Possible to overbuild your cooling system?

Hey everyone,

So I have an E36 M3 that will be seeing track time next year. I plan on doing the major stuff, like bushings, frame reinforcement, fluids, etc over the winter. I know a common-ish problem on the M3 is the fan clutch will go out or something, and this will cause the fan to spin erratically, shredding itself in the engine bay and causing all sorts of damage to other components. So I figure eventually I would upgrade the cooling system. I want to go with something that will be a better design than the oem system, so I dont have to worry about the fan.

Anyways, I was looking at the Zionsville stuff (which is pretty expensive :O) and there are two options that look really appealing. See links:

http://www.zionsvilleautosport.com/store/screen/prod/store_code/6134/product_code/E36CCKI.htm

http://www.zionsvilleautosport.com/store/screen/prod/store_code/6134/product_code/E36ARIOC.htm

One of them has an oil cooler in the kit, which is pretty sweet. Now both of these are probably overkill, but I do like the option of having two fan speeds on the first one. So I wondered: is it possible that you could have a cooling system that works so efficiently that it would prevent the oil from ever reaching optimal operating tempurature?

Does anybody else know of some kind of aftermarket kit that replaces the old fan design? Its bad enough that most people opt to simply remove the fan entirely, but I dont want to go that route. Thanks dudes!

Well you could do what I did and put electric fans on a clutch fan car and draw more power than the alternator produces and have your car shut off if the E36 M3 comes on.

The clutch fan is much-maligned, but if you treat it as a wear item (the viscous coupling does wear - 100k mile service interval) and make sure the fan isn't brittle or chipped, it works really well. Changed at the appropriate interval and not attached to a cracked, chewed-up fan, I've never had one fail.

If you're worried about over-cooling your oil, use an oil thermostat. Or go old-school and just tape over the core of the cooler on cold days.

If the oil doesnt reach operating temperature it wont flow as it was intended to. I imagine the effect would be similar to running a thicker weight. The track section on a BMW forum would probably have good info there. FWIW, I removed the mechanical fan from my E36 and installed an electric fan just for the peace of mind. Old motor mounts can also cause radiator to blade contact. The stock mechanical fan flows a ton of air, way more than any electric that will fit can manage so if properly maintained its far more effective.

The trick is to put your oil-air cooler before the oil-water cooler, that way the oil is kept around coolant temp and the aux cooler is just added cooling capacity.

As long as you have a working thermostat it will regulate coolant flow and should maintain proper engine temps.

I don't know if BMW oil coolers have them but the Porsche oil coolers have a thermostatically controlled oil cooler bypass. The oil only flows through the cooler if the temp gets high enough to close the oil cooler bypass valve.

You can get in-line oil thermostats, too - there was a vendor selling them at the Mitty. They looked pretty easy to package.

This is all very helpful, thanks for the tips guys!

also.. while the fan is much maligned.. keep in mind a lot of it's failure are also the cause of the "dreaded" moneyshift.. bad engine and transmission mounts. If you take a good hard look at your fan and see how close it is to the shroud, you can tell that it would not take much movement to have the spinning blades contact that non-moving surface.. this shreds the blades, causes out of balance issues, and eventually makes the fan "explode" taking out your radiator, waterpump, and possibly the hood

Just swap out to a 1991 318is radiator with the built-in coolant expansion tank, and a 15" SPAL fan. Most of the swapped E30 track guys run this setup and rarely have a problem, if at all. Much easier to bleed, and it's also a cleaner under-hood setup.

In reply to mr2peak:

Does it sufficiently cool the engine? I mean the design is for a 4 cylinder engine, so you can probably understand my apprehension

I've had the Zionsville stuff on my '98 e36 M3 for about 6 years; the aluminum radiator w/ the aluminum header tank, ducting, 16" SPAL puller fan and 2-speed wiring kit. I also installed a Stewart water pump, aluminum thermostat housing and new hoses at the same time. Everything fits perfectly and works perfectly and should last about forever. The car is used almost exclusively on track, driven to events. I do a little instructing now, so I'm out in instructor group and used to do NASA TT events - my point being that the car is used at its limits most of the time.

At VIR in July w/ a 104 degree air temp and bajillion degree track temp the temp gauge sat in the middle session after session. In hideous outskirts of DC gridlock on I66 on the way down, windows up, AC on, 103 degrees, mostly sitting the temp gauge was in the middle.

I'm old and have built enough stuff to have learned that nice things are nice. On the M3 I used the good stuff - not necessarily the most expensive but almost never the cheapest - and the decisions have been validated by both how well the car works, which is pretty much perfectly, but how reliable it is as well. Which is 100%.

There's cheaper stuff than the Zionsville parts, but their stuff is made in the US and the guys you'll talk to there know their stuff cold, and stand behind the product.

I dont mind paying for the best. So Motomoron, you have no problem with streeting the car with that setup? I guess you just run the radiator and no oil cooler? I mean there is nothing wrong with super cooling the water running through the cooling system. You cant really have a radiator that is "too efficient", right? The cooler the better?

So you dont have to worry about the oil never reaching optimal tempurature? I am looking for the best street/track performance, and I really like what you have to say about the Zionsville stuff, maybe I'll go that route.

That Stewart water pump is a magic little thing, we're using them on a couple of cars and they make a massive difference.

I don't know what oil temperature it can achieve on a gazillion degree day. But I run Redline 10/40 and have had analysis done a couple changes after I did the rod bearings (and a VAC oil pump shaft and pan baffle) and all was good.

Cars have thermostats to maintain proper operating temperature. The only reason for larger cooling capacity system is if you're going to exceed the capacity of the existing one. A car with every bolt-on power adder + a tune + race tires/brakes + 20 minute sessions run at race pace can produce more energy than a stock system can effectively dissipate. So more cooling capacity is needed then. Going to forced induction often requires much more cooling capacity. Burning enough fuel to make 350hp in a motor designed and cooled for 240hp doesn't work.

But this has nothing to do with oil temperature. Though an engine that's able to stay at thermostat temp is less likely to build oil temps than one that doesn't.

A big factor is that the stock BMW parts are fragile and unreliable. I've seen an e36 M3 exit the Summit Point turn 1 braking zone sideways at speed due to a ruptured OEM BMW plastic header tank. That's not in my plans, so the Zionsville aluminum version is worth the $.

Unless you are doing 8 hour race enduros in your E36 M3, you don't need an oil cooler. On my GTS2 car, even at Road Atlanta with high temps and 45 minute races, my oil temperature never went above 230-degrees. E46 M3 because of no airflow over the oil pan (better aero on the E46 M3), and a motor that just builds up heat a lot more, you need them.

Don't waste the money on the oil cooler, more likely to overcool or blow a line then worry about overheating the oil.

That said, bulletproof the E36 M3 out of the cooling system but make sure you have a good thermostat as you can overcool water. I am actually switching back to a higher degree thermostat as my car is having trouble keeping up temperatures during racing. Just bouncing off the 170-degree thermostat aside from the hottest of races where it sits around 175-180. This won't be a problem on a street car with the a/c condensor in front of the radiator.

Desmond wrote: Hey everyone, So I have an E36 M3 that will be seeing track time next year. I plan on doing the major stuff, like bushings, frame reinforcement, fluids, etc over the winter. I know a common-ish problem on the M3 is the fan clutch will go out or something, and this will cause the fan to spin erratically, shredding itself in the engine bay and causing all sorts of damage to other components. So I figure eventually I would upgrade the cooling system. I want to go with something that will be a better design than the oem system, so I dont have to worry about the fan.

The fan stops spinning at idle or slow pace when the fluid couple goes bad. It causes overheating in conjuction with a radiator temp switch that is defective and not turning on the electric aux fan. The reason fans destroy shrouds and radiators is because people go to the track w/o checking their motor mounts. Two different issues.

If you source a euro oil cooler housing you can make your own oil cooler kit from Summit Racing hoses, fittings, and cooler for about $400. This is essentially the route I went except instead of the euro housing I went with a Champion Oil Cooler plate to get the extra fittings for gauges. I tracked and raced for years w/o an oil cooler though. If your sessions are only 30 minutes and the outside temps aren't over 100 you will be fine saving the cash by just using good synthetic oil. It won't go over 260F. I put an oil cooler on for long races at sprint race paces. If you do decide you want the oil cooler - buy an oil thermostat to put in the return line or you will never get it to operating temperature on the street. They go for $100 at Summit. Also note - your car will take close to 10 quarts of oil and you will need to get the car hot once before the cooler loop bleeds so over fill it a bit the first time and then get it HOT until the t-stat opens. Then top it up.

I have no mechanical fan and a mishimoto aluminum radiator in my race car - it was affordable, came with all silicone hoses and seems to be of decent quality. The water temps stay nice and steady during 4 hour endurance races in very hot weather.

I also have a 16" electric SPAL pusher fan that is triggered by the factory low setting to come on full blast. It is also wired to a manual switch on the panel. It NEVER comes on by itself unless I pull into the pits after a few hot laps and stop dead. I never really have to use the manual switch.

After doing this revamp on my E36 M3 it's totally bulletproof for the long haul. I've done a few track days (on very hot days) with no issues whatsoever. It will also sit in traffic in 100 degree heat with the A/C blasting without problems.

http://grassrootsmotorsports.com/project-cars/1997-bmw-m3/enlightened-e36/