As many of you know i've been having continuous overheating problems with my Z, thought this was cured the other day as the main leak (behind the back of the engine) Has been blocked up.. it was a metal heater pipe.. what we did was cut off the pipe and made a gasket to cover the hole and use some metal sealant to cure it, car did not have any leaks from underneath, however it has been leaking coolant again overnight... I've done a plenum bypass on the car.. and it still seems to leak.. was driving home from work today and the temperature gauge shot up and then it went back down again and stayed at normal.. I've noticed puddles of water under the car when going out to it the next day... any ideas?

 

What i was thinking was taking it to a specialist and having the engine out and all the hoses completely replaced.. (will need new heater pipes too), how much can i expect to pay roughly if i wish to do this.. As I am bloody skint at the moment.. a quote on this would be great..

 

Any other suggestions to what it might be?

also the car does not seem to perform as well as it did before the overheating issues.. i seem to get a lot of turbo lag at times and then it seems to be fine, i dont know if its running in safety boost.. the boost needle stays half a bar to the left of the last one.. if that makes any sense (when it is idling)

Are you sure it's coolant?...Are you having to top up the rad with coolant?

 

Is the Aircon unit still Fitted? (we tend to use screen demist alot this time of year which automatically uses the aircon system for dryer air to demist?) could be that it's the colder condensed water dripping on the floor...just a thought?

 

I assume you have not had the car long from your join date???....If it is a coolant leak then i would start with the two short hoses that run from the top pipe into the heads...these are prone to spilts which only open when warm and are closed when cold. This was first the job i did when i bought my car, along with a new water pump and thermostat....sudden rise in temp could be a 'Sticky' thermostat valve?

 

I'd change both the pipes described above and the stat as a precaution and whip the water pump off for inspection when doing these two jobs. If the pump is OK (Check bearing and corrosion) then re-fit, but might be worth the precaution of fitting a new one anyway depending on your milage and budget???

 

I'd then get all the undertrays off and undo and re-tighten all Hose clips. Any that don't budge, cut off and replace with new. (If you can afford the time, then take off each water pipe end and re-seal with sealant as you go!)

 

Would also be worth flushing the system and re-filling ensuring you follow the correct top up proceedure as you might not have had enough coolant, or too much air in the system???...do a 'how to' search on this forum for re-filling and flushing the coolant(probably best to register in this case!!...It was the best £20 i ever spent for learning stuff about these cars and i still am after nearly 4 years on here! You'll also find that more people will assist you when subscribed!).

 

Hope that's enough for now. Would have thought that most of these checks can be done 'engine in situ' and you will find as you fix one weak point it will move on to the next without a whole hearted approach! My Car is 15 years old now so leaks were expected when i bought it 4 years ago!

PS.. Safety boost means it won't go above 7psi on the gauge no matter how hard you floor it, but should still sit at centre of the gauge on idle (I stand to be corrected?)

 

Not sure but think that the ECU may kick this in to protect your turbo's if you've had it too warm and will need to be re-set after checking your coolant system!

I'm pretty sure its not the aircon, as the aircon does not work, I do not get any air blowing out of the heater vents at all.. although i can hear the fans come on.. the heating does not work as I have taken off the heater pipe which was leaking and blocked it up to stop a leak

You need to pressure test the cooling system to find the leak. Easy job and most garages have a test kit...

Water pump water seal knackered. Expands when hot and seals, then it contracts when cool (overnight) and leaks. It'll carry on like this for a few months then give way big-time. Carry a large bottle of water in the boot and keep an eye on the temp guage - and then replace the water pump, and do the timing belt at the same time as it's most likly the same age as the pump (supposed to change them every 4 years or approx every 60,000 miles).

 

Good luck

 

Jack