Bremmen M62 90 degree Thermostat
 

Any newer insights on this thermostat?

I believe it's an M62 MAP thermostat with a 90c wax capsule instead of a 105c?

It seems to bring down average temps by all accounts, but store thermostat and low running temp codes/illuminate SES lights sometimes.

What is concerning to me is some say it can cause the DME to switch to a engine warm up map to resolve the perceived problem?

EDIT @Henn28 I see you and JimLev discussing this at an E38 forum? I read through a long thread there but kind of hard to relate with the non-stock cars, the 4.6 is bone-stock.

That discussion has been going on for years over there I think…guys have some strong opinions about lower tstats. I think I understand all the opinions, and frankly I swapped on in mostly out of curiosity. So far I am a fan, if only from the peace of mind that comes with lower system pressures.

I’ve had mine in for over a year perhaps and some brutal summer temps here in New Orleans and have had no problems. No codes thrown and I’ve never seen the MAP cooling activate with it in. I occasionally hook my foxwell up and keep an eye on it. It holds the engine outlet to 95 degrees in my car, and the radiator outlet temps can be 10 or 15 degrees hotter under heavy acceleration, etc. it seems from what I recall they were with the stock tstat. But that’s purely anecdotal. I also see a direct reduction in oil temps of around 15 degrees.

Thanks for chiming in!

I think it is an older thread yes, and certainly getting heated at times lol. But very interesting definitely.

I also think I understand everyone's side there and I am of the same opinion as you that I'd like the peace of mind of lower pressure on the hoses and plastic as well. Your temp coolant range now I think is a good one. Good to hear no wonky behavior so far because of it.

15c drop in oil temp, wow! These engines cook oil IMO and that should help. What were your oil temps before the 'stat?

When I did the motor swap I plumbed a Gulf oil filter housing and a CSF Race universal dual pass cooler so even before the 95 degree tstat the oil never got above 95 degrees, which is where the tstat in the Gulf filter housing opens up. But it was usually at 95 degrees and the cooler was piping hot all the time after the oil got up to temp. Now the cooler will get hot, but generally only after harder driving, or higher rpm highway driving for a while.

Before the oil cooler went in the oil temps were regularly over 105 and upwards of 120. My 2002 4.4 did t come with an OE oil cooler either.

I see! I'd forgotten for a moment you had changed to a 4.6 from a 4.4.

I'm pretty much decided on this and ordering the thermostat now. I see they were pretty much at an all time price high recently but some places are discounting heavily and I think now would be a good time to buy.

Wish I'd known about this sooner, would have tried this instead of getting a standard MAP thermostat when I started getting thermostat codes last year.

So the Bremen thermostat just got in!

Will update when I get time to install it.

Had the Bremen 90c thermostat installed. Added 3l of OE coolant concentrate and filled it to capacity with distilled water.

Just finished bleeding and engine is fully warmed up. Coolant OBC temp now sits at 95C from the previous 105-107C. Engine oil temp reads 83C on the OBC at this coolant temp.

The Bremen thermostat looks to be working as advertised.

It's been 2 weeks since the thermostat has been installed and I must say, I'm impressed!

Temps are now consistently at 94-95C, highest I've ever seen was 97C.

Calculated oil temps range from 75-85C. Since learning it's a calculated value not really too concerned anymore, anything above 70C I considered warmed up anyway.

No downside to observed fuel economy IMO, it seems to guzzle fuel about as much as it usually does. Definitely not the huge fuel consumption increase I saw in the 3.0 when the thermostat stuck open and ktemps were at the low 80's.

The kicker for me is it seems a bit more sprightly now, all the time.

Very happy with this mod!

Nice. My experience too. So far I can’t find a downside to this mod.

It seems to be so. More pep, less stress on one of the most failure prone systems of the car, lots more peace of mind for me.