Oil Coolers

[MGBV8]

Interesting comments on web re oil cooler use.

I understand that the correlation between water and oil temp at sump is around 1.2 - 1.4 however as oil temp around bearings etc is a lot higher this is sufficient to keep oil sweat, so adding an oil cooler to reduce under bonnet temps should not present a problem. So is the maximum sized oil cooler depending upon installation the best route to follow.

[danhay]

What's the problem you're trying to fix?

If the engine is running too hot, then an oil cooler may help.

If the engine bay is getting too hot and causing fueling or other probs, then an oil cooler in the engine bay may not help.

One of my cars has got an oil cooler in the engine bay, but it is fed with air from outside by a duct, and the outging air is also ducted away.

[GreenV8S]

You should never fit an oil cooler without an oil stat. With a stat, you can't do any harm by fitting a bigger cooler, except of cost wasted cost and space if it is bigger than you need. An oil cooler is quite an effective way to cool the engine because the oil runs at much higher temperature than the water. As long as you don't then take the hot air off the oil cooler and blow it over the water radiator! (Seen that done!)

[Incorrigible]

GreenV8S said:

You should never fit an oil cooler without an oil stat.

Oil has an optimum temperature and you'll fry the engine if it runs too hot

On a normal car it doesn't matter, because the water cooling is more than enough to keep the oil at a sensible temperature. You start needing coooler when you're constantly running at high loads and high revs

However getting the oil up to temperature (~90c IIRC although some engines and oils run a lot hotter) should be done as quickly as possible (hence the stat etc) to avoid engine wear

Also note that in some cases (large sumps for instance) engine temp (water) is not a good indication theat the car is warm enough for a good pasting

[streaky]

GreenV8S said:

[snip] As long as you don't then take the hot air off the oil cooler and blow it over the water radiator! (Seen that done!)

That's how the factory set up my TVR 390SE - oil cooler in front of the water radiator. Mind you, there are not too many other places to put it! - Streaky