I am trying to generate an enlightened discussion here about the general operating temperature of a slant.

Here is what I have seen that is worth talking about after you have given the ideas some thought.

I have two temp sensors, one in the head, and one down low in the drain plug of the block As the engine warms up, the head is warmer by about 20-30 degrees for maybe 10 minutes. Eventually they are the same. Typical top temp is around 200-to 205. In the Summer they are the same at cruise. However, in the Winter the block never gets over 180, even though the head is at 200-205. This means in cold weather the engine itself seldom gets over 180. I found it most interesting that the standard temp gauge tells only PART of the story.

1. What are the ramifications of this on wear and economy, if any.

2. Should anything be done to deal with it? Should I maybe design a cover for part of the radiator in the Winter.

It is winter time here, and the car hobby season is pretty much over. It is too cold to work on the car much, even though I drive it often to work. So the forum and its discussions are now my primary involvement with the hobby until warm weather comes back. I am looking forward to some enlightened, thoughtful talk about engine temp and the effects on things.

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What temperature thermostat do you run in the winter, and summer?

Winter time radiator my not see much hot water, and when thermostat dose open a big slug of super cooled coolant migrates into lower block. In summer, radiator maintains a much higher temperature when thermostat is closed because delta T (temperature differential) is much less than during winter.

In other words as delta T increases, the ability of cooling system to perform or its efficiency to transfer heat increases.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I run a 195 in the winter and summer. You wonder if a thermostat with a small hole in it would even things out a bit. This might avoid the sudden change.

Would it help to raise the temp for the fan? Or would this make things worse?

How about the effects of this on engine wear? It has been proven repeatedly that warmer engine temps actually reduce wear.

SAm

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Personally I wouldn't worry about it. If the radiator is doing its job, the lower block temp, will normally be lower then the front of the head. The water will always gain temp as it travels from the front lower block, to the rear of the block and up into the head, and to the front of the head. There is one small hole (about 1/4") at each cyl between the block and head to allow water flow, to even out the temp across the length of the engine. I always drill a small hole (3/32) in the stat, but only as an aid to bleeading out the air.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

I wouldn't worry about it. Remember, combustion is happening up at the top of the cylinders, now down at the bottom.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

If you really want to keep the block warmer and even out the temperatures throughout the engine you need a higher volume coolant bypass. If you look at a lot of German cars they have a thermostat housing with 3 big hoses. When the engine is cold a large volume of coolant circulates throughout the entire engine so it warms more evenly. As the coolant reaches the thermostat opening point coolant is diverted to the radiator.

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Joshua

Yes. Which means a higher parts count, more leak and failure points, greater system cost to build and maintain…

…and yet somehow, those German engines don't seem to last any longer or experience fewer engine temperature related issues than engines with a simple single-acting 2-hose system.

There's a lesson here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sam:

It sounds to me like you have an ideal cooling system .

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Yeah....Im the one who destroyed this rare, vintage automobile.....

That's all interesting. Two things made me post this. One is that I have two sensors, and so the information is available in a way is not to most of us. The second is that the temps end up being the same in the Summer. I just wondered if there was an advantage to either scenario.

Thanks for the feedback. I always appreciate the special insight our bright members have. I think the slant six community has a deeper understanding of many basic things automotive than the average hot rod, who can just buy already engineered stuff for their Chevy or Mustang.

Sam

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I drive my '72 Valiant to and from work daily and when winter hits its tough to watch my co-workers leave with defrosters which seemingly work instantly.
The fixed 4 blade fan on my car doesn't help matters either....constantly sucking frigid air across the rad and block. Thats why I am removing the fan for winter and using a slim electric fan for winter duty (hardly ever comes on). Helps with quicker warm up!

Valleyant, that electric fan will help much. I have had an electric fan on this car for years, although I have changed models and types several times. This helps with the warm up in winter.

Sam

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You worry too much... Ditto Sandy.

Lou

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Home of Slant6-powered fun machines

Not worried. It is interesting Lou, that you and Dan both used the "Worried" term. In general, most people probably worry too much. They pick their own personal worry topic and focus on that. This was not one for me. But thanks for the concerned counseling from both of you.


I just look under rocks a lot. I am simply curious. You never know where there may be some improvement available. It's the same impulse that got me to join the forum in the first place. The car ran OK then. I could have just left it alone, and put gas and oil in it and driven it.

And, I enjoy starting intelligent, insightful conversations on this forum. You never know what gem will surface. I could simply go on line and read Wikapedia on most subjects. But I know you guys, and value the interactions.


Sam

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On those rare occasions when the temperature was stuck in the 20's F, I just taped a piece of cardboard in front of the bottom 1/2 the radiator. Otherwise, the temp. gauge never got anywhere near the normal operating range.

New car technology uses "reverse-flow" cooling, where the coolant enters the head(s) first, then it flow down, into the block, then back to the radiator...
That is a good way to even-out the over-all engine temps but this is somewhat hard to do with the SL6. ( block mounted waterpump, pumping coolant directly into the block)
DD