crunchy

E46 Thermostat upgrade/down grade

13 posts in this topic

Yes im still alive, apologizes to a few

Kinda well over trying to help and inform due to the crap you get in return but thought this was worth a mention.

As many would know and ive learnt the hard way when you cook a M54 that equals dead engine and stripped head stud holes.

So ive done this a few times and works well and yes you could buy a lower temp one from VAC but hey wheres the fun in that, so for the DIY heres mine.

Remove the old setup and use a carbide burr to remove all high spots to give a uniform finish and dia hole, can be done if your savvy with a die grinder.

Once done purchase a thermostat as pictures, i remove the larger bottom plate from the old setup and open the center hole then a few spots of MIG its good to go and the correct install height ( yes i blew a small hole in it )

Now i understand not everyone has the gear i have but i turned up a ally ring to suit the housing and a step to match the new thermostat, i then peen the ally over to retain the new thermostat.

Next is use some silicone to retain it in place with a slight press fit, it can't go anywhere as once bolted up its retained, i also drill a small bleed hole to help bleed the system.

This is now set to 82 deg rather the 97 stock, some say its too cold but rather that than a new motor also your gauge wont show too much different but a scan tool shows another story. 

PS: yes the V10 is done and in the hole and no i wont show progress or pics as well over the crap from the key board experts.

And those being OCD most welcome to correct my grammar :) 

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Very informative, Thank you Sir :D

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What did  you do with the assist warm up electrical side?

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Warm upside from my understanding is there to assist the thermostat to open if it fails nothing more, but i could be wrong. The bypass system is used for rapid warm up and that i havent changed. 

I also left the sensor part in the unit and plugged.

Edited by crunchy

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The electrical heater is to allow the engine to run cooler under load, controlled by the ECU.

It runs at 97 on an M54 (due to the mechanical thermostat setting, M44TU are 105C), but the heater can heat the wax thermostat (to open it) to cool down the engine when more power is required,  as low at the mid/high 80's.

The idea is, that running it hotter means better economy, because more heat is used to make power, instead of being fed into the cooler engine.

The main problem with them, is the element burns out, so it runs at 97C ALL the time, and can't cool itself down when required. It also doesn't warn the driver, but does log a code. If the car isn't scanned, nobody knows it's faulty. any cooling issue, and it's already hot.

 

I think you'll find 82C makes it run rich and hungry as hell. There is no need for a bleed hole either, on a otherwise standard system.

I fitted the Zionsville adapter to our M54, with a fixed 92C thermostat. It came with a bleed hole drilled in it, and the car took forever to warm up - also fuel consumption around town was about 20% more!!!

I dumped it, and fitted one without a hole, and it's much better gets up to 90 really quick, and gets to 92 eventually, and stays there.

 

I also reprogrammed the cluster EEPROM, so the gauge reads properly. Mine will move from straight up and down after about 105C, and peg hot at 115C. Standard, they don't move up until over 115C, and don't peg until something like 125 or 130C! WAAAAY to late!

Edited by Allanw

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I've don't this many times, had no change in economy and warm up time hasn't changed either.

Rather this than a cooked motor which they are well documented for doing.

Each to their own.

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I did much the same thing to my 540 (m62tu) and there was no perceptible difference in economy, but it ran far cooler. 

 

Theven system is only there for emissions, it drastically increases knock limitation under load until the engine temp cools back down. Tree hugging rubbish 

Good work Steve!

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I guess we all have options like butt holes and prefer to see things how we want and take on board everything the manufacture said as gospel, bit like everyone believed the emissions thing with VW......yep.

My S85 V10 thermostat factory is 79 deg, kills the theory some have. 

And we don't test older cars here for emissions and to complain about economy when you sit in traffic not moving for hours a day is counter productive.

Edited by crunchy
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Great diy - thanks steve.

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I'm not disagreeing with the idea at all - I've done the same thing, as I said... just the details are different ;)

You can get the E46 OBC to tell the coolant temp, like you can with the E39 too.

The temp gauge on them is a waste of time - it looks like a proper gauge, but it works like those stupid blue and red lights on new cars - not really any help at all! I seriously suggest modding the EEPROM to make it read more realistically.

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All good Allan don't hate ya everyone's entitled to there opinion, your not wrong about the gauges they are miles out.

Those who rely on the needle sitting in the middle really should check as you said cause by the time it moves up anymore it game over. 

 

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Actually, I found the thread about it: It's piss easy to do, but you need BMW SCANNER 1,4:

http://forum.e46fanatics.com/showthread.php?t=1013600

Those top temps are highert than I thought actually!

Highly recommended mod.

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So agree Allan, check this out i used the OBC function to check the temp against the gauge its miles out.

Needle half way temp 81.

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Edited by crunchy
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