M50nv "normal" running temp?

[The Chauffeur]

Hi all; first things first, I don't wanna sound like "what is the airspeed velocity of an unladen swallow?" , and also, I already looked on the web with conflicting info...

My thermostat bit the dust one of these days, and I replaced it with an 88 C (same as the old one); purged the air twice on different days (nothing came out the second time), but my stupid OCD self is not sure anymore of the normal position of the gauge needle...

So, my question-non question-"please reassure me I didn't screw up" is: just a hair past the middle = OK?

Thanks!

[shogun]

that is fine http://www.nmia.com/~dgnrg/tempgage.htm
I have explained that before: There were in the past a lot of discussions what is right or wrong when the temperature gauge on the cluster temp indicator is right or left of the 12 o' clock mark.
The fact is:
Temperature indication on the BMW is not linear, they call it 'tableau', basically the indicatior at 12 o'clock can mean everything between roughly 75-110 degree Celsius. Everything in between 75-110 is just 12 o'clock. Plus/ minus 1-2 mm to the right or left (deviation cased by the parts installed).
The analog signal ist processed in the instrument cluster and compared with data in the coding plug. A corresponding signal is sent to the instrument. Five temperature support values are stored in the coding plug. Exceeding the temperature limit stored in the coding plug will additionally send corresponding warning information to the check control and display it there.

That is written and shown here on page 4 of the instrument cluster check control training reference book http://www.e38.org/e32/BMW_pdfs/INST_info.pdf
What is NOT shown in the English version I found in the German version, that page showing the temperature diagram curve, and there you see the socalled 'tableau' between 75-110 degree Celsius.

[The Chauffeur]

Thanks a lot, Shogun! That's awesome!

[fo3]

Interesting.
When the weather was hot and I had air in the system it would just be a needle-width above half-mark. After getting any air out and filling with coolant and the weather was warm it would sit on half-mark during hot weather, the a/c on, or stop start traffic.

Here's another thing, I have a thermo fan with a manual dial to set temp. I had it set pretty low for summer (ie fan run more). It is connected to the battery so after parking the car it was annoying the hear the fan cycle on and off for 10min. Also the weather got cool and with the fan set as it was the needle on the gauge barely got past two needle-widths below the half-mark, ie maybe running too cool.
So I adjusted the fan to run less and get the needle up to half-mark for the cooler weather. But still when freeway driving or a very cool night it will keep itself back down below two needle-widths below half-mark and I can't adjust the weather or doing anything about the fact there's lots of airflow when on the freeway.

Only problem is my sometimes doesn't start in hot weather problem (starter does not engage). Hasn't happened again for weeks but last wednesday it was 36C and I had the air con on for 20min drive. After I parked it the thermo fan hardly ran due to last months thermostat fan adjustment. It got really hot in the engine bay after parking it (driving temps were fine). So much heat even the bonnet was hot to touch even though it was in the shade, and of course 20min later the car wouldn't start. E: Seems to me a clue that whatever is causing my car not to start sometimes is in the engine bay and doesn't like too much heat

So I've had to turn the fan down again to run a little bit longer after parking and the temp gauge needle has gone down a bit while driving. Today was a hot day (about 35C) and it doesn't even get to halfway, stays about two needle-widths below the half-mark.
So what I'm saying is my gauge moves a lot depending on ambient temp and speed, from two needle-widths below half when running pretty cool, one needle-width below as normal warm day, on the mark for hot days and maybe a/c on, and just above means a problem to me. But what you're saying is that shouldn't happen because it's a filtered gauge reading.

[ross1]

Not sure why you have that set up. No need to run the engine cooler on a hot day.
If you concerned with operating temps installing a mechanical gauge ought to either ease your mind or reveal a problem.
If you aren't getting up to proper operating temp the first place to look is the thermostat which may not be fully closing.
A small amount of movement from center, more than a needle's width, on the factory gauge can be a pretty significant fluctuation.

[fo3]

Two separate things, 1. where to set the thermofan as it's adjustable, 2. what's causing my failing to start (cooling the engine bay seems to help? Still dealing with that and if thermofan run on helps that's fine for now, plus battery in the engine bay on mine so probably would help that last longer as it cost au$250 - after all heat kills them and this is a car that has a cooling duct for the alternator

Anyway, my temp was even lower today, lower than I have seen it for months/ever, as today was about 20C ambient and I hit the freeway for a drive. It was way below "12 o'clock" when driving on the freeway, closer to the line before it(E: is that what we would call the 9, 10 or 11 o'clock line?).
It only hit near the midway "12 oclock" when stopped in traffic and before the fan cycled on. Starting to think no thermostat is even in there...

[The Chauffeur]

Starting to think no thermostat is even in there...

That's possible, or, as ross1 said, if there is one, maybe it's not fully closing; mine was behaving exactly like yours before I changed it.

[shogun]

Usually if the t-stat is broken in open position the temperature needle in the gauge might go up to normal position in traffic jam or idle, but as soon as you start driving on freeway at normal speed the temperature goes down = more fuel consumption as the Motronic will regulate for cold engine management and colder temps cause more wear on the engine. Everything below normal operating temperature is bad for the health of the engine and bad for your wallet = more fuel consumption.

The normal set up on our BMW with a visco fan clutch and in addition a 2-stage aux fan is basically bullet proof. The visco fan can usually handle all conditions, unless in very high climate and in stop and go, then the aux fan chimes in.
And the aux fan operates automatically as there is a temp switch on the radiator, so no need to set something manually.

[fo3]

Usually if the t-stat is broken in open position the temperature needle in the gauge might go up to normal position in traffic jam or idle, but as soon as you start driving on freeway at normal speed the temperature goes down = more fuel consumption as the Motronic will regulate for cold engine management and colder temps cause more wear on the engine. Everything below normal operating temperature is bad for the health of the engine and bad for your wallet = more fuel consumption.

Yeah, I know, and my fuel economy is pretty terrible which was why I was playing with the aftermarket thermofan thermostats setting to try make it run warmer.

Wouldn't suprise me if there's no t/stat in there because the PO was bad, so I'll guess I'll order one and gasket.
I already had to fit an aux fan thermo switch in the rad because it was missing, as well as the temp sensor in the cylinder head.
E: The viscous clutch fan is gone, replaced with an electric fan in that spot with a manual thermostat

[ross1]

Yeah, I know, and my fuel economy is pretty terrible which was why I was playing with the aftermarket thermofan thermostats setting to try make it run warmer.

Wouldn't suprise me if there's no t/stat in there because the PO was bad, so I'll guess I'll order one and gasket.
I already had to fit an aux fan thermo switch in the rad because it was missing, as well as the temp sensor in the cylinder head.
E: The viscous clutch fan is gone, replaced with an electric fan in that spot with a manual thermostat

Long time to warm up? That's indicative of a stuck wide open or missing stat.

[fo3]

Yeah, a long time to warm up. I now live about 5kms from the highway and I noticed the other day it was still on the end of the cold 'blue' shaded section when I got there.
It's probably stuck rather than missing now I think of it, as fuel economy has dropped from 12l/100km to 13l/100km back in Febuary (19mpg to 17mpg). That was about the time I used off brand fuel because it was cheap ($1.30/L ha ha )and I put it down to that. But that's about when the weather turned cool too. Also usually the economy improves with some highway running but it's not doing that anymore as that's when the engine runs the coldest with low ambient temps I have.

I'm looking around for a t/stat and a local company is selling behr rated at 92C or 88C. Having problems finding a housing gasket there though. Also checked at places like FCP as I'm planning on getting some stuff not sold locally anyway (relays, nuts, seals - even the dealer here orders everything from germany for an e34 and it's a 3 week wait), FCP are selling max 80C, down to 75C and even 71C thermostats. What gives? what is the proper range? I'm guessing 88-92 so FCP don't sell what I want.

E: also does anyone know if the standard thermostat housing needs to paper gasket, or the rubber one?

https://imgur.com/1dlYTKa

https://imgur.com/ZOsBgdB

[The Chauffeur]

Yeah, a long time to warm up. I now live about 5kms from the highway and I noticed the other day it was still on the end of the cold 'blue' shaded section when I got there.
It's probably stuck rather than missing now I think of it, as fuel economy has dropped from 12l/100km to 13l/100km back in Febuary (19mpg to 17mpg). That was about the time I used off brand fuel because it was cheap ($1.30/L ha ha )and I put it down to that. But that's about when the weather turned cool too. Also usually the economy improves with some highway running but it's not doing that anymore as that's when the engine runs the coldest with low ambient temps I have.

I'm looking around for a t/stat and a local company is selling behr rated at 92C or 88C. Having problems finding a housing gasket there though. Also checked at places like FCP as I'm planning on getting some stuff not sold locally anyway (relays, nuts, seals - even the dealer here orders everything from germany for an e34 and it's a 3 week wait), FCP are selling max 80c, down to 75c and 71c thermostats. What gives? what is the proper range?
might have to double check with ecs or bavauto.

I have the same engine as you ('91 525, also), and I got the 88C, which is supposedly the factory recommended for the m50 non vanos; I've read somewhere that cars with vanos run the hotter one, and lower than 88 are for racing applications (please someone correct me if I'm wrong).

Regarding gaskets, I used both, but I installed an aluminum cover; supposedly the plastic covers come with an already adhered flat gasket, but not sure how accurate is that info; I couldn't tell if my old cover had one, as the PO's mechanic slathered sealant all over the place, dunno if they used a new one, or reused an old one...

[fo3]

.

[fo3]

I have the same engine as you ('91 525, also), and I got the 88C, which is supposedly the factory recommended for the m50 non vanos; I've read somewhere that cars with vanos run the hotter one, and lower than 88 are for racing applications (please someone correct me if I'm wrong).

Regarding gaskets, I used both, but I installed an aluminum cover; supposedly the plastic covers come with an already adhered flat gasket, but not sure how accurate is that info; I couldn't tell if my old cover had one, as the PO's mechanic slathered sealant all over the place, dunno if they used a new one, or reused an old one...

I just my order in, inc alloy t/stat housing. Everything I've seen on YT when they have a housing like this they don't use a paper gasket

Also I stuffed up and got the wrong gasket so if I need the paper one I've got to go to the dealer and buy one for $13

According to this and real OEM I just need the paper one https://bmwtis.info/removing-thermos...ngine-bmw-m50/
Also realoem diag is a little confusing with '8' the rubber seal greyed out
https://imgur.com/AurHiEt


AurHiEt.jpg

But not sure how it ties in with the aftermarket alloy housing. Doesn't seem much room for the paper on with the orange seal there. But not confident in relying on that and no paper gasket because the oring with the t/stat seems a little too small to seal right (barely touches all the edges of the housing, it needs to be exact just to have a hope)
https://imgur.com/Itlv2qG


Itlv2qG.jpg

Not sure about using the alloy housing at all. I guess I'll have a better clue when I remove the old plastic housing. I might have to reuse that with a paper gasket if it's completely different inside.

[fo3]

OK, I went and got the paper gasket from the dealer but it's pretty thin paper and I can't see it sealing around the orang seal well. Neither can I see this housing working without the orange seal as it's a huge groove cut and not machined smooth on the inside so it probably wouldn't work with it removed and relying on the paper gasket alone (the paper is pretty thin, much thinner than the aftermarket gaskets I have that don't fit.)
NNSGk1I.jpg

https://imgur.com/NNSGk1I
lsJEtjV.jpg

https://imgur.com/lsJEtjV


Trying to work it all out before taking the car off the road as once I remove the housing then I'm stuck without a car and it's impossible to bus it to the dealer for extra spare parts and most parts are order in so it takes days to get.
Also when I take it apart I'll have nothing to copy as there's no t/stat in there, and probably no seals either - I'm 90% sure the PO would have gooed everything together. The main reason why I bought an alloy housing is I'm worried it is gooed on so bad the plastic housing cracks when trying to force it off so the alloy housing is my insurance policy if that happens.

[The Chauffeur]

Looking at the pictures, it seems you're on the right track. Here's what I did, and it worked like a charm, no leaks at all:

The rubber seal included with my aluminum housing was too stiff and waaaay wider than the original one; as hard as I tried to make it work, there was no way that housing was gonna close properly torqued. Maybe I got lucky, but my original orange seal looked in great shape (very pliable, no cracks), so I had to reuse it.

Yes, the paper gasket is thin, but it's rubberized, if I'm not mistaken; you'll feel it squishing a little when you tighten the housing bolts. From the pictures, it seems your orange seal is the same height as my old one, so it should work; I don't think it has to line up with the paper gasket, as long as they seal their respective surfaces (my paper gasket was a different brand and color than yours, but the shape was the same). Hope this helps, good luck!

[fo3]

OK. Thermostat fitted. Like suspected there wasn't one in there. There doesn't seem to be any leaks just whacking on the alloy housing and all seals and gasket.

I also previously had a leak that I thought was either the float switch or the expansion tank. Stupid behr expansion tank didn't fit. I've read problems about them but thought it may be the person not the part. It definitely doesn't fit, way too hard to push down and get both o ring seals seated. Tried putting it in the freezer, tried lubing with dishwashing detergent, nothing worked and I was worried about breaking the rad plastics so I gave up.
The old one just had one thick seal and seats firmly but not so ridiculously tight. I put the old one put back on and I hope it wasn't that which was leaking, hope the float sensor was the culprit and the new one fixes that leak.

Another thing is the thermofan doesn't work any more. I hope that's because there's a t/stat now. It used to run a fair bit when I parked the car and now it hasn't run at all. The thermostat for the aftermarket fan runs off a capillary bulb was in the lower rad hose off the thermostat housing. Either I crushed the capillary line or the reduced flow/t/stat closing off means it doesn't cycle on as much. I think the bulb should be on the top hose anyway but I didn't think of that while working on the car.
If the capillary is crushed or damaged I want to get rid of that system and try hook it up to the aux fan thermoswitch anyway. I recently replaced the switch for them for a 88C one but I've never seen the aux fan operate unless I have the a/c on.
Next warm day or when I have an excuse for a busy drive I'll get the car hot and see if the aux fan comes on. It should now with a t/stat and the thermofan not working I think. Just idling the car to bleed air and the temp gauge gets up to 1/2 way pretty quick now.

E: I was happy about the state of the cylinder head too. No corrosion or pitting inside the housing area unlike some of the horror ones I've seen on YT.

[shogun]

The housing with the 'rubber' gaskets does not need the paper gasket, that is fully sufficient with the rubber gaskets. I have installed in my E36 M3 also an aftermarket alu t-stat housing and have the same design. I only used a very thin liquid seal portion where you now have the paper gasket, just for piece of mind.
That is also why the paper gasket in the ETK is grayed out.
We have a lenghty discussion on that in the E36 forum.
The older version of t-stat hosuing needed a paper gasket, example https://www.bimmerforums.com/forum/s...+gasket+t-stat
The newer version has instead the red rubber seal.
Cannot find the old thread at the moment as the search function is down, admin is working on it.

Hold on, I found it with a google search, not the forum search https://www.bimmerforums.com/forum/s...mostat-housing

[The Chauffeur]

It also depends on the quality of the parts on an individual basis, IMHO... My aluminum cover was Uro brand, and it included the rubber seal (wasn't even orange, but an off-yellow color ); as mentioned before, the seal protruded way too much from the groove, and it was as hard as a rubber eraser.

I also smoothed out a couple of sharp edges from the cover itself (casting was fair), but the machining on the mating surface was a bit on the heavy side, very uniform, mind you, but still heavy; in my case, the paper gasket took care of that -I've also read all the stories about aluminum covers not sealing properly, with owners ending up installing an original plastic one in frustration!

[fo3]

The housing with the 'rubber' gaskets does not need the paper gasket, that is fully sufficient with the rubber gaskets. I have installed in my E36 M3 also an aftermarket alu t-stat housing and have the same design. I only used a very thin liquid seal portion where you now have the paper gasket, just for piece of mind.
That is also why the paper gasket in the ETK is grayed out.
We have a lenghty discussion on that in the E36 forum.
The older version of t-stat hosuing needed a paper gasket, example https://www.bimmerforums.com/forum/s...+gasket+t-stat
The newer version has instead the red rubber seal.
Cannot find the old thread at the moment as the search function is down, admin is working on it.

Hold on, I found it with a google search, not the forum search https://www.bimmerforums.com/forum/s...mostat-housing

Yeah a lot of videos and instructions I found on the net were for newer cars(e36, e39) and I noticed none of them had a paper gasket. I would have totally been OK with no gasket that if the oring around the thermostat was a better seat to the aftermarket alloy housing or if the thermostat seal was the double sided fitted flat seated kind like this:
797_1.jpg
I noticed some 92C thermostats for newer engines had seals/'o rings' like that, but 88C t/stats for older cars only had the regular one sided small o-ring, also the pics for my car showed a gasket with that small o-ring and had the orange seal around the top hose outlet greyed out, so I wasn't sure which way to go when using a later model thermostat housing but an early model t/stat and thin o-ring showing a gasket needed.

E: I got the uro housing too. I've never heard anything good about uro in general but I had one SAgoon say that is the only good part they make. Plus never read a good review of any of the other brand alloy housing. It looks OK but I didn't think the o ring alone would be good enough as it barely fit - if only the hole for the t/stat was a little bit smaller.