Oil change with an oil cooler.

[DanielJames]

Hello all,

I've googled this a bit, but getting very varied opinions, so thought I'd ask PH for theirs.

I have a Honda Integra track car which has a 19 row oil cooler fitted. Between the cooler and the car there are about 3 meters of hose. This adds about 1.2L to my oil capacity.

I've had the cooler fitted for about 8 months now and have done 3 trackdays and been to the ring. Perhaps 5k road miles. In total I think I've changed the oil about 4 times, but one thing I've never done is flushed out the oil cooler and lines.

The question is, does that need doing, and if so how often? Any tips to carrying this out? It seems that it could become a very messy job very quickly.

Any input appreciated.

Cheers
Dan

[B'stard Child]

Is the cooler thermostat controlled?

Seems quite a lot of additional capacity?

Anyway if you don't blow it out it just dilutes your new fresh oil with the old stuff still resident in the cooler the first time the thermostat opens or as soon as you start the engine if uncontrolled.

One of my cars has two oil coolers fitted with no thermostat control on that one if I am doing any other work at the time of the change I will disconnect the feed pipe and blow thro (the oil ends up in the sump where it can be drained out)

[PhillipM]

Easiest thing with that length of line would just be to unbolt and lift the cooler up so it drains back to the sump before you change the oil.

[Claudia Skies]

In a word, no, it doesn't need doing. You're adding plenty of fresh oil to the engine.

Automatic transmissions might be considered similar. A full drain and fluid change only ever changes about two thirds of the fluid, because a third remains trapped in the torque converter.

In either case if you're worried, just do more frequent changes. There's no need to flush.

[Vacumatic]

I presume that the oil temperature is such that an oil cooler is needed?

I did two laps of the TT circuit, which is over 70 miles in total, taking the revs to the maximum wherever possible, at the end of the 70 miles my oil temperature hadnt reached working temperature, and that engine had an oil cooler.

The Castrol rep was in the pits when I got back and he measured the oil temperature electronically. I asked him how I should measure the temperature when he wasnt around, he suggested a meat thermometer in the dipstick hole.

My Cooper S runs between Turkey and Ham, is this normal?

[steveo3002]

id wana drain it , unbolt it and raise it a bit to let it drain

fair enough youre changing most of the oil anyway , but for a bit more effort you might as well have all fresh oil

[DanielJames]

That's not a bad idea to lift it up and push it through. It is thermostatic though so I'll have to get the engine up to temp first! (which should allow the oil to drain easier anyway).

Yes it's there for temperature, why else would you fit an oil cooler

I can't believe you didn't get upto temp after 70 mile flat out! that's crazy!! (or am I missing the joke)

I got to crazy temperatures after just half a lap at the ring before fitting the cooler, for example.

[Impasse]

Vacumatic said:

My Cooper S runs between Turkey and Ham, is this normal?

[The Wookie]

Vacumatic said:

My Cooper S runs between Turkey and Ham, is this normal?

If it goes as high as Roast Chicken then you're stuffed

[mwstewart]

No need to do anything unless you've had an engine failiure.

[Spare tyre]

I just change it a bit earliern therefore more often

Keep in mind that you have more oil than normal so in theory it should be in bett condition than if you had the normal amount of oil

[ging84]

depends how the cooler is fitted, if it's higher than where the hoses come out the engine, it should all drain back in, if it sits lower, then some of the oil might remain, probably not as much as you might think, as much of it can still get pulled via a syphoning action, but even if some remains, so long as you are not adding something like engine flush, it's not a big deal that some of your oil doesn't get changed, especially given how regularly you seem to be changing it.

[jkh112]

The Wookie said:

Vacumatic said:

My Cooper S runs between Turkey and Ham, is this normal?

If it goes as high as Roast Chicken then you're stuffed

It is rare to get as high as beef, but if you manage it then well done.

[DanielJames]

ging84 said:

depends how the cooler is fitted, if it's higher than where the hoses come out the engine, it should all drain back in, if it sits lower, then some of the oil might remain, probably not as much as you might think, as much of it can still get pulled via a syphoning action, but even if some remains, so long as you are not adding something like engine flush, it's not a big deal that some of your oil doesn't get changed, especially given how regularly you seem to be changing it.

The oil cooler is lower, perhaps by 20cm or so.

Thanks for the informative reply

[mywifeshusband]

The Wookie said:

Vacumatic said:

My Cooper S runs between Turkey and Ham, is this normal?

If it goes as high as Roast Chicken then you're stuffed

At least you'll know when the engine is Goosed.

[steveo3002]

Vacumatic said:

I did two laps of the TT circuit, which is over 70 miles in total, taking the revs to the maximum wherever possible, at the end of the 70 miles my oil temperature hadnt reached working temperature, and that engine had an oil cooler.

are you saying that like its good? cold isnt a good thing to have

[Vacumatic]

steveo3002 said:

are you saying that like its good? cold isnt a good thing to have

No I am not, I blanked off the cooler.

[red_slr]

If you ever have to change the oil cooler then get one with a drain plug. HTH.

[DanielJames]

red_slr said:

If you ever have to change the oil cooler then get one with a drain plug. HTH.

Now that's a good idea.

I ended up taking the cooler off and tipping it upside down. To my surprise, not very much oil came out. Maybe 200ml.

Thanks for the replies.

[Mound Dawg]

DanielJames said:

I ended up taking the cooler off and tipping it upside down. To my surprise, not very much oil came out. Maybe 200ml.

Exactly, the actual capacity of the cooler and pipes is so small that it's not worth the effort of trying to drain it. There's probably more old oil sitting around your cams than in the cooler.

FWIW, thermostatic take off plates have a small bleed hole that allows an amount of oil through at all times even if the stat is closed. If they didn't have this, the first time the stat opened after fitting the cooler you'd get a catastrophic loss of pressure as the pump blows the air through the system and onto your bearings.