365 ci temperature sensor 56 series 62 ???

[hawkfan]

Lexi,

Thanks for the guidance.  I'll do some more searching for additional numbers.

Yep, that "blanking plate" is exactly like mine and in the same spot!  I thought about making another plate and tapping a hole for a temp sensor and installing it but the location is so tight up against an accelerator bracket there would sure be interference issue.

Thanks
Hawkfan

[Cadman-iac]

When I read about this I got curious and looked at mine to see if they had the sending unit in the correct place. Both of my 56's are there. My 55 though, has it on the rear of the left head, right where that plate is. It doesn't have the plate on it though, it's just tapped and threaded.
Just thought I'd mention that in case you were thinking of putting your sending unit in the rear of the head.

Rick

[The Tassie Devil(le)]

Realistically, he best place for the coolant temperature sensor is as close to the engine-side of the Thermostat, where it can register the highest temperature before it can be circulated into the Radiator.

Bruce.

[fishnjim]

I tried to make some sense of this puzzle, for my own edification.   I could not locate a good illustration showing the '56 sensor position in the archives. (doesn't sell cars) 
The parts list shows the temp sensor changes, '55 to '56.   '56 should be the same thru '59, front left(DS) head, as shown.  That's the single pin Delco w/ 3/4 NPT.   The '56 one pictured would be correct.   Important clue; that's not what is here.   Neither '55 or '56 sensor in position.
The '55 sensor has a threaded end electrical connection, so the signal wire end connectors are different.   Pictures are available(ebay) and goes in the back of the head, '55.   The signal wire would be shorter and won't fit the '56 connector.   Most likely, someone blanked off a '55 head and did away with the sensor as it didn't match the wiring.   Really no reason, otherwise, to disconnect, unless the indicator/gauge doesn't work either.
This engine does not appear to be all original '56 and why there's no sensor.
As advised, make sure the VIN number matches to be sure it's even a '56 block.

[Lexi]

Yes, I would love to see some block numbers as well. For those historians out there, the LH head I wrote about with the blank rear plate, does have the heat sensor. I believe the sensor is in the correct place, up front near the water pump top arm. As I wrote earlier in this thread GM admitted to making a number of changes to "major mechanical parts " (quote), as per the December 23rd, 1955 General Service Letter #896 for the 1956 Cadillac model year. The specific changes were not described, though it was noted that many were "dimensional". The Master Parts List notes 2 different part numbers for cylinder heads that year, with all sorts of provisos noted, (linked to various engine unit/serial numbers). Same for camshafts that year as well. Hopefully hawkfan can locate some of those numbers and post for us. That will give us something to chew on during these Covid times.   Clay/Lexi

Edit: Photo image of my Cadillac's engine compartment showing location of heat sensor, close to water pump. See red arrow which points to the mechanical unit I installed, rather than rely on the OEM sender. Same location for installation though.

[hawkfan]

I happened to pull the radiator to have it re-cored as it had a leak and I was discussing  the lack of temp sensor location on my engine with the radiator shop owner.  This individual and his shop harkened back to the day of mom and pop parts stores.  When I brought the radiator into his shop he knew just by looking at what car it came out of.  He suggested that while he was rebuilding my radiator that he could braze a fitting into the top bonnet at the core line so I could install the probe there. Sure enough.  I installed the radiator and the temp probe into the fitting and as soon as the thermostat opened the temp gauge went up to 190 deg.  Shops and owners like these are very few and far between.  Trying getting this service from one of the big parts outlets!  Never happen!

[Cadman-iac]

 Glad to hear that you got the problem solved. The one drawback to the new location is that you don't really know what the engine temperature is exactly until the stat pops open. Another thing that you want to consider is if your stat should stick closed, you won't know that either until it's too late.
Just food for thought.

Rick

[Lexi]

Yes, Cadmaniac makes a good point. What happens if your thermostat sticks shut? Those Harrison radiators were used on Cadillac from 1949 - 1956. Only difference on some years is where the drain cock was placed. Clay/Lexi

[hawkfan]

Before this modification I hadn't a clue what the temp was.  Now at least if the temp gauge doesnt move after I drive it for a bit I know something isnt correct.  For how I drive this car, this probe location works.

[Lexi]

Definitely an advantage. In this hot weather I note my mechanical gauge shows clear signs of movement at least within 1 - 1/2 minutes of fast idle. Then after a 2 - 3 mile drive it would be at around 180, i.e. about opening temperature of the thermostat if working. Clay/Lexi

[James Landi]

Brian,

You're so fortunate to find and employ the services of such good people.  Having owned my share of "vintage" Cadillacs, most independent repair services think you're an old crazy man to dump money into a beloved car.  As one guy told me some years ago, "Why would you want to feed a dead horse."  I have moved to Maine, and discovered a wonderful garage, owned and operated by brothers who charge 65 dollars an hour, and they're respectful, creative, intelligent, and use a variety of internet services for research.   I wish the Club would develop a " National Register of Supportive Automotive Repair and Restorative Shops."  Reciprocal advantages would  more than provide  ROI for all parties.     Happy day,  James

[hawkfan]

James,
Couldn't agree with you more!!!  Glad to see you've found a shop you can trust and not get taken to the cleaners by.  I've rebuilt several vintage cars for myself and others over the years and its something I enjoy doing!  I've made some money at it along the way but I love driving them more.  I enjoy the challenge and enjoy meeting people that share the same passion.  In this day and age, most people are clueless when it comes to getting their autos repaired.  They're at the mercy of the repair shop!

Enjoy the ride!
Hawkfan