New to me CRD Back in Los Angeles, a few questions

SFHLibertyCRD · **Posted:** Tue Sep 03, 2013 12:22 am

Hello everyone, I just bought a CRD and drove it back from Pittsburgh to Los Angeles. Thankfully, things went fairly smooth (except for a hail storm in Nebraska that left two small dings). As of now, the ad is still up, and this is the car: http://www.autotrader.com/cars-for-sale ... ius=0&mmt=[JEEP[][]]&listingId=351185900

I didn't notice anything strange and the car drives great. It has a GDE FT Eco tune since 62k, EHM sometime in the 10k before that. I know almost nothing about the car before 55k.

I did have a few questions for those of you with more experience:

1) I was hoping I would get near 30+ mpg with GDE tune, but my max was 27+, and routinely got 26mpg. I kept it between 65-70mph, obviously almost exclusively highway, AC on and off throughout. How does this sound? Is it realistic to expect that I could get over 30mpg on a trip like this? If so, what should I start troubleshooting (I've read the NB guide, but haven't done anything yet).

2) I drove the car back in 3 days, with two ~900 mile days. On the second and third mornings (longest days), the radiator fluid light came on, but turned off a minute or two after starting the car and didn't come back until the next morning. The engine temp was normal throughout. Coolant looks to be an inch below the line in the tank. I don't believe the PO had any issues with leakage or coolant loss. Is this within normal specs to lose a little fluid? I do not know if it has ever been flushed from the original factory fill.

2) Most importantly, my MAF idle test (rocker health) is consistently a little on the low side of normal or just below. Around 16g/s at 800 feet above sea level. I plan on having the TB done at around 75k. Should I aim to do the rocker arms also? Would I expect to see an mpg gain after both TB and rocker arms are done?

I'll update this thread with additional questions as I have a closer look at the car. I have to undo the oil separator device installed to pass inspection here in California and take care of a few other things (TPMS sensors, etc.).

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Blown head gaskets seem to be common with the KJ CRD. I'd flush system, fill it to spec, and monitor closely and then make a decision. Good luck.

racertracer · **Posted:** Tue Sep 03, 2013 4:28 am

At first, a small amount of coolant loss is what I experienced while on long trips.

3 months and a few thousand miles later, the low coolant level light came on constantly, it lead to a major head gasket and cylinder head replacement.

I believe that if I had done the ARP studs at timing belt time when the coolant loss was small. I would have eliminated the warped head replacement.

Moral to the story.... do the studs at belt change if you have a slight coolant loss now, it is cheap insurance and the perfect opportunity to take advantage of eliminating future head gasket problems.

DOC4444 · **Posted:** Tue Sep 03, 2013 7:00 am

You are probably not correcting the typkcal 10% odo error, so your mileage is better than that. Yes, do rockers with ARP studs, water pump, etc.

DOC

SFHLibertyCRD · **Posted:** Tue Sep 03, 2013 9:13 am

DOC4444 wrote:

You are probably not correcting the typical 10% odo error, so your mileage is better than that. Yes, do rockers with ARP studs, water pump, etc.

DOC

DOC, does GDE tune correct for the 10% odo error?

Racer, I was afraid about that when I started googling around here for coolant loss. Sh**. Anyone know which ARP studs? Also, head gasket or just studs at this point?

I don't do my own work, so I can see how this will get costly . . .

papaindigo · **Posted:** Tue Sep 03, 2013 9:24 am

Just my opinion and as I recall you were pulling the EHM for inspection anyway but I would not reinstall the EHM as I don't think it's needed with a GDE tune.

Other comments:
1. I've dealt with 3 CRDs (2 05s and 1 06) and there is no "standard" speedometer/odometer error that you can count on although you can count on an error. IIRC industry standard is +-5% and the speedo/odometer errors do not correlate so you have to correct both. Speedo is easy to check with a GPS on any stretch of road that's relatively straight for a couple of miles. Odometer it's better to do a few 25mile+ runs on relatively flat and straight roads and then correct mpg based on the appropriate factor. You are driving an aerodynamic brick so anything over ca. 62 mph is cutting into your mpg, at 70 like 10% or so. Assuming proper tire pressure, corrected odometer, speed ca. 62mph/1,800rpm in final lockup (if the F-37 has been performed you need to run up to like 63-64 to get that final lockup and then drop back), not too hilly, minimal headwind, etc 30+mpg is reasonable. Any changes 28-29 is reasonable. 27 is a bit low but that's with an uncorrected odometer.
2. coolant level should be right at the line; 1" down is low. If you don't know about fluid it needs changing for new HOAT only antifreeze like Zerex G-05. There is a drain tool post over on the tech section that's helpful and several how to posts, send me PM/email if you want links. IIRC a head gasket leakage quick check is on a cold engine; crank up and run briefly like 10-15 seconds; crack radiator cap on tank on firewall; there should be no pressure release.
3. I cannot offer MAF idle test/rocker health advice

TPMS sensors. The Dorman ones on Amazon seem to work fine.

No GDE tune does not impact whatever speedo/odometer errors you have. In theory someone with a dealer or dealer equivalent programming tool can do some correction of a known error but not much IIRC

OneCheekRider · **Posted:** Tue Sep 03, 2013 1:50 pm

My CRD was losing a small amount of coolant recently. I found it to be a loose radiator hose. A new clamp fixed it.

papaindigo · **Posted:** Tue Sep 03, 2013 3:34 pm

Yeh I should have mentioned that there are lots of places where you can lose a bit of coolant other than the head gasket especially as the OEM spring clamps loose tension from age or reuse. Best to hunt small leaks with UV dye and a UV light as small leaks can evaporate before leaving any visible trace. Don't forget oil cooler area on passenger side forward of turbo and EGR cooler on driver side toward the rear of the engine.

racertracer · **Posted:** Tue Sep 03, 2013 3:42 pm

OneCheekRider wrote:

My CRD was losing a small amount of coolant recently. I found it to be a loose radiator hose. A new clamp fixed it.

At first, mine was losing coolant out of the coolant hose leading to the EGR valve, I discovered that hose was leaking due to the bulge in the hose by the strap clamp. The bulge was caused by the built up pressure in the cooling system from the exhaust gasket leak.

I was plugging a lot of leaks for a while, making the problem worse by warping the head.

To the OP, do you have pressure under the cap?

thermorex · **Posted:** Tue Sep 03, 2013 6:50 pm

Regarding mileage, I constantly get 21 city and 25 hwy, but I drive 73-78, dependent on max limit (65-70), I don't have the patience to drive with 62... But I can get towards 30 as I go lower on speed.

Tree Catcher · **Posted:** Tue Sep 03, 2013 8:41 pm

Just curious but what type of tires are on the CRD? If you are on all terrain's that will help lower your mileage. I noticed that when I switched from one brand to another, my mileage went up by 1 mpg. I regularly get 29 to 31 on long trips. I just did a trip to Colorado from the Riverside, Ca area and the worst I got was 28 and the best was 31.5 two tanks were about 30.8 mpgs. I was cruising at 70 mph. I Have done pretty much what you have, changed the CAC lines to Samco's and the GDE eco tune along with the glow plugs.

SFHLibertyCRD · **Posted:** Tue Sep 03, 2013 9:04 pm

Thanks, everyone.

My speed was closer to 70 most of the time, with AC at least half the time. I'll have to look back at my fuel log and compare my trip meter to actual miles traveled in google maps and figure out what my discrepancy is. My recollection is that I did not notice much of one.

I added some Zerex G-05 + water for the time being until I have the radiator flushed probably with the TB job. I'll monitor to see what happens. If it keeps going down, I'll look into UV. I asked the PO, and he said he has never had to touch the radiator fluid, but he's only had the car for 6k miles (although he did tow with it a few times during that time).

Racertracer, do I check for pressure under the cap when engine is hot or cold? Last night, when I added fluid, I waited about 4 hours for the engine to cool (everything was still pretty warm), and there was some definitely still pressure when I opened it. Is this good or bad?

Also, which ARP studs are correct for the CRD? Also, what exactly causes the head to warp when there is a HG leak?

Tree Catcher, well, that's a little discouraging about my mileage then. The tires are AT: Yokohama Geolander A/T-s. Size: LT225/75R16. There are still 2-3mpgs lost in there somewhere though.

Also, about mpgs, if you look at my fuelly on the trip, I did fuel up with B100 for 2 tanks, but my worst tank was actually on a 5-20% biodiesel blend from Omaha Sapps Bros. station. I know on my VW, I tend to take a 5-10% hit on B100 biodiesel, but the Liberty seems to show less variation.

racertracer · **Posted:** Tue Sep 03, 2013 9:40 pm

SFHLibertyCRD, any pressure under cap is bad and an indication of a head gasket leak.

Try this test.

Do this in a quiet spot.

1. On a cold engine, remove the radiator cap and relieve any pressure that is present in the cooling system and then replace the cap again making sure it is on tight.

2. Start the engine for one full minute.

3. Turn the engine off and slowly twist off the radiator cap, being very attentive to hear and feel any gas pressure escaping from under it.

If you hear and feel any pressure escaping, then you have a head gasket leak, even if it is the most miniscule amount of gas.

You can confirm it with a head gasket leak detection tester.....

geordi · **Posted:** Tue Sep 03, 2013 9:49 pm

Biodiesel usage after many thousands of miles without it, and your fuel filter is not long for this world. Prepare to change that soon, it is getting plugged with all the built up filth from the tank that is now being scoured out.

Checking the head gasket is simple:
On a COLD COLD COLD engine, open the radiator cap. Ignore any pressure that may exist and release. Hot engines NORMALLY develop some pressure in the radiator system, and it might not release as the system cools. Don't be scared just yet.
Close the radiator cap securely.
Start the engine, run it for 30 seconds or so, no more. Shut off.
Open the radiator cap again - This time, listen carefully for any pressure release. Is there any?
If yes: You have a head gasket problem brewing.
If no: GOOD! Monitor for any coolant loss over time, look for possible hose weeping / white traces around hoses that might show where the minerals have been drying as they leak with the coolant. It could also (very likely) be a leak at the water pump itself, because that pump is 8 years old now, along with the belt. Seals don't last forever.

If it IS the head gasket... You might want to do the APR studs, but you also could (theoretically) just tighten all the factory bolts in-place. It is a pain getting to them, but this is an option if money is an issue and you are doing the work yourself. Please - do the work yourself, NEVER take it to a dealership. The factory bolts do NOT stretch, but may not have been installed with enough torque from the factory.

Mileage - You really need to use a GPS to confirm your speed and mileage in real-time with your vehicle. Using Google Maps for this won't give you the accuracy you need. GPS is accurate to 30 feet. 27mpg is a bit low for the speed, that is only 1mpg more than what I got with my CRD when I was driving 78-81mph with taller load range D tires.

Pump your tires up to the sidewall max - totally safe - and you possibly will see the mileage increase at least 1mpg, possibly as much as 2-3. At 70mph on the speedometer, your ACTUAL speed was most likely 66-67mph. I don't know how those tires specifically would perform compared to any others, so maybe they are fine for mileage on the road... Maybe not. My mileage numbers were using BF Goodrich Commercial TA Traction tires (load range D) in a 215/85/16, the Long Trail variant are the same basic tire in a lesser load rating. Those might be lighter - which is always a benefit to MPG.

Check (replace) the air filter, make CERTAIN that the EGR is fully closed. Consider installing a separate boost gauge (Glowshift.com has some nice options) to verify that the boost that the computer is asking for... Is actually being delivered. Trust, but verify.

Cleaning the MAP sensor is never a bad idea, and could also help you out. MAF sensors do degrade over time, that could be an issue as well - Try running for a tank with the MAF unplugged, see if the mileage goes up. Yes, this will generate an idiot light, but that isn't a big deal.

More MPG are there to be found. Glad you got it home, now get that belt changed!

papaindigo · **Posted:** Wed Sep 04, 2013 9:31 am

stoutdog used bio in his 06 in various %s and consistently took an mpg hit at anything over about B10. As I recall at least a 10%+ hit on B100.

SFHLibertyCRD · **Posted:** Wed Sep 04, 2013 9:33 am

Geordi and Racertracer, 30 seconds or 1 minute, or should I just split the difference and do 45?

SFHLibertyCRD · **Posted:** Wed Sep 04, 2013 12:37 pm

Also, the PO did an oil change right before I purchased the car (it was part of the agreement, oversize filter, Rotella T6). I asked him to collect some used oil for an oil analysis. Will this reveal anything about the head gasket, coolant leak, etc?

For what its worth, after driving the car the 2500 miles across the country, the oil looks like new. This is the first oil change after one full 6k cycle with the GDE tune (previous oil looks pretty black).

I expect that I may have to change the filter at some point (planning on that with TB and everything else around 75k), but I'm not sure how much of an issue it will be with ULSD. When I switched my TDI over to bio with the same mileage, I never had a problem. I'll order one to have on hand though.

geordi · **Posted:** Wed Sep 04, 2013 2:03 pm

That is true, the ULSD does help to keep the tank a bit cleaner compared against the old LSD diesel. I just remember switching to bio (home brew) b100 with my TDI, and killed the filter shortly after. A tank or two in my CRD, and it also ate the filter soon after.

30 seconds or a minute doesn't really matter that much, the point is to have a decent amount of combustion happen, but not enough to actually impart any heat-pressure to the coolant, and certainly not enough to open the thermostat. The coolant will still be cold, and should have ZERO pressure after such a short run. If it does have pressure... That had to come from somewhere, the only logical source is the pistons.

Sent from my iPad using Tapatalk HD

SFHLibertyCRD · **Posted:** Wed Sep 04, 2013 8:15 pm

geordi wrote:

Pump your tires up to the sidewall max - totally safe - and you possibly will see the mileage increase at least 1mpg, possibly as much as 2-3. At 70mph on the speedometer, your ACTUAL speed was most likely 66-67mph. I don't know how those tires specifically would perform compared to any others, so maybe they are fine for mileage on the road... Maybe not. My mileage numbers were using BF Goodrich Commercial TA Traction tires (load range D) in a 215/85/16, the Long Trail variant are the same basic tire in a lesser load rating. Those might be lighter - which is always a benefit to MPG.

Geordi, I remember being puzzled by what was printed on my tire on the trip. Specs are: LT225/75R16 110/107 (D) Max. Load at Cold Inflation Pressure (lbs.@psi) 2335@65. I remember looking at the psi and thinking that sounded really high. They were only pumped to around 40psi by the previous owner so I was a little wary of pumping that much more into them. Are you saying I should have them near 65psi? Excuse the basic newb questions about tire pressures.

geordi · **Posted:** Wed Sep 04, 2013 8:40 pm

No worries about the questions - The only dumb question is the one that is never asked.

It does sound like these are a Load Range D tire, which added to the LT tag puts them into the Light Truck / commercial spec range. This is a good thing for strength and durability, but might be a penalty for weight and mileage. They sound about equivalent to the BFG Commercial T/A Tractions that I liked on my CRD, but in a stock size.

The sticker on the inside of the driver's door (that I can hear someone saying right now - "This is the correct pressure, not the sidewall max") is ONLY VALID with the original stock tires in both size and make. Once you change from the original tires, even to another from the same manufacturer... All bets are off.

Thankfully, tires are USUALLY very forgiving and will safely operate at a wide range of pressures, but you never want to overload them or greatly underpressure them. Too much flex in the sidewall, equals too much heat in the tread and it can (and will) fail on you in unpleasant ways.

Back to your tires. IF they are similar to the BFG tires I used, then 65psi will be perfectly safe for the tire and Jeep... But you might not like the ride much. Give it a try for a while, but I would suggest a number in the 50psi range would probably tighten things up nicely. You never want to be too far below about 20% lower than the sidewall max, or you start getting into the excessive sidewall flex neighborhood.

Don't forget - you bought a JEEP. It won't have a "smooth car-like ride" because it isn't one. It should ride like the rough and ready truck that it was designed to be. You can soften that up a little... But too much will be at the expense of your tires.

New to me CRD Back in Los Angeles, a few questions

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