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Discussion Starter #1
Any body have a lead on an all aluminum radiator for the M5.
It is time for my M5's cooling system to be refurbished and a new radiator is in order.
The EPC list the M5 radiator core as 650 mm wide when it is actually 610 mm wide.
The 650 mm core all aluminum radiator is readily available however 610 mm not so much.
However the E34, 540 used a 650 mm wide radiator!!
I will need to look to see how they shoehorned a 650 mm wide core radiator between the frame rails.
Rod...
 

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Discussion Starter #3 (Edited)
Today, I took a look to investigate how a 650mm radiator could fit in the E34.

The passenger/right side of the radiator is all the way against the frame rail.
I removed the air cleaner box to get a better look and there is at least 40mm of clearance between the frame rail and radiator tank.
So physically mounting the 650mm radiator can be done with stock 540 parts.
The upgrade to a 650mm radiator will require some adjustments and modifications to the air cleaner box/shield, upper radiator hose and radiator bleed tubing.
I will explore if the M5 fan shroud can be used with some modifications to widen the mount points or if the fan shroud from the 540 provide a better fit and finish.
Also, since the oil cooler attaches/clips to the slots on the bottom of the radiator tanks the oil cooler needs a fix for the driver side bracket or a wider oil cooler needs to be selected.

Now I need to take a look at a 540 and other associated 650mm radiator parts to decide which parts are best for the upgrade
Stay tuned.

Attached is the evidence photo for the space available.

So far I don't see any show stoppers.
 

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Thanks for this - looking forward to seeing the final result :)
 

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The 540 shroud is too low down. The blades touch the upper part of it.

The M5 shroud can be made to fit with cable ties, but again - it looks ugly.

There is also no way of making all the heat shields fit with the larger rad.

The upper hose will need an extension which looks ugly, and opens the door to another 2 possible leaking/failure points.

Stick to the 610 in my opinion
 

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Discussion Starter #6
The 540 shroud is too low down. The blades touch the upper part of it.

The M5 shroud can be made to fit with cable ties, but again - it looks ugly.

There is also no way of making all the heat shields fit with the larger rad.

The upper hose will need an extension which looks ugly, and opens the door to another 2 possible leaking/failure points.

Stick to the 610 in my opinion
Fordkoppie,
Thanks for the pointers...
However, with the 610mm there are few if any available all aluminum radiator options!!
I agree, if I can find a quality 610mm all aluminum option that is the easy/comfortable choice.

As for the 650mm upgrade,
I don't HACK, I don't do UGLY; so, if and when I make the upgrade, it will look OE!!!
Also, I'm not afraid of difficult.

As for the heat shields? the 650mm radiator is installed in the E34 & E32 chassis and the factory parts are available to make that fitment without regard to installed engine. The OE M5 air filter box heat shields will be easy to modify and adapt. The front section of the air box may require a little more though, however I think I have that covered.

I anticipate, you would also vote against installing a tilt/telescoping steering column with memory out of an E31 into the M5; because there are no factory parts that match up? not for the faint of heart - but it is Done!
 

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Discussion Starter #7
I thought I'd let everyone know saw the first prototype of E34, M5 radiator from Zionsville.
I did not want to post images now because the radiator needs 1 last change and I didn't want an image of the prototype to ever be taken out of context and misrepresenting the final product.

They use an M5 OEM 610mm radiator core directly from the core supplier then custom fabricate the aluminum tanks so it is a direct fit alloy radiator with no compromises.

What is so cool is the upper tank ends that the rubber cushion fits in for the mount brackets are machined from a block of solid aluminum so it is very strong.

I fitted the fan shroud to it and all the mount points are perfect.

I anticipate I should have the final radiator in another week or so and I will post the images of this impressive alloy radiator then.
 

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Interested in why you believe the standard radiator design should be improved? You usually support BMW engineering against modification. As they had an aluminium radiator available in the 540 I wonder why they didn't fit it to the M5??
 

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Apologies for previous post! I've re-read yours and now realise that you're not trying to fit a standard 540 radiator into the M5 but an all-aluminium radiator in 540 size because of better availability of that size.
 

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Discussion Starter #10 (Edited)
Apologies for previous post! I've re-read yours and now realise that you're not trying to fit a standard 540 radiator into the M5 but an all-aluminium radiator in 540 size because of better availability of that size.
inchyra,
Yep, my initial intent was all about the availability of alloy radiators for the E34, M5 of which there were a few custom builds but nothing in production or off the shelf.
Since then and as an option, I decided to explore having Zionsville Motorsport fabricate and go into production on a direct replacement 610mm all alloy radiator instead of installing their 650mm Type 13, (E34, 540 radiator) in my M5 as an upgrade. As you can read I have been successful. A anticipate once I have a chance to evaluate their final build on the 610mm radiator the direct fit E34, M5 radiator will be available from them.

The only real obstacle for installing the 650mm radiator in the M5 is the wider radiator encroaches into the air filter box space and to accommodate the 40mm wider radiator the front half of the air filter box would need to be modified. I have workable solution for the fan shroud, upper radiator hose and headlight covering but modifying the front half of the air box will take more time than I was willing to invest at this time. Since I'm a factory look (undetectable, stealth) upgrade kind of guy, I will most likely see if I can find an M5 air filter box and when I have more time I work on the modification and fabrication technique to make the necessary factory look modification to the air filter box and provide the clearance for the 650mm radiator. Then I'll do the upgrade.

Until that time I'll use the Zionsville 610mm direct fit alloy radiator as I anticipate the 650mm as with most upgrades to the M5 are more about "want to" than "need to". That is, there is only 6.5% increase in radiator core capacity with the 650mm core and the alloy tanks on the 610mm radiator may provide as much if not more cooling capacity.
 

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Allied to my previous question about the use of plastic for the head de-gas pipe, do you believe the BMW design engineers used plastic / steel(?) for the radiators because of the cost of alloy alternatives or could there be a good 'engineering' reason for their choice of materials??
 

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Allied to my previous question about the use of plastic for the head de-gas pipe, do you believe the BMW design engineers used plastic / steel(?) for the radiators because of the cost of alloy alternatives or could there be a good 'engineering' reason for their choice of materials??
In my view the use of plastics was cost effective for mass production , sufficiently strong for the application (but not optimal) and low weight.

The plastic components were ok when they were new but now are well past their design life and while good for a mass production solution I don't think the plastic components are optimal.

It's one area where our M5s can be improved.
 

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Discussion Starter #13 (Edited)
Allied to my previous question about the use of plastic for the head de-gas pipe, do you believe the BMW design engineers used plastic / steel(?) for the radiators because of the cost of alloy alternatives or could there be a good 'engineering' reason for their choice of materials??
What I think is:
Plastics:
Pros: new aluminum, saves weight, non-corrosive, ease of manufacture, availability of raw material, etc.
Cons: no visible sign of weakening, catastrophically fail without warning,

The question is why any vehicle manufacture would risk a $20k engine with a $10-20 cooling system part, plastic radiator tank and/or why the coolant low sensor is an OBD 3rd priority to only be messaged during vehicle start-up or shut-down? Given the fact that, aluminum does not tolerate overheating, adequate coolant level is critical to engine survival and catastrophic coolant loss can occur any time after the engine is started and before it is shut-down it is beyond my comprehension; OBC priority 3 really!!.

BMW does design most aspects of the vehicle, i.e. form, fit and function however for the cooling system it does not design nor make the radiator, coolant hoses, expansion tank, etc. I anticipate, just about all BMW controls to the finite detail in their manufacturing plants are the body and engine. I anticipate for the balance of the vehicle they will write the specifications and submit the necessary design drawings to have the selected vender (OEM) fabricate the prototype to industry standards, submit them back to BMW for testing/evaluation and provide a quote.

So things like plastic end tanks on the radiator, plastic expansion tank, plastic air bleed lines, plastic plugs or how/what the radiator hoses are made of and what materials the other cooling system parts are made from by the vender are not decisions directly made by the BMW engineering team. I anticipate, if the BMW engineering team in charge of the engine cooling system thinks the vender needs to use other materials they will include that in the original system specification or in a revision to the original specification after they have evaluated the performance of the various prototype parts and assembles from the OEM venders.

With that said,
Plastics like the "glass fiber or mineral reinforced, heat- and hydrolysis-stabilized nylon 6 and 66 grades" (PA66) used for radiator, expansion tanks, etc., were initially selected by the OEM cooling system vender because they were considered adequate for the application; that is, anticipated lifespan, weight savings and added flexibility to manufacturing processes, etc. Of course, this material may be driven by the vehicle industry requirements and if a vehicle engineering team wants something better the cost for an upgrade to an industry standard material could make the cost of the part go up exponentially because other material that have a longer lifespan or will insure a increase margin of reliability may require new process and a special production line at the OEM/vender plant and that cost will be included in the MSRP and therefore make the vehicle less competitive.

With all that, plastic is hear to stay.
Some part materials will be upgraded as new materials such as Zytel® PLUS universal grade PLUS 95G35will become the industry standard, I would not anticipate that update to a 1990 part.
Until then, replacing cooling system parts that have reoccurring failures due to age or can fail with an alloy item is prudent to lesson the opportunity for a catastrophic cooling system failure that is messaged by the OBC as a priority 3.
 

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Good summary Rod especially on the OBC priority 3 comment , I don't know what they were thinking

Is low oil also an OBC priority 3 warning ?

It would be nice to some how recode low coolant in the chip as a priority 1
 

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Discussion Starter #15
Good summary Rod especially on the OBC priority 3 comment , I don't know what they were thinking

Is low oil also an OBC priority 3 warning ?

It would be nice to some how recode low coolant in the chip as a priority 1
Yep, oil level is priority 3 also.
It would be nice to recode the IC however, I anticipate that is a time sink because you start with no help on the current coding. Maybe some day.
It may be easier to use an alternate module to display a message on the IC Display? Like this one!!
Cluster Display - Interfaces 4 Beemers

Attached IC Check Control Module Priority info.
 

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Thank you for your reply. Fascinating and frankly disappointing to realise that the design included components that could cause catastrophic failure without warning. Presumably the design specifications incorporated a 'design life' that was somewhat less than 20 years. I imagine that there were few failures of the plastic components during that design life or the spec would have been amended and / or the warning systems would have had increased priority.
 

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Yep, oil level is priority 3 also.
It would be nice to recode the IC however, I anticipate that is a time sink because you start with no help on the current coding. Maybe some day.
It may be easier to use an alternate module to display a message on the IC Display? Like this one!!
Cluster Display - Interfaces 4 Beemers

Attached IC Check Control Module Priority info.
I like the interface.

I'd like 2 displays from the 4 channels , oil temp and pressure and water temp and pressure.
 

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Discussion Starter #18
I like the interface.

I'd like 2 displays from the 4 channels , oil temp and pressure and water temp and pressure.

I would want to replace one of the redundant displays and add the coolant level sensor since it is an early indication of a cooling system problem - long before coolant temperature and or pressure has changed.
Also, cylinder head temp using a spark plug seal ring probe would be great addition to the engine thermal diagnostics.
CHT Cylinder Head Temperature Sensors 12 mm and 14 mm

I may even want to disable/interrupt the ignition, flash a trouble light and sound an alarm if the cylinder head temp exceeded a safe operating limit!!
The only issue is the cylinder head over heat is not the only catastrophic condition that can destroy a head.
Detonation from a failing injector or a bad fuel pressure regulator (pressure too low - lean AFR) during high RPM power runs are also a big concern.
 
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