1996 Mark VIII Runs Hot, But Coolant Overflow Tank Cool

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Mustang4fn

New member
Agreed. I took it out this afternoon and it still reached the top of the "O" rather quickly, post burping and cooling. My better half is planning a trip to Ford to purchase the thermostat at some point tomorrow.

When I went out a little while ago, in the dark, when I put my flashlight on the coolant in the crossover I saw little shiny specks. I'm surmising its either leak repair or the water pump... Thoughts? (as my thoughts aren't so positive right now...)
 
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Mustang4fn

New member
On another interesting note, my better half just left the Ford dealer and that particular part is discontinued and unavailable nationwide... The parts guy recommended the napa brand, in light of not having it.
 
driller

driller

El Presidente
Mustang4fn said:
On another interesting note, my better half just left the Ford dealer and that particular part is discontinued and unavailable nationwide... The parts guy recommended the napa brand, in light of not having it.
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If the parts guy couldn't get a Motorcraft part, I'd be looking elsewhere.

MOTORCRAFT

MANUFACTURER INFORMATION
Designed, engineered and recommended by Ford Motor Company. The name says quality, dependability and performance. Motorcraft® parts are the preferred choice of Ford Motor Company. From motor oil to transmission assemblies and everything in between, Motorcraft® parts provide exceptional quality and fit. You expect the best, and with Motorcraft®, you get the best. The right part for the job. Motorcraft® parts are designed specifically for Ford, Lincoln and Mercury vehicles and have undergone extensive laboratory and on-the-road testing. They're built to maximize the performance of Ford, Lincoln and Mercury vehicles. And the comprehensive product line provides unmatched coverage. Whatever part you need for the job, Motorcraft® has it.
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tixer

tixer

Lincoln Evangelist
Regardless of brand, I'd check it in a pan of hot water on the stove before installing it.

It's fun to watch, and good insurance.

Chris' comment about 195 being too hot for these cars is an interesting one. Traditionally, 195 has traditionally been my go-to temperature for thermostats.

However, I have significant trust in his knowledge, and will definitely go with that when I eventually replace mine. I've learned something new today.
 
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Mustang4fn

New member
Agreed! The motorcraft thermostat was ordered via amazon last night. I checked with another dealership, who I get parts from for my older mustangs and he corroborated the same information that they are no longer available via ford unless you find someone or a supplier with stock of them.

I'm going to pick up a new water pump today, so I have it. Based on the small metallic flakes I found in the coolant, I want to do a flush and figured a new water pump wouldn't hurt the situation, especially since they're somewhat cheap. Once I drain and take a better look, hopefully I'll know what I'm dealing with... From the looks of things, most everything is original, so eventually I'll need to look towards some other maintenance items, such as new wires, plugs, etc. I'll update everyone once I break into it. Fingers crossed!
 
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chris2523

New member
tixer said:
Regardless of brand, I'd check it in a pan of hot water on the stove before installing it.

It's fun to watch, and good insurance.
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always check, +1

tixer said:
Chris' comment about 195 being too hot for these cars is an interesting one. Traditionally, 195 has traditionally been my go-to temperature for thermostats.

However, I have significant trust in his knowledge, and will definitely go with that when I eventually replace mine. I've learned something new today.
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a 195 is not hot hot, but Ford does spec a 180 for these cars.
 
tixer

tixer

Lincoln Evangelist
Yikes. How I managed a redundant "traditionally," I'll never know. I beg forgiveness from those who noticed... (before and after, this comment)
 
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gbradleyb

New member
I had put in the duralast thermostat in my mark when old one failed and it is 195 not sure if that's when my temp started reading high at top of "o" in "normal"... I can't even find one any lower than that aftermarket. The duralast even claims " oe recommended temp"
 
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mag

New member
The OEM thermostat F3LY8575A is a 188 and can be found I just bought one for $9.79
 
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Mustang4fn

New member
I was able to drain the coolant and for the most part it looked okay. I believe whoever filled it just put in straight coolant, based on its color and a quick gauge test. Inside of the hoses looked a little dirty with sediment, but okay. Replaced the water pump and besides some small deposits, it looked okay. It was a bear to get out though. Had to remove the alternator to get it out. The thermostat came in today. Hopefully I'll be able to get it in within the coming days. Can anyone confirm the orientation of the t-stat in the housing before I put it in? I'd rather not trust whomever replaced it a few years ago put it in correctly...

Thanks again all!
 
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MarkVIIIMarc

New member
Just throwing this out there.

21 year old 65,000 mile car with visible sediment....what is the best way to flush our 4.6's?

What are the temps our fans come on at? I THINK high is about 212. Mustang4fn, have you confirmed your fans work? I have not had the misfortune of messing with mine. Am I correct that if you turn the A/C or Defrost on the fans should kick on?

Also, the old Mustang guys are all about taking IR Thermostats to their radiators to check for blockages from sediment and age. I haven't done that yet but it seems even Harbor Freight are selling them things.
 
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Mustang4fn

New member
Just wanted to update... After getting the car back together and burping the system, it now runs between the M and the A while driving and goes up no further than the top of the M when idling in traffic. What a difference!!!
 
tixer

tixer

Lincoln Evangelist
I "feel" like it's a pretty important part of the car's circulatory system, helping things come up to temperature properly, and keeping them there. I'd sure be hesitant to go without.

But I've never lived in the south... :)
 
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