Help diagnose a cooling issue

medicmandan

Original poster
Member
Oct 18, 2017
8
Utah
I never overheat but in stop and go traffic my temp gauge creeps up and my AC effectiveness drops. Get back up to freeway speeds and everything goes back to normal. Turn off the AC and temp gauge drops to normal. I only notice it in the afternoons/evenings when it is 90+. I took it to the car wash and sprayed out the radiator and condenser thinking it was dirty but that didn't help.

Next it seemed like the fan clutch was not disengaging. I replaced that and the water pump both with AC Delco parts, flushed the system and refilled with Dex. I replaced the thermostat, temp sensor and radiator cap last fall, also with AC Delco parts.

I still thought it was an air flow problem so I had a shop look at it yesterday. They said the fan was coming on as directed by the computer. They could not get the temp to come up over 206 while sitting in the shop with the AC on (dash gauge reading just past 210). He said he could not force the fan to full speed but it was running at the correct RPM as called for by the computer while idling with the AC on (700RPM). They suggested the radiator is plugged. I asked them to use an infrared gun which showed a 20 degree difference between the top and bottom. I am sure it is original but I would think the heating up would be more constant if it was plugged. I can get a new AC Delco for $140, replacement does not look too difficult. They wanted $900 to do that, including evacuation/recharge of the AC from pulling the condenser. Doesn't look like I need to do that.

I am still thinking an air flow problem though. I did install a Derale 8000 transmission cooler last fall in front of the condenser on the driver's side but I would hope that is not restricting that much air flow.

I'm great at replacing, terrible at diagnosing.:smile:

Thoughts?

2005 with 112K miles.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
How did you do the install for the cooler? pics?
 
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djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
That thing looks huge. I think my Hayden cooler is about half of that. Does it sit all of the way down the height of the radiator?
 

medicmandan

Original poster
Member
Oct 18, 2017
8
Utah
It sits about two inches from the top of the condenser and ends at the level of the bottom of the grill. It's mounted horizontal. 9"x11".

Which Hayden do you have? The couple I looked at were similar in size.
 

mrrsm

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Oct 22, 2015
7,639
Tampa Bay Area
A few observations on some possible 'Thermodynamic Complications' at play here:

(1) If your Radiator AND the Heater Core are both clogged up... the normal transference of heat from the locations where the Coolant Temps are being picked up from the Engine Head Coolant Temperature Sensor and Block Coolant Temp Sensor will detect higher Temperatures if the Coolant is sluggish as a Heat Soak... each and every time you are caught at a Red Light during the Dog Days of August ....especially if the Fans do not respond and move enough ambient air through the Radiator to make any real difference.

(2) As for the over-sized Transmission Fluid Cooler...if that Unit was installed WITHOUT your having first Flushed Out your Stock Transmission Cooler Lines... then if it is ALSO clogged and sluggish...that Larger area of Finned Piping will simply act as an additional Heat Soak location. THIS is what all that CRAP looks like on the way out. This procedure is a MUST for the R&R of a Reman or Re-Built Transmission as well:


(3) As soon as you installed the Larger Transmission Cooler in front of the Radiator... it also succeeded in forming a Third Layer of Finned Piping. That condition would naturally transfer its Heat Load from where the Ambient Air first passes through it... and thence on through A/C Condenser Coil...and finally move that already Pre-Heated Air further on at last, through the Finned Piping of the Coolant Radiator itself. So as soon as your SUV comes to a Halt on Hot Asphalt Pavements, surrounded by OTHER Heated Vehicles.... without having enough air moving in front of the SUV to carry away the Heat Load away from All Three 'Radiators'... they in fact would wind up concentrating that Heat Energy ...rather than dispersing it.

(4) In addition to fully functioning EV (or updated) Fans...The Engine Coolant AND the Transmission Fluid must have Clean, Clear pathways within their closed systems to be able to move the Heat Load Out of the Water Column in the Engine and the Core Transmission Components, Gears, Casements, Friction Plates and Steels and Fluid... as well as the built up Heat congesting inside of the Torque Converter at Idle. Beyond Flushing BOTH of these discreet systems... this may also require investigating whether or not there should be four narrow SPACERS adjusting the distance between that New Transmission Cooler Position and the Coolant Radiator to possibly improve the Air Flow characteristics of both.

(5) I noticed that the Installer in the Video used the Vernier (Rack and Pinion) Hose Clamps and did not bend over the lengthy, sharp S/S ends before attaching it flush against the front of the Radiator. It would be nice to know whether those clamps are making contact with the Fins and Piping of the Coolant Radiator or brushing up against the A/C Condenser Coils to wear in over time and cause any leaks.
 
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Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
They wanted $900 to do that, including evacuation/recharge of the AC from pulling the condenser. Doesn't look like I need to do that.

No you don't. The A/C can remain untouched to replace the rad. Given the cost, I'd just replace it.

You could try flushing the heater core separately as per this video. It would be an opportune time to do this while the system is drained replacing the rad.

 
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mrrsm

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Oct 22, 2015
7,639
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How to R&R The Radiator WITHOUT having to R&R the EV Clutch-Fan:


This second Video shows The Trick about getting the Radiator Up and Out Without Damaging the A/C Condenser Coil:


...and ALMOST the Last but Not Least item… Replace the Radiator Hoses with High Quality Ones and be very careful during the Installation of the New Radiator to avoid THIS from happening:


Finally... Last but not Least... The 4L60E Coolant Line Retention Clips...If Man-Handled... THESE damned things will S-T-R-E-T-C-H all out of shape enough to get loose and allow those lines to pop right back out... so they'll need to handled with care. If you look at this magnified image... you can see that the best way to get them On and Off... is to slip a Harbor Freight Hook Tool underneath and then ROLL them around to release the Tubing Lock. When ready for re-installation... hook the curved portion near one of the ends into one of the three Fitting Slots...and ROLL them around until they "Click" back into place. This will prevent them from bending and losing their shape:
5150vImHRbL.jpg
 
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medicmandan

Original poster
Member
Oct 18, 2017
8
Utah
Got it done this morning including new radiator hoses. Had to rewatch one of those videos. Could not find enough clearance between the bottom of the shroud and the outlet until I released the power steering bracket. I think it took me about three hours including clean-up (made a big mess with transmission fluid). No leaks that I can find. Hopefully this solves my problem since I pretty much have a brand new cooling system now.

I'm still missing two small wrenches I was using to loosen the worm clamp at the thermostat. They didn't fall through but I can't find where they landed. I had pulled the alternator when I replaced the thermostat last fall and angled the screw towards the front of the engine. That was quite the challenge to get in there and loosen it today.

Thanks for all the help.

Front and back of old. Definitely blocked with crud that I couldn't see/reach with the sprayer at the car wash.thumbnail-2.jpegthumbnail.jpeg
 

mrrsm

Lifetime VIP Donor
Supporting Donor
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Oct 22, 2015
7,639
Tampa Bay Area
Great follow up images! They more than prove out how much of the Radiator can be compromised when all of that Junk and Detritus gets wedged inside of those fins and defeats its design. FWIW... I could fill a Mason Jar with all of the "Lost Fasteners and Small Wrenches" I've managed to drop into the "Engine Wells of Oblivion " over the years... that is if I could ever FIND them again... LOL.

But seriously... if you can get one of those Slender Telescoping Pocket Pen Magnets.... extend it all the way out and just probe and drag over the general areas you were working from the Top... you'll be very surprised when you hear that mysterious, metallic "Klink" and recover Tools and Fasteners that you completely forgot about owning.

I have one other thing to mention on your behalf... and that is that unlike many who come here for Help... and then literally fight against or ignore much of the advice they get in copious amounts from participating Members... YOU have been a Good Listener... and are a Better Mechanic because of it!
 

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