I use to work for cummins, they do have there own coolant. Might try getting
some of that.

Ed
"Eisboch" wrote in message
...

Tom "HappyFunBoater" Treadway wrote in message
m...
I've got two Cummins 420hp diesel engines. They're both about 5 years
old
and I've never changed the coolant, but I have made sure it was topped
off
through the years. So two weeks ago I decided to replace the coolant.
When
I drained the old coolant, everything looked fine, i.e., no rust or
particles. Then I refilled, slowly, with a 50/50 mix with Prestone
coolant
that met the engine specs. I didn't start the engines until this
weekend -
two weeks later.

Before I changed the coolant both engines very consistently ran around
170F.
The engines are rated for 160-180F. Now both engines run around 190F -
20F
hotter! I ran for about a hour thinking that maybe the coolant needed to
mix, or air bubbles needed get out of the system, but it made no
difference.
The temperature is dead on 190F.

What the heck did I do wrong?

Thanks for your help.
TT



I am not familiar with Cummins coolant requirements, but I had Cats on a
recent new boat that had a specific coolant type requirement. The heat
transfer factor may be your problem if you are using the wrong coolant.
I'd
check with Cummins with your engine serial numbers.

Eisboch