DIY Oil Cooler best practices, tips, help

[houtan]

Planning on adding an oil cooler in the not to distant future so i was hoping to get some feedback from the experts on here that have done their own oil cooler and understand this stuff much better than i do.

There are two articles i have come across that i am sort of using as reference points.

Oil temp: https://www.hotrod.com/articles/engine-oil-temperature/

Oil cooler: https://www.pegasusautoracing.com/do...paign=201807-2

The oil temp article recommends oil temp getting to at least 220 degrees to burn off all deposits and accumulated water vapor. I see the most common thermostat being the improved racing 185 degree version. Does that mean the thermostat is not going to let the oil get to 220 degrees?

The oil cooler article makes a few points i find interesting:

1. Do not mount the cooler with the inlet and outlet pointing down. This is interesting to me because the ER cooler is mounted with both inlet and outlet at the bottom.

2. Don’t run two coolers in series. I believe every implementation of two coolers has been in series. Is this a concern for the n5x? i believe the ER dual cooler setup is in series. This Stett setup is also in series. https://www.ebay.com/itm/STETT-Perfo...4AAOSwy-5btQqh

3. Isolate the cooler from vibration. Is this one important? ER uses some rubber fittings, but a lot of the other companies and DIY setups do not put anything for vibration. The Stett setup in the link above has nothing for vibration.

Would appreciate any feedback you can provide.

[houtan]

Bump. Can someone please help an amateur out? Haha. Am I posting in the wrong sub forum? I feel like the most knowledgeable owners are here.

[mKilgore]

I am merely an amateur as well, but I'll provide my thoughts and you can take them for what they're worth.

I don't believe changing out the oil thermostat would have much effect on your final temperature. A 185F thermostat should mean that it opens at 185F so the oil will enter the cooler at an earlier temperature meaning that it should take longer to heat up, but eventually the temperature will stabilize dependent on the efficiency and cooling capacity of your oil cooler, not the temperature at which it opens. I don't see much value in changing the thermostat. The 135's run normally around 240F, so my goal has always been to have my car run between 230 and 250 on track. I figure that is a good range for hard driving since 240F is what it normally runs at.

I honestly don't know any difference about the inlet/outlet being mounted on top or bottom. Mine are mounted on top but simply because that was the best mounting solution for my upgraded cooler. I guess I could see some issues if you are having to push the oil up into the cooler versus flowing the oil down and filling up the cooler. It makes more common sense to flow from the top, but I have no engineering data to back that up.

The comment about not running in series is interesting. I guess it depends on the efficiency of the cooler. I read the Pegasus article and can't say I really agree with their reasoning. They say a second cooler is less efficient in series because the oil being sent from the first cooler is already cooled and therefore the second cooler will not cool it as much. I think that while this is "generally" true, you have to take into consideration your own setup. If I run on track and have a stock oil cooler, it could run up to 260F? Maybe higher? Yikes. If I run 2 oil coolers in parallel, each oil cooler may reduce the oil temp to 250F. So that's an improvement, but what if I want further reduction in temp? Well, if you run two coolers in parallel, you've doubled your capacity to cool twice as much oil at once, but they are cooling at the same rate. You could change each cooler to a bigger size, but it seems to me that if you run them in series you can get a further reduction in temperature. The first cooler will cool the oil to 250F, like it has been doing, but then that oil will be further reduced by the second cooler, so hopefully you end up with a temperature of maybe 240F (obviously these numbers are a little hypothetical). It makes sense to me to run them in series and that also makes plumbing the lines much easier than running two sets in parallel.

Isolating the cooler from vibration is worthwhile to limit any cavitation of the oil. It is probably not totally necessary, but if you are taking the time to do the oil cooler upgrade, its not much more effort to put in some rubber grommets or mounts.

I ordered an Earls's oil cooler from Summit Racing, EAR-22500AERL, along with a mounting kit, Mounting Kits 1302ERL, that has material along the bottom of the mount to reduce vibration. Along with the an-fittings and line I probably spent a total of $400ish. I am considering duplicating the setup and running a second behind the driver's side bumper inlet.

Hope that helps, and again, I am no expert either but just giving you my thoughts. If someone else has different theories, please share.

[bbnks2]

From what I understand, orientation doesn't matter at all. Fluid dynamics dictate that oil pressure will purge air or something like that.

Mounting a large cooler is tricky to get the fitment right as there isn't much room in the wheel well. You need to mount it as forward as possible to clear the wheel at full lock but then the headlight and HID ballast gets in the way. You'll have to use your imagination on how to design a bracket that gets the placement right. Pop a screw up into the headlight support bracket on one and and connect the other end to the frame rail with an L-bracket. I did a whole write-up on this "diy oil cooler retrofit on a budget."

An oil thermostat is a waste of money. Stock range is perfectly fine.

Parallel does produce superior heat exchange, but, it's harder to implement. The factory oil thermostat housing gives you ports to run a second cooler in parallel. The hard parts is getting the fluid dynamics right. You need to use two cores of the EXACT same same and use oil lines of the EXACT same length or one core will not get as much flow (path of least resistance). Hence why people like berk never had any success adding a 26row on top of the stock 10row when trying to run them in parallel.

The above comments about parallel vs series are incorrect in regard to which is better at cooling. however, he is right that plumbing in series is just plain easier.

I agree on the rubber gormets as well. Just go grab some cheap rubber o-rings from home depot and put them in-between every bolt you use to mount the cooler. It will help a little. The OE cooler is mounted using rubber bushings.

The biggest issue not covered here is ducting. You have ot find a way to seal the oil cooler to the front bumper. Use aluminum sheets from home depot to build a shroud. That is a PIA to get right, but, cooling will improve drastically over just dumping a 26row into the wheel well. That won't do jack since air will just go around it.

[Gary@simod.net]

Removing the thermostat makes a huge diffrence. the oem thermostat flows 30-40% of the oil. Putting a 100% flow rate like the Burger piece or a few others dramatically helps.

I have an upgraded oil cooling system on my 2011 135 dct car. consisting of the following.
1. Diverter valve for full 100% oil flow
2. inline 180 degree thermostat to allow the car to come to temp before the thermostat opens.
3. adapter plate routing oil out of th estock cooler over to a secondary LARGE oil cooler on the driver side then back in to the thermostat and engine.

The second option is to use the same inline t stat then run two huge oil coolers in each corner of the bumper. We have this set up on our shop race car project.

I can post pictures later. Without upgraded oil cooling on track driven hard they go into limp mode. and the aftermarket style, like a CSF oil cooler is not enough to stop the limp home issue.

[Gary@simod.net]

FYI... BMW uses secondary oil coolers on most of the new M cars ALONG with secondary water coolers...

And the 1M uses a secondary oil cooler...

It works...

[dtla1]

Originally Posted by Gary@simod.net

Removing the thermostat makes a huge diffrence. the oem thermostat flows 30-40% of the oil. Putting a 100% flow rate like the Burger piece or a few others dramatically helps.

I have an upgraded oil cooling system on my 2011 135 dct car. consisting of the following.
1. Diverter valve for full 100% oil flow
2. inline 180 degree thermostat to allow the car to come to temp before the thermostat opens.
3. adapter plate routing oil out of th estock cooler over to a secondary LARGE oil cooler on the driver side then back in to the thermostat and engine.

The second option is to use the same inline t stat then run two huge oil coolers in each corner of the bumper. We have this set up on our shop race car project.

I can post pictures later. Without upgraded oil cooling on track driven hard they go into limp mode. and the aftermarket style, like a CSF oil cooler is not enough to stop the limp home issue.

Interested to see those pictures! And for the inline thermostat, how much of a flow loss do you think you might have compared to no thermostat whatsoever?

[bbnks2]

Originally Posted by Gary@simod.net

Removing the thermostat makes a huge diffrence. the oem thermostat flows 30-40% of the oil. Putting a 100% flow rate like the Burger piece or a few others dramatically helps.

I have an upgraded oil cooling system on my 2011 135 dct car. consisting of the following.
1. Diverter valve for full 100% oil flow
2. inline 180 degree thermostat to allow the car to come to temp before the thermostat opens.
3. adapter plate routing oil out of th estock cooler over to a secondary LARGE oil cooler on the driver side then back in to the thermostat and engine.

The second option is to use the same inline t stat then run two huge oil coolers in each corner of the bumper. We have this set up on our shop race car project.

I can post pictures later. Without upgraded oil cooling on track driven hard they go into limp mode. and the aftermarket style, like a CSF oil cooler is not enough to stop the limp home issue.

How much oil flows through the stock thermostat is completely dependent upon how hot the oil is lol... once up to operating temperature the stock thermostat is open 100%. It's a very simple valve. Aftermarket thermostats don't increase flow through the oil cooler. The actual oil feed orifice in the housing stays the same size. All aftermarket thermostats do is open at lower temperatures which extends the amount of time it takes to reach operating temperature. I don't see any issue with running synthetic at 250f.

[houtan]

Thanks for all of the replies.

mKilgore : Please share any info if you end up adding the second cooler. Or if you want to share pictures of your current setup.

bbnks2 : Total agree shrouding is a great help. Did you make a thread about your oil cooler install? If so please post the link if you get the chance. If I find it i will add it to this thread.

Not sure why I didn't think of this earlier, but I decided to email setrab to get their comment on oil cooler mounting. You were right on the money; for smaller coolers, upside down is ok. Please see two emails below.

Hi Houtan,

The reason we would worry about this is if the cooler was so large that the flow wouldn't fill the cooler before the oil exits. in your case, as long as you're using a reasonable sized cooler it shouldn't matter.

Marv Beals

(I sent a follow up email to confirm the 625 wasn't considered large and ask about vibration; response is below)

while 625 is a very high performing oil cooler it's displacement is only 0.55 quart. so, it will charge-fill rapidly.

yes, we do like to insulate the cooler from vibration and flex. in fact, we make nice general mounting bracket solution that can assist you with both issues, see that item here: http://www.setrabusa.com/products/mo...ets/index.html

best,

Marv Beals

Gary@simod.net : What do your oil temps get to driving around town? Do they hit 220? Would love to see pictures of your setup.

[dtla1]

I found some good threads/example of setups in these two threads:

https://www.e90post.com/forums/showthread.php?t=727958
https://www.e90post.com/forums/showthread.php?t=875343

[bbnks2]

Originally Posted by houtan

Thanks for all of the replies.

https://www.1addicts.com/forums/show...php?p=20176395

That was the thread from a few years ago. The oil cooler was a tighter fit on the 128i and require more hacking things up. The 135i resulted in a much cleaner install. The bumper wasn't in the way, no need for a duct, and there are no fog lights to worry about blocking the oil cooler.

With the 135i install, I also made a much nicer bracket. I mounted the cooler with large rubber washers in place for vibrations. I also built a metal shroud out of thin gauge aluminum sheeting (22ga?). You learn through experience lol. Everything is extremely straight forward so there was no need to document how to install the oil line adapter and connect it to the oil thermostat housing. It's one bolt.

[berns]

I run two Setrab 19-row coolers in series.
Currently I run no tstat. For a track car only, you don't need one, but since I drive to the track pretty often and still street drive occasionally, I'm going to install a 185* thermostat. I have an Earl's waiting to go in, but it involves more fittings and more lines, so I might sell it and run this instead.

https://www.mosselmanturbo.com/en/msl-thermostat-n54

Though it's pretty pricey, I do like that it's self contained and easy.

They also offer their own kit with the same cores I use, including brackets. https://www.mosselmanturbo.com/en/ms...it-1-serie-e8x
For this you need to purchase the 1M drivers side oil cooler bracket as well. This setup places the cores in good position and with some ducting would probably be the best.

The way I set mine up is to fill the openings in the bumper. I still need to block off some surrounding areas to force air through the coolers but the angle of the cores isn't ideal. I might revise it soon, however, my oil temps have improved dramatically. I still can't do multiple laps in 90* summer heat, but I can run a full 15-20 minute session in anything under 80* ambient, and I drive hard.

Here's my setup.







Ugly brackets, but I'm no fabricator. They are light and purposeful, each core is super sturdy and the brackets attached to the cooler have rubber to remove vibration.



This was how they sat in the 135i bumper, but they fit much better in the 1M bumper, as they fill the entire opening.

[drunkenup]

Dual 25 rows, mounted off the crash bar/frame rail studs, can build all the mounting using aluminum solid angle: https://www.lowes.com/pd/Steelworks-...-Angle/3006070

View post on imgur.com

You need to trim the crash bar a tiny bit like in the photo, but allows you to set the coolers far back along the fender liners, like the stock cooler. No rubbing issues.

The inner fittings going to the thermostat housing are 60 degree I'm pretty sure- you need to do some trial and error to route the line over the framerail, but under the rear housing of the headlight going this route, but then you can build some nice looking ducting, and these coolers look really nice sunken in the bumper.

[AndyW]

I am in on this thread. I am also an amateur but I did add the factory solution to my 335 without breaking anything several years back, so maybe I'll be able to contribute...lol.

I think I am going to do the oil starvation/oil cooler setup developed by Asbjorn shown in a thread here:

https:// bmw.*rhymes-with-bool-teat*.com /threads/z4-track-ready-sleeper-build.3026/page-2#post-43250

I honestly haven't had overheating issues here in the PNW but I am consistently getting my oil temps to 260 in a 20 min session, so I probably need to add something.

My difference will be that i am planning on using a stock PPK2 cooler vice a SETRAB because i have a custom brake duct in there that limits space. Plus I like the idea that I can just bolt everything up, including ducting without building a custom solution. I am sure mounting the gear pump, AN lines and the wires will be frustrating enough...

Now I just need to hope for an oil pan gasket leak to manifest or something so I can justify the effort of dropping the subframe to changeout the pan...lol.

[beattiecj]

Guys, just add as much cooling as you can.... Especially for the track.

I've added one Evolution Raceworks cooler, yes it's a premium but it fits great, easy to install and has held up great over 5 track days and intermittent daily driving. Do I want more sadly yes, but a caveat is being able to run 20+ min sessions and all track types.

One makes a night and day difference, instead of waiting a lap/2 to cool down one straight of clean air brings temps down.

Look at the M2 cooling is built in every corner of the front end there is even a horizontal cooler in the front bumper haha.

[Gary@simod.net]

Originally Posted by bbnks2

How much oil flows through the stock thermostat is completely dependent upon how hot the oil is lol... once up to operating temperature the stock thermostat is open 100%. It's a very simple valve. Aftermarket thermostats don't increase flow through the oil cooler. The actual oil feed orifice in the housing stays the same size. All aftermarket thermostats do is open at lower temperatures which extends the amount of time it takes to reach operating temperature. I don't see any issue with running synthetic at 250f.

Absolutely not how it works. the oem thermostat like ALL BMW oil thermostats only open 30-40% been like this forever oil temp has nothing to do with the thermostat opening. BMW ALSO puts a restrictor in the return line to help keep the oil in the actual cooler longer you can see it on a stock 135 it is a metal band in the middle ish of the line that band holds the restrictor in place... we remove those to..

We pull them out of all E36 and 46 M cars that run the OEM oil filter housing thermostat unit especially S54 cars which are heat monsters on track... Some of them we end up running two oil coolers on just to keep temps down for racing.



ALL aftermarket thermostats run 100% flow rate when opened up.

I have to go pick the car up when I have it I will post pictures of the street car set up we use and later the track/race set up. We also NEVER leave the opening without a screen or mesh grill on them. on track or even street you can easily get a puncture on the cooler due to how low they are.

I think we have pictures of the street set up on our Facebook page under SIMOD, Christiansburg Va.

[Gary@simod.net]

Here are two pictures.

The thermostat is in line (silver t stat 180 degree) goes to the OEM cooler then T off it and go over to the larger secondary cooler.

[mKilgore]

Originally Posted by Gary@simod.net

Absolutely not how it works. the oem thermostat like ALL BMW oil thermostats only open 30-40% been like this forever oil temp has nothing to do with the thermostat opening. BMW ALSO puts a restrictor in the return line to help keep the oil in the actual cooler longer you can see it on a stock 135 it is a metal band in the middle ish of the line that band holds the restrictor in place... we remove those to..

We pull them out of all E36 and 46 M cars that run the OEM oil filter housing thermostat unit especially S54 cars which are heat monsters on track... Some of them we end up running two oil coolers on just to keep temps down for racing.



ALL aftermarket thermostats run 100% flow rate when opened up.

I have to go pick the car up when I have it I will post pictures of the street car set up we use and later the track/race set up. We also NEVER leave the opening without a screen or mesh grill on them. on track or even street you can easily get a puncture on the cooler due to how low they are.

I think we have pictures of the street set up on our Facebook page under SIMOD, Christiansburg Va.

What is the flow rate and volume of oil from the OEM thermostat vs that of your aftermarket unit?

[AndyW]

Originally Posted by Gary@simod.net

Here are two pictures.

The thermostat is in line (silver t stat 180 degree) goes to the OEM cooler then T off it and go over to the larger secondary cooler.

Looks very interesting. I wish I wasn't several thousand miles away...

So the two primary components are these?:

https://www.summitracing.com/parts/d...hoCQakQAvD_BwE

https://www.ebay.com/itm/AN10-Oil-Fi...53.m1438.l2649

What AN hose do you recommend and how much do you need?

[bbnks2]

Originally Posted by Gary@simod.net

Absolutely not how it works. the oem thermostat like ALL BMW oil thermostats only open 30-40% been like this forever oil temp has nothing to do with the thermostat opening. BMW ALSO puts a restrictor in the return line to help keep the oil in the actual cooler longer you can see it on a stock 135 it is a metal band in the middle ish of the line that band holds the restrictor in place... we remove those to..

We pull them out of all E36 and 46 M cars that run the OEM oil filter housing thermostat unit especially S54 cars which are heat monsters on track... Some of them we end up running two oil coolers on just to keep temps down for racing.

ALL aftermarket thermostats run 100% flow rate when opened up.

I have to go pick the car up when I have it I will post pictures of the street car set up we use and later the track/race set up. We also NEVER leave the opening without a screen or mesh grill on them. on track or even street you can easily get a puncture on the cooler due to how low they are.

I think we have pictures of the street set up on our Facebook page under SIMOD, Christiansburg Va.

I am not sure what you mean by "it doesn't work like that." It works exactly like that. Thermostat spring expands from heat which then in turn pushes a piston down and unblocks the orifice for oil to pass through to the oil cooler lines. Factory thermostat has holes in it so you always have a small amount of flow through the oil cooler even when the oil is cold.

You're partially correct that the stock thermostat does apparently block the oil cooler feed passage by a hair even when it's 100% open. However, it's maybe a 10% overlap at most. There is probably 0 real world difference in flow between a stock thermostat once and something like the BMS oil thermostat delete which is shorter and doesn't block the passage at all. Saying the stock thermostat only opens 30-40% is just plain hyperbole. Maybe you're experience on other BMW's varies?

Here is a picture of a thermostat when fully open:





As for your comments about their being a restrictor in-line on the return line, I can't speak to that. BMW would do it for a reason if it's there. Does the oil going through the cooler return to the pan? I'll check tonight or tomorrow. I was under the impression that cooled oil feeds the engine. No real reason to have a restrictor in that case. I would imagine the necking down of the oil return line isn't actually a restriction at all since again the oil feed/return hole in the oil filter housing itself is probably the main restriction dictating flow. The line switch to a metal line to keep it rigid as it travels over the pulleys...

Where on the line is this restrictor you make reference to? I am not seeing what you are.

[bbnks2]

Originally Posted by houtan

Thanks for all of the replies.

Here is what my shroud looks like:


Core sits in almost the same position as stock. This creates a nice pocket in the bumper for air to well up in and dam up against the cooler. It's sealed to the bumper on all four sides with the shrouding.

[houtan]

Woah. A lot of different setups and excellent discussion. I personally have learned a lot, so thank you for taking the time to share. I plan to update the OP at some point and compile information shared by everyone. What that looks like i have no clue, but i will take a stab at it and then update based on comments. That way when the time comes to pull the trigger, all of the information will be in one place for anyone to use.

I agree with what others have mentioned, the DIY route is more fun, more rewarding, and usually more cost effective. The problem for me is, fatherhood leaves much less time to work in the garage. It literally took me three weeks to get my front brakes done. Ridiculous, i know. Even though the pre made kits are more expensive, sometimes it feels like that is the only route that makes sense. I am just having a hard time paying the extra price when i know i can do it on my own, thus no oil cooler upgrade yet haha.

Here are some questions based on what has been posted:

- Can someone who has the 180ish degree thermostat please clarify: What does your oil temp get to driving around town? Does it literally stay around 180 or does it get to the 220 range. Asking because that hot rod article says the temp needs to get into the 220 range.

The mosselman parts berns posted are really nice. They are pricey, but the thermostat solution is really appealing. Just want to understand if 180 is too low for a mostly street car.

- AndyW asked this already, but what size AN line is recommended? (nice find on the parts posted by Gary@simod.net, that was another question i was going to ask)

I have seen -8 and -10 mentioned. Anyone know the size of the OE oil cooler hose?

- It would be nice to have part numbers for the oil coolers used so we have an idea of what fits. Based on the size of the ebay cooler bbnks2 was able to fit, it seems a setrab 625 is around the max that will fit.

I can try to find part numbers, but i don't have enough information for some setups posted. berns, are you running the setrab series 1? drunkenup, those coolers are massive; can you please share the brand and part number? Gary@simod.net, what part number is the cooler you T-off to (this was really interesting btw, i have never seen that setup before)? What about your race car setup?

- How can we conclude whether or not the factory thermostat is a restriction? Based on what bbnks2, it doesn't seem to be a restriction.

- Anyone have clearance issues with an aftermarket setup and a CSF radiator? After seeing the clearance between oil lines and the fan shroud in some of the pictures, i went and looked under my hood. My oil lines are basically smushed against the fan shroud because of the extra thickness of the radiator. Some of the pictures have much more room. This is what my car looks like.