Side by side:
On the N62 engine, it is known that they run higher degree thermostats around 110c. This was done for emissions and so called efficiency round town which is great but has a huge downside. Due to running hot temperatures, it has an effect on engine seals and anything plastic or rubber. If you look at other BMW models, prime example E46 M3, they do not run a thermostat that high. Other car makers don't tend to use a thermostat of that nature.
With the N62 platform, you can buy calibrated 90c thermostats. So what are the benefits? Lower temperatures mean less pressure on the engine, seals and gaskets will last a lot longer, coolant pressure is reduced etc. After much searching on forums and groups, this particular one was recommended by a few that said it works right out of the box with no coding or mapping required. Simple plug and play. I bought it from
https://electrorefit.com/product/col...ol-engine-bmw/
These thermostats are genuine Wahler ones suppled to BMW with the logo grounded off:
So to install the thermostat, it was a case of remove the old one. I removed the waterpump to make it easier to separate but isn't strictly required but there is a reason why I had the pump off which will be explained later.
So I got on to fitting the replacement hoses but stumbled upon a roadblock with one of the hoses refusing to clip on properly to the radiator. So I removed the rad to see what was going on. I'm glad I did as it was full of crap!
I got a hose pipe and soft brush to remove all the debris:
So this was the problem hose trying to get it to clip in. I lightly sanded down the outside of the pipe that the hose clipped into as there was a little bit of stuck crud on there which seemed to do the trick:
Then it was a case of fitting the new hoses in and everything back together:
Fresh coolant ready mixed:
Now, to bleed the system, fan speed has to be set to minimum, temp set to max, then start to slowly pour in coolant until it you get to the max. Leave the cap open and start the engine. That will enable it to bleed off any air. If the level drops, top it up. After a few minutes, close the cap and get it up to operating temperature. Let it cool down and then check level and top up if required.
I had checked the cabin for warm air as the heaters were set to max heat on low speed but for some reason, was blowing cold air. The car didn't overheat so ruled out an airlock. So I plugged in the laptop and scanned with INPA and found an error code stored for the auxillary water pump stating it was not working. So yet another part was ordered to address the problem. Luckily its very easy to access as its located on the front passenger side connected via 2 hoses. Here's the old and new:
Upon fitting the new pump, you could hear it working with the ignition on. So coolant was able to properly circulate and finally got proper heat coming out of all the vents in the cabin!