Weird case of overheating, not bleeding related. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

JKL1031 · 12-31-2010, 04:33 PM

My problem:

-it is not air, the water pump, the radiator, fan clutch

I can drive the car hours before if overheats. sometimes only minutes. When it overheats, its totally at random, and continues to do it again shortly after restartup.

Without the thermostat in, it runs fine, engine will not heat up depending on ambient temp.

The engine pulls strong and is sound.

The car is warming up very fast from cold start.

No beading or intermix on the oil stick.

Could the headgasket be on its way out, or not properly sealed and sucking air in whenever it feels, or the head be bad? Again the engine runs strong and sound. thermostat has been put in and bled before by myself a pro.

fufanu180 · 12-31-2010, 05:32 PM

I have the same problem. Some sr's are more sensitive than others I guess. If you're running higher boost than the car might be running a little lean causing it to maybe get hotter faster? It's an idea I guess.

Sent from Fufanu180 in ATX!

JKL1031 · 12-31-2010, 05:33 PM

its a KA BTW. You have the same prob, how are you driving? no Tstat?

Also if anyone knows, or can check how hot their bottom hose in relation to the top and tell me.

Garber · 01-01-2011, 09:48 AM

does your coolant system gain pressure quickly? if so, BHG. your engine is pumping hot air into your coolant system.

JKL1031 · 01-01-2011, 10:27 AM

what are signs of cracked head or warped head.

fufanu180 · 01-01-2011, 06:48 PM

Oh I somehow over looked that I guess.

I removed the head and put a new gasket in. Fixed the problem. You'll know if you have a bad hg if you puff white smoke out the exhaust.

Open up the radiator cap and put a funnel on the radiator and start the car. Let it warm up, make sure the fluid is visible in the funnel and watch it. If bubbles are slowly coming up than a coolant jacket has been breached.

Sent from Fufanu180 in ATX!

JKL1031 · 01-12-2011, 06:47 PM

So if my head compression comes back ok, cand I only have a problem with the TSTAT in, and uve bled and tried all hell, would drilling the jiggle valve hole open, or running a Swirl pot eliminate the air problem?

JKL1031 · 01-12-2011, 06:50 PM

I think I do get the slow bubbles, not much smoke its winter here, but the exhaust is gargly, ive observed water come out on a parking backwards on a hill. Im running no cat as well, and if im not mistaken, water is a by product of combustion. i scooped the water up, it was clear.

JKL1031 · 02-20-2011, 09:32 PM

just an update, its warm again, so i pick te car up from shop that was looking for me a new engine. I remove the Tstat, drove the car 130 miles in 74F weather, at operating temp the hold time, and hoses are holding pressure, however both did feel a bit warm. Is there a chance that i still have an internal leak?

12-31-2010, 04:33 PM	#1
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	Weird case of overheating, not bleeding related. My problem: -it is not air, the water pump, the radiator, fan clutch I can drive the car hours before if overheats. sometimes only minutes. When it overheats, its totally at random, and continues to do it again shortly after restartup. Without the thermostat in, it runs fine, engine will not heat up depending on ambient temp. The engine pulls strong and is sound. The car is warming up very fast from cold start. No beading or intermix on the oil stick. Could the headgasket be on its way out, or not properly sealed and sucking air in whenever it feels, or the head be bad? Again the engine runs strong and sound. thermostat has been put in and bled before by myself a pro.

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12-31-2010, 05:32 PM	#2
fufanu180 Zilvia Junkie Join Date: Dec 2009 Location: Austin, Tx. Age: 30 Posts: 481 Trader Rating: (12) Feedback Score: 12 reviews	I have the same problem. Some sr's are more sensitive than others I guess. If you're running higher boost than the car might be running a little lean causing it to maybe get hotter faster? It's an idea I guess. Sent from Fufanu180 in ATX!

12-31-2010, 05:33 PM	#3
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	its a KA BTW. You have the same prob, how are you driving? no Tstat? Also if anyone knows, or can check how hot their bottom hose in relation to the top and tell me.

01-01-2011, 09:48 AM	#4
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	does your coolant system gain pressure quickly? if so, BHG. your engine is pumping hot air into your coolant system.

01-01-2011, 10:27 AM	#5
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	what are signs of cracked head or warped head.

01-01-2011, 06:48 PM	#6
fufanu180 Zilvia Junkie Join Date: Dec 2009 Location: Austin, Tx. Age: 30 Posts: 481 Trader Rating: (12) Feedback Score: 12 reviews	Oh I somehow over looked that I guess. I removed the head and put a new gasket in. Fixed the problem. You'll know if you have a bad hg if you puff white smoke out the exhaust. Open up the radiator cap and put a funnel on the radiator and start the car. Let it warm up, make sure the fluid is visible in the funnel and watch it. If bubbles are slowly coming up than a coolant jacket has been breached. Sent from Fufanu180 in ATX!

01-12-2011, 06:47 PM	#7
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	So if my head compression comes back ok, cand I only have a problem with the TSTAT in, and uve bled and tried all hell, would drilling the jiggle valve hole open, or running a Swirl pot eliminate the air problem?

01-12-2011, 06:50 PM	#8
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	I think I do get the slow bubbles, not much smoke its winter here, but the exhaust is gargly, ive observed water come out on a parking backwards on a hill. Im running no cat as well, and if im not mistaken, water is a by product of combustion. i scooped the water up, it was clear.

02-20-2011, 09:32 PM	#9
JKL1031 Zilvia Junkie Join Date: Nov 2010 Location: MS Posts: 427 Trader Rating: (1) Feedback Score: 1 reviews	just an update, its warm again, so i pick te car up from shop that was looking for me a new engine. I remove the Tstat, drove the car 130 miles in 74F weather, at operating temp the hold time, and hoses are holding pressure, however both did feel a bit warm. Is there a chance that i still have an internal leak?