The Hammer

I am about to change a sticking thermostat and install a lower temp thermoswitch to overcome the increase in S2 engine temp.
I wonder if there is any detrimenatl effect runnung one of our beasts without a thermostat. Other than an increase time to fire up the heater(not applicable where I live) would there be any mechanical downsides (cavitation???)...the circulation rate would go up without all that backpressure. What do you think?

Izzy

Possible formation of acids in the oil. You might experience performance issues from the water pump constantly going without the restriction of a thermostat as well.

I should mention that its not necessarily bad, when an engine is running hot (maybe in the summer) the thermostat is full open anyways. The assembly restricts a decent amount of coolant flow, even running on full open.

Campeck

you engine will take longer to warm up. and therefore deteriorate faster because it will be running cold while your driving for a longer time. dont do it.

Serge944

There is NO advantage of running no thermostat.

Sam Lin

I ran one car with no themostat for nearly a year, no problems - of course this was in AZ where there was no problem heating the car up anyways.

Sam

marky522

Heh, this is funny i am in the process of learning this right now.

IF you run your engine too cool you cause the oil to sludge up, so it wont be lubrication the bearings as much as possible, which leads to excess wear on the engine assembly. As was stated before it will also create acids in the oil by allowing the condensation that builds up inside the engine after shutdown to not be burnt off, which then mixes with engine oil and somehow can actually create sulfuric acid ( thats partially from a lecture cant remember exactly how dont have my notes in front of me). The engine is designed to run at a certain temp for a reason You get peak economy from the engine operating at that peak level also.

Mark

marky522

Oh, and I dont agree that it will wear the water pump any sooner because even with the thermostat in place it places no load on the water pump just causes the water to circulate in the block, i dont see how it could cause premature water pump damage

KuHL 951

Removing the thermostat can be a problem for some people (California); it can result in higher emissions at smog test, especially in the coldest months. There really is no benefit to removing the thermostat unless it's failed and you do an emergrncy repair. It doesn't trick the computer to deliver more fuel like some cars and usually doesn't provide any better cooling unless the old one was going bad. Even in hot weather locales some cars react differently. Moving coolant without restrictions can pass it through the radiator before adequate heat is extracted. On the low-temp thermostat, I had a one on my 83 and it made the fans come on way too often making the engine temp yo-yo like crazy. Every engine has an optimal temp range for a given oil and clearances, the 944 is no different, messing with it will often cause more problems than provide cures.

24stiffy

Yanking the thermostat causes the fluid to move too quickly through the system. There must be adequate time for the fluid to absorb the heat from the cylinder head and to release the heat to the rad. Without a thermostat the car may actually run hotter. If you would like proof of the slow flow idea, have a look at the holes cut into the head gasket for the coolant to flow to the head. The cylinder closest to the water pump has smaller holes than the cylinder farthest away. These holes allow a consistent, efficient speed for the coolant to flow between the cylinders...

shortyboy

hotter climates=no heater=IMO no need for a thermostat.colder climates=needed heater for start up/snow/etc=definately need for a t-stat.i was running one with and without and i noticed no difference.ill be putting in a new waterpump w/o a t-stat.

xsboost90

basically if the engine doesnt reach operational temperature, it will not work efficiently and youll loose power. Take for example my non complicated 69 firebird i used to have. Sure it was 400+ hp and was quick and all, but someone had installed a real low t-stat in thinking cooler is better right? I put the stock temp one back in to get some heat when it got cold outside and the power came way up-not cus the weather was cool yadda yadda either, but because the engine finally reached optimal temp for combustion and in a computerized car, that is alot more important.

Oddjob

Actually, in general, higher velocity and turbulent flow increase efficiency of heat transfer. Has to do with boundary layer conditions, film coefficients, heat transfer coefficient, etc...

I also do not recommend running w/o a thermostat, but because of the potential of the engine running cooler than the designed operating temp. range.

M758

I recommend the t-stat.

The car runs COOLER with a proper one that not having one at all.

I have seen this on may 944 spec cars. On occasion a t-stat goes bad at the track. Short of a replacement you simply rip it out. It helps the car make it through the weekend, but the car always runs better with proper t-stat. Warm up time is shorter and operating temp is better (cooler).

You can however get by for a little while with no t-stat.

Oddjob

Yes, I forgot to mention that when the thermostat is closed, the water pump recycles coolant through the block via a bypass. When the thermostat opens fully, it seals the bypass closed, so all coolant flows to the radiator.

With no thermostat, the coolant will flow to the radiator, but also through the bypass, so as mentioned, it will take longer to warm up, but once it does, it can potentially run hotter since not all coolant flow will be going through the radiator (some flow will be recycling through the block).

tkacki

No t-stat = short engine life.