Thermostat Temp? 75C or 80C?

[cargeek733]

I'm going to be replacing the thermostat on my early, L-Jet equipped 733i soon and I'm wondering which Thermostat I should be using. I know the factory temp is 80C... now is there any reason I should go down to the 75? I live in a high humidity, high heat environment in South Texas along the Gulf Coast...It is not uncommon to see temps easily crest 100F with humidity well above 80% in the middle of summer...would the lower temp benefit me any or is it best to stick to the 80C factory temp?

[Hit Man X]

I prefer 80C. I am in Texas also.

Can do a 745i spec rad cap if you want. 1.4bar

[cargeek733]

Good deal. What's the benefit of the 745i spec, 1.4bar cap?

[yert315]

I prefer the 75° thermostat. I know some will argue otherwise. I’ve been using the 75° unit for 10+ years in every BMW I work on.

I’ve dealt with too many cooling system failures to feel comfortable with an 80°. If something happens to your cooling system while driving, the 75° unit gives you that extra bit of time to catch it and kill the engine before it’s too late. Running colder means your engine won’t be quite as efficient, but I’ve found that to be negligible in my experience.

Obviously, this is not a fix for an overheating engine.

[Hit Man X]

Good deal. What's the benefit of the 745i spec, 1.4bar cap?

Higher system pressure. N/A cars use a 1.0 as I recall. MB W126s I own all use the 1.4 if you care to know that.

[cargeek733]

Thanks for the suggestions gentleman. I went with the 80c thermostat. I wasn't having any cooling issues before so I'll stick with the cap that's on there now.

[cargeek733]

Any of y'all deal with a seized up bleed screw? Going to have to bust out the torch and maybe weld a nut to the screw because part of it broke off when I used vice grips on it.

[motohunter4]

I'd try without a torch. Then replace the screw.

Sent from my LGLS755 using Tapatalk

[cargeek733]

No luck yet. Going to take it to a buddy on monday that has a welder. The new thermostat should be in by then too.