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Oil Temperature (again)


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Hi all. I have what maybe a series of stupid questions....

The S/C has been converted to a 3.8, and has two coolers with fans at the front, these are a modern, matrix type. I have recently got the car back from the specialist and am currently putting miles on it and working out any "Kinks". However, temperature control seems to be an issue. When driving the car, not necessary "on it" the temp will be around the 3/4 mark. specialist says ok. However, as the ambient temps have been 100F+ it's hard to argue. This week however temps have been around 70F and the car under the same conditions has been running at the first graduation on the gauge, even when I have been more than enthusiastic. This brings me to the dilemma. What is cooling the car?

 Is it the in rushing air to the front coolers, or the fans? If the fans were to be disconnected, would the car, whilst moving, stay cool, or do the fans run "most" of the time?

This brings me to a discovery.  The RHS fan, is actually sucking the air towards the front of the car, so the implication is not that the fan is not helping to cool the car, but potentially, actively impeding air flow, and adding to the cooling deficit. Does this sound reasonable, or does anyone have any first hand experience?

The fans are set to come on at the lowest temperature.

Obviously the Specialist is going to rectify the situation, but having spent time and money on this thing i am tiring of the back and forth.

I pulled the 964 out in the same conditions, and no temp issues at all. Appreciate its a different installation but only one cooler v two coolers has given me pause for thought.

Particularly as its been sitting for 18 months un driven, I am ashamed to say it took 7 quarts to get it topped up....... Exxon Valdez comest to mind!

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Not sure if I’m understanding correctly. Is it too hot when the temps hot (3/4 Mark sounds high) and too cold when the weather is cooler? 

If that’s the case, the cooler weather running needs an adjust on the temp the fans kick in. 
Hot weather running, you need more cooling maybe. A front bumper centre cooler maybe, bigger fans? Bigger oil coolers if you can fit them.

Did you say you used 7 quarts of oil (circa 7 litres) to top up your 964?! Blinking eck. Is the drain plug in the tank? 

Edited by Busybee
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I would think that the fan should blow from the front of the car over the cooler as you suggest. 

Perhaps it is worth connecting a proper temperature guage to the engine somewhere to get a more accurate idea of when and how temperatures are affected. With the best will in the world the standard gauge is not very accurate and do you even know if works correctly?

Does your engine have an engine mounted cooler?

As BB says, the normal set up is a centre mounted cooler with a grille. Perhaps change to this?

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@Busybee  Thanks for the reply. Sorry if not clear. Car runs at around 248F in high ambient (100F) My question really is, whilst the fan is going the wrong way, will it actually be making thing worse, or simply not cool? The 7 quarts went in the 964, which leaks a bit....... 18 months of sitting around.

@PhillWhere would be the ideal place to monitor the temperature, other than gauge? As the car isn't a backdate, there is no opportunity for the centre mounted cooler. I have seen a custom install where louvres were cut below the bumper which im OK with, but there are a myriad of 3.8 S/C's running around SoCal, ostensibly without overheating

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A couple of thoughts...

get thyself an IR thermometer and check oil cooler and oil line temps. You can also confirm that the thermostat is opening.

pull the fuse(s) for the fans and see what that does?

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@Sopor Yes, agreed, pulling fuses is next step, just awaiting this weeks temperature increase back to 100+! As to the IR Thermometer, if i point it at a radiator, will that give an accurate indication of temperature, as its shedding the heat?

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IR thermometer is a good idea and helped me gauge temperatures from all over the engine when I was calibrating my thermometer readings (I have EFI so have a thermometer set where the original CIS temperature switch thingummy was, in the left hand chain cover) I don't know if you have a spare hole on the 964 engine to out a similar thermometer.IMG_20200208_091559.thumb.jpg.873875f6835b6ef2d6a7f1486becce51.jpg

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Try to point it at the input and output ports/flanges to confirm the oil is hot when it goes in and cooler when it goes out. Ditto for the oil lines running forward under the right sill cover - one should be v hot and the other rather cool.

And if you’re feeling flush get a FLIR ONE for your phone.

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