overheating in the Jk

eddy89
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overheating in the Jk

Unread post by eddy89 » September 22nd, 2014, 3:01 pm

Hi all,

Im planning on getting a CRD JKU shortly, ive heard about the overheating in the Jk. Is this problem for the Petrol or CRD?
And how often does it occur?

Are there any ways to fix the problem?

any info would be much appreciated.

Thanks

Peter Aawen
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Joined: June 17th, 2005, 8:01 pm

Re: overheating in the Jk

Unread post by Peter Aawen » September 22nd, 2014, 5:59 pm

i haven't been fastidiously following these issues, but I am aware that in the States there was a recall to 'fix' the temp gauges on the CRD engined Jeeps.... only what that sort of fix usually means is that the temp gauge will go up to 'normal' and then never move, altho the engine coolant temps WILL go up and down as load etc varies & the thermostat & fan system cuts in and out to keep it in the specified range. A temp gauge that doesn't move at all is, IMO, broken!! Surely you want to see how much hotter your engine cooling system is getting as the load varies?! Coolant temperatures vary, having a gauge that shows that occurring is a GOOD thing IMO, cos it gives you a chance to change the way you are driving before it becomes an engine destroying issue - and the 'fixed' temp gauges tend to wait until it's too late to do anything to save the engine before they suddenly head for the red!! People need to learn how to drive properly & to take advantage of the info their instrumentation gives them, instead of getting dealers/manufacturers to damp it down so it doesn't upset any of the unskilled/uninformed. :irked:

However, there have been some 'complaints' about overheating CRD Jeep engines, but even in the States where they aren't all that familiar with diesel engines, people more used to petrol engines are finally coming to realise something that applies to most diesel engines, especially turbo diesel engines!! That is that if you keep your foot planted hard in a diesel to try and maintain speed under load, on a climb, or driving into a head wind, etc, then as the revs start to drop the engine will be overfuelling to some extent, even with modern computer control systems, and on a diesel overfuelling means the Exhaust Gas Temperatures (EGT's) rise so the coolant temp rises.... Simple solution is to back off on your right foot a tad, or better yet, change down a gear or two, maybe even use the gears to keep the revs & boost in the sweet spot on the torque curve (& it's NOT EVER going to be with your foot flat to the floor!!) and drive so that the EGT's don't go thru the roof!! If you are pushing your EGT's up, there's nothing that even the best & most efficient cooling system can do to keep things cool, cos high EGT's are up in the range that starts melting metal!!!

And having a temp gauge that does move up & down as the load on the engine varies is a good thing (just so long as it doesn't go out of the 'normal' range) cos it means that your temp gauge is likely to warn you of high engine coolant temps BEFORE it's too late to change your driving style or even stop before you destroy the engine!! ;)
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Peter Aawen
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Posts: 20807
Joined: June 17th, 2005, 8:01 pm

Re: overheating in the Jk

Unread post by Peter Aawen » September 22nd, 2014, 8:40 pm

Excerpt quoted fm one of the Jeep releases about the 'Temp gauge fix' for the CRD engined Jeeps, typo's included...
TSB 08-043-05 "Instruments: Temperagure Gauge Reads Higher Than Normal" was released on August 11, 2005.

...."SYMPTOM/CONDITION:
The customer may notice that the engine temperature gauge may indicate that the engine temperature is high when in fact it is still operating within the normal temperature range. In hot ambient temperatures, and under certain driving conditions of extended uphill driving while towing a trailer, the engine temperature indicator may indicate above the 3/4 normal operating termperature mark on the temperature gauge (but below the engine hot temperature markings). This condition may be caused by an incorrect calibration of the engine temperature gauge."
....
As mentioned earlier, many people get upset about temp gauges moving, but they are meant move in order to reflect the changes that do & must occur in the coolant temps as load varies (otherwise why bother having a thermostat & a thermatic fan?!) and in reality all is fine just so long as the gauge doesn't go into/above the Hot markings! But apparently, this fix (which I think was just a software recalibration on the gauge/display) solved that problem by adjusting where the needle sat on the gauge at 'normal' temperatures.... :rolleyes: :p
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

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