Overheating

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  #1  
Old 02-01-04, 07:06 AM
trainer
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Overheating

I have a 1992 Acura Legend that is overheating. I can start it and let it run in park for more than hour and it does not run hot but if I drive it even 1mile it boils over. I replaced the thermostat then tested the new one and reinstalled. The upper radiator hose does get hot. There is no leaking of fluid unless boiling over from overflow. There is no rattling from the water pump. I tested the fan at the point of the connection it did work but maybe it is too cool outside(40degrees) to activate while sitting still. Help any ideas?
 
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Old 02-01-04, 02:07 PM
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What's the temp of the lower hose? It sounds like a restricted radiator. Did you ever use sealer?
 
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Old 02-01-04, 03:27 PM
bri208
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Re: Overheating

Originally posted by trainer
I have a 1992 Acura Legend that is overheating. I can start it and let it run in park for more than hour and it does not run hot but if I drive it even 1mile it boils over. I replaced the thermostat then tested the new one and reinstalled. The upper radiator hose does get hot. There is no leaking of fluid unless boiling over from overflow. There is no rattling from the water pump. I tested the fan at the point of the connection it did work but maybe it is too cool outside(40degrees) to activate while sitting still. Help any ideas?
I would suggest with the cool upper rad hose the coolant is not full enough, it may appear full and still have air in the system. You need to properly bleed the air out of the system and make sure the coolant is full. How hot can your heater blow when the gauge is reading near the overheating level?
 
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Old 02-01-04, 04:39 PM
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Re: Re: Overheating

Originally posted by trainer
I replaced the thermostat then tested the new one and reinstalled. The upper radiator hose does get hot.
Originally posted by bri208

I would suggest with the cool upper rad hose the coolant is not full enough,
What cool upper hose? The poster said it was getting hot.....plugged radiator.
 
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Old 02-01-04, 04:56 PM
bri208
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Re: Re: Re: Overheating

Originally posted by Desi501




What cool upper hose? The poster said it was getting hot.....plugged radiator.

my bad (mis-read)


well then, I concur.
 
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Old 02-01-04, 08:33 PM
mike from nj
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Re: Overheating

Originally posted by trainer
I tested the fan at the point of the connection it did work but maybe it is too cool outside(40degrees) to activate while sitting still.

don't overlook the obvious, whether it's 40 above or 40 below, the fan should be cycling with the car at an idle.

most 'reverse flow' cooling systems i've seen, with the thermostat on the bottom, takes forever for the lower hose to heat up, that's why i don't use that alone as an indicator of problems.

don't overlook a leaking headgasket. if possible, feel inside the valve cover/oil fill cap, try to scrape the inside of the top of the valve cover with your pinky. light colored foam means bad news.

some cars you can do this, others you can't. depends on how the baffles are inside the valve cover.



some cars have tricky bleed sequences and if not followed will lead to what you have.

if your fan is not working, i would fix that first, before anything else.

you might want to get your hands on some good literature.
 
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Old 02-02-04, 03:15 AM
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Re: Overheating

Originally posted by trainer
I can start it and let it run in park for more than hour and it does not run hot but if I drive it even 1mile it boils over.
A bad cooling fan will have the opposite symptoms. It will cruise fine and heat at idle. The fact that it will heat in a very short distance at cruise indicate poor or no coolant flow through radiator. I wouldn't expect a head gasket problem to create heat that quickly. If you want to find out if your getting curculation, try removing the thermostat temporarily just to see if that bottom hose gets warm then. If it doesn't, blame the radiator. The fan not coming on at 40 degrees doesn't surprise me at all. that seems normal. You could probably run without it all together at that temp.
 
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Old 02-02-04, 09:44 PM
mike from nj
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well then i guess i can only speak from experience then.

when i shovel my car out of the snow, i let it warm up at idle. with 0psi of freon in it(for 2 years now), i can assume the coolant temp alone is causing the fan to cycle at idle, and with the last storm, it was in the teens, and the fan still cycled on both cars i was digging out.

a newbie was working on a 95 2.5L (4cyl.) caravan near me last week. it was in for overheating. after adding a gallon of water and letting it idle for 45-50 minutes, he declared there was nothing wrong and no leaks, must need a thermostat. ( i know better). i took my block tester kit, put it in the radiator neck, and the fluid changed from blue to green within seconds. after he took the head off, we found the headgasket had a small crack in it. it never overheated in the shop, i'm sure it would have blown coolant out the overflow bottle had he tried to test drive it.


i'm pretty sure a clogged radiator would overheat within an hour of idling.


let's see if the original poster has come up with anything yet, or got the fan to cycle at least.
 
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Old 02-03-04, 02:49 AM
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Originally posted by mike from nj

i'm pretty sure a clogged radiator would overheat within an hour of idling.
let's see if the original poster has come up with anything yet, or got the fan to cycle at least.
Being is So Florida I deal with a lot of overheating problems and when I get a complaint of overheating in traffic and cooling back down once moving, it's nearly always a fan problem. The fan is generally not necessary with sufficient air flow through the radiator. On the other hand the symptoms or poor radiator circulation show up when the rpm's are brought up and the engine is under load. that's a very slow process at idle but happens quickly under acceleration or cruise. Head gasket problems, depending how severe they are, usually take a while to build up whether idling or cruising. The fact that the overheating is immediate when cruising doesn't agree with that.
 
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Old 02-03-04, 05:22 AM
Cobblemaster
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Originally posted by Desi501


" Head gasket problems, depending how severe they are, usually take a while to build up whether idling or cruising. The fact that the overheating is immediate when cruising doesn't agree with that. "


The original post says "boiling out the overflow". This may be from the gases from a blown head gasket,maybe not actually boiling, just pushing the fluid out. Is the temp reading hot or just pushing fluid out overflow. A blown head gasket sometimes will push the fluid out quickly while driving but not read hot on the gage or light, until anti-freeze is low. Need to check it there are bubbles coming out of the anti-feeze, may need to have somebody rev engine while you check, usually worse under load though. Take a compression check and see if all cylinders are equal. This will tell you if you have a cylinder is leaking.
 
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Old 02-03-04, 03:36 PM
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I've seen headgaskets and clogged radiators both cause these symptoms.At this point we need some response from the original poster to proceed.After overheating this bad and so often he may need both.Air pockets due to combustion gases entering the cooling system or a clogged radiator will both cause a cooling fan to not operate properly.Mike and Desi don't beat me up now let's keep this post nice.I do think the poster needs to use a block tester before he goes to much further and have the radiator flow tested.
 
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Old 02-03-04, 04:36 PM
trainer
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I have uninstalled the radiator and am going to take it the shop tomorrow. There is not moisture coming from the exhaust nor is the foam in the oil or valve cover.
 
  #13  
Old 02-03-04, 05:10 PM
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Originally posted by trainer
I have uninstalled the radiator and am going to take it the shop tomorrow.
I await your results.

Don't worry davo, I don't disagree with you. he may have done some damage here but I'm betting a new radiator will make it drivable, at least short periods.
 
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