TDF10

Hey everyone, first time poster but long time lurker (both here and on E46 Fanatics [when I had one]). I just finished a major overhaul on my car (2014 535d) as I crossed the 85k threshold. I had a coolant leak coming from the coolant flange and given the work required to access it, decided to replace a lot of items on a preventative maintenance basis. I replaced water pump, engine thermostat, transmission oil cooler housing + thermostat, all associated gaskets and seals, serpentine belt, tensioner, 5-6 coolant hoses, cleaned out my intake manifold, replaced every gasket and seal in the manifold, replaced the coolant reservoir, changed my oil, cleaned out my cabin blower (there were some leaves causing noise), and replaced the windshield cowl.

Prior to working on the intake manifold, I replaced the water pump, thermostat, and several hoses. I took the car for a test drive and noticed that it was not getting up to temperature. It was about 50 degrees outside and as I got on the highway, the car actually want from about 1/8 warm down to cold. When I got back, I noticed I still had the coolant leak and figured that maybe there was air in the system (despite bleeding it) or the thermostat was bad. I replaced the thermostat again and then did the intake manifold work. I fixed the leak and put everything back together.

The car is running great except for the fact that it now won't get to normal operating temperature. I had to run it hard on the highway (90 MPH at a low gear with the turbos spooling) just to get it to normal temp. As soon as I left of the gas and cruised, the car once again started cooling. In the morning, driving it on the roads, it won't warm up normally. I'm at a total loss as to what could be causing this. Since I replaced the new thermostat with one from BMW, I don't think it's that (I tested the old replacement thermostat and it functions fine). I'm wondering if there is any way that a bad battery could cause a poor temperature reading (I've noticed my battery is getting weak)? Aside from that, I'm wondering if coolant got on one of the electrical connectors and is now causing issues? The caveat to both those issues is that the water pump and thermostat are mechanical so the only issue from an electrical perspective would be the dials in the car. I made sure to install the thermostat with the pin down at the 6:00 position (as outlines by BMW) so I don't think that's the issue either. To bleed the system, I just let it burp itself and went through the normal coolant filling procedure.

If anyone can point me in the right direction, I'd sure appreciate it. I'm pretty good with cars and mechanically inclined but this one has me stumped.

seanjordan20

I think you read the instructions wrong. If the pin is not up it will not bleed correctly. The ball valve (black) should be at the 6 and the pin (silver) should sit more at the 10. It's called the bleeder valve pin because it bleeds from the top. Recheck install and bleed system again.

TDF10

thanks for that input. What’s interesting about the thermostat on the 535D, is that there is a notch in the water pump assembly that only allows thermostat installation to occur in one way. I followed that notch and screwed the thermostat housing back in. also, the thermostat doesn’t actually have a ball valve from what I could see. It only had a small jiggle type pin. Do you happen to have access to installation materials that would indicate the proper procedure? Thanks.

seanjordan20

Yes I do. That pin is what's supposed to go upward. You should have seen a black ball that went in that indent you're talking about. No matter what vehicle you work on that pin always will go upward as that is the bleeder pin. It can't bleed if it covered by fluid. I'll find the install instructions and post. I'm sure I'm right about what I'm saying.

TDF10

I was able to find the instructions and I understand what you’re saying. If you look at a picture of the thermostat, you’ll notice that there is only one valve, a pin in the center, and on the other side, a black notch that goes into the water pump/thermostat body. I installed in that manner with the result being the valve sitting at the 6:00 position. I referenced BMW TIS and it says to install “ball valve downward” which is what I did. I’m at a total loss and so confused.

seanjordan20

The one circled in blue should be the pin and the one in red should be the ball valve. The one circled in blue should be pointing up.

seanjordan20

I see the actual part now and those are screws. I do see a hole next to a screw though. No im puzzled at how the system actually bleeds because the ball valve is covered.

seanjordan20

Now my question is what procedure did you use to bleed the system. Did you wait until it was at operating temperature to bleed. That should be when the fan kicks on. Did you use the auto bleed procedure? I'm sure your issue is that you still have bubbles in the system.

TDF10

confusing right?!?

for the bleeding, I self bled using the procedure below. Is using the vacuum system absolutely necessary? I thought this system self-bled.

1. Switch ignition on.

2. Set heating to maximum temperature and fan to low (heater valves are open and auxiliary water pump starts).

3. Add coolant slowly. Fill expansion tank to maximum cold level.

4. Start engine and run at idle for 5 minutes (top up coolant to maximum cold fill level if required).

5. Close cap on expansion tank, press accelerator peda!
several times to approx. 2500 rpm

6. Open cap on expansion tank, run engine at idle for another 5 minutes (bubble free coolant will emerge from return line in reservoir tank).

7. Fill to maximum cold level. Top up expansion tank with an additional 250ml.

8. Close expansion tank.

9. Drive vehicle and monitor coolant level. Top off as necessary.

seanjordan20

Did the fan ever kick on during that process? You performed it correctly. If the fan never kicked on I would perform it again