Thermostat replacement with lower temp opening setting

[searcherrr]

Since I'm going to be towing sometimes (seldom, but some) do ya'll think it would be good/better to install a 180 degree thermostat (IE: it opens up to allow coolant flow at 180 degrees)? or should I just get one of the 190 ones?

I have a tranny cooler on the radiator and the cooling system is in good health. If I put in a 180 degree thermostat does this mean the water pump life will be shorter or is it spinning all the time regardless?

[phil-l]

searcherrr: LATER UPDATE - I wrote this before seeing your thread detailing the overheating issues you've seen - so some of this probably doesn't really apply anymore...


The water pumps spins whenever the engine is running (it's run by the serpentine belt). The thermostat merely controls whether the engine coolant flow includes the radiator or not. When the thermostat is open, the coolant flow path includes the radiator - and so cools the engine. When the thermostat is closed, the coolant flow bypasses the radiator - and doesn't cool the engine. The constant opening and closing of the thermostat is designed to keep the engine at a consistent temperature.

I regularly tow trailers with my 2000 Windstar 3.8 - both a utility trailer that maxes out at a little over 1000 pounds, and a 2500 pound GVWR popup camper. My Windstar did *not* come with the OEM tow package. I've added an auxiliary transmission cooler, a number of towing-specific electrical upgrades, a full-size spare and AirLift 1000 spring airbags to firm up the rear of the van.

I've never run into a situation where the van showed any indications of overheating. The temperature gauge has always been rock-steady. So, based on my experiences, I can't offer any reasons to change the thermostat.

However, I know that early Windstars - including the '95 - were noted for head gasket problems that were exacerbated by some engine cooling issues. If I recall correctly, engine block cooling passages in the 3.8 were redesigned somewhere in the '97-'98 era to help address this problem. So I'm pleased you've ensured that your cooling system is in tip-top shape before towing.

You might also think this would be an endorsement for a lower-temperature thermostat: It isn't. Recall that the thermostat's job is to keep the engine at a consistent temperature. When the engine is heavily stressed, the only thing a thermostat can do is stay open all the time - which means the cooling capacity of the entire system is then limited by design fundamentals, such as the size of the radiator and the flow rate of the water pump. In such situations, a thermostat with a lower temperature setting won't make any difference; it's already fully open and the radiator and water pump are doing all they can. However, it will allow the engine to run cooler during normal operating conditions. This can cause problems, particularly for emissions systems which can't work correctly unless the engine is at the right temperature.

That said, I have occasionally seen problems that were solved by changing a thermostat temperature range. But I've also seen disappointed people who didn't realize that changing the thermostat *will not* change the thermal capacity of the engine's cooling system. I'm particularly wary when people try to use a thermostat to mask a cooling system problem they'd rather not fix.



Update: You can read about the steps Ford took to address 3.8 head gasket issues - which includes cooling system changes - in an article that's now only available in archived form here:

http://web.archive.org/web/200307200...0/article.html

[searcherrr]

Thank you Phil. Very good information. I asked the Ford service manager about the 180 F thermostat and he said it would be fine, but I don't know now what to do. The have the van at the dealership right now and are working on it and again the service manager says it'll be fine. The reason i know the cooling system is in good health is caused I've had it machine pump flushed for twice in the past 2 years and once was just 4 months ago. Also, I know its in good health cause Ford is replacing the water pump, radiator, and thermostat as I type this. I don't want to have emissions or "running rich" problems though cause of keeping the van from getting hot enough. Should I trust the service manager or just see or go with what you said? I really can't see though how the 180 thermostat is going to keep the van from reaching 190 or 195 F though. 190-195 should be hot enough for things to function right CORRECT? Do you think a 180 thermostat will keep it under 190?

I'm gonna go read the article you linked me to. Thanks for that. I wanted to know more about the cooling system redesign as I already knew it was done and yielded 45 more HP than the 95. The redesign took place in 96.

[phil-l]

searcherrr -

I hope things work out well at the dealership.

I don't think the thermostat would make a big difference either way. 10 degrees isn't that big of a difference. And, once again, if the thermostat is completely open - and the engine still wants to overheat - you're at or above the ability of the entire cooling system to get rid of heat. However, if service people you trust recommend the change, I'd go for it. They do this every day and are more familiar with the details.

It sounds like you've done the rights things to keep your cooling system in good shape. Since they're replacing most everything that could cause a problem, I'll be very curious to hear if they discover a problem (a blockage? corrosion? a thermostat that isn't opening *all* the way?) that may have gone unnoticed until now. Please be sure to come back and update us!

[searcherrr]

Originally Posted by phil-l

searcherrr -

I hope things work out well at the dealership.

I don't think the thermostat would make a big difference either way. 10 degrees isn't that big of a difference. And, once again, if the thermostat is completely open - and the engine still wants to overheat - you're at or above the ability of the entire cooling system to get rid of heat. However, if service people you trust recommend the change, I'd go for it. They do this every day and are more familiar with the details.

It sounds like you've done the rights things to keep your cooling system in good shape. Since they're replacing most everything that could cause a problem, I'll be very curious to hear if they discover a problem (a blockage? corrosion? a thermostat that isn't opening *all* the way?) that may have gone unnoticed until now. Please be sure to come back and update us!

Well, they don't recommend the change cause dealer's are strict OEM bible beaters and never recommend changing a single component from factory spec which we all know is complete BS just to cover their asses. He just said it should be fine. If during the winter months up North in IL I notice it being an issue I'll swap in a higher temp tstat.

The thermostat (old one) that they are removing is simply being removed cause they said its good practice to remove it after an overheating incident. I had that old one put in just a lil over a year ago. I feel like its probably still good, but its moot at this point due to its cost and ease of labor to replace.

The culprit that drove all this stuff to hell is the water pump. Apparently 157k is about the life of a Motorcraft pump in the 3.8L engine of a Windstar and I'm pretty confident the old pump was aggravated by previous maintenance when I replaced the idler pulley, belt, and belt tensioner. The new tensioner probably put the final strain on the water pump. In the future I'll probably replace all of those items at the same time IF I REMEMBER.

The overheating as a result of the pump failure caused the radiator to crack and in turn leak. I'm still skeptical that the radiator was busted and thought it was coming from a hose seal, but I didn't actually get down there to see and I sure as hell haven't felt like it. I saved over $400 easy not going with Ford OEM parts too and lifetime warranties on the parts cept the thermostat of course though I really don't know what a lifetime warranty is good for these days.

3 days in a dump ass hotel, paying for that hotel, out to eat, and a huge chunk of change on the van repairs. I'm just happy I was hauling EVERYTHING I OWN in the trailer cause that includes my PS2 to keep me from dying of boredom.

EDIT: Also, I got a tstat with a failsafe mechanism. Its supposed to remain open in the event it fails which by this experience shows me is a good thing cause after I finally pulled over after it initially overheated the radiator was completely empty.

[phil-l]

searcherrr -

Wow! You've had a tough day. Trust me, you have my sympathies. Problems like this are bad enough - without trying to fix them while on the road.

So... What actually failed on the water pump to cause the overheating? Is this an impeller issue (my '95 Contour's water pump has a plastic impeller - an item noted for premature failure), or did the seal fail?

Yeah, if it's apart, I'd replace the thermostat. Though I'd avoid going cheap: A good one isn't that expensive, and the failsafe mechanism might save you someday.

If overcooling is a problem in the winter, I'd just go with the old standby solution: A piece of cardboard in front of the radiator to partially block airflow.

[tomj76]

>So... What actually failed on the water pump to cause the overheating? Is this an impeller issue (my '95 Contour's water pump has a plastic impeller - an item noted for premature failure), or did the seal fail?

That's my question too. Where did all the coolant go? Did you notice a lot of steam coming from the engine compartment, or did it pour out from a leak?

For what it's worth, I feel your pain. Earlier this year our '96 punched a hole in the side of the transmission at the differential in the middle of West Virginia. We fortunately managed to get the vehicle to a repair shop and found a rental car to get home while the repairs were done (it took 2 weeks). We should have taken it to a dealership though or towed it to a franchise transmission shop because the replacement transmission (used) needed rebuilt after 6 months.

[wiswind]

I would stick with the factory temp for the thermostat.
Also, even though you had just replaced it.....it is best to play it safe....and it is a cheap item.
I have a ScanGauge unit that I can leave connected to the OBDII port and see some of what is going on.
My temp stays very stable at about 190 to 192 degrees.
As they have told you, this is much more critical on modern engines for fuel efficiency and emissions.

I have also noticed that the engine goes from OPEN loop to CLOSED loop operations very quickly.....long before the engine is warmed up.....so the 180 degree thermostat would not keep you in open loop operation.
(Closed loop is using the Oxygen sensors for fuel trim, whereas open loop is using preset values from the PCM until the engine reaches operating temperature).
A critical factor in switching from open loop to closed loop is the OXYGEN SENSORS warming up to the optimum temperature......but they have a heater circuit that does just that.

The PCM uses a different temperature sensor than the dashboard gauge does....however the 2 sensors are located right next to each other.
One of the reasons that I got the ScanGauge was to be able to monitor the engine temperature as the PCM sees it.

For your towing situations......I would not worry at all about the thermostat value as the factory recommended, but I would make sure that the cooling system is operating correctly.
I have mentioned a few times....to verify that the low speed radiator cooling fan operation is taking place.
Turn the A/C on, and the cooling fans should be on and STAY on as long as the vehicle is not moving some minimum speed.
The low speed dropping resistor can fail (as mine did) and cause you to only have High speed radiator fan operation.
Now, when in stop and go traffic, I have the A/C on, which keeps the radiator fans running, which keeps the engine....and VERY IMPORTANT, the transmission cooler.
Your auxillary transmission cooler is only effective when there is air moving over it.

[searcherrr]

Originally Posted by phil-l

searcherrr -

Wow! You've had a tough day. Trust me, you have my sympathies. Problems like this are bad enough - without trying to fix them while on the road.

So... What actually failed on the water pump to cause the overheating? Is this an impeller issue (my '95 Contour's water pump has a plastic impeller - an item noted for premature failure), or did the seal fail?

Yeah, if it's apart, I'd replace the thermostat. Though I'd avoid going cheap: A good one isn't that expensive, and the failsafe mechanism might save you someday.

If overcooling is a problem in the winter, I'd just go with the old standby solution: A piece of cardboard in front of the radiator to partially block airflow.

GREAT NEWS !!! VAN IS FIXED!! LEAVING HOTEL AFTER 4 DAYS TOMORROW MORNING!

Total damage at Ford dealership: $708 + $294 new 3rd party parts = $1002 (using Ford parts would've pushed it past 1200) They said the whole thing took 8.5 hours and they ran into some bolts that needed drilling out.

Phil and tomj76 - The van squeaked like mad for several months and always was at cold start and would go away after it warmed up. After I replaced the idler pulley, the tensioner, ps pump, and the belt, the squeaking got better or different each time as I tried to figure out the cause. I would've never thought it was the water pump cause I didn't know it spun with the crankshaft/belt system of pullies etc... due to my lack of ever having removed/installed a water pump before on any vehicle. So it was the seal that blew and it was leaking and steaming all over but it was also leaking from the front at the radiator which made me think it was a hose seal where it met the radiator, but it was the radiator itself. Also, MOST of the COOLANT went into the coolant reservoir on the initial overheating and again the radiator was nearly empty.

tomj76 - ouch on a HOLE in the tranny and 2 weeks + rental car etc.. OUCH OUCH.

I swear the van seems to have more POWER now. Maybe its my imagination, but it really does seem that way. I think the old water pump was causing engine drag. I really do. Here is one reason why... whenever I'd rev it in PARK and let it go to 3 or 4 RPMs the engine would seem to cycle up/down/up/down in RPMs between 3 and 4 never going beyond 4ish. Now when I do this procedure in park it just revs straight to 4ish and there is a slight bit of that old up/down/up/down in RPMs between 3 and 4, but is is WAAAAAAAAYYYY better.... almost gone. The squeaking experienced on startup is COMPLETELY gone and I would advise anyone with this problem especially on cold starts and goes away when warm to replace their water pump if they never have because at this point ALL 95 - 98 Windstars probably need it replaced anyway. I never did it cause I was actually talked out of it by one of the shops I had it in a while back, but I shouldn't have listened.

OPERATING TEMPERATURE - Someone help me out here. The van used to set its temp in the "A" on the word NORMAL on the temp gauge and sometimes it would graze the "M" or even go in the middle of it under towing in situations that provoke heat buildup. Now I am LUCKY if the temp touches the "A" at all and it stays at the bottom of the "L" and may GRAZE the "A" at times, but very seldom. I wish I knew what the temps were, but the fact that it is still in the range that says "NORMAL" is my only assurance aside from Ford stating to me again for a 3rd and 4th time that the 180 Thermostat is fine. I was just worried about that emissions stuff and running rich etc... and the CAT needing to be a certain temp to work right.. but again they state it's fine. If I have problem in the cold I've already looked up the procedure for replacing the thermostat and I'll probably do that if necessary and swap in a 190 F product. STILL I WOULD LIKE TO KNOW THE TEMPERATURE IN F STRAIGHT UP... ANY OF YOU KNOW A WAY I COULD FIND OUT WITHOUT ACTUALLY TEMP MEASURING THE HOT COOLANT? DATALOGGER? ANYTHING BESIDES A DATALOGGER? ARE THERE STICK ON OR PRESS ON TEMP GAUGES I COULD USE AGAINST THE BLOCK?

The cardboard thing is a good idea, but I'd probably rather a piece of sheet metal with 4 holes so I can security tie it through the radiator.

[searcherrr]

I'll check the fans tomorrow myself, but Ford said they were working cause I asked them to check them.

So by what you say I'll be in closed loop with the 180 tstat? Everything should be ok then right?

Originally Posted by wiswind

I would stick with the factory temp for the thermostat.
Also, even though you had just replaced it.....it is best to play it safe....and it is a cheap item.
I have a ScanGauge unit that I can leave connected to the OBDII port and see some of what is going on.
My temp stays very stable at about 190 to 192 degrees.
As they have told you, this is much more critical on modern engines for fuel efficiency and emissions.

I have also noticed that the engine goes from OPEN loop to CLOSED loop operations very quickly.....long before the engine is warmed up.....so the 180 degree thermostat would not keep you in open loop operation.
(Closed loop is using the Oxygen sensors for fuel trim, whereas open loop is using preset values from the PCM until the engine reaches operating temperature).
A critical factor in switching from open loop to closed loop is the OXYGEN SENSORS warming up to the optimum temperature......but they have a heater circuit that does just that.

The PCM uses a different temperature sensor than the dashboard gauge does....however the 2 sensors are located right next to each other.
One of the reasons that I got the ScanGauge was to be able to monitor the engine temperature as the PCM sees it.

For your towing situations......I would not worry at all about the thermostat value as the factory recommended, but I would make sure that the cooling system is operating correctly.
I have mentioned a few times....to verify that the low speed radiator cooling fan operation is taking place.
Turn the A/C on, and the cooling fans should be on and STAY on as long as the vehicle is not moving some minimum speed.
The low speed dropping resistor can fail (as mine did) and cause you to only have High speed radiator fan operation.
Now, when in stop and go traffic, I have the A/C on, which keeps the radiator fans running, which keeps the engine....and VERY IMPORTANT, the transmission cooler.
Your auxillary transmission cooler is only effective when there is air moving over it.

[phil-l]

searcherrr -

I'm pleased you're finally back on the road, after a very tough week.

I've seen water pumps fail like you describe. When they go, it's all over in a very short time.

I have run into situations where a squeaky water pump was just a noisy seal; the bearings were fine. A small amount of quality non-detergent oil dripped into the water pump's weep hole (you'll see this hole in the water pump casting, near the shaft) was enough to quiet it in some cases. While I'm hesitant to recommend this to everyone, I must admit I'm now in the habit of doing this on my own vehicles, just to make sure. It may or may not have made a difference for you back when the original squeak appeared.

The change in the temperature gauge reading tells me that there was some problem in the cooling system internals that was addressed by the work that was done. I won't speculate what it was, but the new gauge reading seems to confirm it. Of course, this is also a reminder to take seriously any new behavior in an engine, even if it isn't yet a problem. Addressing a minor issue today can avert a large problem in the future.

Sorry, I don't know of a quick, easy, cheap temperature gauge solution that reads in degrees. If you can find someone with a ScanGauge unit similar to what wiswind uses, you might borrow it, just to see how well the PCM temperature correlates with your gauge reading.

[searcherrr]

Originally Posted by phil-l

searcherrr -

I'm pleased you're finally back on the road, after a very tough week.

I've seen water pumps fail like you describe. When they go, it's all over in a very short time.

I have run into situations where a squeaky water pump was just a noisy seal; the bearings were fine. A small amount of quality non-detergent oil dripped into the water pump's weep hole (you'll see this hole in the water pump casting, near the shaft) was enough to quiet it in some cases. While I'm hesitant to recommend this to everyone, I must admit I'm now in the habit of doing this on my own vehicles, just to make sure. It may or may not have made a difference for you back when the original squeak appeared.

The change in the temperature gauge reading tells me that there was some problem in the cooling system internals that was addressed by the work that was done. I won't speculate what it was, but the new gauge reading seems to confirm it. Of course, this is also a reminder to take seriously any new behavior in an engine, even if it isn't yet a problem. Addressing a minor issue today can avert a large problem in the future.

Sorry, I don't know of a quick, easy, cheap temperature gauge solution that reads in degrees. If you can find someone with a ScanGauge unit similar to what wiswind uses, you might borrow it, just to see how well the PCM temperature correlates with your gauge reading.

Thanks PHIL !

Where does your temp run on your 2000 Windstar? Is the NORMAL word on your gauge too in that year/model? You mean to say that now that my temp gauge is running on the "L" and grazing the "A" that this is a more nominal temperature range?

[phil-l]

searcherrr -

Truth be told: I can't recall at the moment. The van is normally my wife's daily driver, so I need to verify.

And most of my recent Windstar work has been ABS related. I'll be posting on what I've learned soon...

[searcherrr]

Hello. I am stuck on the road again 14 miles from where I was. Coincidentally I did not pull over for coolant related issues. The van was oversteering like a boat in water. I found that all my tires were inflated to 36 psi. I'd put them all at 34psi before I left on my trip so Ford must've done this or the cold weather? In any case it was dangerously noticeable. I dropped them all down to 33psi. I just originally had wanted a lil more pressure due to towing, but maybe thats a wrong thought?

Anyway, as soon as I was checking the tire pressure and in PARK I immediately heard the cooling fans spin up to HIGH and knew something was wrong. Went in and checked the van temp gauge and it was nearly at H again. I immediately shut it off. No leaks. No hissing. But the coolant IS/WAS at the TOP of the coolant reservoir. I had thought about the coolant sensor or switch, but the physical coolant being that high makes me suspect REAL overheating yet again. Valves? Cylinders? Coolant leaking into oil? Blockage in the engine coolant passages themselves? Wouldn't a blockage have come out during pressure testing?

OMG I'm so fed up. I cannot keep spending money at a hotel etc..

wiswind - both fans work when A/C = ON.

HEEEELLLLLLP ! lol - i am at a Hampton where I had to beg to use internet access letting the van cool off and then heading back to Ford. If it is something that will take beyond today I'm heading back home and will have to postpone my move to the North with m gf.

EDIT: Could the CAT be clogging due to use of the lower F tstat? Seems not though... doesn't seem like it would clog that fast... but who knows and also I know symptoms of a clogged cat are that the temps raise at high speeds and not during idle in park or low 1st or 2nd gear driving.

[phil-l]

searcherrr -

Oh no! Sorry to hear the problem has apparently returned.

I must admit, I'm not quite sure where to head right now - but I'll share what I know about the issues you mentioned.

- Cold weather usually causes a drop in tire pressure. I don't have an explanation for the pressure change. It wouldn't seem the shop would have a reason to touch the tires. That said, I prefer a slightly high tire pressure in my Windstar, even when towing. I usually run about 35 psi, and have noticed no handling problems. Overly-inflated tires can reduced the size of the tire's contact patch, which can cause a "floaty" feeling.

- A cooling system pressure test does *not* check for blockages. It can only verify that there are no leaks in the system. Think about it: If there's something impeding coolant flow in the passage, it doesn't affect the static pressure of the system. Sadly, it can affect the system's ability to cool the engine.

However, I'd like to think that any evidence of a blockage would be noticed when the water pump, radiator and thermostat were being changed. Did the shop mention anything they discovered?

Any leak between a combustion chamber and the cooling system should have bee noticed during the pressure test. A leak between the oil system and cooling system will result in either oil in your coolant, or coolant in your oil. Is there evidence of either? Check your engine oil dipstick - do you see foam or rust on the stick?

A few questions:

- Has the van's interior heating system seemed to work fine during all of this? Obviously, cranking up the heat in the van helps to get rid of engine heat, and is an old trick to help in an engine overheat situation. Does it always blow hot as soon as the engine is warm? Does your van have a rear heater? Does it blow hot, too?

I just had a thought: The last time I changed the engine coolant in my Windstar, I had a lot of problems getting rid of air bubbles that formed in the heating system (my van has the rear heater, so there are coolant lines heading to the back). I noticed that the heater would blow cold, even though the engine was warm. I found a nearby hill, and drove up and down it several times. The coolant level in the reservoir would drop, and I had to add fluid several times until it stabilized. Air bubbles in your system could prevent it from cooling the engine properly.

Since the shop just did a lot of work on it, I'd get back with them and see if this latest experience can help them understand - and finally solve! - the true underlying problem.