2004 250xs overheat alarm at idle?

[fasterbasser]

Anyone have any ideas on what might be causing this? I have checked the stats, and they seem to be working fine. motor is pumping water. mostly happens when water is 75 and up. thanks

[taeheel2az]

Water discharging from the tell tale? Water pressure reading? Water temp (if you have a SmartCraft gauge)?

[Reelsore]

You can have water flow but like taeheel2az said how much pressure do you have? When was the last time you change your impeller and or the complete impeller kit? You need to change the impeller once a year. I personally change just the impeller every year and every other year I change the complete kit meaning the housing that the impeller sits in.

Oh and Welcome to the BBC Mike!

[limit5bass]

My guess is the poppet valve has a piece of debris in it. This will not allow the water to completely pressurize in the engine block. Which will indeed cause a over heat problem at idle. Some times you can run it wide open and it will clear the obstruction in the poppet valve.

[EuropeanAM]

Mike:

Welcome to BBC!

When chasing down cooling system problems, ALWAYS- ALWAYS start at the SOURCE: The Water Pump.

AFTER pump has been replaced (if problems persist), it would then be appropriate to move on to other potential causes, including:

-Thermostats
-Poppet Valve
-Powerhead/Adapter Plate Gaskets

[fasterbasser]

Thanks guys. When I am idleing the water pressure is only 2 or 3 psi. Is that Ok/normal? I do not have smartcraft, but wish I did! I have replaced the impeller within the last year, but never the whole shebang, so that will be my first step. Where is the poppet valve located?

[taeheel2az]

hmmm, , , ,

When the poppet on my Opti wouldn't close, the engine would never warm up past 100. It's located on the starboard side midway back, just above the edge of the lower cowling. The cover is circular, a couple inches wide, and has "ears" where the bolts go that attach it to the block.

I'd do the impeller and see the results before messing with the poppet. 2 or 3 lbs is good pressure at idle.

Digital gauges like SmartCraft were new to me with this engine, but now I'm sold. Without the temp guage, I almost certainly would have blown my engine with a cold sieze when it had the poppet problem.

I'd make sure the outlet of the telltale isn't stopped up with debris. If it is and there's no flow through it, compressor overheating will give an alarm.

[EuropeanAM]

1-3 psi at idle is normal water pressure.

I would indeed start with the water pump (age is irrelevant... a brand new water pump can be smoked easily in under 20 seconds).

And I do agree that checking the telltale is wise... a restricted or plugged telltale WILL result in an Air Compressor Overheat.