# Heater Question???



## ♣300zx♣ (Aug 6, 2004)

OK, on my 86, 300zx, My heat will go ice cold, after the car is warm, and the temp. gauge will rise not to the point of overheating, then the heat works. Whats up, any help would be great.


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## z31 (Oct 19, 2004)

♣300zx♣ said:


> OK, on my 86, 300zx, My heat will go ice cold, after the car is warm, and the temp. gauge will rise not to the point of overheating, then the heat works. Whats up, any help would be great.



check your coolant level. you might have air in the system, or possibly a clogged line. When's the last time you flushed the coolant?


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## ♣300zx♣ (Aug 6, 2004)

z31 said:


> check your coolant level. you might have air in the system, or possibly a clogged line. When's the last time you flushed the coolant?


I dont know, but my coolant light keeps coming on, and I fill it and in about a month its low again. I dont have a leak eathier.


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## Domdogg123 (Nov 12, 2004)

♣300zx♣ said:


> I dont know, but my coolant light keeps coming on, and I fill it and in about a month its low again. I dont have a leak eathier.


are you sure you dont' have a leak? Drive your car around for about 10-15 mins until it's warm, then take the splash guard off, and put a big piece of cardboard or paper under the engine. Leave it overnight. You might not be able to see a small leak cause the splash guard will catch it. Common leaky places are the radiator pipes, and the radiator drain hole. Otherwise, has your car been smoking? like white smoke? that might indicate that you have a blown headgasket and are leaking coolant into your combustion chamber....


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## Zen31ZR (Mar 24, 2004)

A blown head gasket doesn't always show up as white smoke however. Only if enough is escaping into the CC to create the effect. You _might_ get a low compression reading out of that cylinder, that would be the only way to tell. 


From Bror Jace:


> My Honda showed very few classic symptoms of a head gasket leak ... coolant looked clean, no milky residue in the oil, etc ...
> 
> I discovered the leak by doing consistent UOAs ... which showed excessive sodium, potassim and greater lead & iron wear. Mechanics thought I was jumping at shadows because the car ran flawlessly ... until they pulled the head off and found the source of the leak....


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## ♣300zx♣ (Aug 6, 2004)

[email protected] said:


> A blown head gasket doesn't always show up as white smoke however. Only if enough is escaping into the CC to create the effect. You _might_ get a low compression reading out of that cylinder, that would be the only way to tell.
> 
> 
> From Bror Jace:


No, Its a fairly new engine...with about 65,XXX or so it runs fine with no smoke. It only started doing this, when it got really cold out.


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## z31 (Oct 19, 2004)

♣300zx♣ said:


> No, Its a fairly new engine...with about 65,XXX or so it runs fine with no smoke. It only started doing this, when it got really cold out.


Started doing it when you started using the heat?

My SS did this two years ago, try backflushing the heater core. As far as the coolant loss, make sure the cap is holding good pressure. I had a phantom leak b/c of a bad cap too.


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