CHT and coolant

[Itsjustacrowd]

First time posting here and hoping for some good feedback, and thank you!

I have a 2016 GT on E85, recently I noticed CHT will get all the way up to 240+ with highway and city driving, not getting into it at all.
Checked for leaks, etc. Replaced the thermostat with a 170*, still getting abnormal temps.
When draining the radiator I noticed that it was water coming out, not coolant.

Bit of a back story, engine was replaced 60k miles ago from a local mechanic so he would of been the one to put water instead of coolant. Not cool!

Being on a drain for the valve on the bottom of the radiator, only about a gallon or so was drained.

My concern now is that the reason may be that water isn't sufficient enough to keep the heads cool. Also worried about corrosion, etc from water being used for 60k miles

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[K4fxd]

Corrosion might be an issue, depends on if he used distilled water or tap. Distilled is fine. Straight water cools better than any coolant.

I suspect if you only drained a gallon you were low. Try filling it and see if it helps.

 

[Itsjustacrowd]

Corrosion might be an issue, depends on if he used distilled water or tap. Distilled is fine. Straight water cools better than any coolant.

I suspect if you only drained a gallon you were low. Try filling it and see if it helps.

I've always heard that water doesn't cool as well since it has a lower boiling point than coolant.
I have no idea what kind but it just doesn't sit right with me either way.
Hoping no damage was done.

Still tracking down this unsettling cht problem

 

[Itsjustacrowd]

Corrosion might be an issue, depends on if he used distilled water or tap. Distilled is fine. Straight water cools better than any coolant.

I suspect if you only drained a gallon you were low. Try filling it and see if it helps.

Coolant level was full as well

 

[K4fxd]

System pressure is what raises the boiling point. Water wetter helps. All coolant is for is corrosion resistance, lube for the water pump and freeze protection.

If it was full you should have drained more than 1 gallon.

Checked and the coolant capacity is 13.6 qts, so about 3.5 gallons. You should have drained at least 2

 

[ice445]

I've always heard that water doesn't cool as well since it has a lower boiling point than coolant.
I have no idea what kind but it just doesn't sit right with me either way.
Hoping no damage was done.

Still tracking down this unsettling cht problem

Pure water is the best coolant because it has the highest heat capacity. But its corrosive. Your water pump has probably had enough.

 

[KingKona]

The engine is aluminum.

I'm thinking that means corrosion is much less of a concern.

I'd dump the proper coolant in there and just ride. What's done is done, it can't be un-done. I'd bet there's nothing damaged.

 

[Itsjustacrowd]

I ended up getting majority of the water out and got the proper coolant in.
Even with the new thermostat and coolant, CHT are still abnormally high.
What would ya'll recommend to check or what would be the source of that issue?

 

[KingKona]

I ended up getting majority of the water out and got the proper coolant in.
Even with the new thermostat and coolant, CHT are still abnormally high.
What would ya'll recommend to check or what would be the source of that issue?

Ruined CHT sensor?

 

[gimmie11s]

Are the fans working? Start there

 

[Itsjustacrowd]

Ruined CHT sensor?

I don't think so. I'll replace anyways.
Thank you!

 

[Itsjustacrowd]

Are the fans working? Start there

Fans are working properly

 

[ice445]

I'd bet $1 this is an early sign of water pump failure, so I'd investigate that first.

 

[Cory S]

Where are your CHT’s during prolong idle?

 

[Cobra Jet]

Not sure if this will be helpful, but I posted this back in 2019 - TSB 19-2049 from Ford - faulty CHT sensors in 5.0’s:
https://www.mustang6g.com/forums/threads/tsb-19-2049-cht-mil-dtc’s-p1289-or-p017d.120216/

I know OP doesn’t have a 2019, but that’s not to say that a faulty CHT can't exist in any Coyote 5.0.

I wouid check the harness to the CHT, check the pins in the connector AND do a continuity test of the actual CHT sensor to make sure it's in spec before throwing parts at the car.

Here's how to change the CHT if anyone needs it:
https://www.mustang6g.com/forums/th...sor-on-a-2016-mustang-gt.130632/#post-2696524

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