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So Saturday I was driving my excursion for about 45 minutes 70 mph rainy 64 degree day here in Northern Wisconsin truck would only stay at temp if I kept it above 45mph anything below that or idling it would drop out of operating temp where it normally stays .let it idle for 8 minutes she drops to quarter of the dummy gauge .I believe I have a stuck open thermostat. Truck has been doing the same thing these last 3 days it's been close to 75-80 and humid .no coolant lose nothing weird going on with the truck .and I'm going off the dummy gauge..which I know isn't always accurate but it's never done this .unless it's like colder then 40 degree out
Thermostats are one of the easier maintenance tasks on the Fseries. Go ahead and flush coolant at the same time. If you don't have ELC, this is a good time to switch.
IDK nothing about this, but it just seems unusual that it can't even keep temp WOT. Not like it's freezing out.
Ok thanks .I would assume i should go with a stock Motorcraft thermostat .a flush and getting rid of this gold coolant is on my list just don't have the time know
If you can get the IH T-stat. That is the one you want.
This one is the one for the 2006 F350. Check that it/s correct for your year.
For some reason they just last longer than most of the others out on the market.
Noted there were three posts today concerning engine temperatures/thermostats. Must be the season. Like others that have posted, it sounds like a replacement is in order. I like to test the old and the new thermostats in boiling water on the stove when I change them out.. I have done this for years. Others have included pictures on how to do it. My thermostat brand preference is Stant. I have used them in all my vehicles for over 50 years.
As to coolant, I changed to Delo ELC this last time I flushed. It was on sale at Walmart and they even delivered for free. I believe my coolant numbers are down a tad and the delta ELC/EOT is also lower. I called Delo, and the technician said it should be changed every eight years - certainly beats the Gold three year change cycle. As to flushing, I am including a post I made in 2016 which was based on information from various sources. The process worked well for me and was easy. Good luck!
Simple Coolant Flush For The 6.0Background: Over the last 11 years, I have read numerous postings and the inevitable debates on how to effectively flush the coolant system on the 6.0 engine. Lately, some folks have asked how to flush the 6.0. This is my approach on how to do a simple flush.
I am the original owner and although I normally do this kind of maintenance myself, the previous flushes seemed to come due in the middle of the winter so I splurged and paid the Ford house to do the work. It cost me about $80 to $100 labor for them to do it and I considered the money well spent and I stayed dry. I’m now at the 99K mark and the truck is due for a flush. After reading many posts and watching a few videos and also since the weather is nice, I decided to do it myself. As an aside, the truck is used about 50% of the time for towing my fifth wheel and I have towed through 46 of the lower 48 states and Alberta east including Newfoundland in Canada utilizing the Ford gold type antifreeze.
Current Situation: The truck is virtually stock-no tunes or other performance enhancements. There is no crud that is discernible in the degas container. I don’t seem to use or lose any appreciable amount of coolant. The last time I topped up to the “Min” line was 7K miles ago and it required a very small amount of distilled water. I added a Dieselsite coolant filter 35K miles ago and I have replaced the filter several times. Nothing of any consequence was in any of the filters.
The current batch of coolant in the engine looks a tad dirty but there are no floaters or other extraneous particles that can be seen by the naked eye. EOT/ECT delta at 65 MPH unladened on the flats runs between 10-12 degrees F and it has been consistent since I added a Scangauge II in December 2010. I replaced the thermostat that stuck closed and also the water pump in December 2013 when I was down at South Padre Island, Texas. ECT runs a consistent 190 degrees F unladened.
The Plan: I am replacing the existing Ford gold coolant. I have no need to change or upgrade to an ELC coolant. The first task is to remove all the existing coolant in the engine. The second task is to remove the tap water I am flushing with and eventually end up with the purest water reasonably possible in the engine. The third task is to add the antifreeze and bring the coolant up to spec for a 50-50 mix. The fourth task is to run the truck for a week and check for any problems.
Tools:
8 MM Hex socket (allen head type)for removing the driver’s side engine plug.
A Breaker Bar with a ½” to 3/8” drive reducer and a 3/8” drive ratchet to remove the engine drain plug.
Pliers to compress and remove the clamp on the heater hose.
Screwdriver to get the heater hose off of the engine nipple.
Deep socket for installing the Fumoto valve (can’t remember the size).
TDS tester that I use for testing the Reverse Osmosis (RO) water in the house (Amazon $10).
Blue water filter I use on the trailer when I am out.
Garden hose.
Hose adapter consisting of garden hose ¾” FHT x ½” FIP fitting, ½” threaded/slip coupling and a short piece of ½” PVC pipe. See Diesel Tech Ron’s video. Cost about $4.00 for parts at Lowes.
Ramps to elevate the truck on a slanted driveway so coolant comes out the driver’s side engine plug.
An extra “T’ shirt (More about that later).
A big pan to catch the old coolant.
A funnel for adding water and antifreeze.
Materials and Supplies:
4 Gallons of Zerex gold antifreeze.
Vaseline to lubricate heater hose back on to the engine nipple.
Vaseline for the gasket on the coolant filter.
F108-N Fumoto valve (reuse the “O” ring from the engine drain plug).
RTV sealant for the Fumoto valve threads (probably not necessary – I used a small amount).
A length of 3/8” hose to put on the Fumoto valve to direct the water away from you.
9 Gallons of RO water from the RO filter.
9 Gallons of Distilled water.
New Baldwin filter for the Dieselsite coolant filter setup.
Execution:
1. With a cold engine, drive the truck up on the ramps, put in Park and block the wheels. Place the pan under the radiator, remove the cap on the degas container, open the petcock and drain the radiator. While the radiator drains, test the water at the hose spigot. Mine was 638 PPM (parts per million). I added the inline RV blue filter and the reading went down to 499 PPM. I think the inline RV blue filter is really optional.
2. Now that the radiator is drained, remove the engine plug on the driver’s side. The coolant will come gushing out and therein lies the reason to have a spare “T” shirt. Let the engine drain. Clean up the hole. Remove the “O” ring from the plug, put it on the Fumoto valve with a small amount of RTV sealant on the threads and gently thread the Fumoto valve into the block. You may have to back it off a bit and try several times to get it threaded. Tighten it down snug. Ensure the valve is open. Attach the 3/8” hose to the Fumoto valve to direct the water away. The Fumoto valve will provide an easy solution to opening and closing the block drain for the next steps.
3. Assemble the hose adapter and attach it to the garden hose downstream from the blue filter. Find the heater hose which is next to the alternator, remove it from the engine nipple and insert the hose adapter into the hose. You are now ready to do a reverse flush through the heater core. Turn the heater **** all the way up to its highest point and leave it on during the rest of the procedures.
4. Turn on the spigot and flush away. When everything seems clear, start the engine for a moment or two and let the engine circulate the water. Make sure that you have enough water in the engine as you now have two exits for the water – the block valve and the radiator petcock. Start the engine again for a moment or two and continue to flush. Shut the engine off and continue to flush until you believe the water is clear. Flush out the degas container and check for crud. If necessary, remove the degas bottle and clean.
5. Shut the petcock and the Fumoto valve. Reconnect the heater hose to the engine nipple using a little Vaseline to lubricate the hose. You may want to use a little emery paper on the nipple to clean it up. Put the clamp on the hose in the same spot it came off.
6. Slowly fill the engine with the garden hose through the degas container and start the engine. You’ll probably have some air in the system so take your time. Put on the cap.Take the truck out for a short ride until the ECT comes up to 190 degrees F. Put the truck back on the ramps and let it cool down. It won’t take that long. Drain the block and the radiator and then close the block drain and the radiator petcock.
7. Slowly fill the engine with RO water through the degas container. My RO water tested 55 PPM ( I just ordered a new RO filter as mine is at the end of its life).Drain some of the water since you will only be able to get about 20 quarts into an otherwise 27 quart engine. Making sure the petcock and Fumoto valve are closed, fill the engine through the degas bottle.Put the cap on. Take it out for another short ride getting the ECT up to 190 degrees F. Put the truck back on the ramps and let it cool down. Drain the block and the radiator and then close the block drain and the radiator petcock. Sample the engine water from the engine. My engine water tested at 149 PPM.
8. Refill with distilled water. Put the cap on.Take it out for another short ride, let the truck cool down and drain the engine and radiator. Close the petcock and the Fumoto valve. Remove the Baldwin coolant filter and replace. Put a little Vaseline on the rubber gasket. I did not retest the engine water. I would estimate it would be at 75 PPM.
9. Now is the time to add the antifreeze. You should have a capacity for additional antifreeze/water of 18-20 quarts. Put 14 quarts of antifreeze in the engine through the degas container and fill up the rest with distilled water.
10. Start it up, cap it, check for leaks and take a short ride. Refill degas container to the "Min" mark if necessary. After a week, still no leaks and I tested the coolant. It registered as -45 degrees F. Coolant looks clean in the degas container, both radiator hoses are hot and the heater works fine. No strange noises and the truck runs well.
Conclusion: I watched the Diesel Tech Ron Video and he recommended in the video that it was not necessary to remove the engine plug on the passenger side for a simple flush. I used a TDS tester and some may take issue with the applicability of this tester for this application. However, it did give me reference points during the procedure. I used RO water which was free instead of buying more distilled water. Either one will do for the second flush.
All in all, it was a pretty simple process and since I mowed the grass during the periods the engine was cooling down, there was very little idle time. I hope this helps anyone who wants to do this simple flush.
Yes your thermostat is definitely sticking. The stock gauge is somewhat useful for temps below operating. It hits the "normal" position right around 185F so you can use it to detect a low temp condition. Above 185F it won't move until about 225F so it's pretty useless there.
Most of us run some kind of scanner to monitor actual ECT's, oil temps, etc. Very useful on the 6.0 for monitoring the engine and watching for potential issues.
Update .switched thermostat
this morning. Runs great no more fluctuating temp gauge stays wear she should .and I'm almost positive it was the original thermostat form 05 in it
