eagle model 15 running hot

[Jamie]

Ok so for two months i  have been trying to figure out why my eagle model 15 runs hot..  I put new 170 degree thermostats in it.. no help only idols cooler..  New water put no help..  new air filter no help..  Just put in a new radiator I think it runs even hotter now..  It has the hydralic fan set up.. I have had the fans strobed and two shops said they are spinning fast enough..  they spin at 1950 rpm when the engine is at 2130 rpms.. both places said that is fast enough to cool the engine..  I'm not loosing any antifreeze so cracked head or bad head gasket isn't the problem.  I have checked all cylinders with a heat gun and i don't' have one that is running hot...  I talked to a guy today that said.. He would bet it's the fan not spinning fast enough. He said that checking the fan with the engine at top speed the fan might be working fast enough.. but when going down  the road at a lower rpm the fan might not be turning fast enough..  I think it is a fan problem to..  So i need to either change the hydralic pump or the fan motor.. everyone says there is no way to check them to see which one might be bad.. so it's a guessing game.. and the guy i talked to said to junk the hydralic setup and change over to a mechanical set up with a  belt..  If anyone has any idea's let me no.. this is driving me crazy.. the coach will heat up on the flat not just pulling hills.. and yes my guage is working right...thanks jamie

[Geoff]

You don't necessarily 'lose' antifreeze if you have a cracked head, the test you want to make is seeing if there are exhuast bubbles in the radiator.  You can also buy a test kit that checks for combustion in the coolant.

[TomC]

Just because the fan is spinning doesn't mean you're getting enough air through.  You may have dirt build up in the radiator (course you did say you got a new radiator).  On my bus, which is a transit with V drive, but has the same side radiator configuration as you do.  What is important that is sometimes overlooked is the intake side of the radiator.  Since my bus is a 102 and the engine/trans setup is made for a 96 wide, the radiator is set in 13" from the edge of the bus.  It also has a metal shroud the ensures that only the cool air from the side of the bus is entering the radiator.  Without that shroud, the radiator would be recirculating the hot air from the engine and cooling would be reduced.  Do you have a fan shroud that is in good condition?  At idle the fan should be able to hold a piece of typing paper against the radiator.  If not, maybe the fan is not adjust correctly in the shroud.  While it feels like it is pulling correctly, if it is too far outside the shroud, it can just be picking up the air from the engine and pushing it back. The fan shoud be at least 1/3 to 1/2 inside the fan shroud with no more than about a fingers width of space around it.  To show how important this is, most all trucks are going to the "European" style of aluminum fan shroud that has very close fit tolerances and is aerodynamically shaped to be a true venturi effect to get maximum flow through the radiator.  Just my thoughts.  Good Luck, TomC