Novak Conversions Jeep Wrangler TJ engine mounts

What is wrong with all my thermostats?

I wouldn't swap it if it's working.

Flowkooler/Robertshaw is supposed to me more stable, but I really can't tell if it's any more stable than a Stant Superstat based on the TJ gauge. You'd have to compare OBDII data since the gauge is somewhat damped.

Advance swapped out my failed Stant Superstat with a Motorad Ultrastat. Doesn't look bad, but doesn't have the jiggle vent.
 
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JKP said:
I wouldn't swap it if it's working.

Flowkooler/Robertshaw is supposed to me more stable, but I really can't tell if it's any more stable than a Stant Superstat based on the TJ gauge. You'd have to compare OBDII data since the gauge is somewhat damped.

Advance swapped out my failed Stant Superstat with a Motorad Ultrastat. Doesn't look bad, but doesn't have the jiggle vent.
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I redid the whole system mopar everything in 2020,been all over the USA ,no problems,if I sit idling in the summer w/ac it will climb passed half way,I think I might do something to raise the rpm to keep the (wench)lol cool when I go into a store or something.
 
Pick up a bluetooth OBD reader to see what your temps actually are.

Mine will approach 220 if it's scorching out, idling with the AC in GA. The gauge just shows a needle width or so above 210. As soon as I start driving, it's 205 to 210. Mopar rad, Robertshaw thermostat, Advance pump.
 
JKP said:
And the current 05, 06 TJ MOPAR cam sensor is junk as well, it is not the same as the original one.
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Not sure what you mean by current 05-06 TJ Mopar cam sensor…it’s been discontinued for years.
 
Well even with the all new Robert Shaw thermostat, water pump, hoses, radiator, coolant, and trying to bleed the system many times I’m still stuck at 170 again. I’m getting so tired of the replacement parts available for this jeep.

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I like to test stuff once in a while cuz ya can...

You ever test any of the thermostats you have replaced? Take actual temps not via OBD2?

I dont always, but I tested the last thermostat I pulled and the replacement before I put it in. Because you dont know what you dont know :D
 
CMBD said:
I like to test stuff once in a while cuz ya can...

You ever test any of the thermostats you have replaced? Take actual temps not via OBD2?

I dont always, but I tested the last thermostat I pulled and the replacement before I put it in. Because you dont know what you dont know :D
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I never have because I’m just assuming the new part I ordered is good but I expect too much apparently.
JKP said:
Be sure you put the vent hole at the top when you put it in to help it burp.
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Ya i did that.
 
I feel like at this point you should really try testing them to make sure you actually have gotten this many bad thermostats and it's not something else going on
 
lBasket said:
I feel like at this point you should really try testing them to make sure you actually have gotten this many bad thermostats and it's not something else going on
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You’re right. Previously they all were good till about a year then they would get stuck open. So every mid winter they’d die if loose heat then I’d swap it and have heat again. This is the first one that’s stuck open brand new. Pretty bad luck and I can’t think of it being any other issue but I’m going to throw the new one they send in a pot and boil it and see what temp it opens to make sure.
 
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So why not try a Mopar branded thermostat? You've been told how some have installed dozens maybe hundreds without issue. Not worth trying?

And there are many more OEM TJ parts available from non-dealers than you'll find at any brick & mortar Jeep dealerships. Summit, Amazon, eBay, Rock Auto, etc., etc. carry many OEM parts.

Try a Mopar part. Let us know how it works.

Don't fall for the myth that identical manufacturer (i.e. Motorad) equals identical performance.
 
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g.hayduke said:
So why not try a Mopar branded thermostat? You've been told how some have installed dozens maybe hundreds without issue. Not worth trying?

And there are many more OEM TJ parts available from non-dealers than you'll find at any brick & mortar Jeep dealerships. Summit, Amazon, eBay, Rock Auto, etc., etc. carry many OEM parts.

Try a Mopar part. Let us know how it works.

Don't fall for the myth that identical manufacturer (i.e. Motorad) equals identical performance.
Click to expand...

I just bought a spare the other day.but my original is over 5 years old and still perfect.

image.jpg
 
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The4bangertj said:
lol you’d be surprised how tempting that is. Thankfully flow koolers is sending me out another thermostat.
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It will take all of 10 minutes to check it before installation. Heat a pot of water on your stove with a thermometer to watch it. That thermostat should open fully at 195°F.
Take the one you just installed and run the same test. If it also opens at 195°F, then stop and consider what else in your system might not be working properly.

Was that new thermostat clean or is there debris in the diaphram?

Have you brought the vehicle up to temp with the radiator cap off and watched to see if you have flow when you shouldn't?

Do you know for certain the ECT sender is accurate?

Do you know for certain the heater core is flushed clean and not fouled with debris?

Do you know for certain the fit in the thermostat housing is good and coolant is not bypassing the thermostat?

Is your fan clutch unlocking (there will still be some resistance). This in itself shouldn't lead to persistent undertemp conditions but could contribute.

Does your water pump have an overdrive pulley for some reason?

I think the parts you can reliably say are not faulty are the radiator and radiator cap since you aren't overheating. If you test the thermostats, then you can take them off your list.

Bleeding/burping air from the heads isn't correlated with operating under-temp. Air pockets lead to low pressure in the system, which leads to overheating. It's a bit counterintuitive but you'll get flashing to steam which both reduces thermal conductivity in the head and can reach higher temps. Same reason a pinhole in the radiator leads to overheating. Operating at about 2 atm results in a significantly higher boiling temp in the system, something those of us living at high altitude know well in inverse where water boils at say 198°F instead of 212°F at sea level.
 
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g.hayduke said:
So why not try a Mopar branded thermostat? You've been told how some have installed dozens maybe hundreds without issue. Not worth trying?

And there are many more OEM TJ parts available from non-dealers than you'll find at any brick & mortar Jeep dealerships. Summit, Amazon, eBay, Rock Auto, etc., etc. carry many OEM parts.

Try a Mopar part. Let us know how it works.

Don't fall for the myth that identical manufacturer (i.e. Motorad) equals identical performance.
Click to expand...

I recall Blaine or someone else in a different forum post talking about how they’re all the same brand just better qc since the tolerances are graded and then distributed based on that. If they work I can’t imagine how a different tolerance is graded or if it would make it last longer for a thermostat. I also heard nothing but good things about the Robert Shaw so I thought I was good to go. I got a lemon. Been on the bad luck train with many other parts too so it’s not surprising to me.
GoldenGorilla said:
It will take all of 10 minutes to check it before installation. Heat a pot of water on your stove with a thermometer to watch it. That thermostat should open fully at 195°F.
Take the one you just installed and run the same test. If it also opens at 195°F, then stop and consider what else in your system might not be working properly.

Was that new thermostat clean or is there debris in the diaphram?

Have you brought the vehicle up to temp with the radiator cap off and watched to see if you have flow when you shouldn't?

Do you know for certain the ECT sender is accurate?

Do you know for certain the heater core is flushed clean and not fouled with debris?

Do you know for certain the fit in the thermostat housing is good and coolant is not bypassing the thermostat?

Is your fan clutch unlocking (there will still be some resistance). This in itself shouldn't lead to persistent undertemp conditions but could contribute.

Does your water pump have an overdrive pulley for some reason?

I think the parts you can reliably say are not faulty are the radiator and radiator cap since you aren't overheating. If you test the thermostats, then you can take them off your list.

Bleeding/burping air from the heads isn't correlated with operating under-temp. Air pockets lead to low pressure in the system, which leads to overheating. It's a bit counterintuitive but you'll get flashing to steam which both reduces thermal conductivity in the head and can reach higher temps. Same reason a pinhole in the radiator leads to overheating. Operating at about 2 atm results in a significantly higher boiling temp in the system, something those of us living at high altitude know well in inverse where water boils at say 198°F instead of 212°F at sea level.
Click to expand...

The root of this becoming an issue was because I had hot air blowing in the jeep. Temperature read properly. Then over a few days I lost temperature. Each day the temp gauge and my hands got colder. The heater core was flushed 2 years ago, it was blowing hot before this so I have no reason to believe it’s clogged. The temperature sensor was also replaced a year ago, and it has read temps being hot when I’ve had hot air. I have no reason to think it’s faulty especially when it’s still correlating with the heater core.
Thermostat was clean and clicked into the recessed area on the block as expected with the hole on top.
Yes the car was brought up to temp and held for 15 min with the front elevated and radiator cap removed.
I installed a new fan clutch with this thermostat, water pump, and radiator.

Thus my understanding, the only way the coolant is being cooled lower than the desired temp is because the thermostat is opened more than it should. Nothing else would. Yes I didn’t test the thermostat before going in. I’ll test the new one before I put it in.
 
You're right. All indications point to a bad thermostat. Yet you won't use a thermostat that others have had nothing but success with. Good luck.
 
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