Recommended Oil change interval with Oil Cooler left intact
 

Hey yo. Just wanted to pick your brains on the appropriate oil change intervals after having an oil cooler installed and leaving it intact each oil change. So basically the idea is not taking it out to drain during oil changes.

Already read up into a few threads here about some differing opinions about oil changes especially with an oil cooler. One side suggests leaving the cooler intact as fine during the drain and refill cycle. Another side suggests taking it off every oil change interval or atleast 1 in 3 oil changes as a precaution. While another suggests fitting it upside down for ease of draining - which apparantly can cause problems with the dipstick readings.

So just want to 100% clarify this if possible. Oil changes WITH the oil cooler intact - What would you recommend?

I've been sticking to 5000km or every 6 months at the moment. And using Redline 5w-30.

While we're at it. What should the dipstick be reading when cold? I would guess near top H mark right?

I change my oil yearly which usually is about 5000kilometers and it still looks clean. I have a fast intentions 34 row oil cooler on mine and for the last 4 years I've never drained it when I change the oil. Until my last oil change I'd used Castrol full synthetic 5w 30 but now I'm using Penrite 10 tenths 10w40 Esther based oil. My car never uses a drop of oil so it's always on full when I check the dipstick.

Do not drain it during the oil change, there's less than a Qt. in the cooler and lines combined, it will simply dilute with the new oil.
Keep change intervals the same as what the manual suggests, because see above.
Dipstick reading will not change as that is the oil level in the pan and needs to be at full regardless of what parts you added or took away from the oiling system.

On the oil front as mentioned in post #2, I was using an Esther additive to Mobil 1. From what I've read its only purpose is to quiet the valvetrain. It was quiet upon first use but gradually got louder as the oil change interval approached, IMO same as using M1 without.
The last fill I used LiquiMoly Ceratec and the valvetrain was SILENT till the day i drained the pan. Additionally, Ceratec only needs to be used once every 30k miles. So far I'm at 4k miles with it so time will tell.

As long as you are continuing with regular OCI, and your oil and filter are clean (no water, metal, sludge) You can leave it in there. As someone suggested, oil will circulate through there.

My recommendation, is pull it out at 5th oil change (25,000km) and properly flush and leak test. You have good OCI and good oil, you can increase that interval accordingly.



zz

Don't drain the oil cooler. Just do your normal service. The only time you would drain the oil cooler is when doing a rebuild and then it is best just to replace it if you had a major issue with metal shaving contamination.

Leave the cooler as it is, don't drain it. Whatever is left in there won't affect your new oil.