Wrong thermostat installed?

[Ivan_B]

Looking for a second opinion here

Finally got around to replacing my coolant hoses, because the old ones had thick flakes of rust visible from underneath at the metal/rubber junction. The thermostat housing was very difficult to remove, one of the studs was heavily corroded but I managed to get it off without casualties. There seems to be plenty of dirt inside the cooling system, although, the block drain was not clogged as I expected (hi Keith ). Don't be fooled by the bright green antifreeze the PO put in. The thermostat housing has obviously been on the car for a while...

The most interesting thing, I found, is this guy:

 

Based upon the way I understand the Chrysler 201 cooling system, by default, the radiator inlet (upper hose) is closed, and the coolant is circulating through the bypass. From what I see, with the OEM housing, this thermostat appears to be working in the reverse order: the radiator inlet is open by default and the bypass is closed. Was my cooling system closing the radiator while warming up, all this time? ?

 

Also, for the little tip of the day - here's how you drain the block without making a mess:

[Happy 46R]

Hi Ivan, I have never seen a thermostat configuration like yours however I would think that as long as the copper coils were in the block and not the radiator housing the thermostat would work the same as mine does. It would seem logical that as the engine block heats the coils they reach a set temperature and pull the stopper down to allow for water flow. I could be out to left field but that would be my assumption on how it should work. I did however find this in a google search and although it relates to industrial engines it seems to show the style of thermostat you have. Hope this helps sorry I wasn't more authoritative.  Dave

[Ivan_B]

Hi Dave,

 

Thank you very much for the reply. Your illustration is showing a correct OEM thermostat, with the main opening on top (closed when cold) and the bypass openings on the sides (open when cold). The thermostat I found must be from a way different housing configuration. Although, I checked, the way it sits inside the housing, its valves will only be able to open about half way up. So it looks like when both - hot and cold, the flow of coolant in my engine was open through the radiator and the bypass at the same time, with the radiator part becoming somewhat more restricted with rising temperature ?

I already ordered an OEM thermostat, waiting for delivery.

https://www.ebay.com/itm/256372276175

[OldPly]

Maybe it's stuck open ?  In the old days people would test them in a pot of hot water , hang it in water (don't want it touching sides or bottom of pot) if you want to get Fancy add a thermometer

You can do the reverse and put in freezer dry don't want any mosture freezing it stuck and stopping it from moving 

[Ivan_B]

No, it is definitely closed. You can easily see it on these old bellows-type stats. When its open, the bellows are expanded like an accordion ?

Also, the good-old boiling pot method is still very much in use. I am planning to do it when I get the new thermostat delivered. I got the 160-degree (instead of 180) and will test them together to make sure that both work and the new one opens before the old one.

[Sniper]

10 hours ago, Ivan_B said:

I got the 160-degree

Why? You're not doing anything useful running that one

[Ivan_B]

I am hoping that it will help to keep the engine running a bit cooler (which might not necessarily be the case, depending upon a variety of factors). I like when the needle is in the middle of the gauge

[Dave72dt]

A thermostat does not limit how hot an engine will get.  It only determines the temp coolant starts to circulate through the radiator. A cooler thermostat if the system operates and maintains it at that temp may not be the temp the engine runs most efficiently at.

[Sniper]

What Dave said.  The thermostat sets the minimum operating temperature.  If you're running too hot, and "middle of the gauge" really means nothing, then there is an issue elsewhere.  Put a thermometer in the coolant and see what it is.

 

Very generally speaking, high running temps at low road speeds is usually an air flow issue.  As a rule of thumb, if you can put a piece of paper up against the outside of the radiator and the fan holds it there it's usually ok.  My 51 had an issue, turned out there was a lot of very fine dust packed onto the fins of the radiator.  So while the airflow was sufficient, the heat transfer was impeded by the dirt.  A good hosing out of the fins fixed it.

 

High running temps at highway speeds is usually a water flow issue.  Check that the coolant level is good and the thermostat isn't partially closed.  Sometimes the impeller on the pump comes loose or has eroded away.  Wrong pulleys got installed at some point, belt is slipping, etc.

 

My 51 had a 4 blade fan, Chrysler, at some point, put 6 bladed fans on these engines.  I don't know their reasoning but it may apply to your situation.

 

Of course this assumes the water jacket isn't full of crud and we all know that happens.

[Ivan_B]

12 minutes ago, Dave72dt said:

A thermostat does not limit how hot an engine will get. 

It could, when the current working temp is below the maximum thermostat threshold, which can be the case under certain conditions. I do know about the OEM temp and efficiency, though, that's true.

 

Anyway, is seems you guys won, this time. Here is a fresh pot test:

Both old and new stats open at the same time, and both still work ?

 

The car is running fine on the road, it's just I get nervous at a parking lot or the light when the needle starts to fluctuate toward the right. I know it is very likely still within specs, for these cars, but still... My radiator is clean on the outside. The system will be flushed today. Never heard about the paper trick to check the fan, will try that, thanks.

[Booger]

When your cleaning dont forget water distribution tube

[Ivan_B]

38 minutes ago, Booger said:

When your cleaning dont forget water distribution tube

Not this time. I am not planning on removing anything, just changing the thermostat and hoses. Will flush the block, radiator, and heater with water, that's all. I suspect that the block should not be that bad, since my drain was not even stuck ?

At least, I'll see what the flush brings out, first.

[9 foot box]

   The Bishop and Babcock name reminded me of a brass piece that I found. I think it’s from a beer tap or soda fountain apparatus. Tod Fitch has an excellent site for replacement parts for early Plymouth up to 48. Ply33.com. That’s an original thermostat, for sure. Rick D.

[Ivan_B]

7 hours ago, 9 foot box said:

The Bishop and Babcock name reminded me of a brass piece that I found.

The NOS Thomson thermostat I got, also has the same insignia on the back. B&B must've produced the bellows and sold these to various thermostat manufacturers... Or different places were simply branding their thermostats.

[Ivan_B]

Another great find from inside the engine:

This was tucked inside the head, behind the spark plug holes. I incidentally stumbled upon it, when feeling the perimeter of the thermostat opening, for debris, with my finger. Hopefully, I did not pull anything important ?

[Plymouthy Adams]

OH NO you ripped out the thermostat grounding wire......?

[Sam Buchanan]

Your engine needs deworming!!

[Los_Control]

You never know when you need a piece of wire for a roadside fix, just a handy place to store it.

[Ivan_B]

59 minutes ago, Plymouthy Adams said:

OH NO you ripped out the thermostat grounding wire......?

Come on, guys, this is not funny... The above statement actually made me stop and think, for like ~3.5 seconds...  ?

This must be a long awaited "hello" from the Chrysler engine casting techs. No other ideas how it got there.

Edited February 5 by Ivan_B

[Ivan_B]

I have finally replaced the hoses and thermostat. I think it works exactly like I expected: the car is now warming up extremely fast, and then settles at about 180. Just as it should

[Booger]

Ivan I donk know wtf that wire was...it should not have been there. But good to see running temp is normal. Now lets get the cholestoral down

2 hours ago, Ivan_B said:

I have finally replaced the hoses and thermostat. I think it works exactly like I expected: the car is now warming up extremely fast, and then settles at about 180. Just as it should

 

[Sniper]

On 2/4/2024 at 6:09 PM, Ivan_B said:

This must be a long awaited "hello" from the Chrysler engine casting techs. No other ideas how it got there.

 

Odds are it's a reinforcing wire in the sand core, kind of like rebar in concrete.  There to keep the core in one piece will after the casting cools.  The sand comes out, the wire does not.

[Dartgame]

Just an fyi - the muscle era v8 stats fit in my 52 and work fine. Maybe for yours as well. Easy to check at a parts store. I like the robertshaw style stats, vs the cheapo's the big box stores sell.

[Ivan_B]

Thanks. I already got the NOS off E-Bay. I like the accordion style bellows 🤣