Oil cooler - effect on oil pressure?

[Alex j B]

Speaking to a mate on saturday about fitting oil coolers, he seems to think that fitting an oil cooler will lower the oil pressure, as it has more space to pump the oil round?
Is this true, as I know the oil pumps aren't that great at the best of times.

Alex B

[NigelR32]

I personally dont agree with that theory.

What he forgot to say though, is that the cooler the oil, the higher the pressure.

Regards

[Dave_R1001]

Would you not just add a bit more oil to the system when fitting a cooler?

[lightspeed]

No it won't.
The pressure is set by the clearances at the bearings.
Worn bearings = low pressure.

Fitting the cooler will reduce the pressure at the bearings only if it extremely restrictive hoses, fiitings and matrix were used.

[Alex j B]

Also, does it matter what size the cooler is, as I've found the ideal cooler, (for my use), but not sure if they need to be a specific size? (sorry if its a dumb question, but I don't want to break anything!)

Alex B

[rasonline]

aBOUT Alexjb comment:

wouldn't have thought that adding more space to the system will reduce the oil pressure (keeping all other factors constant, such as temp, etc.)

I would imagine that the oil pump would just fill up the extra space first and then continue as normal.

I mean, if you take a hosepipe with water pumped in it, and now you extend the length of the hosepipe you do have more capacity. Fill in a little more water and it gets rid of the extra air that is all. Then once this is clear, it will build up pressure as normal.

Remember, this is assuming that all other factors are constant, and not taking into accont that the average oil temperature will now be lower and may impact oil pressure. My point being to demonstrate that simply increasing the space within which the oil is pumped shouldn't automatically reduce the oil pressure, as it operates within a closed system.

Somebody please correct me if i'm wrong?

[oilman]

It won't affect oil pressure however it should affect your choice of oil.

With a cooler you can use a thinner oil.

Cheers
Simon

[andy g]

sorry to hijack this thread, but i have just had a mocal oil cooler fitted to the engine, can i now use a 10w to 30w oil now as im currently using 15w 50w???? was using the latter as was worried about the oil temperature without the cooler.
cheers

[oilman]

I would recommend a 5w-40 as a good choice.

Cheers
Simon

[Chris Wilson]

Most oil cooler pieworks are too small a bore. 5/8 inch minimum IMO. I see a lot of kits using 1/2 inch hose and forged fittings. Bad, again, IMO. A coller and hoses will reduce flow, and have a pressure drop, just like an intercooler. Properly sized hoses, matrix and fittings will minimize this.