Replace Thermostat with Higher Opening Temp?

DOC4444 · **Posted:** Sun Aug 16, 2009 11:50 am

GDE's coolant temp diagram suggests that when most CRDs are not being stressed with high ambient temps and tow loads, they may be running at around 170 deg Fahrenheit. This would seem low for optimal mileage/power. My experience with 4 cyl normally aspirated race engines (Formula Ford 1600) is that they run most efficiently between 185 and 210.

An additional benefit for our CRDs would be better cabin heat in cold weather.

BTW, the viscous heater costs a full 3 MPG in our extensive back to back testing.

We run with the VH relay removed at all times (No CEL, BTW) and use a FIA blanket in the winter.

Anyone (GDE?) care to weigh in on finding a thermostat that opens at a little higher temp?

DOC

Diggerfreek · **Posted:** Sun Aug 16, 2009 11:56 am

I may not be from GDE, but I can tell you that 95% of all Caterpillar engines run either 180 or 185 thermostats on the industrial engine and heavy machinery side. Now the other 5 percent makes up the heavy duty truck segment. They run either 210's, 215's or 220 depending on the model of engine....

Fulltimer · **Posted:** Sun Aug 16, 2009 1:06 pm

My locale Jeep dealer said that changing it would cause problems with the computer. Now that is for the 3.7L, don't know about the CRD.

Terry

DarbyWalters · **Posted:** Sun Aug 16, 2009 2:04 pm

Being in Texas...I guess I should run with the VH Relay pulled. Where is it located?

warp2diesel · **Posted:** Sun Aug 16, 2009 3:51 pm

.....Good Luck swapping it out for a higher temp thermostat.

In the Land of Theory, a Diesel engine would run more efficient at 275f coolant temp instead of the 180f - 215f range. When Delta Hawk Engines were in the development stage and I interviewed for a job that never materialized, Doug (the owner)wanted a coolant that could be tested at 275f, I suggested Propylene Glycol. Some Gear Heads who want to push the envelope have run straight Propylene Glycol at 275f and have had improved mileage. One trick they have used is running a Zero PSI radiator cap since Propylene Glycol does not boil at 275f. I do not know if Delta Hawk is running their Diesel Aircraft Engines at 275f, I can't afford to buy one or the experimental aircraft to mount it in to find out.
Another alternative coolant is oil, some small diesel engines use oil in their coolant jackets.
Cummins had a test engine under development with ceramic pistons and cylinders and no coolant system, I don't know what ever happened.

As a general rule, the thinner the cylinder walls/liners are the higher the temp is required to have the cylinder temp optimal (for normal ethylene glycol coolant).
To put this in simple English, if you want to run a low temp coolant have thick cylinder walls and the cylinder temp will be optimal, thinner cylinder walls you run a higher coolant temp.

For me VM has done a good job of Engineering, any of the bugs we have to put up with are due to Stupid Government Legislation and Stupid Bean Counter Over Rides on Chrysler Engineers at the time. Ya, cost containment is a good thing, but in my Personal Experience, Bean Counters will waste $100,000.00 to save $1.00, just to say they are doing their job. Any good Engineer with a gram of pride in his/her work will go way beyond expectations in developing a great product at a reasonable cost with out the Stupid Bean Counter in his/her way. All they need is some guidance and defined goals, not some moron with the one word vocabulary,"CUT".

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The KJ CRD thermostat starts opening at 176 F. The newer engines from VM sold in Europe have thermostats that start opening at 190 F. The higher coolant temps do help the efficiency on this engine. Not sure if a higher temp thermostat is available. It is a sealed unit on the KJ and not very serviceable.

DOC4444 · **Posted:** Sun Aug 16, 2009 10:46 pm

Darby,

The viscous heater relay is in the box under the hood. You can find it on the diagram. It seems to kick-in at about 35 deg fahrenheit. The relay only runs the VH so removing it does not affect anything else and no CEL is set. (We only put it in for dealer warranty visits so everything is dead stock.)

GDE,

Sounds like the "new" thermostat might help power, economy and "economical" cabin heat in winter. But , do they expect us to replace the motor if the thermostat sticks closed and needs to be replaced? Please keep us posted if you come across a reasonable way to install a higher temp thermostat (a secondary one, perhaps?).

DOC

nursecosmo · **Posted:** Mon Aug 17, 2009 12:30 am

Would one of these work? You would need to use a thermostat with a builtin bypass so that the hose didn't just stay full of cold water. Or just drill a small hole in the thermastat plate.
http://www.specialist-components.co.uk/ ... egoryID=36

http://web.tiscali.it/elise_s1/

http://files.qedmotorsport.co.uk/k-seri ... itting.pdf

Another much cheaper option is to mate two thermostat housings together so that a hose fitting is on each end, then just splice into the radiator hose. Two of these might work. http://www.jegs.com/p/JEGS/JEGS-Aluminu ... 6/10002/-1

nursecosmo · **Posted:** Mon Aug 17, 2009 12:35 am

This one looks even better. http://www.wilsonmanifolds.com/shop/ind ... tail&p=100
Or this one. http://store.atechmotorsports.com/egnse ... toview=sku

danoid · **Posted:** Mon Aug 17, 2009 8:45 am

I ran without the viscous heater relay for one year. Then I noticed that dirt was getting in the empty socket. With a pair of really small screwdrivers you can remove the cover from the mini ISO relay. Once the cover is off - rip out the armature. Replace cover - replace relay - no more corrosion problems from dirt/water in empty relay sockets and no actuation.

I also did this for the fuel heater relay.

warp2diesel · **Posted:** Mon Aug 17, 2009 9:55 am

GreenDieselEngineering wrote:

The KJ CRD thermostat starts opening at 176 F. The newer engines from VM sold in Europe have thermostats that start opening at 190 F. The higher coolant temps do help the efficiency on this engine. Not sure if a higher temp thermostat is available. It is a sealed unit on the KJ and not very serviceable.

Correct me if I am wrong, but the new VM 2.8L has an Aluminum Alloy block. Aluminum dissipates more heat for given surface area than cast iron. Since the aluminum disapates more heat, it will allow the block to supplement the heat rejection of the radiator. Since the Engine and the thermostat was designed by VM for which I have more respect than the Rampant Chrysler Bean Counters, I am sure that they carefully considered the opening temperature of the thermostats for both generations of engines. I am sure that with all of the sophisticated equipment VM has used in their engine development they have taken into consideration the temperature of the pistons, cylinder liners, and cylinder head when they chose the opening temperature of the thermostats for both generations of engines.
To put in simple terms VM Engineering = Well Thought Out.
Chrysler Engineering = Battle wounded and overly compromised by Bean Counters with a few good ideas managing to get through.

VM Produces a Quality Product for multiple applications that far exceed any Chrysler Specifications.
GDE has the incite and inside sources for what ECM tune features and other performance options were compromised away by Bean Counter Nagging and Management Poppas Arrogance who think that we the end users are Stupid.

For someone who has a bunch of mods, I will leave great enough alone and not mess around with VM has done a Great Job of Engineering, such as the opening temperature of the thermostat.
For the Chrysler Bean Counter Compromise Excuses, I will mod them away.

warp2diesel · **Posted:** Mon Aug 17, 2009 9:57 am

danoid wrote:

I ran without the viscous heater relay for one year. Then I noticed that dirt was getting in the empty socket. With a pair of really small screwdrivers you can remove the cover from the mini ISO relay. Once the cover is off - rip out the armature. Replace cover - replace relay - no more corrosion problems from dirt/water in empty relay sockets and no actuation.

I also did this for the fuel heater relay.

35f seams a little high to kick in a viscous heater, is there any way to change it to something like 0f?

Let me guess GDE is working on it.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The block on the newer generation VM engines is still cast iron. The difference is the KJ uses liners and the new engines do not. This changes the cooling channels around the cylinder bore.

As for the viscous heater, GDE can tune the on/off settings as desired by the customer. In cold weather, the VH is a benefit for the first 5 minutes to speed the coolant warm-up, after that it is useless.

CATCRD · **Posted:** Mon Aug 17, 2009 12:04 pm

warp2diesel wrote:

danoid wrote:

I ran without the viscous heater relay for one year. Then I noticed that dirt was getting in the empty socket. With a pair of really small screwdrivers you can remove the cover from the mini ISO relay. Once the cover is off - rip out the armature. Replace cover - replace relay - no more corrosion problems from dirt/water in empty relay sockets and no actuation.

I also did this for the fuel heater relay.

35f seams a little high to kick in a viscous heater, is there any way to change it to something like 0f?

Let me guess GDE is working on it.

It's actually about 45ºF based on observing my CRDs. I run with the relays removed until it's below freezing.

warp2diesel · **Posted:** Mon Aug 17, 2009 1:02 pm

GreenDieselEngineering wrote:

The block on the newer generation VM engines is still cast iron. The difference is the KJ uses liners and the new engines do not. This changes the cooling channels around the cylinder bore.

As for the viscous heater, GDE can tune the on/off settings as desired by the customer. In cold weather, the VH is a benefit for the first 5 minutes to speed the coolant warm-up, after that it is useless.

Good thing to know, Parent bore engines do not have the concern with cylinder seals like the wet sleeve engines do. That must be why VM could go to the 190f thermostat and raise the efficiency.
I can remember when I was younger the problem John Deere had with their wet sleeve engines blowing out the "O" rings on the liners. I swapped out a bunch of liners that summer I worked as an Intern in a John Deere dealership. Improved "O" ring material and Improved coolants have put problems like John Deere had into the History File and even the engines that had that problem in the past have all been fixed by now.
My experience as an Intern years ago may be why I am cautious on jacking up the opening temperature on thermostats with wet sleeved engines.

DOC4444 · **Posted:** Mon Aug 17, 2009 3:14 pm

With GDE assuring us that running these rigs for hours at max power at 239 degrees is nothing to worry about, I find it hard to believe that using a thermostat that opens at 190 instead of about 170 is likely to be a problem.

DOC

CRD Joe · **Posted:** Mon Aug 17, 2009 3:14 pm

So can we get these higher temp thermo's or not?

CATCRD · **Posted:** Mon Aug 17, 2009 3:23 pm

Our thermostat is sealed inside an aluminum housing that bolts to the block or head, I forget which. Search sir sam's posts, he had a couple pictures of it taken off.

Sir Sam · **Posted:** Mon Aug 17, 2009 3:33 pm

CRD Joe wrote:

So can we get these higher temp thermo's or not?

Short answer, no.

You would need to find a spare housing, open it up, find a thermostat that could fit in place, and then modify the housing to be reusable. I kinda have that in mind for the future.

CATCRD wrote:

Our thermostat is sealed inside an aluminum housing that bolts to the block or head, I forget which. Search sir sam's posts, he had a couple pictures of it taken off.

Heh, more than a couple(something like 20 pictures of one thermostat), though I don't have those pictures only anymore.

warp2diesel · **Posted:** Mon Aug 17, 2009 3:49 pm

Start with a piece of mahogany, make a model, split it, mount it on a piece of 3/4" plywood, make a core box and start pounding sand.

http://en.wikipedia.org/wiki/Sand_casting

You can make anything you want, I would use scrap aluminum cylinder heads for my raw material.

been there done that.

Have fun

And Good Luck, may you prosper and sell a lot of thermostat housing upgrades

Replace Thermostat with Higher Opening Temp?

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