CRD Safe Operating Temperature?

Fossil Free Fuel · **Joined:** Fri Nov 30, 2007 10:18 pm **Posts:** 6

I've searched, I've combed over the FSM and I've talked to many a Jeep Tech that have no idea what they're doing... So here are the questions:
What is the average operating temperature your seeing on the Liberty?
What is the highest safe temperature for the Liberty?
Heres some background for the question:
We are a vegetable oil fuel system design company and we've converted an 05 Liberty. We had a hard time with warm up and have for the moment added an electric fuel heater to the system. We converted this in the fall and were seeing good VO temps (165-180) but we've never seen the coolant temperature much above 170 F. Its been hovering around 163-165 F. First course of action was to make a grille cover. So we cut plates and to block a significant amount of the airflow. This gained us maybe a degree. Then we changed the thermostat. Changing the thermostat was annoying but all in all did nothing for the temperature.
From what i understand of the Liberty it runs cold, the FSM states the thermostat mediates the temperature to 173 F. Our fuel system relies on a series of coolant based heat exchangers and we're used to seeing 180-210 F coolant temps. This gives us our desired 160 F VO without an issue. With the Liberty coolant temp of 165 that were getting we need electric assist to achieve the proper temperature of the VO. That being said its not really all that cold and we don't have snow on the ground here (Pittsburgh) yet so I'd like to bring the temps up before we have to deal with colder temperatures. So thus far we've changed the thermostat (manifold) and added grille covers. My thoughts on warming it up are either machining a new manifold that will mount to the block and accept a standard thermostat of a higher rating or regulate the coolant flow to the radiator with a valve. The benefit of the new manifold is that it could be applicable for anyone with the liberty so that they could replace a thermostat like a normal application rather than a 200 or so dollar integrated manifold. The benefit to us is we could model it after say the powerstroke thermostat or something that has a variety of temperatures available. The second option is to install a valve in the upper radiator hose to manually restrict coolant flow to the radiator. This gives the ability of adjusting more flow in the summer or when towing and less in the winter. Our conversion utilizes a controller that gives a coolant temperature readout ( http://i2.tinypic.com/6two64k.gif ) so we can constantly monitor actual temperatures to ensure that the vehicle isn't overheating. So with that the FSM says 173 Our actual readout says 165 (we've changed the sender for our controller a few times to ensure it wasn't a bad sender or ground) and the dealers say between 140 and 210; what are your temperatures? Also, I've heard rumor that the European engines were overheating and blowing the head gasket which is why they brought the temperature so low. I haven't been able to confirm that and from searching it seems like there are folks that have ran up to 215-220 F when towing in the summer. So... What is the average operating temperature your seeing on the Liberty? What is the highest safe temperature for the Liberty?
Thanks in advance,
~Colin

Fossil Free Fuel · **Joined:** Fri Nov 30, 2007 10:18 pm **Posts:** 6

The Vo system draws hot coolant off the engine block through a series of heat exchangers traveling back to heat the tank then comes back to the front of the vehicle and back into the coolant path. Although we may be restricting the flow to the radiator if we added the valve, we have added a significant amount of cooling to the circuit.
Thanks,
Colin

bugnout · **Posted:** Wed Dec 12, 2007 9:33 pm

My CRD typically runs around 168, been up around 200 when towing, never got to the red line, engine seems to derate when it gets hot.

Interesting idea, but that CPU limiting when it gets warm might be something you have to overcome.

chrispitude · **Posted:** Wed Dec 12, 2007 9:35 pm

I don't know what our 2006 CRD runs at, but I dug out my OBD-II tool today so I'll be able to get some around-town measurements. I do know the needle got just under 3/4 when towing up some long grades last summer. I wish I knew what temperature that corresponded to. The fuel economy really drops in the winter with our CRD, so I wouldn't be surprised to learn that it runs a little too cold for peak efficiency.

- Chris

UFO · **Posted:** Wed Dec 12, 2007 9:38 pm

Interesting observations about the operating temperature. Might explain more fully why GFSs VO converted CRD died. Definitely keep those VO temperatures up and change your sump oil often.

DarbyWalters · **Posted:** Wed Dec 12, 2007 10:11 pm

I too have the upper grill blocked...you could block the lower section since it gets a good portion of cool air from that location. The problem is the CPU and temp control...you might need to find a way to defeat or modify the signal...like we have done to our SEGR boxes. Maybe you will HAVE to go with a mix of SVO and Diesel to keep things flowing?

Let us know how it goes!

Fossil Free Fuel · **Joined:** Fri Nov 30, 2007 10:18 pm **Posts:** 6

The gauge on this has never even really come up to half way it always sits a hair under...
Bugnout- CPU limiting? I think i may have not communicated that clearly. The user is able to monitor coolant temp consistently so if they saw the vehicle coming to higher than desired temperature they would be able to open the valve a bit to allow more flow... Unless your talking about a limp mode? My benz throws the vehicle into a limp mode if it starts to overheat.. im not sure what temperature that is actuated at but it can't be less than 210 because if i recall correctly folks towing have seen these temperatures without an issue?
Chris- if you have a chance to pull some numbers that would be much appreciated...
UFO- From my experience with the Liberty it seems like any less heat exchangers and your not getting the oil anywhere close to a desirable oil temp... That being said i don't know the conditions of the GFS engine failure and I've heard rumor that Grease car killed 2 as well. Frybrid is the only other company i know of that has converted one but they don't have any temperature monitoring and in theory the system will not switch until the coolant hits 180. Based on my observations they have lowered the switch over temp, done something to increase the temperature, or its never switching over.
~Colin

gmctd · **Posted:** Wed Dec 12, 2007 10:24 pm

Using a Chrysler enhanced-OBD2 scanner, I never saw any variation from ~165deg, unloaded, which is midway between the 1/4 and 1/2 marks - remembering that Diesels do not produce much BTU until loaded, you might want to load your test mule up with ~7500lb trailer, do some comparison runs on steep hills to determine what it puts out under stress with the oem tstat, such that the VO tstat does not become a potential 'nuther problem.

ECM regulates in-tank fuel temperature by regulating excess bypass fuel - it can take drastic steps to compensate if fuel temps are non-controllable, as they may be with re-engineered higher-temperature engine coolant resulting from VO-enhanced higher temperature tstat range.

You will not see the greater effect if not doing unloaded vs loaded testing

Uffe · **Posted:** Thu Dec 13, 2007 3:43 am

Fossil Free Fuel wrote:

Also, I've heard rumor that the European engines were overheating and blowing the head gasket which is why they brought the temperature so low. I haven't been able to confirm that and from searching it seems like there are folks that have ran up to 215-220 F when towing in the summer. So... What is the average operating temperature your seeing on the Liberty? What is the highest safe temperature for the Liberty?
Thanks in advance,
~Colin

I can dig into that for you. Give me a day or two to talk to some people about this overheating euro problem, I might be able to say something about it.

But first I need to know if what you're talking about is the 2.5CRD which was made for the euro market from 2001.

Regarding temps, I've never seen the needle cross 1/2, and I've towed a 2-horse trailer, loaded approximately to 2 tonnes.

chrispitude wrote:

The fuel economy really drops in the winter with our CRD, so I wouldn't be surprised to learn that it runs a little too cold for peak efficiency.

That's also caused by the higher air density when its cold outside. Air density relates directly to the drag force, and that will give the car some extra resistance to work against when its cold. You can also see it as the air is getting heavier, and the heavier the air is the more "weight" you need to wade through when driving. I work in the wind power industry and during winter we see some pretty hefty production from those wind turbines.

Here you can read a bit more about wind energy, if I didn't manage to convince you

http://www.windpower.org/en/tour/wres/enerwind.htm

bugnout · **Posted:** Thu Dec 13, 2007 10:31 am

Fossil Free Fuel wrote:

The gauge on this has never even really come up to half way it always sits a hair under...
Bugnout- CPU limiting?

I have a Scangauge II and monitor water temp while driving. so the 168 temp is what I see everyday. It doesn't vary much unless I'm towing.

I guess the CPU limiting I was refering might be the same ECM fuel temp management issue gmctd referenced, but I've also noticed that as the coolant temp starts to rise, I loose a bit of top end and performance from the CRD. I've always thought (with no actual evidence) that the ECM was protecting the engine from abuse. The performance (passing power) tends to come back once I get coolant temp back to normal.

My point is, if the ECM is monitoring fuel and coolant temp and effecting performance based on that data, then your going to have to figure out how to fool the ECM.

danoid · **Posted:** Thu Dec 13, 2007 10:39 am

I really only watch the coolant temp when towing (27' 5600# camper).

Flat around 90 degrees ambient: Temp slowly creeps up to 222, then hydraulic fan kicks in and slams it back down to 209. Temp slowly creeps to 222, repeat.

Flat 80 degrees ambient or lower: Temp stays around 215.

Most any grade: temp quickly goes to 220, hydraulic fan kicks in and keeps it there.

Only once: temp made it past 230, warning chime went off, started to lose power, waited until transmission hit 240, then converter clutch locked up in second, made it up on limited power, at top of hill both temperatures quickly went back to normal, kept on tugging...

hawk521 · **Posted:** Thu Dec 13, 2007 12:03 pm

According to my Scangauge II my Liberty CRD stabalizes at 164 degrees F and doesn't vary more than a degree or two under normal driving.

I suspect the slight variation between vehicles is due to the production tolerances of the thermostats. But it does appear from all the posts above that approx 165F is where the engine designers wanted it to run.

chrispitude · **Posted:** Thu Dec 13, 2007 12:25 pm

I never realized how cool these things run until we pulled it into the garage after running some errands. I popped the hood to let the engine cool off enough to change the fuel filter, only to find that the engine was cool enough to work on it with no problem.

- Chris

retmil46 · **Posted:** Thu Dec 13, 2007 1:07 pm

If you have the EGR disabled on this SVO conversion, that would go a long way to expalining why it runs so cold.

The exhaust gas cooler dumps a significant amount of heat into the cooling system. Since first running the ORM, I saw my warmup times driving to work essentially double. In cold weather, I can watch the temp gauge go down a notch just sitting at a stoplight, especially if running cabin heat.

I've seen the same thing at work - over the years, as they've added progressively more EGR into the driving cycle, the radiators we put on the OTR rigs have essentially doubled in size to handle the extra heat load from the EGR cooler.

I don't tow with mine, just commute to work 20 miles each way 45 to 55 mph some stop and go, and occasional run at 70 mph on the interstate, running at least basic ORM. Temp according to SG II fluctuates between 168 to 172.

If this SVO conversion is running ORM/SEGR and you're also pulling off heat more or less constantly to warm the SVO tank, I can understand why it would be running cold at all but high loads.

Fossil Free Fuel · **Joined:** Fri Nov 30, 2007 10:18 pm **Posts:** 6

The model that was converted is the 2.8L I'm sure there are design differences from the 2.5 so I'm not sure if the person relating the head gasket issue was referring to the 2.5 or 2.8 (if the 2.8 is even available in Europe?)
The EGR is not disabled but the SVO system does draw a significant amount of heat. So based upon the responses thus far normal temp seems to be 165-168 with no load and we seem to be alright until 230 or so when the safety overrides begin kicking in. The issue we may have to deal with is the fuel mapping as it relates to coolant temperature. So If we go ahead and install the valve, regulate the coolant temp to say 190 or 200 we should be alright assuming fuel mapping doesnt change too much at these temps. Thanks for all the responses...
~Colin
Heres the link to the thread with some photos:
http://biodiesel.infopop.cc/eve/forums/ ... 6061015222

gmctd · **Posted:** Thu Dec 13, 2007 4:10 pm

You can get a better profile by monitoring the Inlet Fuel Temperature sensor in the fuel manager head - ECM monitors that sensor to control in-tank fuel temperature, increasing cooler lift pump fuel bypass to offset hot fuel flow from the rail and injectors - should be a good indicator of CRD performance vs elevated fuel temps

Uffe · **Posted:** Thu Dec 13, 2007 4:29 pm

Fossil Free Fuel wrote:

The model that was converted is the 2.8L I'm sure there are design differences from the 2.5 so I'm not sure if the person relating the head gasket issue was referring to the 2.5 or 2.8 (if the 2.8 is even available in Europe?)

Most certainly is. In both Wranglers, Cherokees (Liberty in europe is called a Cherokee) and even dodge nitros.

If you go to vm motoris site www.vmmotori.it you can see that both the 2.5 and 2.8 had cooled EGR.

DarbyWalters · **Posted:** Thu Dec 13, 2007 4:33 pm

I also remember that at the time the 2005/2006 CRDs came out...there was a previous generation 2.8L CRD ... different from out own ... and now the newer Panther Version of the 2.8L CRD is out.

chadhargis · **Posted:** Thu Dec 13, 2007 9:23 pm

Wow! 33,000 gallons per acre per year. Sheesh! Why are we wasting time with soybeans?

flash7210 · **Posted:** Fri Dec 14, 2007 11:31 am

This is all very interesting...
So our little 2.8 has a normal operating temp of about 170F?
What is the thermostat set to open at?
Would operating temp closer to 200 provide better efficiency?
Can the T-stat be changed? (Probably not because it seems to be
contained in some sort of special housing)

For you ScanGauge guys, what temps correspond to stock gauge readings?
i.e. what temp is the engine when the gauge is right in the middle?

CRD Safe Operating Temperature?

Who is online