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Hummer H3For the Hummer driver who wants the rugged look and off road capabilities of the Hummer, but in a smaller size and with a more fuel economy friendly engine.
Mod gone wrong! The engine needs to be at a certain temperature to operate as efficiently as possible, this is between 195°-205°. The method of controlling this temperature is the thermostat.
Not sure I understand what you mean, gone wrong how? Car operates just fine with the t-stat on top. My only concern was the temp increasing on a cold start, but it's short lived and drops down to normal operating temp. I figured it's just the temp sensor location vs. where the t-stat is.
Originally Posted by NFS
yes that’s the mod that I saw but the thermostats that come with the kit is 180 degrees. I ordered one that is 160 degrees this way with this heat in south Florida it should be fine but I have both of them so I will test it out . Also they mentioned that very important to make sure that the thermostat
Is facing the right direction from engine to radiator
Yes followed the same mod, everything is installed properly. Difference is, his H3 is a 3.5L the water outlet is slightly different allowing him to just cut it short to make room. 3.7l has different housing that will require machining if you want to do it right.
Last edited by MadDogBimmer89; Aug 2, 2023 at 06:24 PM.
Not sure I understand what you mean, gone wrong how? Car operates just fine with the t-stat on top. My only concern was the temp increasing on a cold start, but it's short lived and drops down to normal operating temp. I figured it's just the temp sensor location vs. where the t-stat is.
Originally Posted by MadDogBimmer89
temp going way up to 220F on a cold engine before it opens and brings temps down to 190F
Wrong placement, which you verified!
OEM thermostat is rated to begin opening around 195° and will reach the fully open position around 20° higher.
OEM thermostat is rated to begin opening around 195° and will reach the fully open position around 20° higher.
We must be talking about two different things. Wrong placement of the inline t-stat? Seems about right to me.
Original 195F t-stat on the bottom is out, housing gutted. New inline 180F t-stat installed on top which works fine apart from the initial cold start. It doesn't open until coolant tempt at the sensor reaches 220F, I suspect either air trapped inside as today it opened up at 212F - see below. Or there lack of flow, which means the T stat is operating via heat soak. If that's the case this is usually solved via bypass to allow coolant to continue circulate to prevent hot spots and more evenly distribute temperature, some people drill a small bypass hole in the t-stat.
We must be talking about two different things. Wrong placement of the inline t-stat? Seems about right to me.
Nope, I'm "talking" about the >PERFECT< placement for the OEM thermostat! When the coolant temperature reaches around 195°, thermostat starts to open! My 3 runs within the normal operating temp & idles smooth as glass.
Nope, I'm "talking" about the >PERFECT< placement for the OEM thermostat! When the coolant temperature reaches around 195°, thermostat starts to open! My 3 runs within the normal operating temp & idles smooth as glass.
I see, your truck must be an exception then or you're located in cooler climate. Can't say the same about mine nor hundreds if not thousands of people out there including Colorado folks who experience the same issue.. 195-220F may be the normal operating temp, but once it's 110-115F outside it's a different story. T-stat was moved to upper hose for the sake of convenience mostly. I still think where the original t stat is located is stupid but that's a different discussion.
We must be talking about two different things. Wrong placement of the inline t-stat? Seems about right to me.
Original 195F t-stat on the bottom is out, housing gutted. New inline 180F t-stat installed on top which works fine apart from the initial cold start. It doesn't open until coolant tempt at the sensor reaches 220F, I suspect either air trapped inside as today it opened up at 212F - see below. Or there lack of flow, which means the T stat is operating via heat soak. If that's the case this is usually solved via bypass to allow coolant to continue circulate to prevent hot spots and more evenly distribute temperature, some people drill a small bypass hole in the t-stat.
Make a hole in the thermostat housing the size of a needle. and everything will work great.
Make a hole in the thermostat housing the size of a needle. and everything will work great.
Make a hole in the housing? If you mean the thermostat - similar to below then that's the plan.. Obviously not as big, other option is to tap into the housing just before the T-stat and run a hose to the heater core, this way there's circulation going to the T-stat. BTW OEM thermostat housing actually has a bypass hole otherwise we'd see similar phenomena with the OEM thermostat installed.
Example of bypass hole drilled out, helps bleed trapped bubbles and keep coolant flowing. OEM H3 3.7L Thermostat housing. You can see a small hole incorporated into the housing for just that, bleeding air and keeping coolant flowing.
I see, your truck must be an exception then or you're located in cooler climate. Can't say the same about mine nor hundreds if not thousands of people out there including Colorado folks who experience the same issue.. 195-220F may be the normal operating temp, but once it's 110-115F outside it's a different story. T-stat was moved to upper hose for the sake of convenience mostly. I still think where the original t stat is located is stupid but that's a different discussion.
@ 110°-115° ambient, your coolant temp should MAX 100° above (210°-215°). You need to do more research:
