change t-stat
 

I've been keeping my 87 pretty well maintained, keeping up with repairs and maintenence. Since it only has 132K on it and runs perfectly and looks like new naturally I want it to last for another 130 or more. From what I've read it seems like the weak link on these 603 engines is the head, if it ever overheats. For this reason I am going to put in a new OEM thermostat and new OEM hoses. The radiator was replaced by MB at 90K. I see this as cheap insurance against a possible engine failure due to being overheated, especially if my wife is driving it on one of her frequent highway trips between Phoenix and Tucson in temperatures over 100 degrees with the A/C crankin. Any other suggestions? Has anyone tried the water wetter product? Is the MB coolant really better?
Thanks, Brian

you might take it to a radiator shop and have the cooling
system completely flushed.

don

I've used water wetter on every diesel for years, seems to help a little bit.

Why not get a 110'C temperature switch, bond it to the head and use it to drive a flashing light and buzzer.
Tell your Mrs that if she continues to drive with the lamp and buzzer, then the car will be toast.

I would definitely change the thermostat. You have 132k miles on the car so it will fail sooner or later. Mine failed at 169k but I live in New Jersey where it's not 100 F everyday. A thermostat is really really cheap so go for it. Oh yeh, it only takes about 10 minutes to change (240d).

thanks

Kamil,

Since all the parts (unless replaced) on the car have 132,000 miles, then by your theory, all the parts should be replaced. In other words replace the entire car now because eventually all the parts are going to fail.

I have thermostats 24 years old and over 200,000 on them and I'm not about to replace them unless they stop working properly.

If it ain't broke, don't fix it (or you might fix it until its broke).

Overheating an aluminum head means running it hot with out water. Normal operating temperatures up to the red mark (such as going up a long grade in hot weather) will not damage the head.

The heat indicator on the head is a good idea but it should be set to a temperature of about 250*F that sets off the warning. There should also be a red light warning for no oil pressure.

P E H

Two Schools of thought:
 

If you fell it is time to change it change it.
The only warning please take the new thermostate and place in pot of water and bring to a boil with thermometer and verify that it open at the right temp. The QCA on these are not great. There has been a bunch of us who has gotting bad one's.
PEH back flushes his fuel filter, I don't know about oil filter. And if very frugel and that works for him, I just wish he could let other maintain and spend their money as they like since they earned it.
He has a problem with "pre maintance."
And when you over heat and ruin a head I don't think he will warrent you cost to replace it. So please consider the source and conquences.
Charlie

I'm with Charlie on this, I've learned the value of preventive maintance from my many years in the USN. My car had 143,000 on the clock when I bought it and one of the first things I did was buy all new filters and in the process discovered that the last service was done improper and the air filter just rattled around in the housing, O'ring on oil filter post was bad and needed replacing. The car was running too cool most of the time, but would go over 100C real easy, so I decided to replace the thermostat and water pump. Good thing I did, the thermostat was stuck open, and the bearing in the water pump was very rough.