V35 Coolant Evaporating/leaking

[greenpool]

Hi there,

While driving yesterday (35 C heat) the coolant started to leak through the hood of the car. When I had a look it was boiling and vaporizing.

The first symptom seemed to be when the A/C temperature although on the lowest stopped being cold and then I also noticed the temperature gauge go all the way to 'H'.

I've currently got water in in the coolant tank.

About 2 years ago I had the same problem. I believe a radiator flush fixed the issue.

I'm just wondering why is this happening again. Is it expected? or is the problem more serious?

thanks..

[xntrq]

Firstly, water. I was told never to run water (unless distilled, even though, just don't do it).

Water expands in heat and boils = added pressure on the radiator = fracture. Whether it be a hairline or a large crack, when things heat up, the crack will open up and thus goes your coolant. Water can also cause rust and I've seen some pretty good rust f**k on engines where they've completely disintegrated the inlets.

Secondly, find out roughly what area it's coming from, either front, middle or back of engine bay.

Front - Radiator

Middle - Possibly some hose loose or cracked due to age or other chemicals that could have come in contact and dissolve a part. Highly unlikely that it would be anything serious like engine parts, but it is still a factor to consider.

Rear of engine bay or firewall - Likewise with middle, but could also be the coolant running into your firewall.

I wreck mainly R33 and R34s and with them, yes there an occasional problem but since your car is a V35, I'd guess there would be better stuff in there.

My suggestion:

Diagnose where the coolant is coming from, change the radiator if that is the case.

Pick up sludge or rust remover additive at your local auto store and run it according to the instructions on the bottle (usually has to be left in for a certain ammount of KMs)

Buy Anti-Freeze & Anti-Boil Coolant

Once leak is diagnosed and repaired, additive is added into coolant and run for the specified KMs by manufacturer of the additive, flush and refill coolant with the same stuff you used before.

Bit of work but would save you a heap in the long run, also gives you the peace of mind that it won't happen again, not in your ownership anyway. Also don't run your car when the temp is right up to H. I don't run my 34 higher than 75% of the temp gauge.

Estimated Total cost if DIY: $250

Edit: Don't forget to bleed the air out as well. There should be a screw plug thing within the coolant line that is the highest point of where the coolant runs, unscrew it, run your engine till it sits at its normal temp, get a mate to help or pull on the throttle cable in the engine bay (MAKE SURE IT IS IN EITHER NEUTRAL OR PARK AND HANDBRAKE IS ON, otherwise you will run yourself over with a phantom driver). Leave it off until you get a constant stream of coolant running out. It will spit air, bubbles and coolant out then when all air is bled, constant coolant. Bleeding will require you to replace the coolant lost as it goes. I do this by using a 1.5L coke bottle, cut off at the bottom, no cap and tipped upside down to where the radiator cap is, hold it down firm and funnel coolant in. You'll see the level rise up and down and up again and down lower again as it flows through the radiator.

This is a general idea coming from R33/R34 RB25 experience.

[scotty nm35]

Just search, there are many overheating threads for VQ series engines and they all point back to poor bleeding procedures. (the coolant system is fail in VQ's)

If you can hear a waterfall behind the dash, or if there is a cupful of coolant missing from the system, the whole cooling circuit can airlock causing no coolant flow. Let it cool and top it up fully from the rear bleed point as a start. You may have to re-do it a few times.

Here is a recent thread on the subject.

http://www.skylinesaustralia.com/forums/topic/418084-help-cracked-headhead-gasket/?hl=%2Boverheating#entry6713914

[greenpool]

Had a mechanic look at it and he said that the thermostat motor is fautly. Replacement/fix quoted to me was about $1000

Am I being overcharged or is this figure correct?

[xntrq]

lol yes they're bending you over and using the remaining cash to buy lubricant and lube you up.

Thermostats you can buy genuine Nismo ones on ebay for under $150.

$850 for labor, your judgement. I'm no mechanic but if it's faulty, it wouldn't leak, just wouldn't workand car will overheat unless the thermo stat is damaged itself then fair enough. Get a few mechanics to look at it and see what they say. My guts still tells me that it's the radiator and water problem

[scotty nm35]

It's 3 screws to get the thermostat out, then dunk it in boiling water to see if it opens. You will need to get the water up over 85 degrees before it does, so do it in a pot on the stove.

The mechanic is ripping you, and probably doesn't even know where the thermostat is on the VQ.

[Dobz]

Had a mechanic look at it and he said that the thermostat motor is fautly. Replacement/fix quoted to me was about $1000

Am I being overcharged or is this figure correct?

Hmm thermostat motor? If my calculations are correct this mechanic is talking shit.

Chances are it's not bled properly or you have a leak.... or your radiator cap is old and can hold proper pressure anymore.

And xntrq I have to correct you. Whether you use tap water or distilled water it will be the pressure in the cooling system that determines the boiling point. Higher pressure pushes the boiling point higher so if you have a leak or the raditor cap is old you can't hold enough pressure in the system and the water boils.

[greenpool]

Thanks all. I found someone to sort it out.

[xntrq]

Thanks all. I found someone to sort it out.

Post your solution so others may find it helpful in the near future

[bigkevracer]

And PM Scotty nm35 for his coolant bleed kit or you'll hate yourself when you try and bleed the system.

[Sakthi25]

Hi Mate,
I bought a skyline v35 250gt 2005 model clocked 75000 kms last week,, i experienced pretty much the same problem you had experienced aeround february this year.In one service station they said coolant flush should solve it and in other they said thermostat and coolant flush to be done and gave me a quote of 900$ .. please tell me what you ended up doing which solved the issue for you.. need an advice badly,, two days back when i was driving it got so heated up even smoke came a little bit piut of front bonnet and then the cooolant was spilled and fuming,,Is it the thermostat which is causing the problem.Thermostat change with a coolant bleed should solve it??

[Sakthi25]

hI Greenpool,

I badly need an advice on how did ya sort this problem out,, im experincing the same in my V35 250GT,, what solved the issue,, thermostat and radiator/coolant flush fixed it? need a peace of mind here,, thanks!!!