Greetings all

I will get right to the point...In the past till now my 1990 f250 351W is suffering from improper temperature reporting to PCM...

Is there another..Lower spot in the block i can relocate my temp sensor...To insure 100% immersion in coolant?

I'm sure i have sum sort of leak..But it is so slight i can go 3 months without adding coolant.

Apparently, air pockets, or maybe poor circulation in that sort of location is almost like an air trap non top of the Intake

bout 4 years ago i replaced Intake manifold gaskets do to a leak...But there must be like a halfa pin hole leak...Not Visible!! But always enough to keep my sensor dry or not fully immersed.

Its Like a thorn in my ***...When I take the time to air bleed the system and top off the coolant...My 351W Runs Great with decent fuel mileage...But soon keeps declining as air or coolant level drops slightly

Between watching the temp gauge..and feeling engine performance and fuel consumption going down over a week or more..Untill i bleed it again.
It is the coolant problem as i have been threw a 100 of these cycles

If Anyone has any ideas out there It would be appreciated..Thanks fellas

 

Drill a 1/16" hole in the thermostat. Every engine I build gets one...instant prime and small amount of flow through the radiator helps shock when it's -20f and the thermostat opens and lets that cold coolant into a hot engine.

It will increase warm up time slightly especially in cold climates.

 

I started doing this 20+ years ago when I read that 300-6 Ford engines usually showed more wear in the #1 cylinder. The theory is the cold incoming water shrinks the cylinder bore.

There are obviously more benefits than just this.

 

Makes good sense Dale..In fact,,its been awhile since i changed a thermostat...but if i remember correctly..some thermostats come with that option

I dont want you cats to think i'm just a lazy ***...I should just bite the bullet and pressure up on old "Gretta" ( the only woman that ever put up with me for 26 years!! LOL)
and find that pin hole leak.
I'm just busy as hell and not tryin to look for trouble with her right now.
This sensor apparently is in big time with the pcm.
bad design i think about its location...if you see how its placed..the only thing thats not making it a perfect air trap..is that the circulation coolant that flows thru a pinhole @ the radiator for the throttle body.
the hole in the thermostat is a good idea, but unfortunately Usually where there is a leak..there is air getting in the system..i would think

anyway..i guess i need to change my location..after 14 years in Newfoundland I am now back home in Florida

I will tell you this..when the break in oil came out of gretta..she has only seen synthetic oil religiously...And I now know the extra bucks Paid off big time

 

Have had plenty of t stats with the check valve, simply cut off with a side cutter and place valve in trash. The hole will always be bleeding, uphill, downhill always working.

Also be sure your overflow/reservoir line and tank are clear and working.