PDA

View Full Version : Running with no thermostat?



dowsett6
12-08-2010, 04:25 PM
If I was to take the thermostat out, the only downfall would be that the engine takes longer to heat up to temperature?

Taking it out would be the same as one going bad and staying open correct? So our engines (1.8T) can run without them?

Thanks guys,
-Robert

powersmokin
12-08-2010, 04:29 PM
yes

coolgraymemo
12-08-2010, 04:35 PM
i believe so.

i was running mine with a bad open thermostat for a while.

dowsett6
12-08-2010, 05:56 PM
Awesome.

So at lights or when stopped but still running, would the engine cool down to much by constantly flowing the coolant through the rad?

From what I have seen while searching so far is that it doesn't cool down all that much, but that was with a busted thermostat and not just a missing one completely.

frameshift18
12-08-2010, 07:54 PM
If the thermostat is completely missing, or failed open, coolant would be flowing through the radiator at all times. Thus when you are moving the airflow over the radiator would be cooling it down and never letting it reach operating temp.

Ldiaz12
12-08-2010, 07:59 PM
Yea you should be fine... Hold on Im going to ask my friend Robert about this just to be sure... He knows all.. Haha

walky_talky20
12-08-2010, 08:18 PM
Why do you want to do this? Just for diagnosis or something else?

When my brother and I were kids we had a field car. Converted an old Corolla from 4 cyl to 3, as the engine was blown (removed piston, rod, and rockers). It overheated so badly that we ran with no t-stat just to make it usable, lol. Ah, good times.

brettj20
12-08-2010, 08:27 PM
Unlike in the 'old days' it's very bad to remove your thermostat from a modern vehicle. As well as regulating engine temp. the thermostat provides flow restriction without which coolant often will not flow uphill to your heater core (which is very often the highest point in your cooling system.) Another important benefit of flow restriction is that it prevents errosion. Very often, shortly after removing the thermostat, radiators develop leaks requiring radiator replacement because the tops of the tubes (in the top tank) have erroded away. Leaving the thermostat out entirely also reduces the pressure that the coolant in the engine develops. This decreases the temperature at which the coolant boils and can cause bubbles of air in the coolant at the hottest places in the engine. These bubbles then act as a thermal insulator which makes those hot parts of the engine even hotter. But your temperature guage will still be showing 'normal' temperatures. If the engine runs hot in one particular area, it can damage the piston rings eventually causing the car to smoke, burn oil, and eventually cause total engine failure.

Read more: http://wiki.answers.com/Q/Is_it_bad_to_remove_the_thermostat#ixzz17aMAe3dS

dowsett6
12-08-2010, 09:08 PM
HAHA, Thanks Louis.

Walky: I'm looking into installing an electric water pump.

Brett: There is a couple issues with what that person said.

-there should be no air in the system meaning that when primed properly the coolant can flow uphill even without back pressure. Just run a garden hose up a hill...
-the erosion wont be an issue either because I don't run straight water. I run 75% coolant / 25% water, and its the oem coolant so it is safe for aluminum.
-the boiling point can't change as none of the coolant properties changed, It will only take longer to get to a boil.
-the electric water pump I am looking at is 20gpm which is going to be way more than the stock water pump moves so coolant wont be creating hot spots in the engine.

The stock coolant system on the 1.8t holds 7litres of coolant according to the Bentley manual. Which would mean a 20gpm pump would pump the entire coolant 10 times through the engine every minute. I am looking for an electronic controller to control the voltage to the electric water pump so I can vary the speed with the temperature. I might have to end up designing my own controller though as I haven't seen anything yet. It would solve the issue of flowing to much all the time, so the coolant actually heats up.

auh
12-08-2010, 10:08 PM
Why do you want to run with out a thermostat? I was alway told it was a bad thing to do because the coolant moves through the radiator faster than its supposed to and doesn't properly cool. Even with an open thermostat there is resistance going through the system, and by taking out the t-stat you getting rid of any resistance at all.

brettj20
12-09-2010, 12:26 AM
well in my own words, running without a thermostat is not a good idea, Your engine needs to reach its operating temp. you can harm your engine by having no thermostat because it will be ether running to cold or to hot. In some cases running without a thermostat your coolant will not have a chance to cool down, because their isnt anything holding it back. your temp will be fluctuating to much, your gas mileage will not be the greatest, you can harm your motor, Your engine will be happier running at operating temp (around 190 degrees) why are you wanting to run a electric water pump? are you haven problems cooling?

sa_seahawker
12-09-2010, 01:03 AM
I always thought that 'warming' an engine is just as important as 'cooling' one. Just like BBQing where reaching a particular temp is necessary to achieve maximum efficiency. [>_<]

brettj20
12-09-2010, 08:53 AM
I always thought that 'warming' an engine is just as important as 'cooling' one. Just like BBQing where reaching a particular temp is necessary to achieve maximum efficiency. [>_<]

x2 [up]

somebody5788
12-09-2010, 09:18 AM
The electric pump could work but I cannot see any reason why one would do this?? A lot more money for no benefit at all. The stock cooling system on these cars is very very good.

Dan[FN]6262
12-09-2010, 09:55 AM
run a fucking thermostat. its there for a reason.

Chris@RevoUSA
12-09-2010, 10:29 AM
1.8t with a stuck open thermostat will never get up to temp at most normal highway cruise speeds, having no restriction at all of a missing thermostat I would think that even at moderate speeds it would start to have trouble and at highway speed may just be way too cold all the time.

An engine not up to temp is not running efficiently, as someone said warming up an engine is as critical as cooling one. You may end up with the car always running in the cold/warmup areas of the maps which will seriously hinder performance and waste a ton of fuel if it is really cool.

weaselciuy
12-09-2010, 11:14 AM
if you remove the thermostat you cant place the sealing and i think it will leak coolant at the flange. Or it can get loose and get lost in the hoses/radiator.

dowsett6
12-09-2010, 01:33 PM
Looks like I will have to design a holder for the thermostat then, maybe like Bigboost did with his vr6 build.

brettj20
12-09-2010, 03:22 PM
why are you going to run a electric pump ? is there a reason behind it or are you just being different.

dowsett6
12-09-2010, 05:04 PM
I guess just being different haha. The only thing on my accessory portion of my crank will be the alt and I am going to be having it mounted down low, basically where the water pump sits right now. I could leave the water pump and move the alt to just above it to make a triangle shape with the belt, but that would require creating a new pulley for the water pump as it runs off the accessory pulley on the powersteering pump stock.

blacka4
12-09-2010, 05:14 PM
the car will not properly warm up and when you are driving it in the cold it will never warm up and you will have no heat. Having a stuck open thermostat has the same affect as not having one installed. Just leave it there. If you wanted get one that will open at a lower temperature to help cool the engine sooner. Not running one is stupid

Controlling how fast the water moves through the system isn't going to help any. you will have all that cold air running over the radiator and it will cool the water faster then the engine can produce heat to warm it back up.

My advice, DON'T DO IT.

brettj20
12-09-2010, 07:51 PM
seems like alot of trouble for something that already works good, I would put that money into something else on your car, like turbo, injectors etc. its a cool idea tho

dowsett6
12-09-2010, 07:59 PM
the car will not properly warm up and when you are driving it in the cold it will never warm up and you will have no heat. Having a stuck open thermostat has the same affect as not having one installed. Just leave it there. If you wanted get one that will open at a lower temperature to help cool the engine sooner. Not running one is stupid

Controlling how fast the water moves through the system isn't going to help any. you will have all that cold air running over the radiator and it will cool the water faster then the engine can produce heat to warm it back up.

My advice, DON'T DO IT.

So the thermostat completely stops the coolant from flowing while the water pump just keeps trying to cram more and more into it?






seems like alot of trouble for something that already works good, I would put that money into something else on your car, like turbo, injectors etc. its a cool idea tho

I already have a BT setup. 630cc inj, and maestro, ect...

brettj20
12-09-2010, 08:47 PM
yes the thermostat stops the coolant untill the engine reaches temp, then releases coolant.

dowsett6
12-09-2010, 09:26 PM
But even with the thermostat closed, the water pump would be pumping coolant through the engine in this order? water pump > block > heater core > water pump.

It would also branch off from the block > turbo > upper rad hose > oil cooler due to there being no flow through the thermostat?

Then once the thermostat is open the oil cooler would flow the opposite direction?

blacka4
12-10-2010, 05:13 AM
So the thermostat completely stops the coolant from flowing while the water pump just keeps trying to cram more and more into it?

yes the water pump pumps water with the thermostat closed. When the theormostat is closed it closes off the engine from the radiator, and heats up the water. Once the water reachs 190 the thermostat opens and allows flow to the radiator to cool down the coolant. Once the cooant is cool enough the theormostate closes again.

When the theormostat is closed the engine moves coolant through your heatercore, turbo, engine block and head. If you look at the water pump there usually is 2 inlets and 1 outlet. with the water passages in the block and head it is possible to have the water pump move water throughout the system with the thermostat colsed.

I'm unsure of the direction of the water but it usually starts at the bottom and works it way up. So I would have to guess, the order is:

Engine > heatercore > Turbo > water pump

After the thermostat opens that allows flow through the head and upper rad hose into the radiator then that returns to the water pump via lower rad hose.

By oil cooler you mean where the oil filter spins on?

I don't have my bently on me to get you the actual flow direction

weaselciuy
12-10-2010, 05:36 AM
dont do it :), AUDI did alot of tests with this sistem, who knows what your build will rezult, atleast wait for summer to do it, when themps reach HOT !!!!

Nebone
12-10-2010, 10:03 AM
Car will run rich most of the time if it does not reach operating temperature and oil temps will be much lower as well. Many factors get affected.

27litres
12-24-2010, 03:58 PM
there should be no air in the system meaning that when primed properly the coolant can flow uphill even without back pressure. Just run a garden hose up a hill...
Brett was referring to the fact that if you have low pressure and the coolant can boil (which it can - see below) you create water vapor, not air, which will have devastating effects.

the erosion wont be an issue either because I don't run straight water. I run 75% coolant / 25% water, and its the oem coolant so it is safe for aluminum.
Erosion is an effect of rapid coolant flow, the mixture makes no difference. You're thinking of corrosion, and anyone who doesn't run an anti-corrosion coolant is an idiot.

the boiling point can't change as none of the coolant properties changed, It will only take longer to get to a boil.
The coolant on its own in your mixture will increase the boiling point of water to about 115-120 degrees celcius. However, the pressurisation of the system to about 25psi (1.6 atmospheres) will increase it to about 130-140 degrees celcius. And that's not allowing for the fact that pressurised coolant is more efficient at heat exchange than non pressurised coolant.
Have you ever attempted to run a modern engine with the pressure cap open? They nearly always rapidly overheat due to inefficient cooling - it doesn't take much for a modern engine to suddenly heat up. Cooling systems are remarkably efficient when operating properly.
As stated above, if the coolant has a chance to boil, you're stuffed!
The thermostat may not stop it pressurising, but it will slow it down and possibly result in lower pressure through the system.


the electric water pump I am looking at is 20gpm which is going to be way more than the stock water pump moves so coolant wont be creating hot spots in the engine.
Just because it flows rapidly doesn't mean it will get to all the nooks and crannies.


Thermostats are critical to your engine operating correctly.

It is vital for a modern engine to reach operating temperature as soon as possible.

Your fuel injection system uses a temperature sensor to tell the ECU when the engine is hot enough to transition from "open loop" to "closed loop"
Open loop is the same as choke on older cars. The ECU won't take any readings from the CAT's or MAF in calculating fuel flow and will run a rich mixture which has been calculated to run the engine when cold.
Removal of the thermostat will cause the engine to warm up slower and possibly not reach the temperature at which the ECU switches to closed loop. This will result in heavy fuel consumption and carbon build up on engine components and possible blockages to items such as the catalytic convertor.


A modern engine also is required to run at an optimum temperature to optimise fuel consumption in a "lean burn".
This gets maximum heat into to CAT's for minimum fuel consumption and emissions. This has been very carefully calculated and mapped by the manufacturer and requires careful control of the engine temperature via the thermostat.

Your oil will take longer to heat up, maximising friction and minimising engine longevity - no matter how thin an oil you use.

Not to mention your heater will take an age to get any decent heat. Possibly none on a really cold day when you most want it.

vtraudt
09-07-2017, 06:17 AM
The coolant on its own in your mixture will increase the boiling point of water to about 115-120 degrees celcius. However, the pressurisation of the system to about 25psi (1.6 atmospheres) will increase it to about 130-140 degrees celcius. And that's not allowing for the fact that pressurised coolant is more efficient at heat exchange than non pressurised coolant.
Have you ever attempted to run a modern engine with the pressure cap open?.[/QUOTE]


The water pump is not generating the pressure in system. It is the thermal expansion of a closed system that builds pressure. The pump has minimal pressure capability. Just take a hose off (cold engine) under put your thumb on the hose.

No thermostat: not great for daily driver or in winter. Racers do it all the time. Also possible to drill holes into thermostat or use housing only, take innards out.

Why not use electric pump with thermostat in place? Similar to running electric power steering pump for racing.

andyrew
09-07-2017, 08:31 AM
7 year bump buddy?

Cedric16
09-13-2017, 07:45 AM
HAHA, Thanks Louis.

Walky: I'm looking into installing an electric water pump.

Brett: There is a couple agence matrimoniale ukraine (https://www.femme-ukraine.com/) with what that person said.

-there should be no air in the system meaning that when primed properly the coolant can flow uphill even without back pressure. Just run a garden hose up a hill...
-the erosion wont be an issue either because I don't run straight water. I run 75% coolant / 25% water, and its the oem coolant so it is safe for aluminum.
-the boiling point can't change as none of the coolant properties changed, It will only take longer to get to a boil.
-the electric water pump I am looking at is 20gpm which is going to be way more than the stock water pump moves so coolant wont be creating hot spots in the engine.

The stock coolant system on the 1.8t holds 7litres of coolant according to the Bentley manual. Which would mean a 20gpm pump would pump the entire coolant 10 times through the engine every minute. I am looking for an electronic controller to control the voltage to the electric water pump so I can vary the speed with the temperature. I might have to end up designing my own controller though as I haven't seen anything yet. It would solve the issue of flowing to much all the time, so the coolant actually heats up.

I think that proceeding with replacement will be better than trying others solutions, you can proceed by yourself to do it, it's quite easy, this B5 A4 PDF (http://www.forum-audi.com/img/members/5/audi-a4-b5-remplacement-de-la-pompe-a-eau.pdf) illustrate everyrthing you need to proceed safety & economic. :)