What is the hottest thermostat available?

[79Mercy]

I don't have a overflow hose conected to it but everytime after a drive there is some coolant on the rad. where it has come out of the overflow nipple. Is the cap causeing that problem. I don't have to much coolant in the rad.

[79Mercy]

But also before I started to have trouble with it it would stay just alittle above 80c. and never move from that spot. Does anyone know why it doesn't stay there any more?

[Cobb2]

I was only able to find a 176 degree f stat for my 240d. It had a 170 in it from the dealer. The old one did not open fully and it would run into the white mark before hte red at 120. Afterwards it stayed cooler, but did stay on the next mark up from 80 in 100 degree weather. Now it stays in the middle and on colder days it will stay on 80.

I too use to boil over and loose coolant or burn it at a gallon a month. I installed an aftermarket universal over flow bottle and it seemed to lessen the problem. I also removed the lower rubber seal on the rad cap, so it would easily blow over into the over flow nipple, but not the atmosphere to lessen any possible hose failures from the pressure.

Maybe you need to loose the mechanical fan for the electric upgrade to make it come on as needed to warm up faster?

79m, maybe you got a blown head gasket, timming has advanced to cause it to run warmer than before? Maybe you got tranny fluid in your antifreeze making it cool less effectively or crap in your radiator?

[79Mercy]

There is no any oil in the coolant or tranny fluid in the coolant. MY mechanic says that it is okay to run at 100c. I just would be more comfortable if it ran down near 80c. like it did about 3 years ago.

[Cobb2]

Its my experience as a former mechanic that a car suddenly starts to run hotter than normal its likely a blown head gasket. Sounds like you got part of the trobule shooting resolved regarding the mixing of fluids. The second part of the test is a compression test of all the cylinders to see if its blown across cylinders or into the oil/water jackets.

It could also be the winter mix of fuel burns hotter than summer fuel too. In general a change like that is a concern, but with cars this old and changes in fuel quality, addatives now-a-days its not easy to trouble shoot.

The only other thing that crossed my mind short of the thermostat failing early is that your antifreeze mixture isnt right and it boils off before it cools effectively and you neeed to add more water or antifreeze depending on which way it needs adjusting..

[79Mercy]

It did not happen all of the sudden. About 3 years ago my rad when bad and it leaked all the coolant out. So I had a new rad. put in and ever since it has stayed near 100c. It never goes up to the red or the white under the red it barley goes above 100c. In the picture I drew a line at where it stays.

[Cobb2]

Oh, ok. Sounds like maybe the radiator isnt as efficient as the last one or thermostat.

Mines likes to sit where you put the mark at. In the winter a bit lower and summer a bit higher to the next white line.

I wouldnt worry in this case.