I noticed something strange today. My Ram usually runs just a scoshe above 200 degrees (according to gauge). When idling and at cruising speed the temp seems to climb a bit. When I give it the gas when taking off from a stop the temp will suddenly drop 20 or so degrees. I'm the one that also has the coolant smell under the hood but for the life of me I cannot find any leaks. I even laid cardboard underneath overnight to see if there were any leaks. There were none. I'm starting to think this may be a water pump problem. Clutch fan is good,hoses are new and I'm pretty sure the thermostat is fairly new. Any idea here ladies and gents?
Thanks!

Scott

 

That little by-pass hose that runs from the water pump to the engine block may be leaking. Mine leaked onto the timing cover and was being burned off before it would even hit the ground. Take the alt., a/c, and the bracket off the motor. (just lay the alt. and a/c back...don't disconnect). Look on the timing cover and you should be able to see if anything has been leaking. It will be clean looking where some antifreeze has been. Also check the timing cover gasket. I know that you have to pull the cover off but that is a weak point of the cooling system. The points at where the cooling fluid comes and goes to the engine is where it has a tendency to corrode and leak. That is also a potential for leakage that will burn off before hitting the ground. Before pulling the cover, check both sides of the cover where it bolts up to the block. There may be some corrosion there that could cause that. Hope this helps.

 

THERE ARE ONLY TWO WAYS FOR THE WATER PUMP TO GO BAD. EITHER THE BEARING CAN S..T THE BED, OR THE IMPELLER CAN SEPERATE FROM THE SHAFT. IF THE BEARING CRAPS OUT THERE IS A RELIEF HOLE ON THE PULLY SIDE OF THE WATER PUMP THAT LEAKS COOLANT AS IT SLIPS BY THE BEARING. THE IMPELLER SEPERATION IS A VERY UNCOMMON PROBLEM, BUT IT HAPPENS. THIS IS USUALLY A PROBLEM WITH REMANUFACTURED PUMPS. WHAT HAPPENS IS WHEN THE SHAFT IS COLD IT WILL STAY BONDED TO THE IMPELLER. AS IT HEATS UP AND THE SYSTEM PRESSURIZES THE IMPELLER WILL START TO SLIP. THIS HAPPENS BECAUSE THE IMPELLER IS MADE OF A MUCH SOFTER METAL AND EXPANDS MORE THAN THE SHAFT. THE PRESSURE IN THE SYSTEM JUST CAUSES MORE RESISTANCE FOR THE BLADES TO SPIN. I NOTICED YOU SAID THAT YOUR TRUCK USUALY RUNS JUST ABOVE 200*. THIS IS A LITTLE WARM. I HAVE INSTALLED MANY NEW DEFECTIVE THERMOSTATS BEFORE. YOU MAY WANT TO PULL YOUR THERMOSTAT OUT AND BOIL IT IN A POT OF WATER. IT SHOULD OPEN AT WHATEVER TEMP. THE THERMOSTAT IS RATED FOR. I WOULD CHECK THE CIRCULATION HOSE BETWEEN THE PUMP AND THE INTAKE MANIFOLD LIKE THE OTHER GUY SUGGUSTED FIRST. I HAD THE SAME PROBLEM.

 

You guys are awesome! I will check all of that out this weekend. Glad I found this site,I cannot imagine how much money you guys just saved me. I'm half decent with a wrench but just to have a place determine what's wrong with it can sometimes hurt the wallet.

Thanks again

Scott

 

mine stays right about 200 all the time. what is the normal temp that the 5.9's should be at.

 

There's seals in the water pump that can also go bad. I've had that happen before. Just a slight seal leak that evaporates before it gets to the ground can drive you nuts. Have you checked the fluid level? The rapid change in temperature usually points to a low coolant level, but could be from a lowered flow rate due to the impeller being messed up.

 

Yea low coolant level and check the thermostat housing had 2 that leaked and burnt off with no drips should see crust around it. While your there why not fire in a 180* thermostat?good luck.[sm=smiley20.gif]

 

The coolant was low once since I bought it at the beginning of Dec. Since then it has not seemed to go down. The seals in the water pump is interesting. I'm starting to think that since this truck is 9 years old and only has 43k miles maybe that's a culprit in this coolant smell/leak. An old man had it before me and didn't even drive it 5k miles a year and kept it in the garage. I've heard that sometimes when vehicles sit too long they start getting leaks and other problems.This guy basically only drove to the store and back,lol!...and yes,I think I'm going with a 180 degree thermostat for sure!

 

I wouldn't do the 180* thermostat. Because the pistons are aluminum and the block and heads are iron, they expand and contract at different rates. They are sized so that at the factory operating tempurature (200*), the different materials are at optimal working tolerances. The problem with a 180* thermostat is that the pistons will not be fully expanded. It's only a very small amount, but will contribute to premature piston ring wear.

 

Thanks for the info,much appreciated. One other question. If someone uses a Jet chip and the mfg says for optimal performance to use a 180 degree thermostat will that still cause premature piston wear? Or will the settings of the chip tweak the factory settings to off set this? Just curious because I used to have one on my old Jeep and it never seemed to run right with the module and 180 thermo. I never really noticed any HP/TQ gains via the butt dyno. Some swear by the Jet chip,others swear at it,lol!