Oil-Water cooler

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Nick R

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So I found out from reading yesterday that the Cruze 1.4 has a oil-water cooler. I've heard of oil-air coolers being common. So it just seems that with cooling the turbo, and the oil-water cooler, the coolant is going to take more of a proverbial "beating" than it would in a normal N/A engine.

Is there any truth to this thought? Also how much should I worry about idling it for an extended period of time shutting down? I know not to rev the heck out of it and then shut it down immediately, but how long should it take for the turbo to cool down enough to safely shut it down? Or will the coolant cooling the turbo keep it within safe temps so the oil won't cook in the bearings?

Never owned a turbocharged car, and I worry about things like this. I have more questions, but I'll just leave it at this for now.
 
Not really. All it means is that the radiator is a wee bit bigger than it would otherwise be. Oil-water cooling is very effective and takes up a lot less space than having a separate (and necessarily larger) oil-air cooler. With the oil-air system, all the waste heat from all the systems goes into the cooling water, and the radiator is sized appropriately to get rid of all that heat under worst-case conditions. Its worked for automatic transmissions for 60 years, after all. :-)
 
My Integra came stock with this system also. The biggest advantage is coolant heats up much faster than oil and with this cooler the coolant heats the cold oil much faster and holds it at close to coolant temps. Every car should have one. Dan
 
Both my Volvos have this....actually, so does my 4Runner...

It cools the oil just fine, as others have said, you increase radiator size a bit to increase the heat-rejection from the coolant. It does warm the oil more quickly too...it's a good system.

With any Turbo car (and I've owned several), you should let it idle for a good 20 seconds before moving it to ensure good flow to the turbo. As soon as you step on the gas, it spools up...and at max RPM, it can be spinning at over 60,000 RPM (that's not a typo..).. The cool down should always be at least 20 seconds, to ensure that it's at minimum RPM before engine shutdown...if you've been driving hard, then that turbo will be really hot, and idling for a few minutes (with both oil and coolant flow through the bearing housing) will cool it down so that the bearings don't get "coke" or carbon, build up in them...and with care, they will last a long time - both my Turbo cars have the original turbo in them...

I really recommend synthetic oil in a turbo car, because of the high temps to which you can get the turbo...and if not synthetic, then change more often...since this is a Cruz, I assume it specifies Dexos?
 
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Both TDIs have them. It's beneficial on both ends - for cooling the oil (when it's hot) and for warming the coolant (when it's cold).

Unless you've really been caning the snot out of it I wouldn't give shutdown a second thought. There's plenty of slow, side road, alley & driveway driving before I shut the car off to give the turbo bearings plenty of time to cool.
 
Originally Posted By: scurvy

Unless you've really been caning the snot out of it I wouldn't give shutdown a second thought. There's plenty of slow, side road, alley & driveway driving before I shut the car off to give the turbo bearings plenty of time to cool.


I agree! And if one were to calculate how much fuel they are using by idling the engine for one or two minutes on each shutdown, I bet a few years of doing that would cost the same as the cost of replacing the turbo! Besides, if the turbo ever fails, it's an excuse to put on a bigger one for more power!
smile.gif
 
Oil-water coolers are very common and work well. No added strain on the coolant if the radiator is sized properly.

My inclination (coming from an Audi turbo) would be to drive easy for the last few minutes. If you have to pull off the interstate and stop, then yes I would let it cool idling for a minute. If you drive through a neighborhood at low speed, that should be sufficient.

Does that car have an electric water pump? Some turbo cars do and will keep coolant flowing after shutdown.
 
Heavy equipment, bulldozers & loaders etc, use oil/water coolers and water intercoolers. Air/oil is considered "light duty".

To make things more interesting aircraft use fuel/oil coolers (sometimes called fuel/oil heaters).
 
Originally Posted By: scurvy

Unless you've really been caning the snot out of it I wouldn't give shutdown a second thought. There's plenty of slow, side road, alley & driveway driving before I shut the car off to give the turbo bearings plenty of time to cool.


Agree...so, for me, cruising slowly down the street cools it off, and I wait about 10 seconds in the driveway itself...but that's not always possible...and I like the car, so I'll spend a few extra seconds here and there...

Turbo for this car is about $1500, might be able to get it rebuilt for a lot less, upgraded for a bit more...either way, that buys quite a bit of idling time...
 
Originally Posted By: DR Racing
My Integra came stock with this system also. The biggest advantage is coolant heats up much faster than oil and with this cooler the coolant heats the cold oil much faster and holds it at close to coolant temps. Every car should have one. Dan


Right. It is not only about cooling, but for warm up. This really helps when it's cold.
 
3VZ on my old 4Runner had one...when I went to replace the hoses and asked for the oil cooler hoses, the local Toyota dealer didn't know what I was talking about...they weren't told about them.

Was sort of mounted to a second oil filter boss on the side of the block.

As to turbos, on my DI Nissan, only time I idle it is if I pull off a "turnpike" into a fuel stop. Then I idle it for long enough to take my belt off, get wallet out, and open the door.
 
i just drive at low rpm for the last 5 minutes of my drive, so when I arrive I can just turn off the ignition. If the turbo was only oil cooled, I would wait longer.

the manual in my car says to idle 30 seconds for mormal driving, 2 minutes for high speed, no boost operation, and 5 minutes for "spirited" operation. I assume the last one means high speed, boosted operation. Also, these recommendations in my manual are assuming that we are using API SL dino oil.

at 150,000 RPMs, those little stock turbos can heat up...

05 Neon 2.4l
 
My Ford F150 Ecoboost has a system to circulate the coolant after the engine shuts down to cool down the turbos.

Asking a dumb question...how does one tell if their vehicle has this oil/water cooler?
 
in my particular vehicle, the place you mount the oil filter has coolant lines(an in and out) running thru the filter mounting block. oil/coolant heat exchanger
 
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