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#1
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Guys,
During a project I had the front bumper off and wanted to drain the auxiliary oil cooler I have married up against the AC cooler in front of the driver wheel well. I opened the bottom oil hose (Top Bottom in the front setup) and was surprised to have only a little bit of oil trickle out of the cooler (2-3 oz). Seems a little weird that there was such a little amount of oil in the cooler, is this to be expected or has there not been enough oil getting to the Aux cooler? Thanks, -Skip
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Skip '91 964 #54 '97 993 C4S |
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#2
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How is the extra cooler plumbed with the stock cooler? series or parallel?
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Todd -- 18 GT3 (VG) Gone 18 718 Cayman GTS (GT Silver) 14 981 Cayman S (white) 15 991.1 GT3 11 997.2 GT3 96 993 Targa 96 993 C2 tracker 00 986 Boxster S 99 986 Boxster |
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#3
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Todd,
It is in series...Oil into stock cooler, out of stock cooler to aux cooler, out of aux cooler back to engine. -Skip
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Skip '91 964 #54 '97 993 C4S |
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#4
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So where exactly are the oil lines connected on the cooler? Are both on the bottom of the cooler? Or is the supply on the top and the return on the bottom? Either way you could have a significant amount of air trapped in the cooler, which may be what you are seeing.
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Jeff S '14 991.1 Carrera S Coupe '25 Cayenne E-Hybrid '11 997.2 Carrera S Cab '09 987.2 Cayman S '05.5 Audi S4 '25 GMC Yukon XL '17 718 Boxster '18 718 Cayman x 2 |
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#5
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The first cooler is the stock cooler and the input and output are on the top of the cooler. The Aux is a mocal cooler that is mounted such that the input and output are on the front and therefore on the top and bottom.
I can take a better picture, but this gives you an idea: https://picasaweb.google.com/lh/phot...eat=directlink I can check tonight if the input of the aux cooler is the top and output would be the bottom, but let me know if you think that matters. From a trapped perspective, so you think a vaccuum could hold the oil in the cooler? I would be surprised, but stranger things have happened, so I'll take a look at it tonight. More thoughts? -Skip
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Skip '91 964 #54 '97 993 C4S |
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#6
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Looks like the cooler in my car - but I think you want the input at the bottom and the output at the top. That way the air will always be at the top of the cooler and be sucked/pushed out of the cooler, while the heavier oil will start filling the bottom of the cooler and eventually occupy the entire space.
Otherwise, oil fed from the top will quickly fall to the bottom from gravity, leaving a pocket of air in the upper, opposite corner. Air won't be able to escape because the heavier oil will always displace it to the top of the cooler. Not as bad as having both hoses on the bottom, but enough that it might explain why there is not as much oil in the cooler as you are expecting.
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Jeff S '14 991.1 Carrera S Coupe '25 Cayenne E-Hybrid '11 997.2 Carrera S Cab '09 987.2 Cayman S '05.5 Audi S4 '25 GMC Yukon XL '17 718 Boxster '18 718 Cayman x 2 |
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#7
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Jeff,
After looking at the plumbing and checking to be sure which line is the supply/return line from the stock cooler, you are right. The supply to the aux cooler is the top position and the return is the bottom. So, I probably haven't been getting all the cooling capability out of it because of the air stuck in the cooler - is that a correct assessment? It is a quick switch of lines between the in/out on the auxiliary cooler, but that will make one of the lines too long and one of the lines too short. The line that is too long may be OK, but the one that is too short will either need to be replaced or a short extension added to it (is a short extension a no-no?) Thanks for the help, -Skip
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Skip '91 964 #54 '97 993 C4S |
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#8
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If you make the extension using fittings it should be fine - I would worry about a hose clamp approach leaking. Nothing like a high pressure stream of oil to ruin your day
You might also look at the other end of the lines - presumably one goes into the stock cooler and the other goes into one of the hard lines that eventually goes back to the thermostat. Maybe you could swap the lines there? Might have to swap fittings though, as there is probably a hard turn at the cooler and straight or 30 to the hard line.
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Jeff S '14 991.1 Carrera S Coupe '25 Cayenne E-Hybrid '11 997.2 Carrera S Cab '09 987.2 Cayman S '05.5 Audi S4 '25 GMC Yukon XL '17 718 Boxster '18 718 Cayman x 2 |
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#9
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Thanks Jeff - of course I would use nothing less than real oil hose fittings.
Thanks for your help. -Skip
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Skip '91 964 #54 '97 993 C4S |
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#10
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New longer lengths of AN hose probably a lot cheaper than a little hose and 2 pairs of fittings. Would look neater, too.
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Peter (not "Pete") K. 2026 Lucid Gravity Grand Touring (EV Tow Vehicle) 1997 Spec Boxster #671 2016 Cayman S 2016 Toyota Highlander--wife's DD 2017 VW GTI SE (DD) Gone and missed: 2003 Miata ("SM") race car 1992 Miata ("SSM") race car 2009 911 C2S Coupe 2004 Toyota Prius - sold to son's girlfriend 2006 Dodge Durango 2003 Acura MDX 86 Black 911 Coupe race car 86 Gold 911 Targa 82 WineRedMetallic 911 Targa |
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