Thermostat? 87C or 75C?
 

Hello List,

Which thermostat would you use in my 1972 280se 4.5? The 87C or the 75C. Both from Mercedes dealer.

I am in Boston.
thanks

cK
1972 280SE 4.5L

I think originally it came with 87C thermostat but if you drive in Boston (stop and run a red light) a lot you may want to change it to the 75C one in the summer. If you want good heat in the winter, and I am guessing you do, you will need to have 87C one on then.

Yep, be glad that you've got both.... flushing the system and swapping thermostats each Spring and Fall is good mainenance habbit for the car - preventing scale deposits from building up in places like the heater core and adding life to your radiator.

For me the semi-annual coolant system flush is ritual for the first really warm saturday in the Spring.... then again at the final ghasp of warm weather in the Fall.

Those prestone flush systems where you attach garden hose are not bad and coolant wont destroy your driveway or lawn. Treat it like a car wash operation, when the engine is COLD - not even warmed up.

Most garages hate doin coolant flush because it trashes their shop, so this maintenance item generally goes neglected until the car starts to overheat. Orange coolant is what you want, not the green stuff.... something to do with lubricating elements in the orange stuff that matches original MB coolant specs.

That's what I hear but my car is 32yo and I doupt that G5 cooland was around then. I tend to run just H2O in the summer in all my cars but have been thinking of using some kind of rust/scale inhibitor and/or waterwetter.(?) I normally avoid traffic.

It's best to use anti-freeze because it extends both the freezing and boiling points of water.

But water dissipates heat way more quickly and that's what I am after in the summer. I don't want the coolant to hold on to the heat I want it to get rid of it ASAP. Now, if I did have to deal with a lot of stop and go then antifreeze would probably more desired since it can hold on to more heat without boiling over.

Coolant increases the boiling point but runs HOTTER than water..... yet am thinkin 4 ounces of coolant will help prevent rust. Dunno about water wetter but have heard its good stuff.

What nobody ever does is flush the system enough.... i like 6-8 hr valvoline radiator flush combined with an all day drive, say to remote fishing grounds. And yes, the prestone $3.99 garden hose flush kit is decent.... you can even hook it up on feed line to heater core then umplug the return line to cylinder head to power flush the heater core - then move it around to power flush the cylinder head routing water through the radiator too. Flushin the system is fun.

Btw, anybody ever run with NO thermostat at all in Summertime??

Coolant system efficiency is something thats easily measured and appreciated. I guess everybody has hit the heater levers in July to cool the engine by 10-15 degrees at one time or another.

And maintaining the cooling system is something the DIY owner can do a helluva lot better than any garage can.

I have in my old F150 long time ago. As I remember the tk ran great but you could really boil your motor if you happen upon heavy traffic or a moutain - I remeber overheating in Chicago but can't remeber if I had the thermostat then or not.
When I worked in construction all of the machines (backhoes, loaders, scrapers...) ran without thermostats in the summer and they ran all day. The mechanics told me that it did keep the machines cooler and I don't recall any problems.

BTW: I may try a few ounces of coolant with my water this summer.

water wetter i believe is the anti foam and anti rusting additive package form normal antifreeze plus an agent to keep the car cooler. it does work, i'm not really sure how, but the cooling effect can be duplicated with a drop or 2 of dishwashing liquid.

you want some kind of corrosion inhibitor in the coolant all the time, aluminum and iron together will cause problems (electrolisis)

http://www.yarchive.net/car/coolants.html 2nd one down if you dont wanna read the whole thing

Thanks. I'll have to find it.

Galvanic corrosion:
http://www.dansdata.com/images/burn/gunked400.jpg

That's what happens to a PC waterblock after only 6 months.
Imagine what the tiny channels inside your radiator, block and heads look like!

The article can be read _here_.

You NEED a corrosion inhibitor or you WILL recore your rad and flush your block and heater core (if not replace it) for days on end.