Engine overheating.... Sometimes

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scottp11

The Seniorest Member....
I have a 93 civic hatch with a JDM B16A swap. Just recently, within the past 2 weeks, my car has started to overheat. The gauge climbs up to about 3/4 high, and will go back down eventually. Sometimes downshifting helps. It does it everytime I drive longer than 5 minutes, but not so much at slower speeds.

I have a Koyo aluminum radiator (brand new), just flushed the coolant and replaced with new, Flex-a-lite slim fan, which is coming on, Samco hoses, fairly new thermostat.

Thanks for everyone's help in advance. I really need to get this figured out before my engine blows.... :(
 
the reason i ask is because i had the same problem when i was using an Autometer water temp gauge.. i didnt use the sender that came with it, i just spliced it into the stock temp sensor.. i replace my radiator and thermostat and it still did it... once i got a gauge cluster that had a working temp gauge it read normal while the other was up to hot.. it had me trippin all the time
 
the reason i ask is because i had the same problem when i was using an Autometer water temp gauge.. i didnt use the sender that came with it, i just spliced it into the stock temp sensor.. i replace my radiator and thermostat and it still did it... once i got a gauge cluster that had a working temp gauge it read normal while the other was up to hot.. it had me trippin all the time

yeah im with eg6sir, it sounds like an electrical problem to me
 
I got the JDM EG6 guage cluster. I've had it for over a year. It worked perfectly, no overheating issues until just about 1 1/2 to 2 weeks ago. Is there a way to test it, to see if it is the guage cluster? Buy an external temp guage?

BTW, thanks for the responses, I need to get this figured out.
 
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try replacing the temp sensor.. it may have gone bad..
 
So if the temp sensor is bad, my car is not really overheating, right? Just the sensor is bad. I hope that's the case.
 
if its not working properly it may send out the wrong signal saying you're running hot.. thats the only thing i can think of why it would do it out of nowhere since you've covered everything else that would cause it

only other thing i can think of is the headgasket..
 
I hope it's not the water pump also. What are some symptoms of a faulty water pump? Wouldn't it run hot all the time? And the gauge never goes all the way to the top, just about 3/4 the way, then back down.

Yeah, I just flushed the coolant and replaced with new coolant. 50/50 pre-mixed.
 

Hey, could've forgot to bleed it. My mom's Concorde did the same thing after a new coolant bottle, thermostats and flush was done. Turns out it was just a air pocket.
 
Should be a little bleeder valve where the upper radiator hose enters the engine. idle the engine to operating temperature and unscrew that valve, bleed the air out of the system. Use caution though, it'll be spewing hot coolant, too.

Also, make sure the fan is spinning the correct direction.
 
I hope it's not the water pump also. What are some symptoms of a faulty water pump? Wouldn't it run hot all the time? And the gauge never goes all the way to the top, just about 3/4 the way, then back down.

Yeah, I just flushed the coolant and replaced with new coolant. 50/50 pre-mixed.


Naa, bad water pump loses water from the system. Honda water pumps cannot fail except for the seal around the shaft. There is a "weep hole" on your water pump. If coolant is coming out, it needs to be replaced.

Sounds like you need to get a chilton! (or a haynes if chilton is absolutely unavailable.)
 
Naa, bad water pump loses water from the system. Honda water pumps cannot fail except for the seal around the shaft. There is a "weep hole" on your water pump. If coolant is coming out, it needs to be replaced.

Sounds like you need to get a chilton! (or a haynes if chilton is absolutely unavailable.)

I have both, but have never had problems with overheating before this. But yeah, I'll check that bleeder valve thing tonight when I get off work. Thanks for your help.
 
Well, I'm replacing that coolant temp sensor right now. I got it off a 99 Civic Si head, that never had any overheating issues, so.... I'll find out if that's the problem. I gotta wait till the engine cools down a little bit more.

I can't find the "bleeder valve" you're talking about. I looked at both head's (mine and the 99 Si) and don't see any valves in that area.
 
The bleeder valve is right were the upper rad. hose meets the engine. It looks like a large brake caliper bleeder. It points directly up at the hood. I'm with K2e2vin, He said the temp drops when he down shifts, the higher revolutions will make the water pump turn faster and flow a little harder, forcing the air pockets through the system. He doesn't know where the bleeder is which means he deffenitly did not bleed it. I'd bleed it first..sice that won't cost you anything but time... then see if the needle stops dancing around.

If that doesn't work.... check for coolant seepage around the timing cover seals lie PHYERGOD said.... a bad seal on the water pump could cuase these same symptoms.
 
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