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Discussion Starter · #1 ·
After going for a drive my oil cooler lines are cold. Does the oil cooler only open at a certain temp or is it open all the time.

Would I have to or prime the oil cooler etc?

The only thin I can think of is that I used 16v lines in an 8v filter housing. They fit perfectly though?
 

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Just one man's opinion, but in general, oil coolers aren't needed and it wouldn't surprise me that you couldn't detect any effect.
But nobody listens to the old folk anymore, they all think they know better, why, when I was their age I would have been glad to have used cooking oil.......
 

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Just one man's opinion, but in general, oil coolers aren't needed and it wouldn't surprise me that you couldn't detect any effect.
But nobody listens to the old folk anymore, they all think they know better, why, when I was their age I would have been glad to have used cooking oil.......
I think you are developing a sense of humour Jim but I'm inclined to agree with you. I am really not convinced the 900 needs an oil cooler but it's just an indication of Saab design over-engineering. Just for the record, my 16v has a thermostat in the oil filter housing that only opens at about 60°C IIRC, and you can definitely detect when it opens. You can over-cool engine oil.

No one listens to old guys anymore, but I'm way off that I tell myself. :lol:
 

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I think you are developing a sense of humour Jim but I'm inclined to agree with you.
I think he is loosing his hard edged satirical wit ... But also inclined to agree ..

I recall an aero that I had sitting here as a parts car , that was an original Aero ... and to best to my knowledge and its extensive paperwork ... The original motor fitted the oil filter housing was not even tapped for cooler lines . Is it possible that they were deleted in a model year ?

I am interested in Pevas comment re the thermostat in the housing .. I have never seen this ... Perhaps it was Saabs attempt to actually have Viscous oil in the British climate ? :lol:

Stress Less ..S900 .. Drive more :D
Apologies for font size ... I left my glasses in the shopping basket on my Zimmer frame
 

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I'm glad you found your glasses for that bit. That'll teach you not to leave the brake off on your zimmer frame. :cheesy:
LOOK OUT its a Runaway Zimmer ... hit the kerb and I"m off like a Skimmer ....

Hit the pavement with my oversized Asses .... next thing ya know I smashed me bloody Glasses ....

Zimmer safely folks ...Its a jungle out there !
 

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Every oil filter housing (with the cooler outlet/inlets) i have seen has the thermostat in the side. There is a chance that the thermostat is faulty and not opening. Usually after the thermo fans have cycled a couple of times, with the car sitting at idle, the oil cooler thermostat opens (it does with mine anyway)
 

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If you have an oil cooler it should have a thermostat. You don't want to go pumping oil round a cooler on a cold engine a minus 10°C.
 

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Every oil filter housing (with the cooler outlet/inlets) i have seen has the thermostat in the side. There is a chance that the thermostat is faulty and not opening. Usually after the thermo fans have cycled a couple of times, with the car sitting at idle, the oil cooler thermostat opens (it does with mine anyway)

I stand corrected .. I am now curious and will take a close look..On that promised day of daylight some stage down the track :) ... I certainly have never noticed , but also have never studied . no oil temp gauges for me .. which I guess is the only way you know when it opens ...

How does the ATF cooler open/close wheres the thermo on that one ?
 

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Discussion Starter · #10 ·
Ok so I decided to drive the thing for 20 or so minutes, the oil cooler ended up warm which is great! very happy!

Everything has worked out, the intercooler is working great, I was boosting heaps in every gear today, no knock.... :eek: I can't believe it! I'm gonna turn up the boost! :D
 

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If your Aero is a 2.1L, it won't have the oil cooler, or the fittings.
As far as i know, only, and all Australian turbo C900's have the engine oil cooler (not sure if the LPT had one, we didn't get them here).

How does the ATF cooler open/close wheres the thermo on that one ?
There isn't one in C900's

9000's have the thermostat in the T piece bolted to the sub frame IIRC. Some cars have them, some don't..


In regards to engines not needing oil coolers, if this is true, why have car manufacturers still fitted them, even on new cars? Turbo C900s need a way to reduce the increased oil temp created by the oil passing through a hot turbo, hence the oil cooler. IIRC oil temp is generally 10*C higher than coolant temp. For around town driving/ light foot driving in cold weather it may not be required, if you drive the pants off it (*cough*), and/or live in a warmer part of the world, then i would say yes, it would help a lot in preventing the oil from being cooked.. But how were saab to know how their owners drive?
Cooking the oil can cause a few problems, Coking and turning to sludge to name two.. as a rule of thumb oil temps over 120*C usually result in the oil breaking down, losing its viscosity/protecting abilities and shortening the life of the engine and turbo. I believe synthetic oils do have the ability to run a little hotter than 120 but not all the time though.
 

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Discussion Starter · #13 ·
95.

Yeah I will just turn it up so base boost is at 5.5psi (I have drop from installing the intercooler, maybe 2-3psi...

I almost have all the parts for t5.5 now, I just need a trigger wheel and I essentially have all teh parts. Will start working on the fuel rail soon!
 

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Interesting discussion; http://www.saabscene.com/forum/threads/95320-Oil-Cooler-s-Thermostat-amp-Performance
I'm sure my stat opens at around 65°C. I measured it. I think Bentley even mentions this is spec. IIRC. Not that that should be taken as gospel. :lol: This thread suggests it should be higher at around 100°C, but it doesn't seem to be a 900. I'm sure at higher temps it's possible to squeeze another fractional mpg out of the car, which is probably why they do it. My oil never gets anywhere near that.
 

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Higher running temps increases cylinder efficiency as there is less energy loss from combustion - less difference in heat between combustion temps and cylinder wall temps? More power, better fuel economy. NOx emissions rise a little but 3 way catalysts have been vastly improved to burn off NOx so what comes out the tailpipe is somewhat cleaner...
I believe it also puts more strain on the engine oil and other components though.
I read an article a while back of an engine made of ceramic with an operating temp of 800*C and some stupidly high power output for it's capacity..
 

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Interesting discussion; http://www.saabscene.com/forum/threads/95320-Oil-Cooler-s-Thermostat-amp-Performance
I'm sure my stat opens at around 65°C. I measured it. I think Bentley even mentions this is spec. IIRC. Not that that should be taken as gospel. :lol: This thread suggests it should be higher at around 100°C, but it doesn't seem to be a 900. I'm sure at higher temps it's possible to squeeze another fractional mpg out of the car, which is probably why they do it. My oil never gets anywhere near that.
Not to beat an old horse or bring this up from the dead, but i just installed an oil temp gauge in my car and had a freak out moment thinking that my oil temps are way tooo low. BC i remember reading that oil temps are suppose to be around 100c. Mine hover around 70c. I was thinking that my oil cooler thermostat is stuck open or something.. So it is suppose to open at this low of temperature??
 

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Not to beat an old horse or bring this up from the dead, but i just installed an oil temp gauge in my car and had a freak out moment thinking that my oil temps are way tooo low. BC i remember reading that oil temps are suppose to be around 100c. Mine hover around 70c. I was thinking that my oil cooler thermostat is stuck open or something.. So it is suppose to open at this low of temperature??
The stat should open at around 90°C (194°F) at which temp most 900 gauges will read around midpoint. The higher the temperature, within safe limits, the more efficient the engine is, with better fuel economy. If your engine is not hot enough you will suffer poor fuel economy and performance and the oil will not be hot enough to evaporate off the moisture that is developed in the engine as a combustion by-product.

PS - The oil cooler, open or closed, does not have much effect on engine coolant temperature. From memory the oil cooler stat opens at around 60°C.
 

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It would have been handy if Saab had put a drain plug on the cooler, as when you change the oil you always have the 'rubbush stuff' left in the cooler and pipes, so mixing poor oil with new, it's probably not too bad if you change it often like most do, but comes back to the old days when people just used to keep topping up an engine that used oil with new, while the old crap stayed there, and if someone suggested when you changed your oil(with no oil cooler ) to put a pint? of the old oil in with it you would thing they had lost the plot, but that's what it amounts too
 

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The stat should open at around 90°C (194°F) at which temp most 900 gauges will read around midpoint. The higher the temperature, within safe limits, the more efficient the engine is, with better fuel economy. If your engine is not hot enough you will suffer poor fuel economy and performance and the oil will not be hot enough to evaporate off the moisture that is developed in the engine as a combustion by-product.

PS - The oil cooler, open or closed, does not have much effect on engine coolant temperature. From memory the oil cooler stat opens at around 60°C.
I was referring to the stat for the oil cooler. my coolant temps are fine. It seemed weird to me that the oil cooler stat opens at 60°C as that is very low. Normal operating temps for oil are usually around 100-110 °C
 

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I was referring to the stat for the oil cooler. my coolant temps are fine. It seemed weird to me that the oil cooler stat opens at 60°C as that is very low. Normal operating temps for oil are usually around 100-110 °C
The Saab spec for oil pressure is given at 85°C.
Under normal conditions the oil in the 900 engine never gets anywhere near 100°C except sometimes under hard driving in the turbo. The NA doesn't normally have an oil cooler and hardly gets to 60°C.
 
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