Coolant/Oil Heat exchanger question......

[wasserleaker]

Just wondered if anyone can clarify what exactly is the purpose of the coolant fed heat exchanger on a 2.1 engine between the block and oil filter?
is it there to warm up the oil quicker by using the heat from the coolant before the thermostat opens, or to allow the coolant to cool the hot oil when the engine is working hard? or both?!
the 1.9 engines don't have one fitted, is this because a 2.1 generates more heat, and needs it cooling, or is it more important that the oil warms up quickly to running temp in the bigger engine?
obviously VW felt the need to fit it to the 2.1's and i've seen a similar part on a few other cars, just curious to know what it's job is.
thanks

[Ian Hulley]

is it there to warm up the oil quicker by using the heat from the coolant before the thermostat opens, or to allow the coolant to cool the hot oil when the engine is working hard? or both?!

Both

They fitted these on quite a few of the higer performance engines ... i.e. our 1.8 injection Scirocco has one, whereas the carb 1.8 doesn't.

Ian.

[wasserleaker]

Thanks, Ian.

[Red Westie]

I understand that they are oil coolers.....
I must admit to being slightly curious myself.....coolant can reach aound 100C (thermo fan switch set to control temp in the low 90's) oil temp on my old 2litre Passat would reach 125C towing, a difference of around 30C so I suppose an opportunity to exchange the difference (cool the oil to coolant level) but I have always thought this to be a very inefficient way considering the relatively small temperature difference.
It may well be designed to warm up the oil as well although I never looked at it like that but it does make sense given that a small independant radiator would do a much better job, if that job was cooling alone.
Martin