A lesson about overheating! (long post)

 

One of the pipes behind the engine split a couple of weeks ago - it was duly replaced and i had a couple of other bits and pieces done at the same time. I got the usual advice to cary around soe water with me, park uphill and keep topping it up over the next few days to get rid of the airlocks. Well, I had been driving around without any problems for a few days and only had to top up about 50mls total.

 

Today I was happily pootling down the motorway when I noticed my temperature needle beginning to rise (only a few degrees but it wasn't at its normal resting place bang in the middle) - Aha! i thought - I'll put on the heater at 40 degrees and pull over if it gets worse . I drove for another ten minutes and the needle didnt get any worse - in fact it settled down the normal level - brilliant I thought. Then, whilst i was crawling along a slip road towarda a roundabout in the blazing sun the engine suddenly died out. I was surprised I had stalled it and tried to restart but it wouldnt. I sat there for about five minutes and tried again - engine sprang into life and I pulled over onto the hard shoulder. Opened the bonnet and there was a general fog of steam hovering over the engine but I couldnt particularly tell where it was coming from. Using a towel I carefully opened the radiator after the engine had cooled a bit and there was hardly any water in it!!!

 

 

I thought i would wait further whilst things cooled down before adding any more water. Whilst I was waiting a van pulls up on the hard shoulder - chap jumps out and introduces himself and gets on with looking over my car - its none other than the legendary AndyDuff - God of Z Techincal knowledge!

 

 

He looked my car over and suggested a couple of things I needed to do like swapping my knackered rad cap and getting a compression test in the cooling system then he jumped in his van and was off - BIG THANKS again Andy for your kind help. So I filled up with water ad slowly drove to my mate's house.The radiator was almost completely empty though without an obvious leak!!! Needle stayed right where it should be but when I got there I could hear an angry "bubbling sound" from the front right corner of the engine and on looking at the rad cap there was a bit of whistling and steam escaping from it.

 

 

Looking underneath the car there seemed to be two main areas that were dripping. First one was approximately in the area where the radiator filler cap would be if you dropped a straight line from its normal position to the ground. Second drip was in approximately the area where the OIL filler cap would be if you dropped a straight line to the ground. In both cases there wasnt a huge amount of water coming out and it seemed to stop relatively quickly.

 

 

 

Left the car six hours - topped up the radiator again and it took about two litres of water (I dont knwo how much of this was previous airlocks as i had left he car parked upwards). I watched it for a while but when the car was stationary and at rest the radiator level didnt drop at all. I put the cap back on and drove home - no problems at all with overheating or dumping water though I did notice a trail of drips coming from approx the front passenger headlight when i stopped once. Radiator cap was rock solid.

 

I'm therefore quite puzzled as to what has actually happened to the damn thing.

 

 

1. I definitely need a pressure test which I am going to do this morning

 

2. I need a rad cap - I know there are various "performance"ones e.g. Nismo - anyone got any experience of these and the best place to get one from on a Saturday morning or should I stick with a standard cap (in which case where can i get one of those on a sat morning)?

 

3. Do I have a leak at the bottom of the engine or was the water just from the expansion/overflow/AC tank? (it was cold water BTW)

 

 

 

And lesson learned - if your temperature needle goes up STOP and investigate. As AndyDuff explained I put on my heaters at full chat and thought I had solved the problem as the needle came back to normal - in fact because the coolant level was heating up the temp gauge rose and when it leaked out of an unknown location it got to the stage where the temperature probe was no longer being dipped in the stuff so the needle started to fall again EVEN THOUGH THE TEMPERATURE OF THE ENGINE WAS STILL GOING UP!!

 

no signs of HG failure at roadside and it was chemical sniffer tested two days ago whikst in garage - all negative.

 

 

So any ideas peeps??

 

 

cheers (sorry about the long post)

kricky mate. I think i'll wait for the film instead of reading this :rofl: :rofl:

Small world TurboZ - YOU pulled over when my tyre shredd on the M61 - many thanks for that - isnt the Z world small and amazing?

 

Now you are part of the story we will have JackBlack play you in the film looking at the screen and saying "Man that is one LOONG M*thaf*ckin post!

Small world TurboZ - YOU pulled over when my tyre shredd on the M61 - many thanks for that - isnt the Z world small and amazing?

 

Now you are part of the story we will have JackBlack play you in the film looking at the screen and saying "Man that is one LOONG M*thaf*ckin post!

:rofl: :rofl:

Yeah that was me mate :) Couldnt leave a fella zedder by the road without checking you were ok.

Still waiting for you to turn up to mascrat sometime ;)

 

Catcha later mate

Andy told me about this lol.

 

He is now officially a white van man :rofl:

Hello ther Saz - you have PM!

oh no i dont :rofl:

Uh Oh no you dont as I seem to have become a registered user overnight!!

 

Saz any chance of asking Andy about my electric seat problem? I forgot to mention tom him yesterday as I was doing my nut about the car!!

Im sure I can manage that my email is

 

z009athotmail.co.uk

 

email me and ill get him to reply chuck!

Edited August 2, 200817 yr by Saz

He is now officially a white van angel

Blimey lucky git. The rest of us have to wait weeks to get Duffer to look at our cars, and you also had help from turboz as well. I drive round and don't see another Z for months.

 

Anyway you should be able to get a cap from most motor parts suppliers.

 

Have to say that I had problems with my cooling system, matrix went, etc etc.

 

The cold water may well have been condensation from the air con.

 

Good luck with it.

 

Darrell

Cheers Darrell

 

Im never quite sure when the water is overflow or when its been dumped from the engine!

 

Further development today:

 

System was pressure tested and the guy at the garage said he couldnt find a leak anywhere. Since the head gasket tests have been negative as well I can only assume its the rad cap or a really difficult to find leak that only occurs under very high pressures.

 

 

After topping up the radiator i can drive it around without any problem as long as i treat it sensibly and there is no leaking or dripping from underneath. If I give it the full beans however, the needle starts rising within a couple of minutes, I get dripping from underneath the car (mainly an area underneath the passenger side Headlight), and the is a loud "bubbling" sound coming from the area of the passenger headlight (as far as i can make out).

 

 

Does anyone have any idea what the fk is going on with my car? If I could find the problem I could get o with actually fixing it!! At the moment I am looking for a performance Radiator cap on Ebay - is there any advantage with these over a standard cap?

The stock rad cap is more than capable of doing it's job even on a modified zed. Either source a Nissan one or borrow one for a couple of hours from a nearby zedder to eliminate that as the cause.

You happy the viscous fan is working correctly at speed ?

Can you list exactly what jobs you had done whilst repairing the split pipe.

Oh and with engine running, have you unscrewed the air bleed screw on top of the rad until water appears to be wanting to come out ?

smithy

Thanks Smithy!

 

"Either source a Nissan one or borrow one for a couple of hours from a nearby zedder to eliminate that as the cause."

 

 

I have ordered one today off ebay - its a standard one though i notice that some of the upgrades seem to have different opening pressures. Unbelievably, Lythgoe Nissan were unable to source a radiator cap even after giving them my chassis number. The guy on the phone sounded as though he had never heard of a Zed!

 

 

 

"You happy the viscous fan is working correctly at speed ?"

 

Not sure about how to test this mate? Excuse my ignorance but is this the Radiator fan? in which case it seems to be working fine as far as i can tell.

 

 

"Can you list exactly what jobs you had done whilst repairing the split pipe. "

 

Not huge amounts just brake strip/servicing, installation of SS brake line, fitted HID lights / ballasts, Apexi induction, Oil and filter change, Head gasket sniffer test.

 

 

"Oh and with engine running, have you unscrewed the air bleed screw on top of the rad until water appears to be wanting to come out ?"

 

Yes - have done this.

 

 

To my mind the water seems to escape only after hard driving and when the temp needle shows overheating I usually have to replace about two litres in the radiator. As above, the MAIN leak seems to come from the area underneath the passenger headlight and a smaller one at the area under the oil filler cap but could these be due to expansion tank dumping??

you got email Sirmixalot

Thermostat,if not opening will cause overheating and blow water out of overflow pipe at top of rad on right hand side.

Good tip - thanks Blue Nik - I am going to order one tomorrow!

i have the exact same problem with my car, i can't find the couse ether, i've changed the rad cap and didn't work, the last time i went out i came back and parked up and as soon as i turned the ignition off about 2 ltrs of water excaped out the expantion tank even though the temp gauge was at normall :( it's just sat there since, if i don't find the problem soon i'm going to scrap her which i really don't want to do

 

 

i had the same problem with a gt4 that i had, after the head gasket blew (coz i kept driving it like this) i found the problem to be a blockage in the cooling system (turbo water feed)

oh and i took the thermostate out and still the same

Blocked Rad ?

There can be quite abit of oil in the coolant system, possibly flush that through see how it goes from there.

the rad seems to be fine, there was loads of dirt and grime on the out side of the aircon rad which was restricting the air flow through the cooling rad but i cleaned that of and it wasn't that :(

cold pressure test the system to see if you have any external leaks best way to check if no water escaping that way try thermostat make sure the viscous fan is free when cold and gets harder to turn when up to working temp and not free wheeling. water will blow out your rad cap top your expansion bottle then over flow. thermostat or fan sound like a likely option (dose your rad start get hot when its at about 88 degrees if not definatly thermostat