Exactly what the topic says? Thanks.

 

im guessing that it will stay a lot cooler than normal. this might be bad because it might stay cold enough to tell the ECT that the engine isn't warmed up yet, thus keeping the car in closed loop. If you know about being in closed loop, your mixture is richened to heat the engine faster therefore burning more fuel than normal. i dont know at what temp the ECT tells the computer to operate in open loop, so all i can say is try it and then draw conclusions.


Modified by tonis56 at 5:43 PM 5/12/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tonis56 &raquo;</TD></TR><TR><TD CLASS="quote">im guessing that it will stay a lot cooler than normal. this might be bad because it might stay cold enough to tell the ECT that the engine isn't warmed up yet, thus keeping the car in closed loop. If you know about being in closed loop, your mixture is richened to head the engine faster therefore burning more fuel than normal. i dont know at what temp the ECT tells the computer to operate in open loop, so all i can say is try it and then draw conclusions.</TD></TR></TABLE>

Very correct. It would take a loooooooooong time for your engine to warm up, if at all.

 

if you run your car without the thermostat you would have a problem, first of all your engine would be running to cool which messes with the oils viscocity and could cause more wear to your engine parts, also your car well be OVERHEATING since the coolant is passing thru your system to fast and cannot absorb the heat. you would have crappy gas mileage and other problems.. i recommened you dont do that..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by colombian linx &raquo;</TD></TR><TR><TD CLASS="quote">if you run your car without the thermostat you would have a problem, first of all your engine would be running to cool which messes with the oils viscocity and could cause more wear to your engine parts, also your car well be OVERHEATING since the coolant is passing thru your system to fast and cannot absorb the heat. you would have crappy gas mileage and other problems.. i recommened you dont do that..</TD></TR></TABLE>

Overheating? Are you serious? So you mean to tell me that when I overheated and removed the thermostat, the temp gauge went all the way down to cold because in reality I was overoverheating.

(in the words of that dude on ABCs 20/20) GIMME A BREAK

 

what my teacher said it eventually becomes overheating because its running to fast thru the system to absorb the heat

same thing that happens with the ac system, when the TXV stays open because a bad fin sensor or sensing bulb, the a/c blows out warm air, the reason it does that is because the refrigarant is running to fast thru the evaporator and doesnt absorb the heat inside the car because its moving to fast, current needs to be controlled, because it all runs thru pressure thats why a radiator has a pressure cap on it. remember its not cooling down the air its ony removing heat. so think about it...

 

whatever man, if your teacher says so :shrugs:.............

Im only speaking from experience. I ran without the thermostat for about two hours before I got home, and the gauge stayed at the cold level the whole way.

 

ok

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6 SiR &raquo;</TD></TR><TR><TD CLASS="quote">whatever man, if your teacher says so :shrugs:.............

Im only speaking from experience. I ran without the thermostat for about two hours before I got home, and the gauge stayed at the cold level the whole way.</TD></TR></TABLE>

That's because the temp sensor doesn't monitor the temperature of the block, it measures the temperature of the coolant. He's right, just because your meter says it's cold doesn't mean that your ENGINE is cold. It WAS overheating.

Without a thermostat, the coolant moves far too fast to absorb the heat put out by the engine block before returning to the radiator. Thus the coolant arrives at the radiator at a much lower temperature than normal. When passing through the radiator it will be very easy for it to seep out whatever heat it did pick up so therefore it will leave at an even colder temperature.

The coolant is merely a conductor of heat, and when it is only in contact with the hot surface for a tenth of the time it normally is it picks up only a fraction of the heat it normally would ***no matter how cold the mixture is***.

This leads to a great amount of wear on the engine block itself, and eventual warping of components. Not to mention the trouble of running an extremely hot block extremely rich all the time...

The block is designed with the sole purpose of running at a specific operating temperature +/- a certain percentage. And therefore your coolant flow needs to be regulated PRECISELY to take out the proper amount of heat from the motor on a given pass, and then have enough radiator to cool the mixture efficiently before it returns to the block for another pass.

If you want better cooling, get a bigger/better radiator. But do not replace the thermostat with a lower temperature, or remove it. It's doing the regulation that is required.

 

I would over heating because the coolant is flowing too fast to cool down

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by colombian linx &raquo;</TD></TR><TR><TD CLASS="quote">if you run your car without the thermostat you would have a problem, first of all your engine would be running to cool which messes with the oils viscocity and could cause more wear to your engine parts,... also your car well be OVERHEATING since the coolant is passing thru your system to fast and cannot absorb the heat...</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Phat_Jax &raquo;</TD></TR><TR><TD CLASS="quote">Without a thermostat, the coolant moves far too fast to absorb the heat put out by the engine block...</TD></TR></TABLE>
What's the Nusselt number for flowing coolant in the water jacket? How much does it change when the coolant velocity is 30% or 50% higher?

Where did you guys learn about heat-transfer?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake &raquo;</TD></TR><TR><TD CLASS="quote">What's the Nusselt number for flowing coolant in the water jacket? How much does it change when the coolant velocity is 30% or 50% higher?

Where did you guys learn about heat-transfer?</TD></TR></TABLE>
Are they full of **** Jim? I think they are. I've seen many Hondas come through the shop with no t-stats and the engine and the coolant hoses both seem to warm up at about the same rate.

 

Not having a thermostat will not heat up your engine. Just because the flow is constant doesn't mean ****, in fact it will probably kool faster. The coolant is in contact AT ALL TIMES whether the thermostat is open or closed or not there at all, as long as you don't have air in the system, which you should bleed out.
Now not having a thermostat will cause faster wear and tear. The thermostat is made to keep things at a constant temp. Things expand when heated and everything is in harmony as designed with the thermostat. Plus w/ the thermostat better fuel economy is expected.

 

Does anyone know about pressure and it's effect on the boiling point of your coolant? The static pressure in your cooling system is regulated by the radiator cap. Usually around 16psi. This pressure is created by thermal expansion of the coolant and increases it's boiling point approx 2.5 degrees F per pound of pressure (sorry to anyone outside the US for using ancient English measurement). What is not very well known (aparently) is that the water pump creates flow which is restricted by the thermostat. What this does is pressurize the coolant between the pump and thermostat (a.k.a. your engine's water jackets) in addition to the 16psi static pressure. Since the flow rate of the pump varies with RPM, maybe 5psi. at 1000rpm and 30-40psi+ at 6000rpm, this pressurization of the block and head is crucial to the effectiveness of the cooling system. So, contrary to popular belief, it is the lack of pressure in the engine's water jackets that causes it to overheat when no thermostat is present and has very little to do with "the water flowing through too quickly". If you run for a short time and/or at light load your engine probably won't heat up, so you'll never know the difference. Otherwise, if you are convinced that a thermostat is unreliable or just don't like them, you can modify a thermostat by drilling a hole in it or fabricate a restrictor to replace it. I'm not sure what size hole, you would have to hook up a pressure gauge and experiment.

 

As already stated by others, colder operating temps will cause you're fuel injection system to enrichen the air/fuel mixture. In addition to worse mileage, overly rich fuel mixtures will wear your engine faster due to decreased lubrication of the cylinders/rings and dilution of the oil with gas. Definitely bad news for a daily driver.

 

Didn't consider pressure, but it's a good point.

 

hes right its works on heat transfer and charles law, when pressure is added it raises the temperature and also the boiling point, heat transfers by moving to colder areas so when it goes thru your radiator it has to be hotter than the ambient air(air outside) so it can transfer, thats why it needs to be regulated for pressure.


Modified by colombian linx at 2:48 AM 5/14/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6 SiR &raquo;</TD></TR><TR><TD CLASS="quote">

Overheating? Are you serious? So you mean to tell me that when I overheated and removed the thermostat, the temp gauge went all the way down to cold because in reality I was overoverheating.

(in the words of that dude on ABCs 20/20) GIMME A BREAK </TD></TR></TABLE>

Are you kidding me!! Your claiming you removed the thermostat out of an overheating (boiling) car without the car cooling down??? Why did the car overheat in the first place?


It is possible for a car to overheat if you remove the thermostat. On the other hand it does take a long time to warm a car up with no thermostat also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DamageInc73 &raquo;</TD></TR><TR><TD CLASS="quote">Since the flow rate of the pump varies with RPM, maybe 5psi. at 1000rpm and 30-40psi+ at 6000rpm, this pressurization of the block and head is crucial to the effectiveness of the cooling system. </TD></TR></TABLE>
Why do you guys keep posting bullshit!!! If the systems built up that much presure, they would be blowing off hoses left and right.

 

no you dont know

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">If the systems built up that much presure, they would be blowing off hoses left and right. </TD></TR></TABLE>

You've never owned a 1st gen Viper have you?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
Why do you guys keep posting bullshit!!! If the systems built up that much presure, they would be blowing off hoses left and right. </TD></TR></TABLE>
You're right, some Hondas turn a lot more rpm's. It probably is higher.

 

Lots of different things being said here...

On some cars (I don't know which ones) if you remove the thermostat, you disturb the balance of flows through all the different flow paths. So you get lots of flow thru the radiator, & less through the head. Overheating in that case has nothing to do with the fluid 'moving too fast to pick up the heat'.

I'm not sure, but I don't think Hondas are usually set up like that. But I got a feeling that the little disk on the T-stat is supposed to block something off while it goes to full-open. Maybe it shuts off the heater core while pushing all flow thru the head. I've never really studied it since I've never wanted to run without a thermostat.

High pressure from high-rpm waterpump? Any centrifugal pump operates on it's characteristic pressure-vs-flow curve. Pressure can only be built up by the so-called 'centrifugal force' in the impeller, but that's only when the flow is stalled. With or without a thermostat, the flow never stalls because there's always pathways for the flow to circulate.

Higher pressure suppresses boiling (raises the boiling temperature). Sure, that's always true, thermostat or not. But the overall pressure should be controlled by the radiator cap, not the pump.