Ok heres my take. First off, I hate stuff like this, and I love it when its finally solved. But getting there can be a horrible experience.
Anyway, I think you mentioned that on your last trip back south the car was great until you stopped, then it started to warm up. And the fix is apparently a fan and fan shroud, according to the Indy. I buy it. Heres why. The engine makes heat. The thermostat is regulating things by controlling the water flow through the radiator. Air passes over the radiator which removes some heat from the water, then returns it back to the engine. Lets say that coolant of about 88C goes into the radiator, and if everything is going ok, something like 60C goes back to the engine. Now, when you stop, you're reducing the airflow. With a damaged fan and no shroud, there isn't much air being pulled through the radiator artificially. So now you've got 70C water going back. And a short time later, 80C. If theres no flow and everything is heat soaked form a hard run, this is possible. As you sit there and idle, there still loads of heat built up in the cylinders, head, etc from the hard running you just did. This adds more heat than a normal idle, which makes the situation worse. Now you're water temp is 90, or 95... or more. It just sits there and gets worse, since there isn't much in terms of heat transfer in the radiator. The thermostat goes wide open, but it doesn't really matter when the water coming out of the radiator is about the same as whats going in. You replace the fan and the shroud, and it restores the air flow. Now you have some cooling. Things still still get hot... after all you have a huge amount of heat to get rid of from you hard running. But maybe only a few degrees until things get under control again. Hows that sound? An IR thermometer is super useful in these cases. Its also interesting to test difference parts of the cooling system and see the variation in temps. But, its worth noting, that after a hard run, coming to a complete stop is very difficult for a perfect cooling system. The temps are going to go up somewhat. This is why modern cars fake the water temperature until it gets to a certain point... there is lots of natural variation that people don't understand and will complain about. I hope all this makes sense... I'm running a fever now and feel like crap. Jaime On Thu, Feb 19, 2015 at 1:40 PM, dseretakis--- via Mercedes < mercedes@okiebenz.com> wrote: > So my Indy just called. He replaced broken fan and fan shroud. Tested > water pump which checked out ok. Drove car, let it idle for over an hour > and it didn't overheat. He is calling it fixed and he may very well be > right. > But I don't believe it could be that easy. I'm up in Maine for a few days > while his shop is in Boston. I told him to drive it around as if it's his > own while I'm gone. Let's see what happens. > > Sent from my iPhone > > > On Feb 19, 2015, at 1:04 PM, dseretakis--- via Mercedes < > mercedes@okiebenz.com> wrote: > > > > I never tested with IR thermometer. > > I did not block tstat open. The last major thing I did was change that > leaking short hose as I was convinced the problem stemmed from there. I was > obviously wrong. > > My Indy modified the tstat making bottom plate smaller. Not sure what > his reasoning was but it didn't seem to change anything. > > > > Sent from my iPhone > > > > On Feb 19, 2015, at 12:23 PM, Curly McLain via Mercedes < > mercedes@okiebenz.com> wrote: > > > >>> At this point, I would say there are no strong correlations. Unless my > Indy can figure something out, I think I need to do a coolant has test or > oil analysis to rule out head leak. > >>> > >>> Flushing block also should be done but the coolant and visible coolant > passages are squeaky clean. > >> > >> If there are pieces of metal or iron/calcium crud in there big enough > to block flow, you are not going to see them unless you take off the WP > housing and the freeze plugs. > >> > >> When it over heats, have you or Curt shot radiator areas, hoses, block > areas etc with IR thermometer to determine hot and cold spots? That will > tell you where to look for a blockage. > >> > >> Did you ever try running it with the thermometer blocked open per J. > Cathey's instruction? You don't have to have a .45 shell, you can use a > piece of 3/8 OD copper tube gut to the right length and slit lengthwise. > >> > >> The IR Thermometer and the blocked open thermostat are the > fast/inexpensive ways to determine where to look and to isolate the problem. > >> > >> _______________________________________ > >> http://www.okiebenz.com > >> > >> To search list archives http://www.okiebenz.com/archive/ > >> > >> To Unsubscribe or change delivery options go to: > >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > >> > >> All posts are the result of individual contributors and as such, those > individuals are responsible for the content of the post. The list owner > has no control over the content of the messages of each contributor. > > > > _______________________________________ > > http://www.okiebenz.com > > > > To search list archives http://www.okiebenz.com/archive/ > > > > To Unsubscribe or change delivery options go to: > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > All posts are the result of individual contributors and as such, those > individuals are responsible for the content of the post. The list owner > has no control over the content of the messages of each contributor. > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > All posts are the result of individual contributors and as such, those > individuals are responsible for the content of the post. The list owner > has no control over the content of the messages of each contributor. > -- Jaime Kopchinski http://www.jaimekop.com/ _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com All posts are the result of individual contributors and as such, those individuals are responsible for the content of the post. The list owner has no control over the content of the messages of each contributor.
