thermostat question

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trudysduster

trudysduster

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I have a 440 .030 over in my Duster. nothin spectacular. In going to the car show 2 weeks ago when it was 102 outside, I had to run about 40 miles on the interstate and some city traffic. I pulled in the lot and parked and shut it off and noticed the overflow bottle was pouring out water. It has never done this before but yet it has never been runing in 102 degrees before. I think my son overfilled the bottle a little but I was thinking of pulling the thermostat out and running it that way. I dont need it in for a heater or anything. I dont think it will hurt and it may run cooler. what do you guys think about running without it.
 
Don't do it. Without the thermostat, it allow the coolant to flow fast through the system which in turn doesn't give the coolant enough time to cool down in the radiator. That said you could (if you haven't/already are) switch to an Aluminum radiator which will do a much better job then a stock radiator. You could also go to electric fans.
 
seriously i just reversed someones move of taking the thermo stat out it sucked......it had a stumble,when the fluid got hot it stayed hot .bad idea
 
well, I will just change it to be safe. It may have been that the overflow bottle was just too full and it overfilled when the engine shut off. thanks guys.
 
I'd say it was probably overfilled. Was your temp actually up? You could try a stat with a different operating temp. Also, don't forget to drill a bleed hole in the stat flange.
 
ok dont know what the temp was at cuz I only have a dash guage in it and no overheating light came on. I have no bleed hole in it. I have ran this car for several years now and have not had a problem. hat is why I am going with an over fill thought. My question now is why the 2 different opinions in the degree of thermostats, I was thinking of a 160 so why not. what would be the different in 160 or 180. I would think the 160 would open quicker and cool it down faster. And what is the importance of a bleed hole. If a bleed hole is so important, why dont they put one in it from the factory. Just questions guys. I put the overflow bottle at the 2 qt. level. Maybe it should have been at the 1 qt. level. talk to me.
 
The bleed hole helps in filling the system, it allows the system to burp, if you will. I would NOT run a 160*, running and engine too cool can cause premature engine wear.

I run a 180* with a bleed hole drilled in the rim and have zero problems on hot days. You "might" have a bad cap too, if it's not holding proper pressure you might get more overflow than normal. I would also check your bottom radiator hose and make sure it's not collapsing, if it is make a coil/spring out of a coat hanger and put it in the hose.

You don't want a thermostat allowing to fast of a flow because it needs to sit in the radiator long enough to cool. Likewise you don't want one that allows it to sit too long.
 
I have run 160's in just about all my vehicles with out a problem, in fact they will still run at 180*+ anyway, just opens faster on those 100+ days which here is every day after April.
 
It will run fine with a 160*, it's just the general consensus if an engine runs too cool it can cause premature wear to the cylinder walls.
 
This is why 195 is the preferred thermostat for all new autos. I run the 195 in all my cars.
 
If your engine was running at normal temp reading on the gauge there is no reason to change your thermostat. It is normal for a closed system to fill the bottle after shut-off. The engine temperature peaks after shut-down. There are 3 things likely to cause the bottle to overflow:
The most likely is that it was too full to begin with. The fluid level in the bottle should be left low in order to alolw for expansion after the engine is shut off and the coolant will be returned to the engine as the system cools down.
The second thing to check for is the condition of the coolant. Check it with a hydrometer to verify the level of boil-over protection. After shut-down hot spots within the block and heads develop which can result in steam pockets and coolant temps over 212 deg.
The 3rd thing you need to do is pressure test the cap. You said that you've had the car for several years and it's very possible that the cap has deteriorated and is no longer holding rated pressure.
Whether you use a 160 or 180 thermostat will have no effect on the running temperature of the engine. That number only refers to the opening temp of the thermostat. In cold winter areas the 160 stat allows the heater to be effective sooner.
I live in the inland area of SoCal where 100+ degree days are common and my personal choice is a 190 stat with a bleed hole to ease coolant fill.
 
A thermostat only controls minimum operating temperature, not maximum.

For example: An engine at 200 degrees doesn't know or care that the thermostat opened at 180 or 160, all it sees is that they are both open.
 
thanks for the info. I will take the level down in the overflow bottle and see what that does.I have another show this weekend and will have to travel the interstate and will keep a close eye on it. The sound it made when it was overflowing seemed to me it had a hot pocket after it shut down so I am thinking the bottle was too full and overflowed. Thanks again. just wanted to be sure in my thinking.Bill
 
1968FormulaS340 said:
A thermostat only controls minimum operating temperature, not maximum.

For example: An engine at 200 degrees doesn't know or care that the thermostat opened at 180 or 160, all it sees is that they are both open.
Click to expand...

Right, but when the car is warming up to operating temp and the stat opens at 160*, until it gets up closer to the proper 195* mark it is creating wear on the cylinder walls, rings etc.
 
Badsport said:
Right, but when the car is warming up to operating temp and the stat opens at 160*, until it gets up closer to the proper 195* mark it is creating wear on the cylinder walls, rings etc.
Click to expand...

Oh, I 100% agree. I was attempting to make an argument for a 180 degree stat.

I really don't know why anyone would run a 160, it's an all loss no gain situation for the kind of cars we are talking about here.
 
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