Expected Operating Temperature

[rovingscot]

Hi,

In my new-to-me ‘57 Thunderbird (D-Code), I notice that it takes quite a bit of time for the temp gauge to climb off Cold. At least 30 minutes of running. And even then it sits in the lowest part of the “normal” range. It never gets to the middle of normal. This is after driving for an hour or so around town on a 70 deg day.

Is this typical?

If not, I’m suspecting either no thermostat installed, or a thermostat that is stuck open.

Thoughts?

Paul

[ward 57]

You may be right. Some have done that to make it run cooler. These engines like to run hot. 190 deg is not unusual on a warm day and the gauge in the upper end of the white zone. People not familiar with these engines think that is a bad thing when it is not.
I bought the large mouth thermostat as on a hot day it would go over the white line But after a proper tune-up and valve adjustment it rarely goes over the line anymore so it is still in the box.

[55blacktie]

I think your suspicions regarding missing/stuck thermostat are correct; however, the gauge is not particularly accurate.

According to Ted Eaton (eatonbalancing .com/y-blocksforever.com), the location of the sender and the rear of the driver's side head is not the best location; he prefers putting the sender directly behind the thermostat. My intake manifold has been drilled & tapped directly behind the thermostat for a 1/8 npt Autometer sender (& gauge), while the original gauge and sender will be retained.

Test any thermostat that you intend to use by putting it in a pot of water, bring the water to a boil. The thermostat should just begin to open at its temperature rating.

[ward 57]

I think your suspicions regarding missing/stuck thermostat are correct; however, the gauge is not particularly accurate.

According to Ted Eaton (eatonbalancing .com/y-blocksforever.com), the location of the sender and the rear of the driver's side head is not the best location; he prefers putting the sender directly behind the thermostat. My intake manifold has been drilled & tapped directly behind the thermostat for a 1/8 npt Autometer sender (& gauge), while the original gauge and sender will be retained.

Clever. It will certainly give you an idea of the temp at that point along with the stock gauge back where the heat originates.

[rovingscot]

Thanks for the thoughts. Subsequent to my post, I did notice after driving around for an hour or so and then idling in traffic that the temp gauge climbed to middle of the normal range. That is the first time I have seen the gauge at the expected position.

I may go with the “if it ain’t broke, don’t fix it approach” and leave everything as is.

Paul

[MarkR]

I agree. From your description it sounds like an errant gauge or sender. If it’s not boiling over and otherwise working well I’d leave it alone for now. Why poke the bear. You would know it if it’s overheating.

[Rusty57]

Do a search in this forum on the keyword "engine temp" as posted by "Jimntempe". As always, his factual based work addresses a lot of guessing and speculation.

[Jimntempe]

Hi,

In my new-to-me ‘57 Thunderbird (D-Code), I notice that it takes quite a bit of time for the temp gauge to climb off Cold. At least 30 minutes of running. And even then it sits in the lowest part of the “normal” range. It never gets to the middle of normal. This is after driving for an hour or so around town on a 70 deg day.

Is this typical?

If not, I’m suspecting either no thermostat installed, or a thermostat that is stuck open.

Thoughts?

Paul

When I first got my 57 I noticed a similar thing, it seemed like it took forever for the gauge to show much heat. So much so that I thought the prior owner had removed the thermostat. I bought a new thermostat to install. When I took the housing off there was a thermostat already there, same 180 as my new one except my new one was wide mouth style. My next thought was that the old one was defective and with the new one I'd be warming up quickly. Nope, warmed up just as slow with the new one.

It's interesting that these cars are slow to warm up and difficult to cool down! Even here in Phx in early summer it takes miles of driving to get it "up to temperature." My new cars are up to temp in a mile or two.

I've thought about whether that bypass under the thermostat housing might be the culprit. In theory what it does isn't just bypass the thermostat but also bypass the radiator. But perhaps it's not as complete a radiator bypass as thought and it's simply allowing too much radiator flow preventing fast warmup. Most/many cars use the heater core or a double heater valve as the bypass but these cars don't.

[ward 57]

I have never had that issue. Even on a cool day the needle starts moving within a couple of minutes and the choke pulls off and is at mid range on the gauge within a mile or two and that's with no heat riser valve.

[MarkR]

I have never had that issue. Even on a cool day the needle starts moving within a couple of minutes and the choke pulls off and is at mid range on the gauge within a mile or two and that's with no heat riser valve.

I’ve never seen that as well. My 292 was tanked and all water jackets scoured as good as possible 20 years ago. It Has always reached operating temp within minutes here in Vegas. Im using a digital gauge. I can’t imagine any Y Block with a properly operating temp gauge and sender in reality staying that cool.

[Jimntempe]

I have never had that issue. Even on a cool day the needle starts moving within a couple of minutes and the choke pulls off and is at mid range on the gauge within a mile or two and that's with no heat riser valve.

My choke comes off within a minute or so. I have the heat riser on the exhaust wired open. My needle definitely isn't moving within a couple of minutes. Maybe we have different ideas of how fast. It will start moving in 2 or 3 miles but it's a slow climb to the middle.

[ward 57]

That is a cold running engine. I would check your timing. Somebody may have thought that the TDC prominent mark was the timing mark and not the usual 6 deg BTC depending on the trans. It will run but lethargic.

[Rusty57]

Our ‘57 responds very similar to Jim’s. The choke opens soon but it takes a while for the temperature gauge needle to move. It takes a lot of driving to get it to mid-range. For example, on Sunday with about 75 degrees air temp I had driven about 15 miles with 3 stops (shutting of the engine for at least 10 minutes) when I noticed it was mid-range.

I have checked with an IR gun when the needle is mid-range. I check at the engine side of the thermostat housing. Typically I will see temperature readings of 170 to 180.

[MarkR]

We ran some errands last night. It cools down very fast here when the sun goes behind the mountains. Our area was in the 60’s. Within ten minutes digital gauge showed low 180’s at avenue speeds. A little higher at red lights. During the hot months in the 100’s it runs about 190. I’ve seen high 190’s in traffic jams. I have a six blade fan and aluminum radiator.
Blacktie mentioned installing the sender in the thermostat area. Walt Nuckels also preferred it. It would be interesting to know the temperature difference on a healthy original cooling system between there and the original location.

[Jimntempe]

This AM it was high 80's here. The needle left the peg after about 6 minutes/3 miles. That's about 140 degrees.

Using a laser temperature gun I've shot the temp sender area and the thermostat housing and the back of the head behind the sender several times. The readings I get right on the temp sender area and the readings on the thermostat housing are always very close. The readings on the back of the head are usually at least 20 degrees higher. Based on what I've seen I don't think it matters whether the sensor is in the factory position or moved to the thermostat housing.