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Overheating?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=76004		 Page 1 of 2
Author:  Lancer [ Wed Jul 17, 2013 5:39 pm ]
Post subject:  Overheating?
Hi lads-

Just wondering if anyone has any ideas;

I have the 2.8 CRD with 545 auto trans, the nylon fan and Hayden 2905 fan clutch.

We are currently experiencing the worst heatwave here for 7 years - temps of 29 - 30C which I appreciate are probably very cool for a lot of you :) but boiling for us and high humidity.

Twice in the last few days - including this evening, crawling at about 5-10 mph in very slow traffic on the motorway for about 9-10 miles, the engine temp needle moved up to just below the 3/4 mark. This did drop eventually back to normal when I got to open road, although initially acceleration was sluggish. There was also today (and possible the other day but I can't be sure) a smell vaguely reminiscent of overheating clutch - which I am sure came from my vehicle and not another in the traffic.

While I'm here, the brake pedal was also high and tight and only returned to normal after a bit of time on the open road.

Is this normal or should I be looking at something and if so what?

I'd be grateful for any ideas or comments (other than rude comments naturally!)
Author:  Glend [ Wed Jul 17, 2013 7:08 pm ]
Post subject:  Re: Overheating?
If you were at 3/4 mark then the engine mgt system would be reducing fuel to cut the heat generation which is why it was down on power. Was the AC on? Sounds like a complete cooling system check is in order including a radiator flow test. There have been some cases of radiator core blockage due to coolant solidifying in the tubes, normal operation is usually fine but under heat stress the affected core blockage shows up.
Author:  naturist [ Wed Jul 17, 2013 9:14 pm ]
Post subject:  Re: Overheating?
It does sound like something is amiss, but I'm not sure what. Creeping along at 10 mph would tend to send the temperature up, even at a mere 30 degrees C. It hits 35 C here often, and occasionally gets up to 38 C, and I've been towing a 5,000 lb trailer up a mountain at both those temperatures, as well as at 10 mph, and while things got hot, the mechanical fan eventually kicked in and cooled things off quickly. The Hayden clutch should engage at about the gauge you saw, but of course, at 10 mph, there might not be much air flow to do that. I assume you had your air conditioner on, which should have caused the electric fan to run, throwing some heat back onto the fan clutch.

So I guess the first thing I'd look at is whether that electric fan runs when you turn on the AC. And I'll second the recommendation to look for gelled coolant in the radiator.

The brake pedal being high and tight would suggest a problem there. Of course, if the brakes were dragging heavily, that would account for both the sluggish acceleration and the heating up, since you'd have been working the engine extra hard, even at 5-10 mph, against the brakes. That would also account for the smell. Hot brakes do stink. Perhaps you have a sticking caliper or two?
Author:  Hexus [ Thu Jul 18, 2013 2:04 pm ]
Post subject:  Re: Overheating?
There's obviously something wrong. I would go after your coolant first. Make sure to drain all of the coolant out, replace with Zerex G05 (Just pour in 2 gallons then add water to full). Make sure to use the petcock on the front right (Passenger side) to burp the fluid level a few times after running it.

If you still have the issue, you might look at replacing the fan clutch.

I'm in Nashville, it was 102F (38C) yesterday with the heat index, I was stuck downtown, and my temperature gauge never spiked above that one tab left of top center, ever.

You might also have a thermostat issue, was it changed at the 100k service?

When is the last time you cleaned out your intercooler stack, even with some soapy water and a spray nozzle?

Just thoughts.
Author:  papaindigo [ Thu Jul 18, 2013 3:32 pm ]
Post subject:  Re: Overheating?
30C or 86F is not hot enough even at slow speeds to cause that heat rise. Thoughts in no particular order:
1. odd brake pedal and hot clutch smell equals dragging brake pads. Could be the front brake sticky caliper slider issue that's related to the rubber slider boots or could be brake hydraulic problems (ex. bad flexible brake line. Dragging brakes would cut into mpg, slow acceleration, possibly put enough of a load on the engine to cause overheating.
2. check operation of AC electric fan right behind the grill. It's 2 speed and should be running at least at the lower speed much of the time the AC is on and the engine is at operating temp.
3. I don't know how to test the operation of the Hayden although the Hayden site says the fan should be fully engaged at a cold start (presumably overnight) and gradually disengage as the clutch fluid is distributed. That said at ca. 3/4 on the temp gauge both fans should be howling enough to be able to hear from the cab at slow speed with the windows open. FYI Hayden fan clutches are good but don't last forever.
4. "crud" in the stack (radiator, intercooler, AC condenser) in front of the engine. Reverse flush with hose from the engine side and see what comes out.
5. poor coolant circulation due to clogged coolant passages (has been known to occur if the recommended HOAT antifreeze is mixed with "universal" antifreeze) you can pull the 2 heater core hoses and gently backflush the heater core with a garden hose and if "jelly" comes out your cooling system needs a full flush. Another possible cause of poor coolant circulation is a shot water pump.

It's not impossible to only just now discover your temp gauge is calibrated for a gasser not a diesel. See chat at viewtopic.php?f=5&t=75565&p=797317&hilit=gauge#p797317 and also at the link in my post to that chat.
Author:  Lancer [ Thu Jul 18, 2013 6:37 pm ]
Post subject:  Re: Overheating?
Thanks for all the suggestions chaps. I had the ac on the first time, but not the second. The brake pedal went quite "hard" only as the engine temp went up - as soon as I got to open road and everything cooled back down, the brake pedal went back to normal.

It happened again this evening, before I could get off the motorway, but as it started to rise, I opened all the windows and had the heater on full blast, and that controlled it, until I could get to the quieter back roads, then everything back to normal.

The Hayden only went on (together with the new nylon fan) about 2 months ago, so I'd have thought it wouldn't have gone yet!

I'll have a look at the things you've all suggested and I'll report back in due course.

Thanks again for all the help - I appreciate it.

Adrian
Author:  LMWatBullRun [ Fri Jul 19, 2013 12:06 pm ]
Post subject:  Re: Overheating?
How long since you flushed the brake lines?
Old brake fluid = rusty caliper insides = sticky brakes = engine drag.

Even that, however, should not cause overheating. I would do a careful coolant flush.
Author:  Lancer [ Sat Jul 20, 2013 6:46 am ]
Post subject:  Re: Overheating?
10L of Hoat is on its way to me - we can't get Zerex in the UK - its not sold here, but Comma oils do a HOAT coolant which is approved by Chrysler. Should be here Monday. My local independent garage will do the flush and replace; they are mercedes specialists as well and the mechanic suggested that he use a merc flushing material which apparently is very good at getting goo out - is this a good idea or just stick with water?

Looking back at the service receipts, it doesn't look to me as if the coolant has ever been changed - and given the price of Jeep coolant over here, it would definitely have been on the invoice!

The thermostat SEEMS ok and was replaced about 3 years ago; I'll hose out the radiator stack as soon as I can park outside my house:) the water pump was checked by George at http://www.vmdieselspecialist.com/ when I took it up there in May to have the timing belt changed, and it was fine - he replaced the serp belt at the same time and checked all the pulleys.

I'll check the electric fan this weekend to see if its operating properly, but as I said, the rise occured twice when I didn't have ac running.

I was in the same heavy traffic yesterday, but this time, I opened the windows and put the heater on full blast(old school!) and that kept the needle in the right place!
Author:  papaindigo [ Sat Jul 20, 2013 9:55 am ]
Post subject:  Re: Overheating?
I cannot state with certainty but the FSM implies that the electric fan engages based on AC use and/or engine coolant temp which suggests it should run under some circumstances even if the AC is off. Then again the FSM also states that the electric fan is triggered by battery temperature and at least the 05/06 US KJs have no battery temp sensor.

For what it's worth if your heater was producing enough heat to almost drive you out of the vehicle then the heater core is likely not clogged which may be a good sign for your radiator flow.
Author:  Lancer [ Sat Jul 20, 2013 10:02 am ]
Post subject:  Re: Overheating?
Thanks Jim - at least I'll be happy with the coolant replaced and the system flushed - and even if the problem is not solved by that, it's one thing less to look at AND there'll be fresh fluid in there! :D
Author:  Lancer [ Mon Jul 22, 2013 3:41 am ]
Post subject:  Re: Overheating?
LMwat, I have never flushed the brake system. I have to do all my work in the street outside my house, and in the last few years there has been a lot of traffic. I have no access to an offroad workspace,(perils of buying a Victorian house) so that sort of work has to be done by a dealer; looking at the invoice/worksheets, i can't see that its been done. Something else for them to do at the next service. I do change all oils and filters - as that's relatively quick, and can be done with minimal risk of some fool hitting me!
Author:  racertracer [ Mon Jul 22, 2013 4:22 am ]
Post subject:  Re: Overheating?
Lancer, when the outside temps are high and the engine has been running for some time in the heat, you should hear the ac fan come on..... have you in fact experienced this? Does the AC fan come on?

it should constantly cycle on and off when it is excessively hot.
Author:  Lancer [ Mon Jul 22, 2013 4:55 am ]
Post subject:  Re: Overheating?
Racer - I'm not sure that it does. The trouble is, I've been surrounded by heavy traffic including heavy trucks, when its happened, so I can't be sure where any noise - or smell, for that matter is coming from. When I get a clear day this week, I'll run the engine and ac to see if it comes on.

Its very rare that I'm in this sort of traffic, so I've seen any overheating signs since the thermostat was replaced about 3 years ago.
Author:  Auberon [ Mon Jul 22, 2013 7:12 am ]
Post subject:  Re: Overheating?
Hi Hope the new coolant fixes the problem.
Given you have mentioned that you go laning (for the US chaps this is driving along boggy country "roads" but Lancer could describe this better) I have to agree with the idea of getting the brakes properly flushed as a matter of import.
This is too apparent but how clean is the heat exchanger array?
Other than that the cooling aspects I'll leave to the others.
In case:
Given the B Pedal went hard:
Suggest you might be able to check the condition of the line between the intake manifold and the booster from the footpath side and front of the vehicle.
If you can do this one without being flattened you might be able to also check the condition of the one way valve (called a Vacuum Check Valve) at the brake MC - a clean hose attached will allow it to be sucked but not blown through......clean hose of course unless you like a black ring of confidence on the lips :ROTFL:
This is pretty standard for MC/brake booster checking really.......
If there is an odd hissing noise it suggests a vacuum leak.
If yes then:
Engine off shift trans into Neutral.
Pump pedal until all vacuum is depleted from vacuum reservoir.
Press & hold the pedal under light foot pressure. The pedal should feel firm, if the pedal falls away MC is faulty (internal leakage).
Start engine & note pedal action. It should fall away then hold firm under cranking / starting.

If no pedal is noted then pwr booster or vacuum supply or vacuum check valve is faulty (but if the suck - blow test above works it is OK).
Suggest skip the power booster vacuum test given that is the traffic side.

After restarting the engine you should get one (1) or two (2) assisted pedal movements (from the booster reserve vacuum) if assist is not provided the booster needs to be checked (strongly suspected as faulty).

This is not in the FSM but is a handy field test:
Repeat the point of holding light and steady pedal pressure as before.
Crank the engine to start.
The pedal should fall away a little as vacuum is re-established.

Another possibility is the vacuum pump being intermittent but this is clearly not as likely (hopefully).
MC tests would be next to consider.
Author:  Lancer [ Mon Jul 22, 2013 8:32 am ]
Post subject:  Re: Overheating?
Thanks Auberon, I'll try those tests later in the week when I'll hopefully have a bit more time!

My thanks again to all of you for your help and advice/suggestions.

Adrian
Author:  LMWatBullRun [ Mon Jul 22, 2013 3:03 pm ]
Post subject:  Re: Overheating?
Lancer wrote:
LMwat, I have never flushed the brake system. I have to do all my work in the street outside my house, and in the last few years there has been a lot of traffic. I have no access to an offroad workspace,(perils of buying a Victorian house) so that sort of work has to be done by a dealer; looking at the invoice/worksheets, i can't see that its been done. Something else for them to do at the next service. I do change all oils and filters - as that's relatively quick, and can be done with minimal risk of some fool hitting me!

Get that. One thing that helps is speed bleed screws; they make brake fluid changes easy.

Brake fluid is highly hygroscopic and will pull moisture from the air through the plastic bottle in which it is commonly stored, or, more to the point, through the plastic fluid reservoir. You should change it every two years at most.

Few people, except those who have experienced overheated brakes and lived to tell the tale, actually do that. (water is essentially non compresssible, but steam is NOT.) I also suggest ATE racing Blue, or its tan cousin ATE 200. These fluids are fully compatible, but absorb less moisture and have a much higher boiling point than regular dot 3 or 4 fluid.

Not a sermon, just a thought.
Author:  Lancer [ Mon Jul 22, 2013 3:36 pm ]
Post subject:  Re: Overheating?
Not at all LMWat, I'm very pleased with the input. I used to put DoT5 fluid in my bike's brake system (when I rode bikes). I've just checked, and I can get both on Amazon :D How much do I need for the KJ's brake system?
Author:  Auberon [ Tue Jul 23, 2013 1:23 am ]
Post subject:  Re: Overheating?
Initial comment mate is don't go above DOT4 for the Jeep - there MAY be some seal compatability issues. DOT 3 & $ are more than adequate. haven't time now but if needed will happy to discuss amounts.
Don't forget if you get any air in it it the ABS on your model (Export even the same colour as mine if I recall) will need excercising. If you don't - all should be well.
Will discuss cross flushing back end and swirl later if required. You can do this without isolating front to back.
Author:  Lancer [ Tue Jul 23, 2013 3:38 am ]
Post subject:  Re: Overheating?
Thanks Auberon, I was'nt planning on it. The ATE is classified as a DoT4, so should be fine. We do indeed have identical models! As for the cross-flushing - now you are just showing off :D
Author:  Lancer [ Sat Jul 27, 2013 6:17 pm ]
Post subject:  Re: Overheating?
Ok - I wasn't able to try your vacuum tests today Auberon - a few other things cropped up - minor domestic disasters!

However, I did try the fans and the engine fan started running as soon as I switched on the engine - consistent with what Jim (Papaindigo) said was the norm for this clutch; I then got my wife to switch on the aircon at full blast and the electric fan came on after about 30 seconds. The radiator was steaming as well (I'd been hosing it before I started the engine). I now understand the remark about the fans screaming - the engine fan wasn't noisy but the electric certainly made a noise!

Coolant flush and replace on Monday - we'll see how that goes!
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