Test Your Thermostat 

Im a retired ASE master, I always was stuck on stant brand thermostats, but now they have also gone to the sub quality side as well as about all thermostats, I have a problem with my thermostat sticking closed intermittently. once I rev the engine while going down the road after my chime goes off indicating a high temp,it has been opening then and coming down quickly off the H. I have tried many brands since only to have a sticking closed problem all the time. I have even found a OS-oem mopar thermostat and it did the same. system has been flushed,new hoses,cap,reservoir,water pump,and radiator. I found stant went downhill when Motorad bought them out and now they are owned & manufactured in Israel,Galilee. also I remember that if a engine is running cooler then manufacture specs it will ruin the bore. the cylinder specs are determined by the heat it will run at,if it runs too cold the cylinders do not expand to manufacture specs and the pistons & rings with enlarge the bore due to clearance issue

Respectfully, at 04:45 in, you're wrong about the "if it's rated at 160*, it should be fully open at 160*". That 160* is only where it should *start* to crack open. And it won't be be fully open until it gets 15-18* hotter than that.

was your temp guage calibrated or tested to verify its acuracy ,,,great video i like videos like this

It’s very dependent on the spring rate which the wax motor acts against. I’m sure compromises have been made in the last couple years with sourcing springs for bottom shelf thermostats. Bottom line is that you should test them if they are a hassle to swap. And if it acts at too high a temp I’d take material off of the spring, by filing, or sanding if a return isn’t possible.

Here's a bit of experience I've had with a specific brand of thermostat. Every thermostat I've ever put in a car seems to open right around it's rated temp and will hold the engine temp at the rated temp going down the road and prolonged idling will creep up maybe 10 degrees from the rated temp depending on the car. The Motorad UltraStat high flow thermostats, I've used two of those over the years. They will open at the rated temp but on a colder day (65F or cooler) going down the road will run about 10 or so degrees colder than the spec unless you really put a load on the engine to get it hot or get on the freeway for a long time. If you idle in traffic it will get to its rated temp but once you're going it'll cool back off again. If it's about 65F or so degrees out or hotter then it will run at its rated temp going down the road and prolonged idling will creep up 10-15 degrees depending on how hot and humid it is outside. I put one of those in my truck years ago and didn't like it since it was being used as a daily driver year around but for one of my fun cars it seems to work very well. The first one I thought I got a bad one but apparently that's how they seem to be designed to work, never seen another brand of thermostat act like that. It does have a much larger plate that opens than a stock thermostat does. Ever seen any other brand of thermostats act like this?

I always drill a small steam hole in every thermostat sometimes two and I run the hottest thermostat my engine will allow usually 180 or 195 but most of the time I run a 195 even on my carbureted cars

Great information. Thanks for taking the time to share.

Great video, really looking forward to the cooling system video.

I’m so glad I found this channel!!!!!!

Good video, good content. Thanks for the info

Great info with demo!!

Best video on this that I've seen..

Great video , lots of good info!!! Thanks again !!!!

Have owned many hot rods. I toss the thermostat and use restrictor plates.

thanks, very helpful video

Great video. My 65 chevy truck does not have a thermostat but i will after watching your video. My question to you is why does my overflow hose from radiator leak if my engine only running at 175? degrees?

Yeah found this out just yesterday.. been having a issue since vintage air was installed.. 190 thermostat opening around 210 .. 180 thermostat opening around 200.. still questioning the mechanical water temp gauge.

this test is not accurate because youre pulling a cold item in hot water its going to take time for the item to warm up if you put the item in the water before it gets hot then youll get a different result

Thanks for the info got a local part's store thermostat 180 degree in my 396 Camaro never overheats but runs about 200 degrees in traffic, wonder if I should go to the edelbrock 160 thermostat? Keep the videos coming

Just a thought. But would the coolant flow and pressure, possibly help push it open quicker?

What heating element did you use? And a clear glass jar of water?

Were these motorad?