Cheap full time oil cooler mod

#1

May be old news, but I haven’t run across this tidbit anywhere before.

The OE setup has a thermostat to control flow though the cooler. In a quest for a bit higher oil pressure (I’'ve seen as low as 12psi/1000rpm at the end of a session) I decided to eliminate the thermostat and have the oil cooler in action full time. That turned out to be an easy and cheap modification.

All that was necessary was to move the spring to the other side of the thermostat, forcing it to always be "on". This past weekend at RA that was worth an additional 10psi across the rev range at the end of a session. I don’t know if it is designed that way, but I was able to pull the actuator stem out of the thermostat, so I just left it out.

#2

Has anyone else tried this???

#3

no, but I just added it to my list of things to do…

#4

Trying to figure out where this thermostat is - is it part of the oil filter setup?

#5

The oil filter adapter that bolts to the side of the block and accepts the oil filter and oil cooler lines contains the thermostat. The thermostat and spring is held in with a snap ring.

#6

I know of what you speak. I replaced the gasket in there (it was a TSB years ago from BMW - if that leaks, it is a cheap fix). But - I remember about 3 hours on my back telling my wife that my parents were never married, if you you get my drift. Pushing the spring and cap in while putting the snap ring on was not fun. I walked away, went to bed, came out the next morning and had it in before breakfast.

Not looking forward to doing it again - but good advice!

#7

is it item 7 in the picture here?
http://www.bmwmobiletradition-online.com/bmw/showparts.do?model=1113&mospid=47309&btnr=11_0459&hg=11&fg=30

thanks,
bruce

#8

Bruce,

Yes. Do you see the note next to it “See SI111590270”? That is the TSB that I was refering to. The gasket, from the factory, is rubber, and, as you can imageine, that is not a very good place for a piece of rubber to live a long life. The replacement “kit” includes a new cap, snap ring and gasket, this time made out of some other material that is more like a head gasket than a rubber ring.

If you get a little leak out of the engine in that area, and have not replaced that yet - this it almost certainly the source of the leak. And the replacement parts are cheap (like a couple bucks).

This is the DIY I used - it was NOT fun http://e30.bmwdiy.info/oil-leak/index.html

#9

good stuff, thanks

#10

Be Careful though. The reason the thermostat is there is that oil coolers are not designed to withstand full oil pressure when the oil is cold. If you are running mineral 20W50 in cold temps it could blow your oil cooler at start up. This happened to a friend of mine in a Porsche one day at Sebring. His weekend was over before he ver got the car off the trailer.

Don

Don

#11

donstevens wrote:

[quote]Be Careful though. The reason the thermostat is there is that oil coolers are not designed to withstand full oil pressure when the oil is cold. If you are running mineral 20W50 in cold temps it could blow your oil cooler at start up. This happened to a friend of mine in a Porsche one day at Sebring. His weekend was over before he ver got the car off the trailer.

Don

Don[/quote]

Yeah… but isn’t “Porsche” German for “to dump oil”?

#12

jblack wrote:

[quote]I know of what you speak. I replaced the gasket in there (it was a TSB years ago from BMW - if that leaks, it is a cheap fix). But - I remember about 3 hours on my back telling my wife that my parents were never married, if you you get my drift. Pushing the spring and cap in while putting the snap ring on was not fun. I walked away, went to bed, came out the next morning and had it in before breakfast.

Not looking forward to doing it again - but good advice![/quote]

This sounds incredible familiar to me. . . :laugh:

#13

donstevens wrote:

[quote]Be Careful though. The reason the thermostat is there is that oil coolers are not designed to withstand full oil pressure when the oil is cold. If you are running mineral 20W50 in cold temps it could blow your oil cooler at start up. This happened to a friend of mine in a Porsche one day at Sebring. His weekend was over before he ver got the car off the trailer.

Don

Don[/quote]

Blew up my oil cooler in December from just that, it was out 5 degrees and I started it up and my oil pressure gauge showed over 100psi oil pressure then it fell to 0 and I heard something trickling:(

#14

I considered possible cooler pressure limits before doing the mod. To satisfy myself that it should be ok I pressure tested the used and in rough condition cooler to 150psi w/o failure. I suspect that the flex line are more likely to fail if they are original. Mine showed surface cracks, so I had them rebuilt. And I used a new OE cooler rather than the one off the car as it had seen abuse.

#15

sorry to open this old thread, but…
I just got this cap/ring/clip kit and was thinking… couldn’t I just cut the spring to shorter length and have the best of both worlds?

thoughts…

#16

That won’t change the temperature at which the thermostat operates.

#17

jlevie wrote:

Jim, quite some time has elapsed since the start of this thread. Are you still of the opinion that the oil tstat could be worth 10psi?

That’s a pretty good arguement for running one of the various solutions that deletes it.

#18

I’ve seen no difference in oil pressure with or without the thermostat & cooler, if the oil temperature never exceeds about 220F. If the temp gets higher than that and the thermostat is open full time the pressure is a bit higher than otherwise.

#19

jlevie wrote:

I’m not sure I understood that.

Lets say oil is <220deg. Tstat is closed and oil pressure is not impacted by the tstat and oil filter housing, correct?

Lets say tstat is around 220deg. Now oil goes thru a partially open tstat. What does that do to pressure?

Now lets say that oil going out is 225 so tstat is fully open. It goes thru the cooler and comes back at 220deg. Is OP now higher because oil going into the galley is cooler?

I understand that your tstat opened at 220deg, but aren’t they supposed to open at 180deg?

#20

help me figure this one out…

just did hyperfest this weekend and prior to going i removed the spring and t-stat. my hottest temps got to 239!!! prior to this mod i was getting up to 212 hottest.

what’s up with that??? think i’m going to put it back in.