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crunchy

E46 Thermostat upgrade/down grade

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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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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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On 1/10/2018 at 11:03 AM, Allanw said:

 

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!

Bit of a thread dredge, but can you tell me what thermostat you used with the ZV adapter? I’m trying to achieve a similar outcome using an M50 tstat housing but haven’t yet found one suitable. 

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pretty sure M50 and M52 use the same thermostat??? (not M52TU though), but the temp varies depending year etc.

Anyway, mine is 11537511083

I don't think the other housings fit, unless you modify it quite a bit.

The M54 plastic housings have a tiny bleed hole that let the air out easily, from the inlet to the outlet.

You also need to make sure the plate on the back of the thermostat is the correct depth - it's what forces coolant out to the radiator when then thermostat is wide open. If it doesn't shut onto the hole in the block, coolant can recirculate in the block, as it does with a partially open thermostat.

 

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40 minutes ago, Allanw said:

pretty sure M50 and M52 use the same thermostat??? (not M52TU though), but the temp varies depending year etc.

Anyway, mine is 11537511083

I don't think the other housings fit, unless you modify it quite a bit.

The M54 plastic housings have a tiny bleed hole that let the air out easily, from the inlet to the outlet.

You also need to make sure the plate on the back of the thermostat is the correct depth - it's what forces coolant out to the radiator when then thermostat is wide open. If it doesn't shut onto the hole in the block, coolant can recirculate in the block, as it does with a partially open thermostat.

 

Am using M50 vanos on the B30, allows the old type housing to fit. 

 

How given the B30 tstat has a 37.5mm distance from flange to bypass block plate & the M50 unit is only 25mm, does the adapter plate somehow compensate for the different blocking plate heights? Am confused as to how the M50 item would work given the  B30 bypass port is recessed 10mm further into the head than the M50. 

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Have you measured the depth in the actual head? Are they different by the same amount as the stats?

The housing holds the stat directly on the block, I'm sure.

It's a long time since I saw it in the flesh, but I think the M54 'stat has a much longer spring on the plate??? I wonder if it blocks eariler, relative to thermostat position, then has more opening travel after blocking the port - as in, it blocks the port earlier, to force coolant from the radiator in faster, to pull it down from 97 to 87 quickly.

I do know, the hottest ours ever got was up to 95C, and I assume the 'stat was WIDE open then. I couldn't hear the viscous fan, so I assume the radiator coolant temp was low enough to hold it there. It never goes past 92C unless I do something to provoke it (like a hiding, then sit with no air movement for a while).

 

 

 

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2 hours ago, Allanw said:

Have you measured the depth in the actual head? Are they different by the same amount as the stats?

The housing holds the stat directly on the block, I'm sure.

It's a long time since I saw it in the flesh, but I think the M54 'stat has a much longer spring on the plate??? I wonder if it blocks eariler, relative to thermostat position, then has more opening travel after blocking the port - as in, it blocks the port earlier, to force coolant from the radiator in faster, to pull it down from 97 to 87 quickly.

I do know, the hottest ours ever got was up to 95C, and I assume the 'stat was WIDE open then. I couldn't hear the viscous fan, so I assume the radiator coolant temp was low enough to hold it there. It never goes past 92C unless I do something to provoke it (like a hiding, then sit with no air movement for a while).

 

 

 

I found the M54 tstat port to be just under 46mm depth, seemed to match up with the longer tstat spring - hence my puzzlement as to how the M50 part reaches far enough to block the bypass port. 

 

Will recheck my measurements tomorrow morning when I get home from work but I think I had them right. 

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Rechecked the measurements, got 43mm port depth & 37mm tstat on the M54; 33mm / 27mm for the M50. 

I had an early M50 Ali tstat housing milled out to allow an o-ring to seal the thermostat and leave the bottom of the flange flush with the housing surface, allowing the gasket to seal as normal. 

 

If the M50 unit will work it’ll certainly be the easiest solution!

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Sorry - can't help much more without pulling the car apart (not happening :P).

I wonder if they have different expansion rates/ratios?

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3 hours ago, Allanw said:

Sorry - can't help much more without pulling the car apart (not happening :P).

I wonder if they have different expansion rates/ratios?

Sigh, guess I'll have to get off my arse & figure this one out for myself after all.

I assume the adapter plate fits between the thermostat & the M54 housing? Paper gasket fills the gap from head face to adapter plate, then the rubber gasket on the plastic housing seals between the housing & adapter plate? (bloody hell I hope that makes sense!)

Will do the pot of water test with the M50 tstat on my days off, who knows, maybe it will open far enough to reach the bypass port after all. I emailed Zionsville directly and asked if they could supply me with the part number, unsurprisingly they declined but kindly offered to sell me a $130 thermostat instead.

 

I suspect the answer to this puzzle is tantalisingly close............as it's the last issue to resolve before the project car can be driven I'm hoping this one won't take too long to figure out

 

 

 

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Hahaha! Yes you do... Sorry. You could buy my E39 and dismantle it to check it all :-) I had to fit it enough times already, to get it leak free. I'll help where I can, but I'm just not taking it off again :P

I'll even leave the new clutch and flywheel in the boot if you buy it! 

Setup is: block | paper gasket | thermostat | adapter | M54 housing.... The paper gasket = crap! I used a quality silicone and set it up correctly before assembly. the first  two times (paper gasket) it leaked/weeped, and with no gasket it's fine... it's been on a few years.

The thermostat is held against the block by the adapter, and I'm pretty sure there is an oring in there, between the adapter and thermostat???

The zionsville setup isn't quite the engineering masterpiece they seem to think it is. They go on about the 110C mechanical thermostat... but that's only the V8's, the M54 is 97C. I did have the original thermostat the kit came with, but I think I threw it out a few months ago. The hole meant there was enough coolant flow to cool the engine on long downhill decents, and in winter, it never got past low 80's with the somewhat short trips we do. Once I replaced the thermostat to one without the hole, it would warm up to 90C well before the first morning stop and hold constant temps between 90 and 93C.

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On 4/18/2018 at 5:14 PM, Allanw said:

Hahaha! Yes you do... Sorry. You could buy my E39 and dismantle it to check it all :-) I had to fit it enough times already, to get it leak free. I'll help where I can, but I'm just not taking it off again :P

I'll even leave the new clutch and flywheel in the boot if you buy it! 

Setup is: block | paper gasket | thermostat | adapter | M54 housing.... The paper gasket = crap! I used a quality silicone and set it up correctly before assembly. the first  two times (paper gasket) it leaked/weeped, and with no gasket it's fine... it's been on a few years.

The thermostat is held against the block by the adapter, and I'm pretty sure there is an oring in there, between the adapter and thermostat???

The zionsville setup isn't quite the engineering masterpiece they seem to think it is. They go on about the 110C mechanical thermostat... but that's only the V8's, the M54 is 97C. I did have the original thermostat the kit came with, but I think I threw it out a few months ago. The hole meant there was enough coolant flow to cool the engine on long downhill decents, and in winter, it never got past low 80's with the somewhat short trips we do. Once I replaced the thermostat to one without the hole, it would warm up to 90C well before the first morning stop and hold constant temps between 90 and 93C.

Hmm, might be keen on the flywheel & clutch setup depending on how the existing one holds up......

 

Measured the M50 tstat at 99* & it expands to a little over 37mm - seems to me that it never blocks off the bypass port at all. 

 

Realistcally, aside from slower warmup times is this ever likely to be a problem?

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It doesn't affect warmup - just high temps - when the port is blocked, the incoming water is entirely sucked in by the pump from the radiator. If the port is open it cycles around from the head down to the pump, and the thermostat opens a little to let some cooler coolant in that mixes into this flow.

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