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For the car folks...
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Millennium
Clinically Insane
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Jan 24, 2006, 10:45 AM
 
My car's radiator seems to have died again. This makes the second time in just over two years. I've never had the car actually overheat, per se, but even after the car has been running for about ten minutes, the coolant temperature gauge is already all the way to the high end. At first I thought I might just need an oil change -I was a bit overdue- but when I went to get the oil changed I asked the guys to check out the cooling system, and they didn't find anything. As with the first time, adding coolant did seem to help for about two weeks, but then the problems started again.

I'm sure that there isn't a coolant leak or anything. It seems likely that my radiator is dead, since this is what caused the problems last time. But for a radiator to have died this quickly, I figure there must be some aspect of car radiator care that I'm getting wrong. Does anyone have any tips on radiator care that might be helpful, or other things that might cause these symptoms?
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Rev-O
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Jan 24, 2006, 11:10 AM
 
I'd start by checking the thermostat. Thermostats can stick open (car never seems to heat up), or can stick closed (car over heats within several minutes). Eh, maybe I have that reversed, but I don't think so. Thermostats are cheap enough, and can range from easy to pita to replace as a diy job.
Would have thought the guys who checked out your coolant system should have looked for this, but if they were just you basic quick lube jockeys they may not have thought very hard about it.
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ghporter
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Jan 24, 2006, 11:44 AM
 
The thermostat is your most likely culprit. If it sticks closed (as Rev-O mentioned) then the coolant inside the block stays there and gets hotter and hotter-and most temp gages show block coolant temp, not overall coolant temp. The good news is that it's usually very easy to change out a thermostat and it's not terribly expensive. Since they are fairly cheap, it won't hurt to change it out to see if that fixes the problem.

The way you check a thermostat is to place it in hot water and increase the water temp until the thing pops open (it's kind of dramatic when it happens) and then check the temperature of the water. You can "look at" a thermostat and say "yep, that's a thermostat," but you pretty much have to remove it to test it. In other words, the oil change guys are NOT going to really test a thermostat. At best they'll look for coolant leaks and hose status.

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NYCFarmboy
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Jan 24, 2006, 11:52 AM
 
agrees, very possibly the thermostat.

an inexpensive repair if you can do it yourself, and shouldn't be that expensive to even have a mechanic change it.

http://www.inct.net/~autotips/tstat.htm

good luck



Oh in the meantime, keep your heater on high/hottest setting to help cool down the water circulating in your engine.
( Last edited by NYCFarmboy; Jan 25, 2006 at 01:40 PM. )
     
Sky Captain
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Jan 24, 2006, 11:55 AM
 
Could have an air blockage in the cylinder head.
Open the bleed valve(usually on the thermostast neck) and allow air to escape along with about a cup of coolant.

Cooling fan relays could be bad also.
     
Rev-O
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Jan 24, 2006, 12:12 PM
 
Originally Posted by ghporter
The thermostat is your most likely culprit. If it sticks closed (as Rev-O mentioned) then the coolant inside the block stays there and gets hotter and hotter-and most temp gages show block coolant temp, not overall coolant temp. The good news is that it's usually very easy to change out a thermostat and it's not terribly expensive. Since they are fairly cheap, it won't hurt to change it out to see if that fixes the problem.

The way you check a thermostat is to place it in hot water and increase the water temp until the thing pops open (it's kind of dramatic when it happens) and then check the temperature of the water. You can "look at" a thermostat and say "yep, that's a thermostat," but you pretty much have to remove it to test it. In other words, the oil change guys are NOT going to really test a thermostat. At best they'll look for coolant leaks and hose status.
I was going to mention the boiling the thermostat thing (it is dramatic), but I gave up testing 'em. If I go throught he trouble to get out the tools and pull out a thermostat I'm putting a new one in! They're cheap enough for the peace of mind

You can even run a car without a thermostat in place, but I've only done that in the summer. Thermo went south on a sunday evening at my folks house in BFE. Took it out, drove home... got lazy... left it that way for a few weeks...
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leehotti
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Jan 25, 2006, 01:37 PM
 
Figure it out yet?
     
vmarks
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Jan 25, 2006, 02:47 PM
 
He didn't say which kind of car he has, but after the thermostat or some sort of blockage, you could also suspect the water pump itself.

Some 1990s vehicles had water pumps with plastic impellers. Plastic, heat, pressure, age equals broken impeller, meaning the water doesn't circulate.

I think I would start by testing/replacing the thermostat, and while I had it open, flushing the radiator, engine, and heater core with a garden hose.
If this post is in the Lounge forum, it is likely to be my own opinion, and not representative of the position of MacNN.com.
     
Railroader
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Jan 26, 2006, 02:32 AM
 
Are you getting flow through the radiator? Are you getting the correct pressure in the cooling system from the water pump?
     
leehotti
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Jan 26, 2006, 09:33 AM
 
Easy way to check this theory, you know. Just put your hand on the radiator. If it's warm, then it's getting coolant. The engine would have to have been running for a while (long enough for the htermostat to open), but if the radiators warm/hot, then it's getting coolant flow.
     
wdlove
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Jan 26, 2006, 01:07 PM
 
I wish you all the best with getting your coolant system fixed Millennium. Hopefully it's something simple.

"Never give in, never give in, never, never, never, never - in nothing, great or small, large or petty - never give in except to convictions of honor and good sense." Winston Churchill
     
   
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