How do I fix my overheating problem?

Tiny
THANVAS
  • MEMBER
  • 1991 HONDA ACCORD
  • 200,000 MILES
Can you help me with my car overheating? I'm running my car with no thermostat. I by pass the fans for the condenser and for the radiator so they are always on. I have a new radiator. I don't have any coolant leaks.I just replaced the water pump. The car is still overheating. I could drive it for around 20min before it overheats. Then I have to turn on the heater to bring the temperature down. I can't figure out what the problem may be.
Saturday, September 10th, 2011 AT 2:00 AM

14 Replies

Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
So your not losing/replacing coolant?
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Saturday, September 10th, 2011 AT 2:15 AM
Tiny
FIXITMR
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Is your AC radiator dirty blocking airflow?
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Saturday, September 10th, 2011 AT 2:26 AM
Tiny
THANVAS
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  • 46 POSTS
I'm not losing any coolant and the radiator is brand new.
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Saturday, September 10th, 2011 AT 2:33 AM
Tiny
FIXITMR
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Yes I know are you saying your AIR CONDITIONING radiator is new too?
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Saturday, September 10th, 2011 AT 3:58 AM
Tiny
FIXITMR
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Check your plugs to see if they are really white tip color. You could be running to lean which means running hotter.
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Saturday, September 10th, 2011 AT 4:19 AM
Tiny
JOESMITH
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  • 4 POSTS
Are you sure your not running cold? Bypassing the thermostat seems kind of bad. I'd say the coolant is not circulating if its overheated
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Saturday, September 10th, 2011 AT 8:55 AM
Tiny
THANVAS
  • MEMBER
  • 46 POSTS
I'd been running without the thermostat for two years and the car was running cool and not overheating. Joe Smith, I also suspect I might have a problem with coolant not circulating properly around my engine, because when I touch the bottom of the radiator hosing it seems hot and shouldn't it be warm or cooler? What would be the best way to troubleshoot a coolant circulation problem? I have tried disconnecting the top radiator hosing and turning on the car momentary to see if water is gushing out and it does, so this should at least tell me that my water pump is working right? How would I check for obstruction in other parts of the system?
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Saturday, September 10th, 2011 AT 11:02 AM
Tiny
FIXITMR
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What would be helpful would be a cooling system flow diagram. And yes that engine should be running cold just based on it's age and lower friction/compression condition.
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Saturday, September 10th, 2011 AT 3:41 PM
Tiny
FIXITMR
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Also the cylinder head is the primary cause of heating the coolant. If flow thru the head is restricked then you are gonna overheat. The thermostat DELIBERATELY causes this restriction to provide enough hot coolant for heater core. Removing it should make the whole system cooler. When you say the heater is working (hot) it would indicate you still (now) have a head flow restriction even without thermosatat.

Was any work done on car prior to this recent overheating. Sometimes silicone is used to seal things and excess can break loose and clog passages.
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Saturday, September 10th, 2011 AT 4:44 PM
Tiny
THANVAS
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Thanks for reminding me. I remember last winter, ever since I remove my thermostat, my heater never got hot. Now it is. So you think the problem is restriction in the head? How could I check this and what could I use to unclog the passages?
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Saturday, September 10th, 2011 AT 5:10 PM
Tiny
FIXITMR
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A flow diagram is needed to determine the coolant paths for that engine. Usually clogs are resolved by backflowing (reversing) the passages in question. If it is a corrosive clog it may be impossible to resolve without removing/replacing part.

Question is whether your heater is getting hot before other parts of system. I have an infrared temp reader from harbor freight $10 that I use to check temps around parts. Like compare top and bottom hose on radiator and heater hoses etc.
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Saturday, September 10th, 2011 AT 5:25 PM
Tiny
FIXITMR
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Also you could try replacing radiator cap as this controls overflow and expansion which if not working right can cause problems.
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Saturday, September 10th, 2011 AT 5:27 PM
Tiny
THANVAS
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  • 46 POSTS
Do you know if the radiator fan for a 1991 Honda Accord suppose to blow directly on the radiator or is it suppose away from the radiator towards the engine?
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Sunday, September 11th, 2011 AT 1:04 AM
Tiny
FIXITMR
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Towards engine. It sucks air thru radiator imitating the natural air flow direction. Fan shroud should be intact/undamaged to guarantee maximum flow.
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Sunday, September 11th, 2011 AT 8:39 PM

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