Overheated while in a drive thru - questions

[P-71]

About 3 months ago I had my oilfilter adapter replaced due to a leaky gasket. I know the shop guys and there are a few mod motor dudes. I gave them the burp procedure article we all use and the wrench said he did it when done. I drove the car for about a month on and off but it was parked a lot. No leaks under it. It's not a DD. just a weekend fun-car.

The last two times I drove it the fan came on a lot when idling or in a drive thru.

The last time I finally noticed that the temp gauge was climbing steadily and the car had a slight knock when I let the clutch out at low RPMs (manual swapped). I noted this as I was on an on ramp so I thought the air through the radiator would help bring temps down. It did not so I got off the highway a 1/4 mile later and got to my house a couple blocks away.

I popped the hood and the reservoir had boiled over from the cap. It had spilled coolant enough that I saw white smoke while driving I assume from the spillage, not the exhaust. The reservoir had coolant in it while still hot

I have not driven the car since, only started it to move it around. It makes no funny noises or blowing smoke so I am hoping it is air in the system that initially did not cause overheating until I let it idle a few times while parked

Today I started the burp procedure and I am currently letting it cool for the final top-off. The car was down a full gallon of coolant(!).
Later, tonight I'll test drive it and see if it happens again. If it does, and there is no leak, assume the headgasket is done? What else might the issue be? The oil was clean on the dipstick and smelled normal.

I hear of dropped valves on these engines on cyl 8. What causes this issue and could it be on my car? So far the engine is pretty quiet, It has always had a little valve train noise but no real clatter or knock.

[Mr. Man]

I bet there was still air in the system.

[P-71]

I bet there was still air in the system.

Followup: looks like you were right. Took it for a spin and so far all OK. I am getting coolant coming from under the reservoir cap though. Gonna look for a crack

In other news my windshield cracked from a stone chip and the cold snap we had yesterday and some kid threw a pack of firecrackers under my car at a stopsign. I smoked his whole family out with a rolling burnout.

[Grimrepairman]

It's possible the cap is bad and not holding pressure. With the correct adapters they can be tested, however a replacement is cheap insurance compared to potential engine repairs.

[justbob]

It's possible the cap is bad and not holding pressure. With the correct adapters they can be tested, however a replacement is cheap insurance compared to potential engine repairs.

+1 also the fill plug Oring has been known to let off pressure.


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[RubberCtyRauder]

Cylinder 7 and 8 have a poor cooling passage, sort of like a dead spot. They run hotter and bend a valve if bad enough, the head cooling mod addresses this.

[P-71]

Well it overheated again today. I made it 10 miles, let it cool for and hour and drove it home with the heat on high. It started overheating in exactly 10 miles. Right at my driveway. No boil over this time. Fan came on and temps started to climb. No sign of coolant getting past the fill plug but the O ring looks kinda worn out. No coolant leaked out the reservoir cap this time but I caught it early.

When I got home I let the car completely cool and removed the crossover cap. I added about 1/2 cup of coolant so it was not notably low. Oil smells OK and no white smoke. engine sounds fine. Upper hose was hot and seemed to have coolant in it, It drained out after cool down.

Kinda stumped. T stat sticking maybe?

[P-71]

+1 also the fill plug Oring has been known to let off pressure.
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Is there a source for the proper O ring and cap? Any ol' Dorman cap OK?

[offroadkarter]

Is there a source for the proper O ring and cap? Any ol' Dorman cap OK?

Cap

https://parts.autonationfordwhitebearl ake.com/oem-parts/ford-cap-9c3z8101b?c=Zz1jb29saW5nLXN5c3 RlbSZzPXJhZGlhdG9yLWFuZC1jb21w b25lbnRzJmw9NyZuPUFzc2VtYmxpZX MgUGFnZSZhPW1lcmN1cnkmbz1tYXJh dWRlciZ5PTIwMDMmdD1iYXNlJmU9NC 02bC12OC1nYXM%3D

I don't think you can get an o ring from ford for just the crossover tube plug, they sell the entire plug which doesn't even come up for all 4v's (but it will fit). Alternative is to buy a pack of all crossover tube O rings on ebay which has the plug O ring

https://parts.autonationfordwhitebearl ake.com/oem-parts/ford-cap-f3ly8a500a

[P-71]

Ordering now
I assume this T stat is the one to get? I recall reading that this car needs the bypass style T stat. (hole in the plate). I gotta be honest. I am not sure where the housing is on these cars. I looked for a youtube tutorial but most are for Mustangs. Any tricks for the thermostat install? I know you can crack the intake on a 2V. Any pitfalls?

Thanks for all the advice. Wish I knew why this thing would all of a sudden act up. Ive taken some really long trips in this car after manual swapping it and it has been perfectly reliable until now.

https://parts.autonationfordwhitebearl ake.com/oem-parts/ford-engine-coolant-thermostat-7l3z8575d?c=Zz1jb29saW5nLXN5c3 RlbSZzPWNvb2xpbmctc3lzdGVtJmw9 MTcmbj1Bc3NlbWJsaWVzIFBhZ2UmYT 1tZXJjdXJ5Jm89bWFyYXVkZXImeT0y MDAzJnQ9YmFzZSZlPTQtNmwtdjgtZ2 Fz

[decipha]

sry to hear about your bad luck

if im not mistaken the thermo is in the lower radiator bypass hose housing

be sure to get a stock temp (195F) thermo

would be a good idea to verify your cooling fan(s) are working as well.

[P-71]

sry to hear about your bad luck

if im not mistaken the thermo is in the lower radiator bypass hose housing

be sure to get a stock temp (195F) thermo

would be a good idea to verify your cooling fan(s) are working as well.

Fans are definitely on and going nuts as temps rise. It looks like if you follow the hose on the right the houing is actually kind of suspended mid-hose just in front of the fan?

[TORINO]

Ordering now
I assume this T stat is the one to get? I recall reading that this car needs the bypass style T stat. (hole in the plate). I gotta be honest. I am not sure where the housing is on these cars. I looked for a youtube tutorial but most are for Mustangs. Any tricks for the thermostat install? I know you can crack the intake on a 2V. Any pitfalls?

Thanks for all the advice. Wish I knew why this thing would all of a sudden act up. Ive taken some really long trips in this car after manual swapping it and it has been perfectly reliable until now.

https://parts.autonationfordwhitebearl ake.com/oem-parts/ford-engine-coolant-thermostat-7l3z8575d?c=Zz1jb29saW5nLXN5c3 RlbSZzPWNvb2xpbmctc3lzdGVtJmw9 MTcmbj1Bc3NlbWJsaWVzIFBhZ2UmYT 1tZXJjdXJ5Jm89bWFyYXVkZXImeT0y MDAzJnQ9YmFzZSZlPTQtNmwtdjgtZ2 Fz

The correct stat is MOTORCRAFT RT-1110