450 SL running hot, please advise?

[Walrus]

Originally Posted by Benzmeister

Performance Products in CA want almost $1600 for an brand new servo.

FYI: My Winter Performance Products catalogue advertises a digital replacement climte servo for around $600US, IIRC.

[mattcara]

Ive been concerend with over heating my 560SL since i first bought it. and i will tell you after many trips to the mechanics and after enless reading on websites. trust me ,it is normal for the engines to run hot, even close to redline. i know it sounds crazy, but these cars do run hot. its perfectly ok!

its something i never get used too! but it is what it is.....

[Benzmeister]

is in F degrees, mine runs at 175 degrees to 200 degrees, normal for this car. The owners manual and the shop manual say, when the gauge gets into the red then worry. As far as the digital servo replacement. If that is your concern send it to Performance analysis in Tenn and they will rebuilt it for you. I understand but don't know for sure, these digital servo is not a plug and use arrangement. Also performance, wi replace the plasitc body with aluminium, which is lengthened the life span. I think I wrote in another post, you have to back flush and change your anit freez every two years, YOU ALSO REMOVE THE SERVO, to back flush as stuff can get in there and foul it. I have a hose that connects from the engine to the heater core after the servo is out so you can back flush the heater core also, as anti freeze from the heater core passes thru the servo also. I am still topping off the anti freeze daily as the heater core takes a lot of anti freeze the anti freez ran out for quite a while before clean water did. But it also gets warmer and wamer each time I use it. Yestersay the ambient temp was such the AC kicked in, now I am satisfied everything is working. I top off with distilled water and not antifreez. The mixture is very crictical 55% water and 45% anti freeze is the proper mixture for the 4.5L V8 and it predecessors. Not 50/50 as on most cars. Don't worry as long as your not in the read, but do post how hot the engine does get?

[mplafleur]

Originally Posted by stanm

Thanks Robert but I'm not familiar with "Water Wetter", what is it
and where can I get some?

I did add anti-freeze @ 45% strength when I repalced the thermostat
but had little improvement with dropping the temperature. I was hoping
to raise the boiling point and perhaps making it run a bit cooler.

Today I repalced the water pump and it STILL runs as hot as before....
Any other suggestions would be very welcome at this stage!!!!
[I am willing to try the watter wetter, who knows???]
Happy Thanksgiving! Stan

Adding anti-freeze will not lower temps. Anti-freeze actually has less heat transfer than water. What it does is protect the metallic surfaces from scaling and rusting and lowers the freezing point.

[abe g]

I have an 450sl 1977 and this is just my opinion. I think that everything you have done was unnecessary! Temp variation from 175 to 200 plus is average and normal for a 107. None of your indications warranted radiator cleanout, thermostat replacement,etc. Just a case of changing parts with no reason,Sorry to be so blunt. Regards,Abe G PS with 135000 miles and water pump replacement only for cooling system.

[strelnik]

Originally Posted by abe g

I have an 450sl 1977 and this is just my opinion. I think that everything you have done was unnecessary! Temp variation from 175 to 200 plus is average and normal for a 107. None of your indications warranted radiator cleanout, thermostat replacement,etc. Just a case of changing parts with no reason,Sorry to be so blunt. Regards,Abe G PS with 135000 miles and water pump replacement only for cooling system.

I have just purchased a 107 but with the 116 3.8L engine. Is the same true for the 380 series? This is a far cry from my diesel or my fintail.

[Graham]

Originally Posted by abe g

I have an 450sl 1977 and this is just my opinion. I think that everything you have done was unnecessary! Temp variation from 175 to 200 plus is average and normal for a 107. None of your indications warranted radiator cleanout, thermostat replacement,etc. Just a case of changing parts with no reason,Sorry to be so blunt. Regards,Abe G PS with 135000 miles and water pump replacement only for cooling system.

My '72 SL runs at about 180F, but does go up to about 195F (hard to read that gauge!) when idling at lights or in heavy traffic. I have had car for 20 years, and I think it is running hotter at idle than it used to. Time for a flush, I guess!

One thing to check is that the proper thermostat is in the car.

The old SLs use a 75C thermostat while the newer ones use 84C. Presumably they increased the operating temperature for environmental reasons.

[abe g]

In my opinion, anything up to 210 F steady reading on hot run is normal. Just about what I stated previously, 175 to 200 plus, really no porblem. Regards,Abe G

[JoshC450SL]

Originally Posted by mattcara

Ive been concerend with over heating my 560SL since i first bought it. and i will tell you after many trips to the mechanics and after enless reading on websites. trust me ,it is normal for the engines to run hot, even close to redline. i know it sounds crazy, but these cars do run hot. its perfectly ok!

its something i never get used too! but it is what it is.....

If this is true. Why did the original posters car run normal at 175 forever then all of a sudden run hotter? Mine is doing the same thing now and I don’t know what’s going on. It almost reaches the 200F but goes down as I drove and it’s at a good driving condition it nears 175 but never goes down from that till the engine is off and cooling down for the day.

But again. Mine is doing this now and didn’t run this hot ever. I had a 1974 450Sl ten years ago and it didn’t run past 175.

Any insight or idea what is going on with that?

[JoshC450SL]

Originally Posted by abe g

In my opinion, anything up to 210 F steady reading on hot run is normal. Just about what I stated previously, 175 to 200 plus, really no porblem. Regards,Abe G

If it’s not problem why does the normal operating temp say 175 and it stays there? Why would it go hot at all if not malfunctioning?

[rmasteller]

It's interesting that you picked up a conversation/debate in a 14 year old thread.

Regardless, boiling point of water is 212F/100C. That is increased by about 45F/25C with the 15psi cap on the tank/radiator, bringing the boiling point to about 257F/125C. Nobody should worry about 200F/94C on their gauge, unless the gauge is way off, their pressure cap isn't working, they're running straight water, or have a combination of these bad things.

https://auto.howstuffworks.com/cooling-system7.htm

[JoshC450SL]

I found this thread because it’s valuable information. Also. The factory books say the normal operating temp is 175*. Regardless if 200 is okay for these 107’s. I don’t believe it’s normal. Why have a temperature gauge at all if the temp doesn’t matter?

I don’t think my gauge is broken. It’s not the fan clutch. But the fan before I replaced the clutch wasn’t blowing a mass amount of air like it normally did before it over heated. It has to be something else.

I’m working currently on replacing the thermostat.

When I squeeze the bottom hose when the car is off. I can hear like a single tone like a ring or bell as I squeeze the hose. It’s coming from the thermostat housing part of the water pump. Anyway. Is that normal for it to do that? I imagine it like a blown light bulb with the filament rolling around in there. So I imagine while there is something metal rolling around in there. I don’t know.

You said to not worry about 200 on the gauge. But I am worried because everything is so hot when I lift the hood. The hood. Everything is hot. When before this all happened wasn’t hot. Just the valve covers and parts near it. Not everything. I replaced my reservoir cap too. It’s holding pressure.

Thank you
Josh

[Sugar Bear]

If it was mine I'd start with flushing the cooling system with CRC ThermoCure and replace the thermostat. After thorough rinsing replace the coolant with no more than 50% coolant and the rest water. Add a bottle of RedLine WaterWetter.

Good luck!!!

[JoshC450SL]

My car has stopped staying hot. When I drive in town it stays between 175-200. When I’m on the interstate or the car in at a steady speed it stays at 175. Still working out the kinks.

[engatwork]

Josh is the radiator original? If it were mine and radiator was original I'd remove it and either replace or have it recored.