High water temp. Can’t figure this out.

[blckstrm]

I think it's time to take a little break and just see how it responds to what you've done.

It can take a while for air bubbles to burp / work their way out of the system. The last time I did this I saw crazy temps from the OBDII sender but the rad wasn't even very hot. I drove it once or twice and temps were kind of all over the place. I took a long freeway drive and after that it finally settled down.

We've even seen that with your experience in this thread - it was much higher initially, but your later posts were seeing more normal temps. If you'd seen those later temps initially you wouldn't even have started this thread.

On top of that, you found that this aftermarket sensor CAN be up to 20* off, which is about what you saw.

You have a new thermostat and a new fan switch - let's just see how it does for a week or so while you work the bubbles out of the system.

[ewrjontan]

I’ve been running a genuine bmw 88 degree c thermostat. The new one is the same.

Well, I tested the temp sensor and it seemed to be relatively accurate with different temps.

Anyways. Should be getting the car together today and we’ll see what happens.

[ewrjontan]

Ugh. So got the car on the road today; 70 degree weather at night. Still reading about the same. Idle after coming to a stop can hit over 200. After idling for a while it drops to about 194-196. While moving I was seeing 196-201. I’m going to try and do some more bleeding but it does seem to be fine with no apparent air bubbles.

Could it just be the fact that the thermostat closes and then the temp sensor is reading coolant that isn’t flowing? I have seen a lot of people reporting super low temps with thermostat measurements so idk.

Might just drop in a whole bottle of water wetter and call it a day at this point.

[pbonsalb]

I don’t see what is wrong with those temps. If you want cold temps with a hit engine at idle you need airflow and that will be done through fan control.

[ewrjontan]

So at the track currently and 60 degrees. Car got up to 210 towards the end of the session. Quickly cooled down on the final cool down lap to 201 or so. Not bad but not great. I think one’s we hit 70s I’m going to have to start backing off. 😢😢

[bmwstephen]

Would it be too much to go back to the factory radiator and test it out? Considering how much you are bleeding the current system might as well give that a test.

[ewrjontan]

Eh I’d rather just swap out with a track presented radiator at this point.

I will say that I did give a few pops of the bleeder screw after a few sessions. No real change. Was reaching about 216 on average and occasionally would hit 219-221 and id back off for a lap or get stuck in traffic. Quickly dropped back down to sit at 216.

After the event I was driving home and was cruising down the highway at around 192-194. It was about 60-70 degrees outside so that’s pretty good. Sitting at a the few stop lights I had stopped at I seemed to be sitting around 190. Perhaps a good track day was needed to get some of those last bubbles through the system?

We’ll see. Not sure if there are going to be too many more 80+ degree days left to truly test. Also tested my old fan switch. Seemed to be working fine.

[pbonsalb]

What is wrong with 210F at the track? Or 219F? Boiling point of water with a 15psi cap is about 265F.

[ewrjontan]

I was under the impression based on past threads here that 220 is getting pretty high. 230 or perhaps 240 being guaranteed head gasket failure. Obviously 216-221 is still far from 230 but I’m more “mad” at the fact that plenty of people with similar and/or stock setups are somehow managing under 200 degree temperatures.

[hakentt]

You are at the point where head gasket is so old, it lost some of its sealing qualities. Some combustion gases get into the cooling system reducing the efficiency just a small amount. Plus, there is more read on...
Then you downgrade with inferior S54 Z3 radiator that has smaller surface than M3 radiator that bmw made it that way in order to fit the oil cooler under it, that radiator is thicker 42mm vs 34mm, it is well known that thinner wider surface would cool better than thicker smaller surface, that is because the rear of the core has to deal with now hotter front facing core of the radiator. And add the fact that S54 is more efficient engine and it's combustion temperatures are cooler, that is because it uses the exhaust camshaft as sort of a EGR valve effect, vanos gives it more overlap so that some exhaust gasses can reenter the combustion chamber thus cool down the combustion.
I am in the hottest city in the country and in the middle of the summer I can race my 1995 M3 with stock quality BEHR radiator and BEHR clutch fan all day long and temperatures always stay withing proper operating range.

[ewrjontan]

Interesting. Makes sense. Maybe I will have to just get a stock one or perhaps just go with a csf all aluminum. Oil temps were well under 250 so I don’t think I’ll need an oil cooler any time soon.

That’s a real bummer though. I see so much about how the s54 radiator is such a great upgrade with no mentions of needing to use the oil cooler.

Also. Did a combustion fluid test which was negative.

[tiMASTER]

The S54 Z3 radiator is the same part as used in the Euro E36 M3. Including the 3.2.

Not similar- same part number.

[bmwstephen]

The S54 Z3 radiator is the same part as used in the Euro E36 M3. Including the 3.2.

Not similar- same part number.

I think what Hakentt meant to say is that the z3M radiator (used in euro motors and s54) was that those specific cooling systems were optimized for it. The way the head design, cooling channels, expansion tank, water pump, 80C thermostat, oil cooling setup all impacts the overall temperature when using the euro specific radiator would not apply to the US motors.

The US engines were bored out standard motors and even retain the same cooling system because that was what it was optimized for. If there were any real benefit in the euro/z3m cooling system, I am sure that even the LTW would have incorporated it (after all the US LTW was provided with a lot of euro GT aero parts and oil pans because it likely yielded track benefits)

[Braymond141]

I think what Hakentt meant to say is that the z3M radiator (used in euro motors and s54) was that those specific cooling systems were optimized for it. The way the head design, cooling channels, expansion tank, water pump, 80C thermostat, oil cooling setup all impacts the overall temperature when using the euro specific radiator would not apply to the US motors.

The US engines were bored out standard motors and even retain the same cooling system because that was what it was optimized for. If there were any real benefit in the euro/z3m cooling system, I am sure that even the LTW would have incorporated it (after all the US LTW was provided with a lot of euro GT aero parts and oil pans because it likely yielded track benefits)

BMW had no financial incentive to keep throwing Euro parts at the Lightweight. That does not correlate to said parts not being useful.

Let’s stop speculating and especially stop backing anything Hankett has to say.

[hakentt]

Interesting. Makes sense. I see so much about how the s54 radiator is such a great upgrade. Maybe I will have to just get a stock one or perhaps just go with a csf all aluminum.
Also. Did a combustion fluid test which was negative.

There you go again believing these vendors who make up bogus "upgrade" myths. CSF radiator is another junk that brake at the welds all the time. Why do kids like you don't believe that stock BEHR radiator is the best?

[Braymond141]

CSF is straight trash. As are many aftermarket cooling solutions.

[blckstrm]

BMW had no financial incentive to keep throwing Euro parts at the Lightweight. That does not correlate to said parts not being useful.

Let’s stop speculating and especially stop backing anything Hankett has to say.

Amen. OP did a coolant test and there were no exhaust gasses present.

The lack of comparability is making this hard to determine if there's something wrong or not.

The opportunity is past, but I'd have been interested to see if you could push the car past 225. Contrary to popular opinion, you don't automatically blow a head gasket when the needle starts to move (which is at 225). If you don't know why your car is getting hot, yes, you should pull over and figure out what is wrong. But if you're paying attention and know why you're hot, you can push it past a little without causing damage. I wouldn't go deep into the red, but it's not catastrophic to let the needle move north, especially when you know you can bring it back down quickly.

But it would have been interesting to see how the temps you're reading at the upper hose correlate with the what the car is seeing. If you're seeing 226+ and the needle isn't moving yet, they're not in sync. You could have figured out what reading correlates to the car seeing 225. Which would have let you compare with the temps guys here read via OBD.

You still might be able to at least get one data point. Warming up, the needle hits 12 o'clock right about 170 reported via obd. What temp does your sensor show right when you hit the 12 o'clock position?

[ewrjontan]

Man. I always heard csf was decent. Better than mishimoto at least.

I will check the gauge at 170 on my next drive.

Good news though. Seems like the track definitely made some difference. 77 degrees today. Bright and sunny and the car was enjoying 192 degrees when moving. Coming to a stop it would creep up a bit, usually around 196 once to 198 at a long stop light. But definitely was sticking to 192 once I was moving for a couple of minutes.

Did some more research on the s54 radiator and it does seem to be not as good if not paired with the oil cooler, so that sucks. That being said, I probably can get by at this point at the track with a little bit of water wetter thrown in.

[blckstrm]

Man. I always heard csf was decent. Better than mishimoto at least.

I will check the gauge at 170 on my next drive.

Good news though. Seems like the track definitely made some difference. 77 degrees today. Bright and sunny and the car was enjoying 192 degrees when moving. Coming to a stop it would creep up a bit, usually around 196 once to 198 at a long stop light. But definitely was sticking to 192 once I was moving for a couple of minutes.

Did some more research on the s54 radiator and it does seem to be not as good if not paired with the oil cooler, so that sucks. That being said, I probably can get by at this point at the track with a little bit of water wetter thrown in.

I've made this comment before, but I've been running between 188 and 192 almost no matter what - and I have an 80* (176* F) thermostat. If you have an 88* (190* F) thermostat and you're running about 192 in operation, you're doing great.

[zellamay]

Man. I always heard csf was decent. Better than mishimoto at least.

.

I read the same thing: avoid Mishimoto, but CSF are okay. I bought a CSF for my 98 M a few years ago. No problems at all.

[Braymond141]

There is nothing of quality with CSF. Same bullshit welds as the rest of the lower end cheap Asian labor products. Then they top it off with an “hour” polish, that looks like trash, to attract shiny object syndrome people on the internet. They also look awful installed regardless of their functionality.

[ScotcH]

do you have proper ducting in place? The gap under the rad where the oil cooler should go is closed?

[ewrjontan]

do you have proper ducting in place? The gap under the rad where the oil cooler should go is closed?

Correct. Fabricated a shroud that directs all the air coming in from the center bumper vent to the aux fan shroud. Gap for the oil cooler is blocked off. Made a huge difference after install. Temps at stop lights still creep up but as soon as you get moving it dropped a lot quicker than without.