SOLVED !! - Thoughts on temp spikes with AC on
 

So I’ve done a bunch of research here and yet maybe I’m missing something?
My AC runs good as expected. Blows cold. However in NON-highway driving and especially at traffic lights the engine temp will begin a quick rise with the AC on.
The electric fans spin good and blow towards the engine. The fan clutch is good. The compressor sounds okay.
Normally the temp runs a little below the midpoint on the gauge and will increase a bit above it if I’m sitting at idle for 15 min plus but nowhere close to redlining. All components of the cooling system, and I mean ALL, have been replaced over the last year or so.
I’m outta guesses. Any ideas?

Im kinda getting to a point where if I can’t figure it out I’m still looking at yanking the system and losing some weight. It’s an 80 buck commitment for a d2 pulley and a new belt. I’d rather have air but if it remains undiagnosed then I’m ready to scrap it.

what type of radiator are you running? What type of fan clutch?

I replaced my fan clutch with an Astro van clutch.
Noticed that even with good elec. fans at idle sitting in drive thrus and such would creep up to 212 in summer. Found that if I raise the rpm up to 1200-1500 it would stay at 186. All numbers are from an UG.

Clutch is original stock LR. Radiator is an all makes am replacement.

Forgot to mention I had a credit to use up so I applied it to a good deal on a pair of 10” flex a lite fans. After really feeling my current fans out they just seemed like they had no balls. Worst case I got a pair of decent electric fans to play with.
Considering getting my old stock radiator repaired. It’s sitting out in the shed. Ugh....

I can concur with this. My thinking was that either the engine fan would move faster as a result or the water pump was turning quicker thus moving more coolant at a higher rate, or both? If I don’t run my ac it’ll still increase temp at idle but very very very slowly. With ac on it’s pretty damn quick.

If nor already done you may want to remove belt and check the a/c clutch pulley bearing for dragging. A failing bearing can put quite a load on an idling engine.
......

interesting thought about the A/C bearing.

I had the same as ROB99 this past summer. I re-cored the radiator after replacing the fan clutch the summer prior. It hasn't been hot enough to really test it out however.

ROB, if you are running the original fan clutch, replace it. The difference between my 16 year old clutch and a new one (OEM bought from AB) was pretty significant. The new is MUCH more aggressive.

Having said that, a new fan clutch did not solve my problem.

Check the alternator too for bad bearings while your at it - mine where toast and it was a noticeable diff (like I added 5hp to the engine) once I replaced that.

I have a 4 core all aluminum rad - brand new hoses, pump, tstat - etc. Mine will still creep up to 220 with the a/c full blast on a hot day at rush hour

You may be on to something here. Checked it tonight and there’s that familiar jing jing rubbing noise when I spin the pulley. Looks like I’m putting a bearing in shortly. Even if it doesn’t solve the problem it may lengthen the life of the compressor....

Alt is in great shape. Smooth as silk. It’s a nice magneti marelli unit I dropped in about a year ago.

Okay. Problem solved !!
Sunday I put in the pair of new flex a lite fans I had bought and I’m good now. Today I put the truck thru the temp rise trifecta. Stop and go local traffic, hitting the first red light after highway driving, and the dreaded drive thru wait. All without a raise in temp whatsoever. Not only that but while ac is running the temp drops slightly from its usual and stays there consistently.
So, my hunch was right and the old fans, which worked, just didn’t have the balls anymore. The air flow from the flexalites is vastly superior.

Post some pictures of how you mounted the fans. Would like to see the setup along with what model number fans did you use.

thanks for the follow up. always nice to see a problem get resolved.

ROBB, I appreciate the follow up and glad you figured it out. I suspect I'll be installing new fans next spring.

I'm guessing you used Flexalite 390. I've also seen folks use Hayden 3670.

The Flexalite (@ $85) blows 775 CFM @ 5A draw while the Hayden (@ $50) blows 650 CFM @ 5.4A.

Were the Flexalites "direct fit" or did you use some other method to fasten them to the fram of the radiator?

Hello All,
I would like to see some images too. I have been reading through the forum and very curious about this setup. For one my 96 D1 just has the viscous fan, so are you guys running additional fans along with the viscous fan or removing the viscous fan and running with an aftermarket electric fan setup?

T.I.A

The electric fans we are discussing sit in front of the radiator. They are turned on when the A/C is on or the coolant temp rises above a specific temp (IIRC it is 212 deg...but could be 220).

Thanks for the reply Walt.
So these electric fans are an addition to the viscous fan for extra cooling security?

Yep. Supplemental cooling based on A/C and/or temp.

Auhhh interesting!
I look forward to seeing images of this setup, seems like it makes for tight quarters in that area.

Thanks :)

Will post pics tomorrow. I did use the 390’s. Like 85 a piece thru Jegs. Free shipping.

IMPORTANT NOTE: The fans come pushing the wrong direction. However they’re easily reversible. Directions comes with the fan how to do. Takes two min to reverse the fan blade directions. Don’t switch the wires.

Mounting is is indeed interesting and required some thinking. First remove two bolts on each side of trans fluid cooler. Then slide it down a few inches. Otherwise you are NOT getting the fans out. New fans will not fit existing mounting tabs so I used the mounting kit that comes with each fan. Looks like:
https://cimg4.ibsrv.net/gimg/landrov...7b623864e.jpeg
Theyre meant to run between radiator fins but that’s no go. So.... I bent all four mounting tabs forward and carefully pulled one of each of the mounting “dreadlocks” thru the threaded hole on each tab. Then after all four are pulled thru I bent the tabs back to almost normal. Then I ran a dreadlock thru each corner of the fan and worked the fan in there. There is NOT a lot of room to work with but doable. Right side is harder due to hood release crap.
After fan is lined up slide the locking tabs down the dreadlocks until flush and fan is firm. Word of caution, it is HARD to pull the dreadlocks thru the mounting tabs. Little room to even get them started and they are like literally the width of the bolt holes. It’s slow going, but again, doable. Use pliers. Pull an inch, reset, pull an inch, repeat....
Also be sure to spin the fan blades in the housing before you totally lock up the lock tabs and make sure you don’t bind the fan housings. You’ll know. If blade spins free you’re good. If not, reposition. Repeat for both sides and crimp wires. Blue to blue and black to black.

Oh yeah, the fans are not like 10” perfect diameter, 360 degrees either. The housings are like 10.5” one way and 11.5” the other. You want the taller side going up and down. They’re is NOT a lot of room to work with. It is snug as a smug bug in a rug man.

Whats cool is when you run them parked with hood open, if you put your hand over the top gap between the two radiators you’ll feel the air surging out. They sure do push harder than my old ones did.

https://cimg9.ibsrv.net/gimg/landrov...3480497ac.jpeg
https://cimg0.ibsrv.net/gimg/landrov...8c11d30d3.jpeg
https://cimg1.ibsrv.net/gimg/landrov...cdefdc6c5.jpeg
https://cimg2.ibsrv.net/gimg/landrov...c863473d6.jpeg
Sorry for delay. Between work, crap weather, and starting to raptor line my truck I been crazy busy. Kinda hard to take good pics to show but....

Thanks for the images.
So these are in front of the radiator(behind the grill)?

Correct. In front of the radiator is the ac condenser which looks like a smaller radiator and the fans are in front of that. All being behind the grill.

Nicely done and I believe I will do this soon. These pics are helpful. Thank you.

Looks good. How loud are the fans when they are running? Also did you connect them to the original wiring of the old fans or did you wire them to a switch and relay?