubbles in the system.

 

Sorry to hear about your probs Adam, hopefully it'll be something nice and cheap :)

 

Cheers again

 

Pete

When mine went there was not a drop of water in the oil. It was all one way traffic the other way.

 

How much brown stuff was there? How brown is is? The original gunk that I saw was pretty light that my neghbour who owns a garage thought as some of that block that is used to fill pinholes, sort of magnolia colour but when it went big time it was the same colour as dairy milk chocolate. On a positive note, as long as you keep an eye on the temperature guage and the oil level, if you get the same failure as me as least you can probably drive it (although don't blame me if it goes pearshaped). You'd just have an oil cooled s opposed to water cooled Zed. Probably run a little hotter due to the differenc ein specific heat capacity between oil and water though.

 

One final word. If they haven't seen a Zed before, don't go anywhere near them. Mine had both heads replaced by Nissan 5 1/2 years ago, and in theory they know what they're doing. Although the head job was OK I suppose, they broke just about every connector/clip in the engine bay and lost half the varous bracket around the engine that hold connectors, etc. If only I'd known more then:(

I dont think its head gasket!,the slightly brown slightly gungy stuff ,in my opinion is a form of stale water/rust particles that are in bottom of exspantion tank,over a period of years it must build up with some form of shit,especially if someone has previously run it with no antifreeze!get it cleaned out totaly(god knows how you remove the x tank ,looks a bummer to get tank out!,just get em then to replace shagged pipe,,if it was oil in water du to head gasket it would show around underside of engine oil filler cap(brownish sludgy stuff like runny choco ice cream)and it would be in rad on underside rad cap,could be wrong but have gut instinct its not the head gasket(hope i'm right!)

PS,you say they have flushed it ,have they actualy cleaned out the x tank aswell!

Thanks mate - looking through various searches I see you've had waaaay too much experience on this topic :( .

 

Hmm the brown stuff is more like a pastey magnolia colour, certainly not dark, the covering on the dipstick was/is pretty uniformly spread over the bottom couple of inches, a little guey towards the bottom.

 

Hopefully Jeff will look at it soon

 

It drove home from the garage fine but there's no grin factor when you've got a nagging "impending doom" feeling. The garage certainly tested it : +20km on the clock! :rolleyes:

 

Thanks again posidrive

 

Pete

Originally posted by andyduff

£1.5k for headgasket replacement??? :eek: I'm reviewing my prices!!! :D

 

Yeah Duff maybe you should....Nissan wanted £5K in labour off me for a headgasket swap. Since their technicians took about 3 hours to work out my car is an import, reckon you should be aiming nearer the £7K mark....!

 

 

Hope all goes well with your poorly Zed. Mine overheated once and I got away with it (phew!) but seems like bad news all round. Best of luck!!!

Thanks Tony!! They cant have cleaned out the x tank because the gunk was looking just the same (I think) and thy would have at least wiped the dipstick.

 

It probably comes out via the wheel arch, anyone? Might be worth doing to wash it out properly.

 

I hope you're right too, do feel a bit better though :)

 

Pete

So what was used to temp repair pipe,has you obviously drove it home,would be a bit risky going to far i think,take of the pipe,go to Autoworld up town,give him pipe,ask for same as,if not in he will get it for next day,bit safer than leaving dodgy one on,and if you get pipe i will come round ,give you hand;)