I have an 07 R56S that is pretty much a dedicated track car. Lately I have been having issues with it overheating while pushing it on the track. This started happening after I had a downpipe crack (80% of the way around the pipe) which leaked hot exhaust gas onto the valve cover melting the corner of it. I noticed the valve cover after the first track session and did not leak any oil out or throw any codes. After replacing the valve cover I started having this over heating issue. I have done the following to try and diagnose it with no success: Leak down test Coolant pressure test while cold Coolant pressure test while warm Checked Air/Fuel ratio's on the dyno Installed oil cooler The Leak down test was performed at 50psi with the engine hot, #1 had 49.5 psi, #2 had 49.5 psi, #3 had 49 psi and #4 had 49 psi. That all looks good no issues there. The coolant pressure test while cold holds 20 psi for a couple minutes with very minimal leaking, maybe 1 or 2 psi. When I hooked the coolant pressure gauge up while the car was running I had 8 psi of pressure with the engine at 230 degrees (normal operating temp for my car). I revved the car up to 5000 rpm for a sustained amount of time with no increase in pressure. I took the car to the dyno and ran 10 or 12 runs back to back and my air/fuel's were all at 12.0 in the upper RPM range. I even installed an oil cooler on the theory that the oil temps were increasing, causing the coolant temps to rise. Some more background: I have never had the actual ECU tell me that the temps were too high, I have just been making that determination based an aftermarket gauge. I did verify with a data logger through the ECU that the temps I am seeing on my gauge are consistent with what the ECU is seeing, well actually like 7-8 degrees hotter, but the gauges are in different locations so this seems OK to me. I have learned that the electronic thermostat in the R56's has two different settings, one opening at 221 degrees while under normal driving and one opening at 180 degrees while under high load. I have seen similar behavior in my car. While driving on the street, the car maintains it's normal operating temp of 230 degrees. When initially starting out on the track, I see the coolant temps drop down to 190 or so initially, then climb pretty quickly to around 230-240 degrees when I back off the throttle. One lap after backing off the throttle the car temp decreases to around 220 degrees. I have been going crazy trying to figure out what is happening and I have a couple of theories. 1) The thermostat is not allowing the proper flow through causing the car to overheat - I am not too convinced with this one as the car temps initially decrease when first starting on the track 2) The radiator is potentially clogged and not allowing a high enough flow rate - I am not sure how to test this. 3) The water pump is not pushing enough water/coolant through the system when the thermostat opens all the way. 4) I have a bad head gasket/warped head - The tests that I have performed tell me this is not the case, but I know that many overheating issues are attributed to a warped head or a blown head gasket. Short of just trying all of these things does anyone have any experience/advice they would like to throw my way?
If you have a head gasket leak it won't manifest itself until hot in most cases. The gas will displace coolant in the head causing overheating. Find a shop with an exhaust gas analyzer for an accurate test; another tool is this http://www.bosstoolsupply.com/index.asp?PageAction=VIEWPROD&ProdID=11810; I've seen it used with good results. On a low mileage car obstruction of the radiator is not likely, but any radiator shop can test quickly if you take the radiator in while off the vehicle. What is happening that you consider to be abnormal?
The issue that is abnormal, is that my car is overheating on the track. The temps are climbing up to 240 when I used to see around 190-200. The confusing thing for me is that my car runs around 230 on the street with no overheating issues, and when initially getting on the track the temps drop to 190 or so. Under normal use, the temps would stay that low on the track. So if heat is an issue for a head gasket leak (which I completely agree that it is), it would seem that I would have more of an issue while street driving than track driving, due to the higher normal temps I see on the street.
While I think 240 is hot, there's no mention of hotter temps or the expansion tank cap blowing. When coolant boils, it converts to a gas which becomes much hotter and creates greater pressures. It sounds as if the system is able to maintain a temperature ceiling, and it does have the capacity of recovery, symptoms not indicative of severe overheating. Tried bleeding the coolant system yet?
Could the fan belt be slipping? My car does not gain temp on the track (water temp, the oil temp climbs to a point, then stays the same, depending on the ambient temps) even after a whole session.....
240 is pretty much where I shut it down. I did let the temps climb to around 244 one time. The coolant system has never gotten hot enough to boil over or for that matter even trigger the ECU to complain about the temp. I am certain that if I keep pushing it on track the temps would continue to rise. I am just trying to avoid causing any more damage than has already been done. I have bleed the system, both manually bleeding the system as well as a complete coolant replacement with a vacuum pump. I also changed the oil and there is no sign of any mixing fluids.
Track = 240 (used to be 190 -200) Street = 230 1. Can you get some datalogs from the ECU? This may provide more confidence in the measured values as opposed to the occasional glances at a gauge while on the track. This will definitely give you more data to study and look for relationships to other parameters (i.e. rpm, speed, boost, etc) at the very least. 2. For my R53, track = 200, and street = 194 as a point of reference. 3. Can someone provide data on what is normal for an R56? 4. Have you considered just yanking the thermostat on your 'pretty much dedicated track car' ? 5. Is it possible that the oil cooler placement has limited flow to the radiator? With 230 on the street and 240 on the track, I keep thinking about air flow. Provided of course that there are no coolant flow issues, and I agree this is unlikely.
I suppose it could be... I don't hear any obvious signs of a slipping belt. I will have to inspect it more closely tomorrow.
A couple of things... I have had a temp gauge installed for over a year now and am pretty good at watching it when in the straights. The 230 on the streets and 190-200 on the track is very "standard" for my car, regardless of the ambient temp. The R56's don't have a traditional mechanical thermostat. It is a large electronic device that kind of resembles a heart. There are two settings programmed into it, the first settings tries to keep the car at 221 (ECU temp) when under "normal" driving. The second setting tries to reduce the car temp to 180 under spirited driving. The oil cooler was something that I just recently installed to try and alleviate the overheating issues. I am not sure if it might have made it worse, but the problems existed for it was installed. The stock R56, as well as the R53, has a heat exchanger, which is basically like a little radiator for the oil, using coolant to cool it down.
'Little' is the operative word, it is really small. It is more of an oil temp conditioner than an actual cooler. Meaning it has greater function in quickly raising oil temps when the engine is cold, as opposed to lowering oil temps when the engine is hot. I understand your frustrations, something has changed and is causing the higher track temps. I would think that a weak link could be the complex thermostat device. As mentioned above, is it possible to remove it from the system just as a flow/temp test? Assuming the set points are ECU controlled, has the ECU been touched lately, or rather coincident with the symptoms. I wonder how difficult it is to read the set-points to verify the values?
I doubt it is possible to remove the thermostat, here is a pic, it is #4: I have the DimSport remote flashing device with various tunes, including the stock one. I have tried all of them with the same results. At this point, at $100 the thermostat and housing is the cheapest component to replace. I will most likely start there. The other issue is that I have to be on the track in order to test any theory. Which is getting pretty expensive.
As Brian said, "normal" temps for my R56, via Scangauge, are 220 for street driving and 190 for the track.
Damn, that thing IS a heart shaped device. I hate changing parts as a shotgun approach to remedying a situation, but I presently do not see a better path to take. Also on your tune, I have complete confidence in your original tuner, just did not know whether or not any others had been in there. Clearly, with you having the Dimsport flash tool and swapping tunes, you have eliminated that possibility. Need some input here folks!
So, how's the overheating issue? Did the new thermostat get installed? Kinda hard to test though without a good hot track session.
Yes, definitely good luck with today's test. Hopefully you can get it back down to the 195 range for the track. Also, as Keith pointed out, make sure that system is well bled as air pockets are hot spots, also they just expand and force coolant out of the reserve/overflow tank pressure cap. Unfortunately, I do have some experience with this mess. After some careful and thorough bleeding on my R53 the next track event (which had 15F higher ambients) was accomplished with no coolant overflow mess. Also, for your dedicated track car you should consider a much lower than MINI recommended % (maybe 25% instead of 50%) of antifreeze in the coolant as well as running Water Wetter. Every little bit helps.
Still overheating. I am going to hook it up to a GT1 and make sure there aren't any codes that I can't see and then it looks like some head work is in my future.
Grrr, that has got to be frustrating. While I do not have a better next step at present, head work might be jumping ahead a little bit. So exactly what did you see as a max hot temp? Was it 195ish, 215ish, or way up in the 240 range? I mean, did it get any better?