Oveheating - for anyone not on LOST as well

[Lancer]

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!)

 

[Mopars-Only]

The electric fan is supposed to assist the mechanical fan when you are in that situation. Also, if the clutch fan is worn enough to not properly drive the fan in that high temp situation, it will do that very thing. It all comes down to not enough air passing the radiator.
I would check the electric fan and the fan clutch. I see you name a specific fan clutch, and for that reason one would not expect it to be worn out yet; however, it remains a possibility that that clutch fan is not functioning properly.
One last point, it is the nature of water pumps to not properly circulate water if the level is dangerously low in the cooling system, though that is the least likely reason for this problem. Make sure you look at the coolant level too.
Hopefully that helps you find the problem. It may interest you to know my stock clutch fan hub failed on my `05 CRD 2.8 somewhere around 90K miles. I replaced it with a stock Mopar fan hub and now nearing 50K miles later it is still working just fine.

Mopars Only

 

[Lancer]

Thanks Mopars - the Hayden went on about 2 months ago. I had it fitted because a couple of the experienced guys on Ausjeep and on LOST found that the Hayden "kicked in" at a lower point in the temp curve than the stock unit - with benefits to the cooling.

I had the timing and serpentine belts replaced at the same time, and the water pump was checked then and found to be fine.

It started to heat up Friday eve in the same circumstances - very hot, humid, a lot of very slow(5-10mph) traffic over about 8 miles; I opened all the windows and put the heater on full blast - kept the needle on the right mark. As soon as I got to open road - heater off, no problem. On only the first occasion did I have the aircon on.

It has been suggested that I get the cooling system flushed and refilled; looking back at the service invoices, I can't see that it's ever been changed, and given the price of HOAT from a jeep dealership (where my servicing used to be done) I don't think they'd have forgotten to charge! I'm getting that done anyway - it must be a good idea just on general principle!

Any suggestions about the brake? Only got a fairly hard pedal when the vehicle was crawling and getting hot; as soon as I got back onto open road - back to noirmal.

How do you suggest I check the clutch and electric fan?

 

[Mopars-Only]

To check the electric fan, observe that it is spinning fast when you have the A/C on, I am pretty sure it comes on with the A/C. The clutch fan can be checked by shutting the engine down when fully warmed up, as when you return from a drive somewhere; with the engine off you reach into the shroud from the back and spin the fan some, it should be pretty tight if it is working properly. If it spins easily it is not engaging as it should be when at operating temperatures. You can, with a practiced eye, rev the engine when very warm and observe that fan with a light, if you learn how to do so you can easily determine that fan is lagging behind in speed.
The Jeep factory service manual says you can check the stock fan by spinning it when cold, fan hubs that allow the fan to turn more than five turns are defective. It also says you can point a strobe light at it and observe it while above 195*F and see that the fan is not spinning the proper speed. However, since you have an aftermarket fan, you would be better served to use that maker's diagnosis or use the common sense tried and tested methods I listed first.
It is a good idea to change the antifreeze, and the owners manual even has a maintenance schedule within it, as does the service manual if you have one. I seem to recall the HOAT antifreeze/coolant is good for a hundred thousand plus miles, but my memory could be incorrect so check that schedule. I know I change my own about every two years, for what that is worth.
As to your brakes, it must be that the vacuum was not sufficient to add any assist to the brake master cylinder. It has a vacuum pump and associated plumbing on the engine which supplies vacuum assist to the master cylinder power brake booster. I am uncertain how a slightly overheated engine could cause that to malfunction, but it may still be the case.

Jeff

 

[JLRockies]

My CRD overheated whenever the temps were above 70 pretty much the entire time I owned it with the exception of the first year. Every part that could be swapped was, dealer couldn't figure it out, no one could figure it out.
My solution:

Replaced it with a 4Runner.

 

[JLRockies]

It was an awesome winter vehicle though.

 

[Lancer]

Thanks Jeff, I'll do those tests. The fan itself is the Jeep nylon model from the 3.7, the clutch is aftermarket though. As for the HOAT, you are right - my schedule says every 100k miles as well; however its my experience with a number of vehicles over the years that replacement of fluids is really on a mileage or time basis, and although I've only done about 60k miles, it's a 7-year old vehicle. I think its unlikely that any fluid stays in good condition that long! The flush and replacement takes place next Monday.

I appreciate the advice.

And it's been a long time since I saw you post JL - how have you been? I used to enjoy reading your comments.

 

[Mopars-Only]

I don't mean to tell you the water pump is bad, but.. if the coolant/antifreeze is low, it will pump better when revved up a bit.. At idle they overheat due to the pump's inability to effectively circulate water at lower revs, when there is too much air space at the impeller. This is not peculiar to any make or model, they will basically all do this, because the water pumps are basically of a very similar design. Impeller type pump, if I remember correct is the proper name for automotive water pumps.
My CRD overheated only one time. I was climbing a steep bridge crossing the St Johns River, pulling my enclosed trailer with a heavy load of lumber. I do that fairly often, and so I knew it should not be overheating. That was when I found my clutch fan hub to be worn out and replaced it with a new OEM Mopar fan hub. That solved the problem for me. I can park my Jeep and sit with the A/C on and wait on the wife thirty minutes in some store if I have to do so, and it will not overheat, not even reach the middle of the gauge in 90* + temperatures. Your Jeep should do as well as mine, so something is malfunctioning.



Jeff

 

[Lancer]

Ok - the electric fan came on about 30 seconds after the ac was switched on; the engine fan started spinning as soon as the engine was started up - according to Hayden's website, the fan should be engaged when starting from cold - until the clutch fluid is distributed after some minutes, but I haven't had the opportunity to run the engine to operating temp for a couple of days, so I'll see how that is on Monday. I'd hosed the radiator to get any muck out out before I started the engine to look at the fans;although running for only a few minutes, there was enough heat in the rad for it to steam off the water on the surface from the hosing.

Fluid level seemed ok.

I couldn't spend very long today - couple of minor domestic disasters to attend to, but hopefully I'll get more time tomorrow, and as I said - cooling system flush and replace on Monday.

 

[Lancer]

Well, flushed and replaced on Monday. The mechanic (he's worked on my KJ since I bought it) told me that a lot of "muck" came out. He ran the engine for 3 and 1/2 hours after - no overheating. I took it for a run later and got it warmed up - fan clutch had engaged and the fan was going great guns. Tried the newspaper trick - fan kept going. The electric fan had not engaged, but I hadn't run the ac and the external temps had dropped to 20 - so didn't really get hot enough to engage. The front of the rad was cool to the touch - unlike before the flush when I hosed it, and steam came off the rad after only a couple of minutes.and it was HOT to the touch! He also checked the thermostat at my request, and that was fine as was the water pump. So far, so good!

He couldn't find any issues with the brakes, so I suspect that unless/until that crops up again in a situation where more information can be gained, I will have to accept that as one of the peculiarities of my KJ's character! No harm seemed to have been done, and he told me that the discs and calipers did not show any indication of anything unusual. I'll have the brake system thoroughly flushed at the next service in a month.

Thanks for the help and advice Jeff, I do appreciate it.

Adrian

 

[Mopars-Only]

You are of course most welcome. It sounds like you have your cooling problem solved, and it is hard to imagine all that gunk in the radiator. It is a guess and nothing more, maybe it is from left over casting sand, a wad of paper packing that dissolved over time within the cooling system somewhere. I know each time I have changed my antifreeze, I have drained it completely, then flushed it with clean water and drained it again; never got anything out of it but water and HOAT.
As far as brakes go, my only issue has been the rear caliper pistons swelling up and causing the calipers to bind. I replaced both calipers around 90K miles, and one of them has done it again. I replaced that one this time with an aftermarket rebuild that has a metal piston in the caliper, it is said to correct the issue with the composite pistons swelling due to a panic stop. I expect to change out the other caliper with the same soon, just as a preventative measure.
Good luck with your Jeep, I am glad to read you have sorted it out.

Jeff

 

[Orlando]

Hi Lancer

Be careful with radiator flush - good idea on older vehicles but I did mine so well that the inner core of the radiator got blocked. Had to replace it caused the temp problem got worse climbing uphill. All good now so it seem. With overheating common problem in jeeps, the cooling water quality is very important. Correct antifreeze / water mixture will prevent corrosion and never allow the use of tap water or even worse borehole water. Only use distilled or deionised water (low impurities as specified in the manual). This will prevent scaling and improve heat transfer on the engine block and radiator. I also replaced the engine oil every 5000km too avoid unnecceasary friction heat caused by old oil. In SA the summer temp can easily reached 40 C so doing the small things right makes a big difference.