Dr. C36

hey guys,

finally installed lower thermostat and got a chance to test her out. The cars temps are now at a rock steady 79-81 on the temp gauge no matter what you do. I will have to wait and see how it operates in the summer but it works perfectly. Got my lower thermostat from www.azautohaus.com for rediculously cheap.

if you want to do it just get the 80C 91-93 W140 500SEL thermostat , its direct replacement for ours (our stock ones are 87C). The total install time should be about 10-20 minutes, however mine was so encrusted in there I had to pry it out with a flat head, took me a solid 20 min just to get that old sucker out, took a total of 45 min for me.

The thermostat is only $20.73 on azautohaus (retails for $36), heres a picture of it:



Pic of stock one to compare (they are slightly different but W140 one is direct replacement):



I HIGHLY recommend for ALL C36 guys to keep our cars running at a nice cool temp in both summer & winter. This mod applies to all M104 engines and its great cheap insurance to reduce the stress on your cooling system over the long term.

Hope this helps

silence

do you know if the part number is the same for c43?

this is something i'm planning on doing as well (and soon)

also, did you test it before installing to check accuracy etc.? i don't know how the quality is on these pieces, but i've seen some crazy variances/tolerances? with some oem style thermostats (from other brands)

-drew

ohlord

v.s.188f is not that much less stress on your cooling system and most likely is reducing the power output of the engine.Your emissions are likely to go out of range if you smog test the car in your state.Why not use the proper thermostat that lets the engine get up to it's designed temp?Change your coolant per the maint schedule,check your belts and hoses,shut off the a/c going up the grapevine and that will put less stress on the cooling system

if you insist on a lower temp tstat or even the proper one autohausaz.com has oe or oem and very accurate.

Dr. C36

Nope, That is only true for 75C or less. 80C is totally fine and I ran it on my previous M104s. On stock thermostat sometimes I had thermal runaways where temps would shoot up in the summer w/ AC on but that would never happen with the 80C in, it does a much better job of preventing those random temp spikes we all know too well in the summer (those put a great strain on the radiator and other plastic cooling system components.)

I appreciate your input but this has been beaten with a dead horse, the 80C is the best cooling upgrade you can do on these cars.

Dr. C36

Can't do this for 43, sorry, totally different thermostat housing. accuracy is dead on as promised, temps are exactly what they are supposed to be. Stock was 87 (just as its supposed to be) now its 80 (just as its supposed to be). AZautohaus carries all the top quality OEM brands, they don't carry bad brands.

silence

oh i wasn't suggesting the brand wasn't oem- just wondering about accuracy

Dr. C36

at most is usually variance of +/- 1 degree C it starts opening up at 79 and is fully open and does not pass 81, where as stock is roughly 86-88. Hope that helps.

NitrogenBalance

Drew, contact PTE from this board as he made a custom one for myself and many others. PM me if you need conact info. I have yet to install the phelonic spacers he made as well, trying to finish my intake mani port and polish first.

Anyways, the thermostat mod was very impressive. Temps dropped like a rock just as they should have. Car will barely break 80 during the hot days. IATs......are another story.

silence

well,i got my crazy plan for the iat's... i'll contact him