Overheating- Overflows on shutoff, suction after cooldown

[Matt45]

1994 Explorer was overheating, I later found a good sized leak on the heater control valve. I replaced the valve, put some 50/50 coolant/water in, ran the engine put more in.
I drove around the neighborhood for a while, at about 25mph, low temp. I accelerate hard and the engine quickly heated up, then starting overheating.

After I stopped and shut off the engine, I hear bubbling/boiling(bad sign) the overflow fills up and well...overflows. After I dunno 10/15min the overflow is sucked empty and the upper radiator hose collapses under vacuum.

I'm assuming it's the thermostat and I will be replacing it (local pep boys has "Stant" brand, they good? Will be getting 180f aswell). Plan on flushing it out too

I've searched and there are plenty of threads with overheating issues but I'm looking for answers to my somewhat odd situation.

-Oil doesn't seem to have water in it, normal colored
-Coolant does seem to be discolored, brownish, with little flakes/debri, possible clog?
-Does not seem to overheat idling and at low speed, so probably not a fan issue
-Cab heater puts out good heat
-Overheats at high speed/RPM apparently

 

[R&T Babich]

... After I stopped and shut off the engine, I hear bubbling/boiling(bad sign) the overflow fills up and well...overflows. After I dunno 10/15min the overflow is sucked empty and the upper radiator hose collapses under vacuum ....

This sounds like the 13 lb spring in the radiator cap is not working, but the seals are.
I'd stick with a 192 deg thermo, but try a new cap first.
How high does the temp gauge get?

 

[Turdle]

Why would you even consider a 180 degree thermostat? The ecm will not be happy bout that--

 

[Kevlar7R]

It's your radiator cap. Replace it.

Probably wouldn't hurt to buy a bottle of prestone radiator flush and do that too.

DO NOT buy the pressurized flush kits that hook up to a garden hose. Your cooling system is designed for 13lbs of pressure. Your hose is between 25 and 60 lbs. Those flush kits usually end up bursting radiator hoses. Not right away, mind you, but a month later, when you're 100 miles from anything and it's super inconvenient.

 

[Turdle]

My "garden hose" flush kit has slits cut into the T adapter to relieve the high water pressure. In other words, water flows out of the flush kit adapter to the fitting, but some pressure goes where it is needed.

I think the newer ones have this issue addressed.

 

[Matt45]

I was considering the 180f thermo because it was suggested online elsewhere just so things run cooler but I have no problem sticking to oem

 

[Kevlar7R]

I was considering the 180f thermo because it was suggested online elsewhere just so things run cooler but I have no problem sticking to oem

Dude, it's your radiator cap. Change that first.

 

[Matt45]

Dude, it's your radiator cap. Change that first.

Oh, ya I know, I'm getting a new one, but I was a just stating why I considered the 180f thermostat

Should all the air make it's way out by itself after the flush or is there a special procedure?

 

[R&T Babich]

... I was a just stating why I considered the 180f thermostat ...

A 180 deg thermostat would just allow full flow of coolant to the radiator starting at a lower temperature. It would not "cool" any better. The thermostat tries to regulate coolant flow to keep the engine at the set temp. If an engine needs more cooling it needs a larger (or more efficient) radiator. If Ford had used a 4 row core and larger dimensioned radiator there would be a lot fewer cooling issues, but it all boils down to cost (pun intended).

I have an E-150 with a 351W and installed a class C RV radiator - 4 rows, couple of inches wider. There was a filler plate that was easily removed to put the wider radiator in. Now the gauge come up to temp and it takes a very hot day, very steep hill, with a boat trailer to get the temps up a little bit higher than normal. The class C we have could use a larger radiator, but there isn't one available. I added an engine oil cooler which does help keep the engine temps down.

 

[Matt45]

Ya I just read an article about the whole lower temp thermostat thing and how it's pointless, over on a Dodge forum the thermostat swap was commonly recommended for a easy little performance mod, now I can't believe I believed it.

I was going to work on it today but it's just way too cold out to work, with water especially

 

[Matt45]

Um, ya, so it was the thermostat, just for anybody reading this thread with a similar problem. But it's a definitely a lot easier to replace the radiator cap first, some engineer was kind enough to route a cable that conveniently blocks one of the bolts for the thermostat housing.

 

[Kevlar7R]

since the thermostat and the radiator cap sit in the same system, its not uncommon for them to both fail. People tend to overlook the cap, but it is crucial for cooling performance.