CSF Radiator Issues

[mKilgore]

Originally Posted by Cobra1956

Didn't see it but might just have missed, did you bleed the system including running the heater?

Yes, I actually ran the bleeding process twice. Car ran great on track and never had any issues in warm weather.

[2011N55E92MHD]

Hi OP,

I have the n55 engine. I have a 3 series but you seem to be having the same issue as me. I swapped my raditor with the CSF high flow in August of this year. My engine was getting a little too hot with spirted driving in the summer being on MHD 2+. I replaced my water pump and thermostat while I was at it. My car was at about 85k and it was about that time. This was done by a trusted inde BMW shop that has done countless jobs over the years. I have never had an issue, so I don’t even consider a mistake in the installation or identifying if a cable looked suspicious.

I used this pump: https://www.fcpeuro.com/products/bmw-water-pump-pierburg-1151945597

I used this thermostat: https://www.fcpeuro.com/products/bmw...ly-11537601158


The car drove perfect and my temps were looking right within spec. I was very happy. Then starting on 11/14 when it started to get into the 30s in the Midwest, I started throwing the 348A code. The thermostat reading zero and the fan on 100%.

I cleared it and it was fine, but I want to say it has been back 5 times, including today. I started researching the issue, first assuming that it was a faulty thermostat. However, once I started finding tons of threads of n55s, CSF radiators, and cold weather; here I am.

Then I realized that it had just started to get truly winter cold here as well.

I don’t think it’s my thermostat or water pump since they have less than 5,000 miles on them and this only happened when the weather changed.

I think that given these circumstances it must be overcooling the engine like some suggested. Causing the engine to throw the code for the “fault”.

I took my car out today. It was about 32 degrees and sunny. My car was struggling to get to operating temp. I was at about 180F after driving for about 15 minutes maybe. I was actually seeing the gage creeping downward, below 180F if I was at a stop light or if the rpms were lower.

I have never seen the car temp ever creep that low while it was running. Including when I drove the car in sub zero temps with the stock parts last year. This was also with MHD coolant target on sport.

After some spirted driving with high rpms, I managed to get the engine up to operating temp. However, once I returned to more normal driving. I gradually began to creep out of operating temp down toward 180F.

No codes were thrown at that point. However, tonight when I took out the car. I threw the code taking my friend home. I cleared it. Then the thermostat starting working again.

At this point I am thinking the issue is CSF being too good at what it does. Which I’ve seen fourm posts from the last 5-6 years talking about the same issue. However, we have people here who have the raditor, who claim to not have a problem. I notice a lot of these guys are tracking the car. Is this raditor just too big for street driving in colder weather in places, like the Midwest?

Luckily I was about to put my car away for the winter, so I am going to be scientific about this. I am not going to do anything yet until I have a chance to drive my car this Spring and Summer, I am in Ohio.

If the raditor is the issue, is it possible to tune/code the computer to account for this raditor? It sounds like based on posts that CSF has heard this from customers before.

If that’s not possible, someone mentioned blocking part of the raditor. I wonder if it would be possible to find out the most optimal block % and then design a 3D print that you could clip onto the rad for cooler months if you drive your car year around.

I will report back this Spring everyone!

Also, I just thought of it now, but in MHD I have my coolant target on sport. So, tomorrow I am going to swap that to stock to see if that will allow the car to be the proper temp.

[ShocknAwe]

All you're gonna do with MHD sport coolant target is kill your WP faster. It's a track setting.

[mKilgore]

Hi 2011N55E92MHD, your situation is typical of what I experienced as well. I do not think it is based on any issue with your water pump and thermostat. The sport cooling target in MHD is something to consider. I had not thought of that, so I'll be interested to see if that makes much of a difference.

As far as coding goes, I do not know the answer. I know that it would not be something as easy as using bimmercode or something like that to simply turn coding on and off, but you'd have to go deeper into the systems to actually change the code itself? I'm already out of my wheelhouse right there haha.

A 3d-printed cover with clips that could cover the lower third/half of the kidney grills would definitely be cool.