OVER HEATING

Sergio del Castillo · **Posted:** Fri Aug 17, 2018 2:32 pm

I have a 05 CRD with 216,000 + miles on the clock. Got it new in February 2005. I have had only a few occasions when the heat gauge went past the middle point, basically while climbing Mt. Washington and also at Pikes Peak, but never have gone to the red mark, not even pulling a 2,000 lbs trailer over the Appalachians at highway speeds.

On the last month I have had several occasions when the needle had gone past the middle point on the city (stop and go) with the AC at full blast while in Florida, but returned to "normal" at highway speeds. Outside air temperature in the high 90'sF.

Last night, coming back from DC to MD, about 13 miles, at mid point of the trip the needle went to 3/4 point, in heavy stop and go traffic, air temperature in the 97's F. Turned off the AC and continue home while the needle returned to normal with the movement of the car in less that one city block. This noon I checked the operation of the relays for the electric fan and they worked fine in low and high speed. The mechanical fan seems to be operation OK also. But a short trip for an errand,6 miles round trip, after fully warming up the CRD on and air temperature in the 98 F range, the needle went past the middle point about a full notch. This short trip in the city involved some heavy acceleration, 0 to 45 mph, with the AC on. I will try the same route without the AC, and the same acceleration, latter today.

Any ideas other than a leaky head gasket?. i have no coolant lost. The level in the tank appears not to have changed. I topped up in FL with about one cup, just in case. :cry:

Thanks.

Mountainman · **Posted:** Fri Aug 17, 2018 2:41 pm

Is the fan howling like a monster? It should be. If it is, then the thermostat is sticking, but highway speeds with high load should also get warm if it's the thermostat.

My bet is you want the GM fan mod. Don't even waste your time with stock or Hayden. Hayden's come bad out of the box often

Mountainman · **Posted:** Fri Aug 17, 2018 3:04 pm

Actually, it can be tough to put enough load on the engine at freeway speeds even in hot weather on flat Florida land. But maybe with the AC on max.
Still most likely the fan. I've only seen one of the factory stats stick partially closed. They are really good at failing open, and that's the only thing that they're good at actually

WWDiesel · **Posted:** Fri Aug 17, 2018 3:09 pm

More items to consider:
Have you checked outer cleanliness factor of AC condenser, CAC (intercooler), and Radiator coils for any debris, i.e. bugs, grass, etc...
Do you know if you have the correct HOAT G-05 coolant in your system?
When is the last time you have flushed and cleaned your entire cooling system?
All of these items can have an impact on cooling performance.... :juggle:

Sergio del Castillo · **Posted:** Fri Aug 17, 2018 6:02 pm

Yes: The AC conderser/CAC/Radiator are clean. I do check on them ever time that I return from a long highway trip. Mainly in the midwest, there are a lot of bugs there at dusk. Garden hose pressure wash and blown from behind with 40 psi compressed air.

Yes: the coolant is rather new. Changed at 5 years and then again at 10 years with the correct one.

Yes a new OEM thermostat when the original failed open, and then another new one ,no fail this time, with the second coolant fluid change, just in case.

The electric fan rotates a two different speeds, but do not make any mechanical noises, just air flow noise.

The mechanical fan have been checked two times, plus I have a new OME spare that I got just in case.

Yes while driving on the Florida flats, AC on full blast, highway speeds, the needle moved to just the center, it is in city driving, stop and go, hard acceleration when the needle move close to the 3/4 mark. I have no had the chance to test the stop and go driving without the AC yet, will do it tomorrow.

Could it be that a fault transmission, shifting in city traffic, cause an engine to over heat, but not the transmission fluid? I checked the transmission fluid and it was at the correct level, correct color and did not felt abnormally hot nor smelled. I am not satisfy with the way that the transmission behaves around 45 to 50 mph at constant speed nor with slight acceleration after some coasting. It is not TC clutch, I am familiar with hat one, looks more as erratic shifting, I am talking with the transmission technician about this, but I can not reproduce the behavior with him on board.

I am hopping that it is not the cylinder head gasket. Timing is not good for that $$$ repair.

WWDiesel · **Posted:** Fri Aug 17, 2018 10:14 pm

Sergio del Castillo wrote:

I am hoping that it is not the cylinder head gasket. Timing is not good for that $$$ repair.

For your sake, I hope it is not the head gasket either! :juggle:

Mountainman · **Posted:** Fri Aug 17, 2018 10:20 pm

How did you check the fan?
The HG isn't leaking if you're not losing coolant. A really slow leak isn't going to cause you to overheat either

Sergio del Castillo · **Posted:** Fri Aug 17, 2018 11:14 pm

I checked the fan by the resistance to spin freely, first when it is cold, before starting the engine. Later after returning from the errand, fully warmed. There is not appreciable difference that when I did it a few months ago as par of the spring routine check after the winter months. Nor when compared to the spare unit (cool only), obviously when hot the resistance to spin is higher.

Two trips to Florida, the first one with no signs of overheating, one to Connecticut without overheating, and one to the outerbanks, NC without overheating. At home after a week or so of local trips started to show the signs of overheating, but not all the time. Just last night went to the 3/4 mark. :banghead:

PS: I also replaced the serpentine belt at the time of the change of the timing belt at about 190K miles mark

Mountainman · **Posted:** Fri Aug 17, 2018 11:41 pm

I would idle it in drive at home in hot weather with a grill block (cardboard) if necessary to get it just past half on the temp gauge and verify that the fan then starts roaring much louder than before. OEM and hayden's are crap and sometimes don't even make it 30k miles. It may have just quit locking up enough.
I think it should lockup (mostly anyhow) one or two ticks past half on the temp gauge.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

My understanding is that the impeller of the water pump can wear out.

Was this changed out when the timing belt was done? An improved water pump is offered by I.D. parts as part of their timing belt kit...

https://www.idparts.com/timing-belt-kit ... -2721.html

A worn out water pump would cause overheat conditions similar to what you are describing, Sergio del Castillo. A worn out water pump will not flow enough coolant to keep the engine cool in heavy demand situations, especially stop and go traffic where the engine is idling along and the pump is not spinning very fast.

I also support the idea of using the GM fan clutch and 11 blade fan for heavy duty and high ambient temperature applications. In seriously heavy duty conditions a mechanical fan without a clutch may be necessary. There have indeed been some disappointed CRD owners with both the O.E.M. fan clutch and the Hayden fan clutch.

flash7210 · **Posted:** Sat Aug 18, 2018 9:41 am

Let’s face it, it’s been a long hot summer. Everybody is running a little hot.

First thing I would do is replace the fan clutch. As recommended above, the GM fan and clutch seems to be the best option.

If you don’t know if or when the water pump was replaced, it’s probably time for a new one. They are supposed to be replaced at every timing belt change.

It’s also helpful to know exactly what temperature it’s getting to. The stock temp gauge sucks in this aspect.
One thing people do is use a IR temp gun and when the engine gets really hot, they stop, pop the hood, and point it at the thermostat housing.
Others use their android device with torquepro app and elm327 Bluetooth adapter to see actual temperature from the coolant temp sensor.

What I find most interesting in this case is how it compares to my CRD.
I live in Florida, use the AC frequently, and have no overheating problems.
In fact, I removed my engine driven fan several years ago. Using only the electric fan.
But, I rarely find myself stuck in traffic on a hot summer afternoon.
So maybe that’s the difference.

TKB4 · **Posted:** Sat Aug 18, 2018 12:00 pm

I live in west tn with a few more hills than florida but not mountains . I too, do not even have a mechanical fan on the crd i drive every day. Its regularly over 95 several days a week this time of year and up to 104 at times. I run ac all the time so the electric fan is on and I have no overheating issues. I can also tow a john boat or 4 wheeler without overheating in this weather but not a ski boat or 3,000 lb equipment trailer.

So I would guess its reduced coolant flow through the radiator or less likely the thermostat. One interesting experiment would be to remove your mechanical fan and see if it acts the same for just a few miles of course. If it acts the same, either the fan isn't functioning or the fan shouldn't have much to do with the problem. Obviously removing the fan won't help the overheating.

I agree, the head gasket is not the issue in your case even if it did leak a little.

Let us know when you find the cause.

Sergio del Castillo · **Posted:** Sat Aug 18, 2018 12:25 pm

OK, lets determine the exact conditions.

A.-The fan clutch have been checked in the past and found OK. I will check it today again.

B.- The electric fan was checked yesterday and found OK.

C.- The coolant, thermostat, and water pump replace with the timing belt and serpentine belt at 190K miles +/-.

D.- The overheating only happens with the AC on, in heavy traffic, stop and go, mostly city traffic. It have never happened without the AC.

Next step: After checking the fan clutch, I will have the AC system checked. Why?: My intuition tell me that if the high pressure switch malfunctions, that will increase the temperature at the condenser, thus the electric fan will to the radiator thus increasing the coolant temperature. Otherwise why the temperature returns to normal when the AC compressor is turned off?
Any Ideas?
Thanks to you all.

Mountainman · **Posted:** Sat Aug 18, 2018 12:33 pm

The AC compressor adds load to the engine, and the condenser adds parasitic heat to the intercooler, radiator, and transmission cooler.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

flash7210's quote: "It’s also helpful to know exactly what temperature it’s getting to. The stock temp gauge sucks in this aspect.
One thing people do is use a IR temp gun and when the engine gets really hot, they stop, pop the hood, and point it at the thermostat housing.
Others use their android device with torquepro app and elm327 Bluetooth adapter to see actual temperature from the coolant temp sensor."

I had neglected to write this... good point on the part of flash7210.

Apparently some of the 2005 model CRDs had wonky O.E. temperature guages. The best way to find out if yours is malfunctioning is to perform BOTH of the tests that he prescribes, (hopefully with an accurate infrared temperature gun), and then compare the two temperature readings. If the temperatures are indeed different, then either your O.E. guage is pooched or the O.E. temperature sending unit is malfunctioning.

Sergio del Castillo · **Posted:** Sat Aug 18, 2018 4:38 pm

UP DATE:
Back from my road test. Fully warmed, about 30 minutes city driving, stop and go with some heavy acceleration, NO AC. The temperature gauge did not move from what have been "normal position" for the last 13 years.

Fan clutch move easily by hand. No lock, no hard resistance. Obviously faulty. :evil:

Next step. Replace the fan clutch. :juggle:

flash 7210 quote is very good, but my IR thermometer stop working last fall. By my account, the exact number is not a mandatory information in this case. I take the information from the gauge as an index to if it is always in the same location ("normal position"), move up to overheating, ("above normal"), or moves down ("below normal"). The exact temperature will be an important factor if you are checking on the thermostat operation, but after all these years on the same position, with two different thermostats, "normal position" is normal.

Will keep you posted after replacing the fan clutch, and performing another road test.

WWDiesel · **Posted:** Sat Aug 18, 2018 5:12 pm

Since you are going to purchase and install a new fan clutch, you may want to consider upgrading to the GM HD V8 11 blade fan & HD clutch?
see this thread:> viewtopic.php?f=5&t=82941
available from NAPA....

GM Severe Duty Fan Clutch NAPA 271625
GM 11 blade HD Cooling Fan NAPA No. 8552223
GM 11 blade fan requires four(4) GM 11516869 bolts, they have different threads and are a bit larger. (bolts to attach fan to clutch)

A tip for removing a mechanical fan! Slide either a piece of thick cardboard or thin sheet metal in front of the fan up against the radiator so if the fan were to happen to drop or fall forward for any reason, it's metal blades will not damage the radiator... :wink:

Once the fan shroud is unbolted, it can be pushed back against the engine far enough to slide a piece of protective material in place!

Trust me, it can happen :roll:

Also a great time to convert the fan shroud into a two piece fan shroud to make easy removal of only the top half the next time you have to perform any work on the fan or clutch.

:SOMBRERO:

GordnadoCRD · **Posted:** Sat Aug 18, 2018 5:53 pm

x2 on the GM clutch and fan mod.

One more thing... With the fan shroud removed, examine the radiator / intercooler assembly. Normally as delivered, you will find a gap ranging from 1/2 inch up to 1.5 inch between them.

This allows (especially when sitting idling in traffic) the hot air drawn through the radiator to circulate back around the edges of the radiator, get drawn through again, and receive even more heat, until it becomes heat soaked, and stops removing heat from the coolant.

I solved this problem with some closed-cell foam backer-rod, of thickness slightly more than the existing air gap. I pressed it in place around the periphery of the air path, and made it secure with spots of polyurethane adhesive, so the fan wouldn't draw it out of place.

With only these mods, I can hold my hand at the front grill, and feel the air getting sucked through at idle.

Sergio del Castillo · **Posted:** Wed Aug 22, 2018 5:12 pm

Today I have the AC system checked by the AC technician. It was working as should be working. Engine temperature keept at 180F, per the technician OBD reader. At my insistence, I got him to remove the fan clutch, even though he said that was OK (he got the proper tools and I don't). As soon as we had it out and spinning it by had, it made a clicking sound and started to spin freely, I mean no resistance at all. It appear that there was an intermittent fault in one of the components inside the fan clutch housing.

Replaced the clutch and tested with no signs of malfunction. No signs of abnormal engine temperature in the way home (14 miles) with the AC on at full blast, rural roads, no city traffic though. I will keep an eye on it, but I believe that the issue is solved for the moment. The original fan clutch lasted about 200,000+ miles. the one that is in now have only about 5,000 miles, and was stored in the right position. Lets see how long will last. :juggle:

Thank you all for your input and recommendations.

OVER HEATING

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