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Normal operating temp for 70 BB

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Old Aug 26, 2002 | 08:32 PM
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From: Brandon FL
Default Normal operating temp for 70 BB

210 is the middle of the guage, with A/C off runs just below that mark, with A/C on, just above it.
Seems to want to spit a little coolant out of the overflow once in a while.
Opinions??
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Old Aug 26, 2002 | 09:22 PM
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Default Re: Normal operating temp for 70 BB (joevette57)

Sounds good to me! :)
Do you have a cap on your radiator? (or do you have an expansion tank?)
If cap on the radiator, check your coolant level when the engine is cold.
I dont know about 1970,(check your manuals) but for 1968 the service manual (and owners manual) specifies a fill level 3 inches below the filler neck. Three inches is way lower than a reasonable person would fill the radiator, but overfill it and it will puke the excess out, along with a lot more!! :eek: MJ
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Old Aug 26, 2002 | 09:39 PM
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From: Brandon FL
Default Re: Normal operating temp for 70 BB (MNJack)

MNJACK,
The car has an expansion tank. The way it sets I believe I have the tank half full. The reason I'm wondering about the temp is this:
I brought the Vette in today to have a tranny leak diagnosed. He said the leak is from the pump area of the trans. Since there are low miles on the tranny he said the most likely source for this type of failure is a temp problem.
Leaked developed driving the car around 65MPH on a 75 mile trip. Noticed some smoke coming from underneath the car. I pulled over and found that the tranny fluid was leaking down onto the right exhaust pipe. Checkd the obvious: (pan gasket, speedo inlet, and line fittings) to no avail. That's when I took it to the tranny shop.
.
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Old Aug 27, 2002 | 10:03 AM
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Default Re: Normal operating temp for 70 BB

Joe,

MJ is right on with this one...

If you look in your owner's manual, I think that you'll find that the normal operating temperature is supposed to be right around 210° (which is exactly where you are at. By the way, if you don't have an owner's manual, it might be a good idea to pick one up as they are a good source of information on exactly how your car is supposed to operate... Some items are obvious, but others not so obvious.

As far as the coolant overflow, if it is just "spitting" as you say, it is probably something minor... An overfilled radiator (as MJ mentioned), a weak or lower rated radiator cap, etc. I would look at the simple things first before beginning to worry about it.

As far as the heat issue that your mechanic mentioned, he may be correct in as much as big blocks do tend to run hotter than small blocks. Still, I doubt that this is not much more than just a contributing factor to the problem (if it is a problem at all). Keep in mind that while there may be a legitimate problem here, it may also be a case of the mechanic covering his own butt if he was the one that originally did the work. I don't know your relationship with this person or his professional reputation, so you'll have to determine which is the case.

Regards,
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Old Aug 28, 2002 | 06:02 PM
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From: Brandon FL
Default Re: Normal operating temp for 70 BB (Rowdy Rat)

Found out today that heat wasn't the real factor in the tranny leak the transmission had been rebuilt with what looks like a powerglide torque converter. (high stall maybe?)
The converter was not installed correctly and gouged the hub end along with a few other problems. Since the thing is out of the car anyway. Had him check the clutched. OK, but a little burnt. More metal in the pan than I'd like to see so. We're going to do a total rebuild.
As far as the coolant spitting, talked to the folks at Be Cool this afternoon, he said that's probably happening due to heat sink by the engine after it's turned off. He claims that if the car's running at 210, it's not unusual for the temp to rise up to 260-270 upon shutdown.
To be sure however, I'm going to temporarily install a mechanical temp guage an make sure my dash guage is accurate. Be Cool recommended a high flow 160 thermostat as well. This way I will have full flow at 180.
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Old Aug 28, 2002 | 06:17 PM
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Default Re: Normal operating temp for 70 BB (joevette57)

He claims that if the car's running at 210, it's not unusual for the temp to rise up to 260-270 upon shutdown.
Very true! That is why it is so important to have a battery cutoff switch and use it! The high temp after shutdown can melt wires under the hood, creating shorts and electrical fire. Especially bad if you have shut the car off in the garage and you are already in the house!
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Old Aug 28, 2002 | 11:03 PM
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Default Re: Normal operating temp for 70 BB (joevette57)

Be Cool recommended a high flow 160 thermostat as well. This way I will have full flow at 180.
Does this mean that your bb can run at 180? That is interesting as I am looking at buying a 74 bb and I just hate heat!!
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Old Aug 30, 2002 | 03:43 PM
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Default Re: Normal operating temp for 70 BB (joevette57)

I have a '73 BB and the owners manual says it is normal to run up to 230 degrees, but to be concerned if it hits 250 degrees :eek:

I prefer to stay on the cool side of 200 myself.
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Old Aug 30, 2002 | 03:59 PM
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Default Re: Normal operating temp for 70 BB (joevette57)

I thought 235+ degrees was normal for a Big Block ?!?!? - :lol: :jester
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Old Aug 30, 2002 | 06:06 PM
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From: Maple
Default Re: Normal operating temp for 70 BB (verskel)

my 454 runs 180-195 depending on temp. outside and how i am driving...the oil temp. is usually around 210-225...
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Old Aug 30, 2002 | 11:52 PM
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Default Re: Normal operating temp for 70 BB (1bad69)

:seeya
my 454 runs 180-195 depending on temp. outside and how i am driving...
Same here... but if I get stuck at a long red light it could climb to 210! :mad I enjoy driving it in cooler weather. :yesnod:
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