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Guest Message by DevFuse

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Will my car Overheat without a Thermostat?

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8 replies to this topic

#1 LuckyPistol


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Posted 05 February 2006 - 09:18 PM

I am at my wits end with my cooling system.....:banghead:

I have a new Water Pump, new fan clutch. The radiator has been replaced with a new one. (not sure how long ago.) new thermostat.

Bought a new radiator cap.

Now, my temp gauge is getting very close to the red. Each time I get in it in the morning, I will drive about 2-4 miles and then it gets hot. ALSO, the overfill tank is bubbling. I have searched and read alot of posts about bubbling, and it seems to be Head gaskets. But I dont think it is.

So, here are my questions..

1) I want to try and maybe just take out the thermostat and see if it is the culprit. Now, some said to me, that if I do this, my mileage will suck (How much?) I get about 24 mpg now. So a little less wont hurt if it stops this overheating. What if this does not stop the overheating?

2) I took off the hoses going to my Heater core. Used the garden hose to clean it out. Seemed like my heater core was dribbling out the water on the other end, just a stream really. So, I was thinking......

Maybe the water isnt circulating fast enough through the heater core, making the Antifreeze spill over into the overfill. Does anyone know if this sounds like a good idea? I have read a few posts about this, but no one addressed the overheating part.

Well, Please HELP ME, thanks !!!!

#2 cowboystrait


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Posted 05 February 2006 - 09:26 PM

heater core maybe .take ur statout but if u keep on runnin it hot. well cuz u will warp ur motor thats a fact cuz i dunn it:banghead:

#3 idosubaru


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Posted 05 February 2006 - 09:59 PM

you can run without a thermostat but that's a band aid and not a permanent fix.

is there any coolant loss? if you drive the car for awhile (can you do that without it overheating), does it loose any coolant?

if there's coolant in the system and the overflow tank is bubbling then it could easily be a headgasket. if it's just straight water in there, then it's possible it's boiling and not really air bubbling.

i'd do a compression test as it only takes a couple minutes.

#4 mikeshoup



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Posted 05 February 2006 - 09:59 PM

Yeah, definitely do not play with heat. Pull out the thermostat and see if that's the culprit.

#5 TomRhere


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Posted 05 February 2006 - 10:03 PM

New T-stat doesn't always mean it's a good one. Pull the T-stat out, drop it in a pan of water and heat it up. Would help to have a thermometer in the water, so you can tell what temp it is. T-stat should start to open when it gets close to it's rated temp.

Restricted heater core won't cause the engine to run hot, just means you don't get good heat in the vehicle.

Running without a T-stat may/may not, cause engine to run hotter. But it won't hurt to do a test drive with it out, just to see what it does without it in there. It will take the engine longer to reach operating temp without the T-stat, so in effect, you could loose some gas mileage while it's warming up.

One other posibility is a defective lower radiator hose. It could be seperated on the inside, and blocking the flow of water to the waterpump.

If the vehicle has A/C, there could be debris between the evaporator and the radiator, blocking air flow.

#6 GeneralDisorder


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Posted 05 February 2006 - 11:07 PM

Sorry to say it, but you need to check for hydro-carbons in the coolant - just to be 100% sure it's not a blown HG.

Run a compression check too. Verify that your head gaskets are good before you dump any more $$ into the cooling system.


#7 Monte


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Posted 05 February 2006 - 11:12 PM

No, you're car won't overheat without a thermostat, it'll run cooler then it would with one. So as the others posted, you can take it out to see if it's the problem without worries of the engine overheating because of taking the thermostat out.


#8 rllywgn


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Posted 06 February 2006 - 12:39 AM

unless its a blown headgasket... most likely will overheat without a t-stat... ive had a couple do this on the limp home..

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#9 NoahDL88


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Posted 06 February 2006 - 12:39 AM

With the bubbles, its probably a head gasket.

As for will it overheat? the thermostat dose 2 things, it obviously regulates temperature by opening and closing, but it also limits flow by restricting the size of the coolant passage, which keeps the coolant in the engine longer so it can absorb heat, and then transfer it to the radiator.

Cliffs notes, check for exhaust gas in your coolant, and yes, without a thermostat, your engine, althgough it will read lower, you engine will be running hotter.

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