Radiator Nightmare
#17
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Originally Posted by Fogey1
Imo000 wrote:
"Any of the artermarket coolers will work just fine. .... with the aftermarket coolers you can get near ambinet if the cooler is large enough. ..."
Correct me if I'm wrong, but wouldn't ambient usually be too cold for proper operation of the trans or the engine? There is a designed-in operating temperature range, right? And I thought one of the paradoxical purposes of the oil cooler in the rad was to speed the lubricating oil's rise to op temp. Ditto for the trans? So the bypass thermostat is an important part of the system.
BTW, this is not a slam on aftermarket coolers.
"Any of the artermarket coolers will work just fine. .... with the aftermarket coolers you can get near ambinet if the cooler is large enough. ..."
Correct me if I'm wrong, but wouldn't ambient usually be too cold for proper operation of the trans or the engine? There is a designed-in operating temperature range, right? And I thought one of the paradoxical purposes of the oil cooler in the rad was to speed the lubricating oil's rise to op temp. Ditto for the trans? So the bypass thermostat is an important part of the system.
BTW, this is not a slam on aftermarket coolers.
I drive my 928 as if it was turbocharged. That is, I allow it to warm up to full operating temperature before I attempt any sort of full power or RPM's above 3000. I don't care for blown head gaskets-!
I'm going to finish the install that I stalled last year; I will install the oil temp gauge, the fuel pressure gauge, and the manifold pressure gauge that I bought from Nordstrom last year in the the plastic fitting that I bought from Carl Faucette. When that's done I can evaluate the oil cooler objectively.
As to being too cool...your oil needs to reach a certain temperature to insure proper lubrication at all points of the engine. If the oil temperature is too high, then we run the risk of having the crankshaft or camshaft or othe rotating surface meet the block or the head or whatever. Thin oil allows things to touch, and heat makes the oil thin. Synthetic oil resists this a very small! amount.
-Lets say you built a 928 with two radiators. One for the coolant as from the factory, and one for OIL. Oil capacity increases by a HUGE amount! And lets say you drive one mile to work each day in your 928, and one mile back, a total of 10 minutes per day.
Q: WHY would this be the worst possible scenario?
N?
#18
Rennlist Member
Originally Posted by Fogey1
Imo000 wrote:
"Any of the artermarket coolers will work just fine. .... with the aftermarket coolers you can get near ambinet if the cooler is large enough. ..."
Correct me if I'm wrong, but wouldn't ambient usually be too cold for proper operation of the trans or the engine? There is a designed-in operating temperature range, right? And I thought one of the paradoxical purposes of the oil cooler in the rad was to speed the lubricating oil's rise to op temp. Ditto for the trans? So the bypass thermostat is an important part of the system.
"Any of the artermarket coolers will work just fine. .... with the aftermarket coolers you can get near ambinet if the cooler is large enough. ..."
Correct me if I'm wrong, but wouldn't ambient usually be too cold for proper operation of the trans or the engine? There is a designed-in operating temperature range, right? And I thought one of the paradoxical purposes of the oil cooler in the rad was to speed the lubricating oil's rise to op temp. Ditto for the trans? So the bypass thermostat is an important part of the system.
#19
Race Car
I think there's a good reason why my wife's 968 Tip has ATF lines going from the trans to a cooler built in to the radiator, and then from there to an external cooler, then back to the trans. Best of both worlds. If the warming effect from the coolant was not necessary, I doubt Porsche would have gone to the extra trouble of setting it up this way if they were already planning to install an external cooler.
Dan
'86 928S 5-spd w/LSD
Dan
'86 928S 5-spd w/LSD
#22
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I thought one of the paradoxical purposes of the oil cooler in the rad was to speed the lubricating oil's rise to op temp.
Do not know about the auto trans, maybe that has open flow - but would it not be better to keep the trans fluid cool?
Marton
#23
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Marton, the engine oil heats up relatively quickly. Trans fluid does not. Oil needs to be at a minimum temperature for effective performance, and a trans cooler in the rad will help it warm up quicker, then when the trans temp exceeds water temp it will help cool it.
#24
Race Car
Originally Posted by SharkSkin
Dan, you say the 968 has the extrenal cooler *after* the one in the rad? Interesting...
Dan
'86 928S 5-spd w/LSD
Last edited by dprantl; 02-02-2010 at 06:12 PM.
#25
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All the 928 automatics after 1983 have an external trans fluid cooler as well as the internal heat exchangers in the radiator which are in the HOT side of the radiator. The 87> have a long thin one at the top of the a/c condensor.
#26
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Originally Posted by dprantl
You know, now that I think about it, I'm not quite sure which direction the flow is. It may very well be the external first, then the rad cooler...
Dan
'86 928S 5-spd w/LSD
Dan
'86 928S 5-spd w/LSD