Is there a good thermostat solution?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

thefunk wrote:

I've got the HDS unit in mine. Yes, Expensive. But guess what, you bought a vehicle with known engineering failures, and the factory thermostat is at the top of the list. If you plan on keeping the rig for anything near 100k miles, bite the bullet and do it. The engine heats up as quick as a gasser, the heater will finally melt ice off your windshield, and you'll be WARM even when it's darn cold outside. The temp gauge will stay firmly planted exactly where it should be no matter what the weather is or what you're doing with it. Could you modify a factory gauge? Sure, but unless you're a machinist with a penchant for working with aluminum and pot metal assemblies that never were meant to be screwed with, and you have no other hobbies or interests in life other than proving it can be done (which is a fantastic hobby, don't get me wrong) you're going to have tens of hours invested into solving a problem that could be solved in about 5 minutes with a hit to your credit card that you'll forget about a month or 2 later when you're cruising around in sub-freezing weather with toasty feet.

And at the end of the day, when you open the hood up you get a nice anodized assembly to look at, not JB weld and hose clamps.

This is one of the best explanations I have read from one of my customers for why any CRD owner should purchase a H.D.S. Model 001.

But I will add that, even after spending a huge amount of time modifying your O.E. thermostat housing, you will NEVER come close to the quality, extra features and performance the Model 001 offers.
You simply can't expect a O.E. cast aluminum housing to compete with clean sheet design serviceable housing engineered specifically for a larger thermostat valve and manufactured using 6061 T-6 machined aluminum. There will always be some doubt that your modified housing will fail, while the Model 001 will perform way better and will never fail.

CRD owners have been modifying O.E. housings for years now. Modifying another one will not be breaking any new ground here.

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

The cheap thermostat is in and the needle stays between the 12 o'clock tick and the one to the left. I am guessing that means that 188 is about the actual operating temperature of the thermostat. I will see if the cheep code reader I have lets me monitor tempt to confirm. I do wish it got to operating temp a little faster.

Dent · **Joined:** Sat Aug 04, 2012 11:05 pm **Posts:** 275

Cheap, good, fast(easy). Pick any two.

Cheap and good, Kap's solution, definitely not fast(easy)
Cheap and fast(easy), the OEM thermostat, not good, you'll be buying another and it's a low temp
Good and fast(easy), the HDS001, not cheap, but nothing on these vehicles is cheap

Oh you could also have cheap, fast, and bad. That's the Crown.

fool4wheelin · **Posted:** Thu Jun 21, 2018 12:47 am

Science and Energy wrote:

The cheap thermostat is in and the needle stays between the 12 o'clock tick and the one to the left. I am guessing that means that 188 is about the actual operating temperature of the thermostat. I will see if the cheep code reader I have lets me monitor tempt to confirm. I do wish it got to operating temp a little faster.

From looking at the dates on this thread did it really take you a year to swap out your thermostat?

Dent wrote:

If you live in a cold climate, you will love the HDS001 when you turn on your heat. I'm in Colorado, and in the winter, I have heat in a 1/2 mile of driving or so. With the OE stat, even when it is working, it took forever to get heat from the car, and it wasn't really very warm on cold days.

This statement makes no sense to me, the HDS raises the thermostat "opening" temperature, but this has no effect on how "fast" the vehicle can warm up and put out heat. Last time I checked 176°F should be warm enough to blow hot air out of the vents.

Dent wrote:

Then there's the mileage argument, but as far as I'm concerned, the fast warm up and doing the job once is well worth the cost.

How much of a mileage improvement can be realized from the HDS thermostat?

I've considered the HDS thermostat, I've just had to put my time & money towards other things on my CRD (GDE Tune, Euro TC, fuel filter head, timing belt, head, head gasket, glow plugs, etc.)

If you had to pick between the in-tank lift pump and the HDS thermostat, which would you choose?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

fool4wheelin wrote:

Science and Energy wrote:

The cheap thermostat is in and the needle stays between the 12 o'clock tick and the one to the left. I am guessing that means that 188 is about the actual operating temperature of the thermostat. I will see if the cheep code reader I have lets me monitor tempt to confirm. I do wish it got to operating temp a little faster.

From looking at the dates on this thread did it really take you a year to swap out your thermostat?

Dent wrote:

If you live in a cold climate, you will love the HDS001 when you turn on your heat. I'm in Colorado, and in the winter, I have heat in a 1/2 mile of driving or so. With the OE stat, even when it is working, it took forever to get heat from the car, and it wasn't really very warm on cold days.

This statement makes no sense to me, the HDS raises the thermostat "opening" temperature, but this has no effect on how "fast" the vehicle can warm up and put out heat. Last time I checked 176°F should be warm enough to blow hot air out of the vents.

The O.E. thermostat tends to fail prematurely... if it fails in the manner it is designed, the thermostat valve will begin to fail to close tightly. This affects warm-up times and how much heat gets into the cab. Also to consider is the difference in operating temperatures of the engine... 203 degrees Fahrenheit verses 176 degrees Fahrenheit makes a world of difference in the cabin... remember that some heat is lost along the way from in the heater core circuit, as well as the heat losses in the cabin. From living in a very cold climate, I can tell you the difference is like night and day.

Dent wrote:

Then there's the mileage argument, but as far as I'm concerned, the fast warm up and doing the job once is well worth the cost.

How much of a mileage improvement can be realized from the HDS thermostat?

You should see an improvement of about 10%... less so if you are living in a hot climate, more so if you are living in a very cold climate. Remember there are always other factors at play when you discuss issues of mileage... total condition of the vehicle, state of tune and condition of the engine, etc., etc. When I changed out my failed O.E. thermostat for a Model 001, I realized a 30% increase in fuel economy in the dead of a Canadian Winter. Also remember to consider that operating the CRD engine at 203 degrees will keep the engine well above the temperature where the viscous heater would kick in. The viscous heater, when engaged, is a parasitic drag on the engine and hence a fuel gobbler.

I've considered the HDS thermostat, I've just had to put my time & money towards other things on my CRD (GDE Tune, Euro TC, fuel filter head, timing belt, head, head gasket, glow plugs, etc.)

If you had to pick between the in-tank lift pump and the HDS thermostat, which would you choose?

I would definitely do both. The lift pump is important, but running your engine SAFELY at a proper operating temperature is even more important. If you are going to do the lift pump, rough in the dip tube and hose for a Webasto TSL17 heater while you have that fuel tank lowered. It is cheap to obtain the parts from a local Webasto dealer, and then you can conveniently install the heater at a later date when you can pony up the cash.

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

It was a year that my Jeep sat broken.

I am going to try and watch the temp using the OBDII reader on the way to work today.

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

It never got to full operating temperature. The drive is 19 miles (25 minutes), it is cool (65), and at 55mph going the back way I hardly touch the throttle peddle to keep it going.

Is this typical for other Liberty CRD drivers? Someone at work who drives an ecodiesel Dodge said he experiences the same.

When it is hot out it gets to full temp in that drive. Maybe on the way home I will get a normal operating number to report.

fool4wheelin · **Posted:** Thu Jun 21, 2018 8:28 am

Science and Energy wrote:

It never got to full operating temperature.

Could you elaborate on what you mean by this? Does your needle not get "almost" to 12 o'clock or are you going off of a temp reading from your scanner?

It can take a while to hit operating temp sitting at an idle, but under normal driving conditions should only take a few minutes (I will time on my way into work this morning). I have no issues warming up when below 0°F outside either.

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

I get to nearly 12 o'clock (between the 12 tick and the one to the left) when at normal operating temp. I think I didn't get there this morning for the reasons sated before. I really take it easy on the throttle to keep MPG up.

Thanks for gathering the information about yours. What thermostat are you using?

Dent · **Joined:** Sat Aug 04, 2012 11:05 pm **Posts:** 275

fool4wheelin wrote:

Dent wrote:

If you live in a cold climate, you will love the HDS001 when you turn on your heat. I'm in Colorado, and in the winter, I have heat in a 1/2 mile of driving or so. With the OE stat, even when it is working, it took forever to get heat from the car, and it wasn't really very warm on cold days.

This statement makes no sense to me, the HDS raises the thermostat "opening" temperature, but this has no effect on how "fast" the vehicle can warm up and put out heat. Last time I checked 176°F should be warm enough to blow hot air out of the vents.

Get one and it will make perfect sense living in North Dakota. I am not the only one to comment on how fast the car warms up to provide heat with the HDS001. I'm also not a fanboy trying to reaffirm my purchase. I've spent a ton of money on this CRD KJ, some well spent, and some wasted. If the HDS001 did not pan out, I would be one of the first criticizing it. TDF offers some explanations above. I think the difference in the OE temp of ~176 F vs. 203 F is the most contributing factor.

fool4wheelin · **Posted:** Thu Jun 21, 2018 10:29 am

Science and Energy wrote:

What thermostat are you using?

I'm using OEM thermostat.

It took my engine ~5 min to reach operating temp on the way to work this morning, but that was in-city driving with a few minutes waiting at stoplights. When going home I'm right on a 55 mph road and I hit operating temp within a few minutes.

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

fool4wheelin wrote:

Science and Energy wrote:

What thermostat are you using?

I'm using OEM thermostat.

It took my engine ~5 min to reach operating temp on the way to work this morning, but that was in-city driving with a few minutes waiting at stoplights. When going home I'm right on a 55 mph road and I hit operating temp within a few minutes.

What was the temp outside?

fool4wheelin · **Posted:** Thu Jun 21, 2018 3:57 pm

Science and Energy wrote:

What was the temp outside?

70°F

flash7210 · **Posted:** Thu Jun 21, 2018 6:28 pm

How are you determining if the engine is reaching operating temperature?
Just the needle position on the factory gauge?
Or something with actual numbers in Fahrenheit or Celsius?

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

Just the factory gauge. The cheap OBD code reader doesn't seem to show the Coolant temp. I will need to look for my blue tooth adapter and look at it with torque.

GordnadoCRD · **Posted:** Fri Jun 22, 2018 1:05 am

fool4wheelin wrote:

Dent wrote:

If you live in a cold climate, you will love the HDS001 when you turn on your heat. I'm in Colorado, and in the winter, I have heat in a 1/2 mile of driving or so. With the OE stat, even when it is working, it took forever to get heat from the car, and it wasn't really very warm on cold days.

This statement makes no sense to me, the HDS raises the thermostat "opening" temperature, but this has no effect on how "fast" the vehicle can warm up and put out heat. Last time I checked 176°F should be warm enough to blow hot air out of the vents.

This is kind of a misleading statement. True, it doesn't perform any additional function from the OEM T-stat. But the OEM T-stat does a relatively poor job in performing the warm-up function, mostly due to poor factory machining tolerances relating to the bypass valve. As the HDS-001 corrects this flaw, and fits a larger capacity T-stat valve, it actually does come to operating temperature more quickly than OEM, in addition to give the option of a range of higher operating temperatures. So the point is not that it's different. It's just that it's better.

flash7210 · **Posted:** Fri Jun 22, 2018 8:37 am

Warm up time is subjective.
Ambient temperature and driving conditions will effect warmup time.
In the winter, driving with the heater on will effect warmup time.

What’s important is whether or not the thermostat is opening at it’s prescribed temperature.
If the prescribed temperature is 190F and you see that the engine temp never gets above 180, then the thermostat is opening too soon (assuming that you don’t have the heater on).

Thermostats are cheaply made and are not precise devices.
Some open a little sooner, some open a little later.
Most thermostats begin to open at their prescribed temperature and are not fully open until 10-15 degrees above that.

fool4wheelin · **Posted:** Fri Jun 22, 2018 12:44 pm

GordnadoCRD wrote:

But the OEM T-stat does a relatively poor job in performing the warm-up function, mostly due to poor factory machining tolerances relating to the bypass valve.

I'm don't disagree this may be the case, but are you basing this claim off of real world experience or do you have actual data from a sample of thermostats showing inconsistent internal dimensions? The OEM thermostats I've seen all appear to be made by "Behr", which I'm assuming have some level of competence and history of supplying the auto industry. Many have stated the OEM thermostat fails in the "open" position, so replacing a degraded themostat with either new OEM or HDS will improve warm up times. Thermostats fail, it's just that to repalce ours is a $120 hit to the pocketbook.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

flash7210:

"Thermostats are cheaply made and are not precise devices.
Some open a little sooner, some open a little later. "

Not the H.D.S. Model 001.... it is most definitely NOT cheaply made. :mrgreen:

The thermostat valves themselves are plenty precise enough for the function they perform. For example, the differences in opening temperatures of two different properly functioning brand new Hemi engine thermostat valves that have the same opening temperatures are so small that the end result would be difficult to detect, even using the same engine in laboratory conditions using precise measuring equipment. In a real world application there really is no difference at all.

It is only when the thermostat valve starts to fail that you get a corresponding degradation in precision. The precisely machined housing in a Model 001 helps a little bit, but when a thermostat valve starts to fail open, precision in regards to temperature control starts to fail as well. This is why I made the Model 001 serviceable... as soon as the valve is starting to fail, you can replace it for about $25.00 maximum and about an hour or so of your time.

"Warm up time is subjective.
Ambient temperature and driving conditions will effect warmup time.
In the winter, driving with the heater on will effect warmup time."

All of the above is correct, although there are other factors at play as well....see below.

"What’s important is whether or not the thermostat is opening at it’s prescribed temperature.
If the prescribed temperature is 190F and you see that the engine temp never gets above 180, then the thermostat is opening too soon (assuming that you don’t have the heater on)."

This essentially agrees with my contention that precision in temperature control is almost entirely the function of the valve itself... what you are describing here, flash7210, is a failed thermostat valve. The best quality thermostat valves never have that level of imprecision when they are new and fully functioning... they would be rejected outright if a run of 190 degree valves were to start opening at 180 degrees.

GordnadoCRD:

"But the OEM T-stat does a relatively poor job in performing the warm-up function, mostly due to poor factory machining tolerances relating to the bypass valve."

You are correct the OEM thermostat assembly does a poor job of warming up the engine, but it is not due to the housing. The die casting technique used to manufacture the housing, (there is no machining performed on the O.E. thermostat assembly at all), is plenty precise enough for the particular function it is tasked with. It is the quality of the thermostat valve inside that determines how precise the temperature control of the engine it is used in. O.E. thermostat assemblies have proven to be rather poor in quality , as they seem to require changing out every 50,000 miles or so. O.E. type thermostat assemblies manufactured by Crown and other such Chinese knock-off companies have an abysmally poor quality record, and can even catastrophically fail. :shock:

I will state again that the opening temperature DOES play a factor in how quickly the engine warms up. A hotter thermostat valve is held tightly closed for a longer time before it starts to open up than a cooler thermostat valve.

Another factor that effects warm-up times is the mechanical cooling fan. It is always moving because the viscous clutch is never fully disengaged, and therefore continually blows air over the engine. At very cold temperatures this will make a difference, and that is why I advocate that CRD owners should switch to an electric cooling fan, unless you are towing very heavy loads in hot weather.

The question I have for some of the doubters on this thread is... why is it so difficult for them to believe the claims of the CRD owners who use the HDS Model 001?

Science and Energy · **Joined:** Thu Mar 30, 2017 9:12 am **Posts:** 246

Well the cheap Chinese thermostat has begun to act up bad. It never did a perfect job of keeping the temp up. When it did, it was closer to the 12 o’clock position. It is getting up to temp seldom now. It stuck once. Not sure what the typical thermostat lifespan is for these but 18 months isn’t cutting it for me. My other vehicles had thermostat last many times longer.

How much is the HDS again? I only remember it being a lot. I may just go with the 188 degree Stant 50388.

Is there a good thermostat solution?

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