Regardless of what all the "they are all the same" naysayers tout, we have used more Mopar thermostats than anyone I know of and have never had a single failure.
Cooling system cleanliness
- Thread starter freedom_in_4low
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Regardless of what all the "they are all the same" naysayers tout, we have used more Mopar thermostats than anyone I know of and have never had a single failure.
OP
I got to examine and test the old thermostat last night and found some interesting things. It was a Stant Superstat but after the motorad acquisition so it has the motorad stamp, and is labeled for 195 which is what I purchased.
It has a jiggle pin but it's in the center plunger instead of the housing and has 3 struts vs the 2 present in the Mopar/Motorad. Not sure what that's supposed to accomplish .
When cold, it appears completely closed as expected.
When heated up, it cracks open on one side in the 150s.
It's opening more by 178.
And really open at 185.
I was really expecting to find some rust or a stray chunk of RTV from the previous owners hamfisted attempt at installing the previous one without getting it correctly seated, but it appears to just be a failure. I won't be using another one.
It has a jiggle pin but it's in the center plunger instead of the housing and has 3 struts vs the 2 present in the Mopar/Motorad. Not sure what that's supposed to accomplish .
When cold, it appears completely closed as expected.
When heated up, it cracks open on one side in the 150s.
It's opening more by 178.
And really open at 185.
I was really expecting to find some rust or a stray chunk of RTV from the previous owners hamfisted attempt at installing the previous one without getting it correctly seated, but it appears to just be a failure. I won't be using another one.
Someone from a previous thread mentioned getting a thermostat from a Mopar dealer only to find out it was a MotoRad.
OP
Could have been me, and Blaine is aware and continues to use them based on his experience with them in larger quantities than many of us will touch in a lifetime. Mopar thermostats have been motorad at least since 2018. I found another thread that made it sound like at one point the original Mopar stat had a functioning air bleed hole, but the current motorad does not.
Motorad supplies to Mopar. If you order Mopar thermostat, you will get Mopar package, with Motorad inside. The motorad inside will be with the correct bleed hole, as they comply to Mopar standard.
Rockauto has both the Mopar listed (520-28186AC) for $34.79 and the MotoRad 5200195 for $6.93 I wonder if they're the same. That would piss me off only to find out I paid nearly $28.00 for the same one.
I don't know about the thermostat, but I have some very bad news for you in general.
Is it a
Mine was foamy as well on this last run of thermocure. No issues that I know of.
Also, in regards to draining the block, it’s been pretty easy since replacing the plug with a steel plug that takes a 5/16 (8mm) hex bit. This allows me to run the plug on an extension between the cats without falling off the bit. I bring it to hand tight using the extension, then tighten it down with the ratchet (no cross-threading issues).
The entire installation takes about one minute. Just use your eye to locate the hole and run the extension with one arm in that area while you hold your top-self up so you can see by holding on to the rail. Easy peasy.
Mine was foamy as well on this last run of thermocure. No issues that I know of.
Also, in regards to draining the block, it’s been pretty easy since replacing the plug with a steel plug that takes a 5/16 (8mm) hex bit. This allows me to run the plug on an extension between the cats without falling off the bit. I bring it to hand tight using the extension, then tighten it down with the ratchet (no cross-threading issues).
The entire installation takes about one minute. Just use your eye to locate the hole and run the extension with one arm in that area while you hold your top-self up so you can see by holding on to the rail. Easy peasy.
Ugh, still can't believe I potentially cross-threaded my engine block drain plug.
Once I found the location of it, I didn't think it was that that bad to work with.
I bought this set from Amazon and used the 6" extension to get enough clearance from everything else to be able to get a socket wrench/breaker bar/torque wrench in there to do what I needed to do.
For positioning, I would recommend going to the drivers side, laying on your back, with your head right by the front tire. If you look to the left, you can kind of see it. But you can then use your left arm, reach up between the cats, and feel around on the engine block for the drain plug. Once you find it once, you can find it again pretty easily. There are several videos online that show this better if you want a visual of it.
Until I have a single failure, I will continue to use Mopar. Not Mopar from Rock Auto or Amazon, Mopar from the dealer. I am more aware of how the aftermarket works than most. There is absolutely nothing that tells me just because it has Motorad on the side of it that it is the same one Autozone sells. I am also beyond unforgiving about that crap, just one failure, just one and I'm doing something else because I'm not buying a cooling system over bullshit failures.
Hey @mrblaine I've been reading this thread and got me thinking, what is your flush procedure? It sounds like you don't drain the block and use tap water but then flush with distilled water. do you use the that "tee" that taps into the heater core hoses? I'm looking into doing a flush as preventative maintenance since I'm at 100k and don't know if it has even been flushed before and I'm not sure what procedure to follow. Thanks!
After the drive around flush with Prestone for a couple of days, then we do the Thermocure. If you leave that in too long, the black is harder to flush out. After a day or so, maybe two, then we pull the thermostat and put the housing back on. We start by filling with tap water and starting the engine to circulate that for 10 minutes roughly. We keep doing that until the drained water is clean and clear into a clean white or light colored bucket. When it is clean, then we do two full flushes with distilled. Drain that, install new thermostat that has a 1/8" hole drilled next to the jiggler. Fill with coolant pre-mix of 1/3 distilled to 2/3 coolant. Start and circulate until we see the coolant movement in the radiator that shows the thermostat has opened, install radiator cap, top off overflow reservoir to the full level.
We have never pulled the block drain and never will.
When you get to the point where you pull the thermostat to get the cooling system running full blast, how long does it take typically to get to the point where yuo are topping off the overflow reservoir again?
I need to flush out my cooling system and just need to set aside time to be able to do it.
when you say drain, do you drain through the petcock?
do you worry about backflushing the heater core at all?
No, we drill a big hole in the bottom tank and then pull off the lower radiator hose each time.
No
OP
I've seen some comments from you (in the cooling system faq thread) that seemed to indicate that there was a point in history that you didn't have to drill the bleed hole. Did earlier thermostats have an open bleed hole, or a bigger jiggle pin hole? Were they also from motorad?
I'm not really going anywhere with that, just curious. The Robert shaw stat looks way different than any Stant or Motorad I've ever seen and I don't know if there's a bleed hole somewhere in it that I can't see.
If you opened up a rig with a failed Mopar thermostat tomorrow, what would be your next candidate?
I'm batting 0% on motorad ultrastat rebranded as Stant Superstat so I'm done with Stant and any motorad that isn't from a Mopar dealer.
No, there's a drainage hole plug in the bottom of the engine block.
It holds about 4 quarts of fluid.
Gotcha, thank you for the replies. I think was overthinking this.