Engine temp rises when I get to cruise speed

[jrvariel48]

Originally Posted by Tinker

Seems like things are moving forward. That's good. Even if it doesn't work.

I agree Tinker, I think I'm on the right track

[Bored&Stroked]

Well, it sure does seem to be a lot better than before - that is great news. I would beat it up on the highway a bit (try to pull a hill or someplace where you can put some load on it) and see how the temps register.

Seems the issues might be related to an air-flow restriction on the shroud.

[The Brassworks]

Removing the fan shroud helped the air get out and your temperature dropped by 15 to 25 degrees bringing you ~15 degrees below your upper bound target. You're reporting a radiator temperature drop of 40 degrees. Keep testing.

Recommendations

• The fan is mounted close to the top header. It should as high as possible to maximize heat exchange.

• The lower panel should be added. ford38v8 and Rich B mentioned the louvers but I would add most of pan is it is solid and it does direct airflow to the core. There should be no downside. You could tape over the louvers temporarily to see if a solid pan helps.

• Greater cfm will help at the lower driving speeds and idle. You bought a flex-a-lite and had success but I still believe SPAL provides the best performance available.

[jrvariel48]

Originally Posted by Bored&Stroked

Well, it sure does seem to be a lot better than before - that is great news. I would beat it up on the highway a bit (try to pull a hill or someplace where you can put some load on it) and see how the temps register.

Seems the issues might be related to an air-flow restriction on the shroud.

I'm hoping to get it out this weekend and do just that!!

[jrvariel48]

Originally Posted by The Brassworks

Removing the fan shroud helped the air get out and your temperature dropped by 15 to 25 degrees bringing you ~15 degrees below your upper bound target. You're reporting a radiator temperature drop of 40 degrees. Keep testing.

Recommendations

• The fan is mounted close to the top header. It should as high as possible to maximize heat exchange.

It is right under the top tank

• The lower panel should be added. ford38v8 and Rich B mentioned the louvers but I would add most of pan is it is solid and it does direct airflow to the core. There should be no downside. You could tape over the louvers temporarily to see if a solid pan helps.

I added the grille and lower pan today for testing.

• Greater cfm will help at the lower driving speeds and idle. You bought a flex-a-lite and had success but I still believe SPAL provides the best performance available.

If it keeps the motor temp where I need it, I'll be happy. Knowing the size and what will fit, a Spal could always be installed.
It's pretty quiet also.

[FlatheadTed]

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to late

[jrvariel48]

It looks like the vents on the lower pan allow some air to go straight through, but mostly on an upwards angle towards the lower part of the motor. The very top of the pan is on a slight upward angle towards the bottom of the radiator.
Let's see how it help as I didn't change anything else.
If all is good, I'll try going back to the 40/60 mix of ethylene glycol and distilled water.

[jrvariel48]

I did 2 tests today with the same results

Test 1

85 degrees 42% humidity Sunny, Grill with lower pan
I let it idle for 8 minutes. T-stats opened at about 6 minutes in.
Temp reached 170* and stayed there.

So I'm clear as to where I'm pointing the laser thermometer.
Top tank-On the back of the tank right next to the inlet.

Bottom tank-Aiming down in between the outlet and the radiator hose.
I don't know if these are the best two spots, so someone please fill me in if they're not.
It's hard to point directly at the bottom tank.

My in-car temp gauge said 170*, laser temp at was top tank at 160*, lower tank 130* and the gauge on the head read 170* and gauge on the water pump read 165*.

When I say say water pump gauge, I have a gauge mounted into the heater hose that's coming off the water pump about 10" from the water pump bung.

My guess that the bottom tank temp(130*) and the gauge in the water pump(165*) are different because the coolant is entering the system and heating up there?? Anyone?

I start to drive around town with starts and stops and speeds up to 35 mph.
Temp rise to 190* and bounces between 185* and 190*.

Get onto the high way at 60 mph and I creep up to 200 then 205 degrees. That was about 30 minutes into running at idle, back road driving and highway.

I was on the high way for 7 minutes at 55-65 mph.

When I got off the high way temp was at 205* As I drove stop and go the temp dropped to 200* and then 190*
Low speed seems to be better as it was before.

At 49 minutes in, I pulled back into the driveway to let it idle for a little bit.

In-car gauge read 200*, Top tank read 195*, bottom tank read 170*, head gauge read 200* and water pump gauge read 185*

Test 2

I fashioned a scoop made of cardboard (from a pizza box) and followed the slight angle of the top of the lower pan where it meets the first row of fins on the radiator into the back of the grill right on top of the crank hole. I held it in with a couple of small clips.

It was now 86 degrees outside

I did the same route as before with NO noticeable difference in temperature.

I'm all ears!

[jrvariel48]

Does anyone agree that ethylene glycol may help in this situation?
I still have a 5 gallon bucket of 40% ethylene glycol and 60% distilled water

[flatjack9]

No.

[cadillac512]

Originally Posted by jrvariel48

Does anyone agree that ethylene glycol may help in this situation?
I still have a 5 gallon bucket of 40% ethylene glycol and 60% distilled water

No-- the glycol/water mix at 40/60 won't exchange heat as readily as the mostly-water mix you have been testing with. It'll boil at a higher temp but that's not the same thing as cooling more efficiently.



Terry

[jrvariel48]

Thank you flatjack9 and cadillac512.

[jrvariel48]

Now for a question on overflow tanks. Here's what I'm reading:

Criscuolo says that the 12-percent and 6-percent (of your system capacity) numbers are added together to give you the required expansion tank size. “I’ll give you an example,” he explains. “Let’s say you have a 13-quart system capacity in your vehicle now after you added a power adder, and you set up your cooling system how you want and know where you want your expansion tank placed. At 12-percent drawdown, you would need 1.56 quarts, and for the thermal expansion, you would need 0.78 quart, which will equate to 2.34-quarts. That’s the smallest size you can get by with for your system, and that’s how it should be calculated for any size system.”

Would this apply to mt pressurized system?

If this is the case, I know my tank is way to small at 20 ounces.

Is it possible I'm overflowing on to the highway when the coolant heats up and expands?

Could that also introduce air into the system?

If I have a 20 quart system, I would need a tank that's 115.2 ounces? Does that make sense?

[cadillac512]

The first thing to know in this situation is: When the coolant level in the radiator is checked after the engine has cooled,is the radiator completely full to the cap? At that time is there still some liquid in the expansion tank as well? If so, your tank is doing its job and you needn't worry. If you were losing coolant you'd soon empty the tank and the radiator wouldn't be completely full to the cap after cooling off.

The recommended tank size seems large to me. In my experience the required size can be quite a bit less.



Terry

[jrvariel48]

Originally Posted by cadillac512

The first thing to know in this situation is: When the coolant level in the radiator is checked after the engine has cooled,is the radiator completely full to the cap? At that time is there still some liquid in the expansion tank as well? If so, your tank is doing its job and you needn't worry. If you were losing coolant you'd soon empty the tank and the radiator wouldn't be completely full to the cap after cooling off.

The recommended tank size seems large to me. In my experience the required size can be quite a bit less.



Terry

My expansion tank is always empty after it cools. The filler neck is on the back of the tank towards the bottom so unless the top tank is completely empty I'll see coolant
I don't know if that's making a difference or not, but I'd sure like to rule that out as a possible problem. I don't know how low I am, it's hard to tell without a top of tank cap to actually look and see. I also wonder about air getting back into the system because the tank is running out of coolant to return.

[cadillac512]

Ah, I understand. As long as the core is covered any air should stay in the top tank above the coolant, and not cause trouble or affect the cooling. However, that catch can shouldn't be empty. It has to either have a leak of some kind or be filling and overflowing the catch can while driving to do that. Maybe a temporary larger can would be a good test. It can be mounted anywhere there's room.

[jrvariel48]

Originally Posted by cadillac512

Ah, I understand. As long as the core is covered any air should stay in the top tank above the coolant, and not cause trouble or affect the cooling. However, that catch can shouldn't be empty. It has to either have a leak of some kind or be filling and overflowing the catch can while driving to do that. Maybe a temporary larger can would be a good test. It can be mounted anywhere there's room.

My thoughts exactly! I’ll make a plastic overflow tank. I might even have an old washer fluid tank that I can convert

[jrvariel48]

Took a ride yesterday with the same results. 78 degrees, 42% humidity sunny
Temp stayed around 190 for the first 10 minutes of back road driving.
Up to 205 on the highway for 15 minutes.
Back to 190 on back roads.
I actually turned the fan off for about 10 minutes of 35-45 mph driving with no temp change and kept the fan off for 15 minutes at 55-65 with not change.

[KiWinUS]

I personally don’t believe that’s how I want one of my engines. Too hot on freeway. Your engine could drive cross country but not at that temp. On verge of too hot. No room for 100+* ambient. Or trash on grille. 78* ambient temp I wouldn’t want over 180-190* highway and driving around town with room for stop n go traffic

[jrvariel48]

Originally Posted by KiWinUS

I personally don’t believe that’s how I want one of my engines. Too hot on freeway. Your engine could drive cross country but not at that temp. On verge of too hot. No room for 100+* ambient. Or trash on grille. 78* ambient temp I wouldn’t want over 180-190* highway and driving around town with room for stop n go traffic

I agree KiWinUS and I'm running out of things to try out. I'm going to try the larger overflow tank for $hits and giggles just to rule it out. After that, I'm at a lose