What needle? The stock gauge is notoriously inaccurate. Being OBDII you should be able to get actual coolant temp readings from the ECU with an adapter and phone app. Not sure what good it would do though if you didn't get a before temp from the ECU.

 

I'll second this, what are the vents from , looks like home hvac returns lol

 

Little critical here, blocking off the vents wouldn't be a big deal to figure that out. Not rocket science.

The heat issue I was having wasn't simply from driving down the road, it was driving and then having to sit idle for a period of time.....my needle would suddenly rise in a slow drive thru waiting in line. I've tried to force this issue over the last 3 days, on 95 degree days......couldn't do it. I'm also not getting what I thought was vapor lock on a hot restart now either. If I parked hot, then went back to restart 20 minutes later, it would resist. There's a lot of heat trapped under there.

If you boil water on the stove, it takes longer with out a lid on the pot, covered or uncovered you'll soon boil water but covered, it'll likely boil over. Basically what's going on here is we're removing lid from the pot allowing it to breath.

Having done this with other brands in the past with cooling issue's, I found placement of the vents to be important. Up front near the radiator, where the cooling is trying to take place is one of the best. At speed, you also get air draw passing over the hood, while if your further back on the hood, there's more dead air. Put a small twig on your hood near the front, take a ride and see how long it stays there........then take another twig and put it back further on the hood in the center, take a ride......you'll probably have to remove the twig by hand once you park it.

I will see about getting temps when time permits and post, not a big deal.

 

I wasn't trying to critical. Just saying the stock gauge is notoriously unreliable and inaccurate. Having actual temp changes from the ECU would make for a good comparison, especially if you ever did want to produce/sell the vents.

 

It's all good.......
Last time I plugged into the ECU and shared some photo's of the readings with 'Scouts, it said one of my o2 Sensors was over 2300 degree's.....if that was actually the case, I don't think I'd still be driving it 7 months later with out changing a thing.....

I have brand new mechanical gauges & pillar mount I need to install, I'll have a look at it once I install them....(I only bought the set up 5 months ago..ugg)
I'll block off, take a looky, then open up....take another looky......I guess I now have an additional reason to complete that install.

Meanwhile.......took a few minutes to do this.......

Indoors, no out side breeze, cut good quality (not toilet paper) paper towel into 3/4" strips....applied with tape, photographed at idle.......







Those aren't light, stringy little streamers......and that's at low idle, no skinny pedal was applied at any time. Placement, directly getting rid of heat where it's attempted to be cooled, taking advantage of the cooling fans....all key.

Hopefully this paints a clearer picture of what's happening....it can only help.

 

I'm interested in these vents. I own a XJ as well and I know those guys swear buy them. I'd love to see actual temp changes to confirm their effectiveness. Even if it's something 5-7 degrees cooler it would be way way worth it. Especially for me it rains every couple months here.

My question is...doesn't your situation indicate that there is an actual problem with your truck? It should be able to do all the things you described above no problem. With out holes in the hood. None of the camel trophy trucks had vents in the hood. Those guys were beating the ever loving crap out of those trucks. Granted they were diesels and not our lovable Alloy Allstar.

 

Camel trucks were diesel iirc, and diesels run cooler

 

The XJ suffers from a rectangle radiator in the wrong direction. Most young asshats place their louvers over the center as they use old Mopar vents, that's all dirty air.......it's better to draw from the front for effectiveness......That's typically a young crowd that knows it all, been dealing with it for over 20 years......Some, in area's like Houston, don't realize running 33' and swapping gears to 4:55 creates an over rev on the motor, causing heat.....then they build strokers.....which fail......Like I said, been dealing with that crowd for over 20 years.....little I haven't seen or read even not being on a forum for 7 years plus..

Trophy trucks.....Diesel yes.....but my theory is the first 2 actually wheel, the other 18 are carrying spare parts.......

Yes, I'm sure my truck has 'issue's.......but, over heating has come up in the past with others.....mine does it while idling in a line, idling wheeling.......what's wrong with distributing heat?

 

Almost forgot...........Old hot rod trick......drill a single 1/8" hole in your thermostat and you'll drop 2-5 degrees....that's been out there since the 50's.

 

The OE thermostats have a hole at 12 o'clock with a jiggle pin. Always reminds me of a fishing lure......

As far as the CT trucks and how they handled heat lets not forget they where new with few miles on em when they competed, diesel or not.

Ours aint new anything......

When I was down in Georgia (in the hottest/humid months of the year) I could watch the needle move while at stop lights....... the gauge may suck but it does go up and down. As soon as I'd take off the needle would drop. A new fan clutch was obvious but the needle still moved just not as much an arc.

An electric fan in my opinion is the way to go, less mechanical draw on the motor, even two more horses in the plus column are better than loosing 10 with the clutch.