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454 160 degree thermostat - NAPA?

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bobct

Advanced Contributor
I'm trying to remember if I bought mine from a parts store or ordered them. I guess the question is more the gasket with Crusader # 96105 (top and bottom). Are these the same gaskets used in cars? I'm sure they have the thermo itself.
 
The gaskets with the rivets are typically marine only...they are the return connection for the sender and switch that can be installed in the housing...
 
If you don't want to pull it back apart, install two star washers underneath the bolt heads.
You may want to scrape some paint away first.
 
All engines need some sort of bypass to the thermostat to insure some coolant flow to the block when the thermostat is closed. In cars this bypass is provided by flow though the heater core. In boats they often have some smaller built in plumbing for the bypass. Crusader does this on many engines but on some just requires a thermostat with some holes in it to provide a low flow when closed. I don't know about the 454. You want to be sure you do not require the holes before you buy an automotive thermostat at NAPA. If you require bypass holes and don't have them you will overheat the block before the thermostat sees enough heat to open.

On my 350's one engine has the holes in the thermostat, the other does not because the water heater acts as a bypass. As I recall the holes (3) we about 3/16" so they are quite noticeable.

CaboJohn
 
CaboJohn is correct about the holes for the bypass. I have drilled holes in my new thermostat and my local marine store has Crusader thermostats with the drilled holes.
 
I think that we're talking about two different things here, and possibly two different categories.
By-pass porting -vs- the air bleed hole in the thermostat flange..... and Raw Water Cooling -vs- a Closed Cooling System.


The by-pass porting is required for some Marine Engines.
The hole in the thermostat flange is for purging air, and it can be rather small.

At the 8:00 O'clock position on the flange of this thermostat, you'll see a tiny brass piece crimped into this air bleed hole.
This hole allows air to escape until the sea water coolant contacts the sensor.
Once coolant makes contact with the sensor, there's really no need for any by-pass porting..... but again, many are set up with the by-pass porting.




I would agree that the auto engine heater core will keep coolant flowing while the engine temp is coming up.... but only if the heater core coolant valve is open.
(no valve shown here)
 
update (with video below) ... I installed a new thermostat and gasket (s) which I got from NAPA. The thermostat is made by "Motorad" which didn't thrill me but I already had everything opened up. Somewhat related, do NOT use their "fail safe" thermostats in your car. The failure rate is terrible and haunted me for a year as chased a slightly hot temp issue on my wife's car replacing everything but the "new" thermostat. I just took the boat out to test the new thermostat and the 33ohm resistor I added on the Stb engine. That gauge was consistently reading low 180's but all my IR readings were low 160's. The gauge now reads 160-162 and I get around 165-167 on the gun. I'm ok with that. On the port side it still seems to be running cool even with the new thermostat. .................................................................. The gauge reads 172ish but I get the following readings using the gun - Base of temp sensor and sensor itself are 145-150, high temp alarm - 147. In comparison to the Stb side, those readings at the same locations are between 160-170............................I tried one last time and got 165 right at the thermostat housing base. That's the only reading that seems to be correct. Is there anything else that would make the engine run too cool or am I creating a problem that doesn't really exist? I do think the new thermo is better because the gauge comes up a lot quicker and my readings before were in the 130's. Sorry about all of the ".......". For some reason the Enter key is not recognized on this forum using my new wireless keyboard. Tab doesn't work either...Bob http://www.youtube.com/watch?v=htaaXsT5zE8
 
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where did you add the resistor (and why)?

I've found that it is best to take the IR readings after the temp gauge has stabilized to ~ 10 minutes when you establish a baseline on an engine. the Sensor units are notorious for not always being "accurate" so i don't think I'd sweat what may be 10-15 deg on the gauge. You can always swap gauges (jumper clips at the panel) to help resolve a difference, if desired.

Finally, did you verify the operating temp where the new t-stat opens before you installed it?
 
Mark, I'm taking the IR readings after about 15 mins of cruising so everything is warmed up fully. I posted another video link above if you're bored and want to see firsthand. I added the resistor because the Stb engine was reading about 20 degrees too high. It's within 5-6 degrees now so I'm ok with that side for now. I did test the new thermostat in hot water and it looked like it was open at around 162 but kind of hard to tell what temp it started. I DO get 165 at the base of the housing but everything else seems to be 150ish...
 
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