Remove thermostat entirely?

cano944 · cano944's Garage

Anyone know what happens if I remove the thermostat and leave it out?These things run so hot.

Chris

Fort86turbo · 08-05-2003, 04:39 PM

i have heard that it can make them run hotter. i just bit the bullet
and changed it.it was a pain in the ass but to me it was worth it as my car was running at the second to the third mark and after the stat change it runs at the first mark.

cano944 · cano944's Garage

Thanks,I will just change to a cooler thermostat.I fear that c-clip.

Chris

TCMdocs944 · 08-05-2003, 05:45 PM

Yeh, I just read an artical on PCA's tech site that said the thermostat works in the reverse of what most other cars do and that there is actually some form of flow even when closed.?.

Anyway, the idea was that it is quite important.

BlueQuestTSi · 08-05-2003, 06:25 PM

The reason it's said that removing the thermostat could make a car run warmer is quite simple, and depends on the efficiency of the radiator.

If the radiator isn't efficient enough, the thermostat being closed will allow the radiator time to cool the water that is inside it. If the thermostat is removed from this vehicle, the water will not be in the radiator for a long enough period to be cooled, and the temperature will continue to climb.

It would appear to me, that the 944's radiator is just barely big enough to do it's job, and wouldn't be able to so without a thermostat.

cano944 · cano944's Garage

That makes it very clear.Thanks.

Chris

1.2gees · 1.2gees's Garage

Hate to say it, but the above is BS.

The thermostat is necessary because otherwise not all of the coolant goes through the radiator, as some recirculates. Without a thermostat, your 944 will likely take longer to warm up, depending on the climate it may run cooler or hotter under normal driving, but will over heat when pushed.
Ahmet

Baza · Baza's Garage

I have to agree with Ahmet. When I took mine out it took forever to warm up, and it still over heated when it did get warm.

Sam Lin · 08-05-2003, 11:30 PM

I've been without a thermostat since I got the car, haven't gotten around to putting it in yet - here in the heat, it hasn't been a problem with warming up or with operating temps, but I certainly don't recommend it.

Sam

adrian jaye · 08-06-2003, 01:40 PM

I'm with 1.2 gees,

the thermostat is an essental part of the cooling system.
The themostat allows the engine to get up to operating tempreature quicker and allows the engine to run at its optimum temp.

Do NOT be tempted to run without it, or use a cooler one.

use the "recommended one" anything is is running on dangerous ground

swimmingly · 08-06-2003, 02:42 PM

Blue and Ahmet are correct. The thermostat allows coolant to circulate when the engine is warmed up and should be closed when the engine is cold so that the car can warm up faster. However, even when the engine is complete warmed up (or running a little hot), the thermostat still regulates the circulation of coolant (especially when the car is under heavy load or being pushed hard some other way) to ensure the coolant sits in the radiator enough to cool off. If it did not regulate the speed of the coolant, the coolant would move so quickly that it wouldn't have time to cool in the radiator. I think Newton's Law of Cooling could work to prove the second part but my calculator is broken right now, so I'll have to try it later.

Paul Glasson · Paul Glasson's Garage

Have not seen my 944's thermostat, but it is common practice in this country due to less severe winters and hot summers, to keep the outer portion of the thermostat and knock out the inner portion. In this way the remaining portion acts as an orifice plate to reduce the flow rate and maintain retention time through the radiator to a similar rate as with the complete thermostat. OK it will be a slightly higher flow rate as there will be a bit less flow restriction.

justin · justin's Garage

I haven't had a thermo in my car for two years and no problems yet,105 temp down here in Texas.

ronin · 08-07-2003, 11:00 AM

Quote:

Originally posted by swimmingly
Newton's Law of Cooling

wanna run that one by me?

ronin · 08-07-2003, 11:00 AM

oh, wait, you mean law of thermodynamics?

tgx · 12-11-2017, 01:33 PM

I have heard over the years many arguments why the thermostat is critical to prevent overheating and none of the arguments suffice.

I can agree that the thermostat will aid in bringing the engine up to operating temperature more quickly than without one. That is essentially the reason for its existence! It aids in getting water to temp to run your heater and is necessary to prevent sludge buildup in the engine from running too cool which is probably the most overlooked function the thermostat has.

The statement that the water will not remain in the radiator long enough to cool makes NO sense at all. If the thermostat opens at 180 or whatever value you have installed, it is NEVER going to close in the event the car is running hot. The thermostat in no way is going to help with a hot running car. It isn't going to magically close and let the radiator do its job longer. Once the thermostat opens the hot water will continue to circulate as if in an open system without a thermostat. Thermostats don't operate on a binary open and close basis (time for someone to invent the solid state thermostat if they haven't already) but on a gradual linear opening and closing. A video on thermostat operation: https://www.youtube.com/watch?v=T8cGKdICJmc. The issue with an overheating car is, there is never any 'cooler' water introduced to cause the thermostat to close. The system is in 'panic mode'.

I have run cars for years without thermostats to no ill effect. I will say that having the engine running too cool from not having a thermostat does make for dirtier oil and will need changing more frequently in cold climates. If I lived in a cold climate I would not run without the thermostat. In warmer climates, it's not doing a whole lot anyway. The effect of running without a thermostat in a warm climate may eliminate some restriction of water flow imposed by the thermostat which may create slightly elevated operating temps due to the added flow through the radiator. Again, I think the effect is not enough to even measure.

If your car is overheating there is a fundamental reason, it might be a bad thermostat but it could be a clogged radiator, messed up cooling fans, a slipping timing belt to pump interface, a cracked head or an ignition issue. Pull the stat and test it, all you need is a pot, some water and a thermometer. Toss it on the stove and see if it opens at the correct temp. If it tests good you could leave it out and your car will still overheat. The problem isn't the thermostat. Conversely, taking a perfectly working cooling system and removing the thermostat will not suddenly make it overheat.

For whatever reason older cars, particularly European ones with virtually no grill area, have very margnial cooling systems. It's not limited to the 944 for sure. I just pulled the engine on my 84 NA to give it a complete going over as I just acquired the car in March. First thing I found upon removal was an improperly installed thermostat. The o-ring was cocked in the bore at a 20 degree angle and and the mish mash of thermostat and sealing rings are not correct which seems to be a real issue depending on which thermostat you buy (what is included in the box) vs what type of pump you have and whether or not your car has been converted from early to late style pumps. Do your research before you blindly start swapping in parts. This is definitely an area where you can get it wrong.

flash968 · 12-11-2017, 10:32 PM

actually, in a properly running car, the thermostat does close while running, and cycles back and forth, though not normally entirely in one direction or another. as stated above, it is not binary. it does cycle though, as the load on the engine goes up and down.

the primary issue is the speed of the coolant. with no thermostat, the coolant travels too fast, and will heat soak.

the reason a thermostat is there is to maintain an even temperature, and not have it swing up and down. without a thermostat, you are subject to wider needle swings. this promotes better combustion. new cars are much better at this. you almost never see that needle move.

an old racer trick is to drill a half dozen small holes (about 1/16") in the ring of the thermostat. this allows a small flow, even when the thermostat is closed, and provides more even running temps. i've been doing this in most of my cars for about 40 years now.

speedjw · 12-12-2017, 05:53 AM

Removing the thermostat allows 30-50% of the coolant to bypass the cooling circuit (radiator) entirely. In almost every case, removing a properly functioning thermostat will cause your car to run hotter, especially when pushed.

I have a cutup water pump at home that clearly shows why. But basically, the center plunger of the thermostat closes the cooling circuit bypass when the thermostat opens, allowing water from the radiator to begin to flow into the waterpump. Take a look at a water pump without the thermostat installed, and you will see a round pipe inside the opening of the waterpump inlet (where the thermostat is installed), that is the bypass, and that is what the center plunger of the thermostat closes when it opens up to allow water from the radiator to flow.