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Official Forklift Driver
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Discussion Starter #1
I'm going to go with a different cooling combo next year. I'm using a stock radiator, 160 degree stat, water wetter, small trans cooler and heaters..... I mean headers. There is a very distinct barrier and right now it's rediculous. :( The roads are dry but I freeze my butt off.

When the temp's are above 85 degrees it runs very hot. Oil get's above 230 and coolant get's to 240 and it doesn't take that long to get there. On the low end of the spectrum 30 degrees is the limit. Under that it takes about 10 minutes warm-up time and 20 minutes of driving (45mph and lower) for the oil temp to hit 180 and the coolant barely get's beyond 170 when I'm sitting at a light.

In the warm weather I get on it and the temps will skyrocket in a hurry! It takes a long time of normal driving to get the temps down just 10 degrees and damn does it get hot in the cockpit!Same extreme situation when cold. As soon as I get moving the coolant will drop right away. The faster I go the cooler it get's. On one 3 mile trip trip on the expressway my coolant went from 165 to 114 and the temps on that night were in the teens. It was starting to get very cold in the car b/c I had to turn the heater off to build up heat.

Right now I'm thinking heat shield for the headers, combo cooler and higher stat. I want the DC Crew to toss some cooling idea's in my direction. I don't care how silly it may seem, I thought that about the debris screen at first but boy I was wrong, that screen really works! There is a guy w/ a 427 c.i. C5 running 170-180 on his coolant and oil so I should have no problem achieving that goal should I?

Thanks, :thumbsup:

John
 

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It may seem silly but, have you thought of making something to block part of the radiator when its cold out.

Are you sure the tstat not stuck open??

Are you using Syn. oil (mobil 1)
 

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DC Crew
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Right now it CLEARLY sounds like your t-stat is stuck open... or has the ability to stick in general.

As for summer, your secondary fan may not be kicking on.

I would replace the stat right away, then take on the next issue this next summer.:thumbsup:
 

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Official Forklift Driver
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Discussion Starter #4 (Edited)
C4CRAZY787,

The stat was good last Dec. when the engine was put back together but maybe it has pooped on me. I'll check it out. I can't remember what oil I used on the last change. It might have been Carquest brand non synthetic. I used either Mobil 1 or Redline in the summer, I don't remember which but I do know I was looking for better cooling. I was hoping the Carquest would help warm it up in the winter.

Patrick,

What secondary cooling fan? :laughing:

That might not be a bad idea for me to invest in one of those too. :thumbsup:
 

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Is your radiator the original? Maybe it needs to be flushed, cleaned or replaced.

I don't think I'm understanding how a stuck t-stat would cause the problem.

If it sticks shut, I think it would warm up faster and still run hot in colder temps. If it sticks open, then I don't see how it would run hot in the summer/higher outside temps.

Am I missing something???
 

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A working tstat should bring the engine temps up to the designed opening temps 160* in this case, unless it stuck open or drilled out.

War said his temps droped from 165*(open) to 114* on a hwy run the stat should have closed to keep the temp up.
 

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Super Moderator
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ASSUMEING YOUR COOLING SYSTEM ITSELF IS WORKING PROPERLY, YOUR PROBLEM APPEARS TO BE A BAD or INCORRECTLY FUNCTIONING,THEMOSTAT,THATS NOT OPPERATING CORRECTLY, OR MIS-ADJUSTED IGNITION TIMING OR A LEAN FUEL AIR MIX IN THE ENGINE.
iD SUGGEST CHECKING YOUR IGNITION TIMING VERY CAREFULLY AND CHANGING TO A 190F THERMOSTAT FIRST

SECOND you should realise that the OIL system does much of the engines cooling and a 7-8 qt baffled oil pan will normally absorb and cool the engine a great deal more than a 5 quart oil pan, due to both the larger oil supply and the larger surface area on that larger oil pan thats outer surface has a greater area expossed to the cool air flowing under the car that will normally be well over 120 degrees cooler than the oil inside that oil pan.
adding a 8qt oil pan helps cool the engine a great deal, so much in fact that the 10.5qt custom oil pan on my corvette require the use of a 190f thermostat just to allow my oil to get to the minimum 215f degs necessary to burn off the moisture that sometimes accumulates in a non-running engine!
ead this over carefully
IVE POSTED MOST OF THIS BEFORE BUT IT FITS HERE AS A SOURCE OF INFO FOR THE NEWER GUYS

the thinner the oil the faster it flows, the faster it gets to the surfaces that need the oil film, and the easier it is for the oil to flow thru the clearances,the engines operating temp. the engines clearances,and the oils thermal limits plus the engines ability to maitain sufficiant oil pressure and volume over the engine entire operating range effects the best oil choice.
since mineral and SYNTHETIC OILS in the 10w30 or 10w-40 range are the standard for most engines thats what the clearances are set up for in most engines


I found this diagram I find it interesting but all the data I've seen before I saw this diagram and which I trust considerably more than this diagram tends to point to slightly higher average temperatures being ideal.
I have repeatedly said that your oil temp should keep above 215° to allow moisture to burnout of the oil and that your coolant temp should stay in the 180-220 range, remember OIL IS THE MAIN LIQUID CARRIER OF HEAT AWAY FROM THE RINGS,BEARINGS,ROCKERS,SPRINGS,AND PISTONS, AND ITS OIL RUNNING DOWN THE INNER BLOCK SURFACES THAT ALLOWS THAT HEAT ABSORBED BY THE OIL TO TRANSFER TO THE BLOCK AND COOLANT

SMOKEY YUNICK, in several places in several books, refers to extensive dyno testing he did for General Motors, where they consistently found, that both engine wear and hp production benefited when the oil temp stayed above 215° but below 240°, and the coolant temperature stayed between 180 and 220, degrees, or as SMOKEY said, trying keep your oil hot, but your coolant, about 20 to 30° lower in temperature but the coolant should never be below 180°, and should not exceed 220°, while temperature should never below the below 215°, and 235 to 240 is about ideal, mineral base oils tend to start breaking down over 240°, synthetic oils can easily handle temperatures up in the 270 degree range in for extended periods, but they performed best in their lubrication in cleaning function went down in the 240 range
 

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DC Crew
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I am haveing the problem on the heat side. I have since found out my 2nd fan is not coming on. On normal days my coolant and oil run about the same temp.
 

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Mr. Casino
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Assuming the engine is set up correctly and the cooling system is not performing as it should be, we have to look at the coolant flow through the system and where it is meant to collect heat and remove heat.

Assuming the coolant is at the proper volume and mixture, the engine generates heat raising the metal and oil temp. The coolant temp then rises to the setpoint of the thermostat.

The water pump is trying to move water from the colder coolant storage area(radiator) though the engine.

When the thermostat open the flow of coolant(lower temp than the thermostat setting) starts flowing into the engine removing heat until the thermostat closes and stops the coolant flow.

As long as the coolant from the radiator stays below the thermostat operating temperature then coolant can do its job.

The thermostat controls the engine temp. If it sticks closed the engine will overheat. If it sticks open then the engine will not reach the setpoint in cold and if the weather is hot the engine will run hot because the coolant doesn't spend enough residency time in the radiator.

The radiator itself must provide coolant temp lower than the thermostat setting if the engine is to be cooled.

Thermostats are cheap so put one and eliminate one possible trouble spot.

Radiators have to transfer heat and if they are fouled the heat transfer goes to hell. The more they heat, the less fluid they will carry and the heat removal goes down until the heat input is reduced or increased air flow is enabled.

So if the engine is set up properly, the coolant system is full, you put in a good thermostat, the water pump is working and the hose aren't colapsing, all that leaves is the radiator/fans.

In worst case conditions, the radiator and fans should remove all excess heat and the thermostat should cycle.

Setting the fans to operate at a higher temp than the thermostat will cause the engine temp to find its way to the fan setpoint and the thermostat's main function will be to maintain a minimum engine temperature in cold weather.
 

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C4CRAZY787 said:
A working tstat should bring the engine temps up to the designed opening temps 160* in this case, unless it stuck open or drilled out.

War said his temps droped from 165*(open) to 114* on a hwy run the stat should have closed to keep the temp up.
Still doesn't answer my question because you are only addressing one of his cooling problems. WarMachine also said it runs hot in the summer?

If the stat was stuck open, the water would not be staying in the motor as long and shouldn't be running hot, like he said it does, as fast as it does. I'm missing something here.

If it's sticking open in the winter, and sticking closed in the summer, then it would make sense. But, his current problem doesn't seem to be the t-stat to me.
 

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Mr. Casino
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BubbleHead said:
If the stat was stuck open, the water would not be staying in the motor as long and shouldn't be running hot, like he said it does, as fast as it does. I'm missing something here.

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The coolant isn't staying in the radiator long enough to cool. The heat is coming from the engine and the radiator cannot remove it fast enough. Once the cycle gets started it continues to build and the engine temp rises. Depending on the efficiency and capacity it may be able to hold its own with lower air temps.

My 79 would run fine until the ambient temp reached 90 deg F. After I had the radiator cleaned etc. It would behave until the temp hit 95 Deg F. I played with a lot of things even to the point of removing the thermo. The thermo out made it heat more quickly in hot weather. The old radiator just didn't have the cooling capacity anymore and I was planning on installing a new aluminum with fans. Unfortunately now I have to wait for the next one.
 

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That's interesting, I see your point but, why the huge jump in the temp when he got on it? I can't see the temp jumping that fast just cause he floored it. I do understand what you are saying about the heat build-up but, not the big spike. It seems like it was ok before that.

I ran my car in high school with no stat and it was fine in the summer, froze my ass off in the winter.:laughing:
 

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Mr. Casino
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The quick rise when my foot got heavy was a given in hot weather. I really believe if I installed a radiator with better specs the problem would have subsided.
 

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Official Forklift Driver
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Discussion Starter #16 (Edited)
BubbleHead, elints & grumpyvette,

The coolant was flushed before I did the work on the engine and the upper and lower radiator hoses are new. I also cleaned the exterior of the radiator as well as straighten any bent fins. I couldn't check the stat yesterday but I should have some time later on toaday to do it. The engine is running ok, FP is fine, timing is good but there is one thing, KNOCK! I get knock counts on the scan tool everywhere, it doesn't matter where I set the timing or fuel pressure I still get knock counts and I can't seem to find the source of it. I did notice the fuel trim counts are w/in the normal range (115-141) all the time so it's not going lean.

The larger oil pan has always been on my mind but that and a larger radiator are a last resort. How much more oil can I put into the system w/ a large oil cooler? Will an oil/trans cooler combo be adequate or should I go w/ separate coolers?


I'm probably forgetting something, I've had two phone calls while I was typing this response and it's thrown me off track and I've had this reply box open for over an hour now. :laughing:
 

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My $$ is on a sticky tstat.. on the knock counts, make sure the knock sensors are not to tight, they are very sensitive.
:buhbye:
 

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Mr. Casino
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There's a slim outside chance that the knock may be caused by water in the fuel system. This usually happens this time of year when the tank isn't full and the vehicle sits with the ambient temp cycling permitting heavy condensation to build up. A large dose of a Zylene product will usually cure the problem after you burn the fuel. If I remember correctly, it suspends the moisture in the fuel. You might also check the fuel filter for moisture buildup.

I tend to believe the main problem is the thermostat. It's a cheap fix.

HTH

P.S. Don't forget to wash and wax the car when you are finished. :D
 

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El Teafive
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Yeah I would swap the T-Stat as well..

With my modded motor it will get over 200deg on a HOT (90+) Day. but the with the 160 T-stat (with 2 small holes) it stays around 170-180.

I also removed the Oil cooler, I did not see any change in oil temp with or without it.
 

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Sounds to me like your t-stat is stuck partially open allowing some flow (enough to kill your heater when it's cold) but not enough for the hotter days.
When you punch it the water pressure might be slapping the t-stat shut
Start with the stat!!
 
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