Running warm

[Sniper]

I have an issue with my 51 Cambridge running warm, maybe too warm as the oil pressure drops off to near zero.

 

Back story, when I got the Cambridge it never like to get warmer than 150 degrees or so, check via my new Autometer gauge and an infrared temp gun.

 

Figuring the hack that maintained the vehicle before put a 160 degree thermostat in I bought a new 180 degree stat from Napa. 

 

I looks like this.

[50mech]

I think part of your post went missing....?

[Sniper]

Upon removing the thermostat housing I found a 180 degree thermostat installed with the "to rad" arrow pointing to the head not the radiator, upside down compared to the photo above.

 

Figuring that the flow of water was opening the thermostat early I put the new one in with the arrow pointing to the radiator as specified.

 

My engine now runs 200 degrees or so as verified by the gauge and the gun.  Oil pressure drops off at hot idle now. 

 

So I do some research and it looks like I should be running this thermostat, not the one Napa sold me or RA says I should be running.

 

 

[Sniper]

1 minute ago, 50mech said:

I think part of your post went missing....?

 

Patience grasshopper

 

[Sniper]

So, this is my question, has any one else run into issues running hot using the first thermostat?

 

Will the second one fix my issue?  I can get a new one from Vintage Power Wagons for a not too crazy price, $20.

 

Or should I just put my existing thermostat in upside down and live with it (not)?

[50mech]

If your housing has a port that runs forward to the water pump then it's external bypass and needs the second thermostat. If it doesn't it's just nternal bypass and needs the type you have. 

Edited March 23, 2020 by 50mech

[50mech]

Also according to my manual 165 is correct except in a very cold climate.

[Sniper]

My manual says 185 and I believe the bypass thermostat looks like this

 

 

[Sniper]

Based on the manual I have's pictures of the early/late style bypass setup

 

 

[Sniper]

As you can see, the info out there is confusing and it has been so long since I fooled with a flathead era car I don't remember these details.  Which really doesn't help since those I did fool with were the early style bypass arraignment.

[50mech]

I believe that's the new version. The NOS part you showed is bypass as well. ...I think.

 

But more to the point, I run the type you have with no issues.

Edited March 23, 2020 by 50mech

[Sniper]

Must be something else then, I wonder what?  Ran fine till I put in the new stat right side up.  I assume you have it installed like the first picture?  If so I'll put it and test it's operation.

[50mech]

I do, spring down.

I did check too and make sure my cylinder head was correct for internal bypass and I didn't just have the wrong housing on there.

[Sniper]

Thanks, I will pull the thermostat later this week and test it's operation.  As for the head, well I have the right housing for the year and the engine is original, which is not to say someone didn't swap heads in the past.  Another excuse to get on with the Edgy head swap.

[50mech]

There's always the water distribution tube to check.

If you're thermostat was in backwards before, perhaps it caused enough restriction to mask an issue there...?

[Los_Control]

My 218 flathead when I first got it running after sitting 20 years. it warmed up and continued to climb straight to over heat level.

Then go to remove T-stat and was already 1 bolt broke in the T-stat housing. I think this is why my truck was taken out of service for a long sleep.

 

I found the water distribution tube clogged, and the block was filled with original casting sand.

If you open your block drain plug (located near distributor) no water/coolant comes out, most likely you have casting sand also ... think most all do.

 

I fixed these two problems, now idle in driveway with no T-stat installed for 45-60 min, it runs at 160. Then it will start to creep up to 180, fast idle and drops right back to 160.

I imagine if I drove it, the temp would not reach 160 with the air flow. I need to install a T-stat to get to 180 operating temp.

These engines normally run cool.

If you are reaching 200, I suspect you have a circulation issue.

 

1 hour ago, Sniper said:

So, this is my question, has any one else run into issues running hot using the first thermostat?

I have been hanging around these forums for a few years, is common to use the modern T-stat you show .... I bought stant 13478 for mine. Is 180 degrees.

Pull your t-stat out and see where it runs .... only takes a few min and think you will at very least, establish a base line and see what a T-stat will change.

[Los_Control]

fwiw, I plan to pull my engine at a later date, not this date.

I  removed the water pump and radiator, snaked a piece of flat bar through the grill into the dist tube and rodded out the calcium and lime.

Removed the oil fill tube, distributor, and the soft plugs.  Then snaked Ford wire up into the block and pulled all the sand out. Be amazed how much sand comes out ... people claim it is left over from when the block was originally cast'ed, they just never cleaned it out. Why everybody has same issue .... I do not think hot tank cleans it out. Just sits there.

 

Total cost is gaskets and 5 soft plugs ...maybe $20, just labor to get er did. And now in West TX is a great time to fix this.

[Tooljunkie]

Im using a thermostat like in op’s first photo,160 degrees and a newer slant 6 radiator and a 4 lb pressure cap. My temp gies to 200,drops to 165 and stays there. 40 psi oil pressure regardless of temperature. 
timing and fuel mixture may play a part in this as well. 
 

when i got my truck, 51 fargo 218

it was seized. I did very little other than knock it loose, beat on the valves and fired it up. Cooling system was plugged pretty bad,water, compressed air and wires and rods poked every way i could. Lots of gunk. This was before i knew about the water distribution tube,so i have no idea if its intact. 
 

the low oil pressure when hot would concern me,i would check to make sure oil isnt diluted from gas, due to a sunk float or ruptured fuel pump diaphragm. 
that was my first problem, sunk float. Buddy helping refused to check it when he cleaned carb. 
 

[Sniper]

Well, I do have an oil leak, somewhere in the front and I want to replace the steel plugs with brass.  I have a new water pump on hand, a full engine gasket kit, new head bolts, washers and studs coming, a speedi sleeve for the crank hub and a modern timing cover seal.  I might just pull the engine, clean it up, do a bunch of work to it, clean the engine compartment and go from there.

 

I rebuilt the carb a month or two ago, float was ok then, no external signs of it being an issue and my plugs look good.  I changed the oil after this issue popped up and the pressure looks ok, for now but I haven't run it as long or hard since either.

Edited March 23, 2020 by Sniper
more info

[Young Ed]

5 hours ago, Sniper said:

Upon removing the thermostat housing I found a 180 degree thermostat installed with the "to rad" arrow pointing to the head not the radiator, upside down compared to the photo above.

 

Figuring that the flow of water was opening the thermostat early I put the new one in with the arrow pointing to the radiator as specified.

 

My engine now runs 200 degrees or so as verified by the gauge and the gun.  Oil pressure drops off at hot idle now. 

 

So I do some research and it looks like I should be running this thermostat, not the one Napa sold me or RA says I should be running.

 

 

Napa has a modern thermostat that comes with a spacer and a rubber donut to mimic that OEM one pictured

[Sniper]

On 3/23/2020 at 9:57 PM, Young Ed said:

Napa has a modern thermostat that comes with a spacer and a rubber donut to mimic that OEM one pictured

 

 

Got a part number?  Because what NAPA sold me is the first pic I posted.  No spacer, no donut.

 

Thanks.

[Young Ed]

1 hour ago, Sniper said:

 

 

Got a part number?  Because what NAPA sold me is the first pic I posted.  No spacer, no donut.

 

Thanks.

Thm 55

[Sniper]

Thanks, buyers guide stops at 48 for Plymouth applications, but goes to 54 for Dodge applications, odd.

 

 

 

 

[Dartgame]

I have a suggestion. Pull the thermostat out. Put it on the stove in a pot of water and slowly heat it up. Keep checking the water temp while observing when the tstat opens. Be sure to stir the water while doing this. My bet is yours is like most replacement stats, and it opens too hot. I've had many  common replacement 180 tstats, that are new, open at close to 200F. My recommendation is to buy a robertshaw style tstat from a v8 muscle era mopar application. I have had no issues with robertshaw stats opening at the correct temp. After learning this many years ago, I check all new stats this way before installing. Hope this helps.