200 2.5 Overheating

[ToledoBendChamp]

0D188269 Mariner Magnum EFI 1993

Engine gets hot when Idling. Water pump, poppet, T stats have all been checked/replaced. Thermostats open correctly, but visible steam comes out of the holes where the water leaves T-stats. I believe exhaust is getting into the cooling system some how.

This engine has done this for quite some time. It will cool off once up and running. All powerhead gaskets are new, as it was recently rebuilt, but it did the same thing before the rebuild. Failure was due to detonation, pre ignition.

Is this common for the engine? Any things to focus on? I have a spare LU I'm thinking about putting on the see if that will make a difference. IT has always had good WP, but the pisser dribbles like an old man.

[leonreno]

Is the alarm actually going off? You can check the temp in front of the thermostat housing with an IR gun to see if it’s actually hot and on which side. The thermostats open at 143 degrees which is hot and sometimes steamy depending on outside conditions.

[sleeper bird]

i had the same problem with my 04 efi,changed and tried everything,after joe pointed out that my water psi was high at idle around 10 or so if i can remember correctly.I was told that probably exhaust gas leaking past head gasket o'ring and getting into the coolant passages.Sooo i decided to pull both heads and change the head gaskets,i put new bolts although i was told i didn't need to that solved my heating up in idle problems been two seasons now.not sure what the upside to having an o ring head gasket is im sceptical of them myself they showed no real visual sign of failure.

[JOE54]

was same block used ????were both gaskets changed under pwerhead??if water pump has been repaired with all 3 gaskets replacing case shouldn't stop it, inspect poppett valve and grommet in block,report accurate wpsi at idle, no sir not common, and some of us don't dribble

[JaySmithRacing]

What’s your water pressure at this idle heat horn issue , if it’s more than 5-7 lbs at idle you have a blockage of spent water leaving the block , at WOT any more than 18 psi points to a blockage ...

Jay @ JSRE

[ToledoBendChamp]

Thanks guys.. it always seems to be simple. The port T stat was stuck shut.

[EuropeanAM]

Nice when you find something simple to address!

[sleeper bird]

Nice when you find something simple to address!

yes it is

[JOE54]

seems mine are never that simple , glad it was for you, good luck JOE "non dribbler" YET