Lifting the hood for cooling

[Waytec]

So the summer is coming and I need to do something about the XJ getting hot.

I was thinking about cutting and putting Run Cool vents in, but I have seen guys putting spacers on the hood hinges and lifting it. How well does this work? And how thick of spacers are you using?

I am liking this idea because I can lower it back down for the winter.

 

[ntsqd]

By lifting the rear of the hood low vehicle speed cooling may well be enhanced, but high(er) vehicle speed cooling most likely will not. The base of the windshield becomes a high pressure area as vehicle speed increases. Opening the rear of the hood in these conditions can allow that high pressure air to enter the engine bay. While it is cooler, it tends to "dam" airflow through the engine bay - which means that it can reduce the airflow through the radiator.

Louvers in the middle of the hood will allow hot air to escape the engine bay during low speed operation. At higher speeds the middle of the hood is a low pressure area. Having the louvers in this area can actually cause the low pressure to pull more air through the engine bay. The downside to this is that the exiting hot air then is blown into the base of the windshield where most vehicles have their vent air intake.

The way to test where the high and low pressure regions are is to tape 1"-1.5" long sections of yarn in a grid onto the hood, and then go for a drive. Need only do one side as the other will nearly mirror it. The yarn will trail off in the direction of the airflow where it is high pressure, and will flap around randomly where it is low pressure.

The rivet-on louver panels are convenient, but expensive. Louvers punched around here run about $1.50 per louver. Try looking for a local street rod shop and ask them about louver punching. The black areas on this XJ's hood hide louvers punched by a mutual friend of mine and those two guys. (Yes the XJ towed that drowned 4rnnr out of there.)

 

[SWbySWesty]

Here are a few pics that I've gathered showing the spacers and I'm sure you can find write ups here and there.

 

[XXXpedition]

i used to have that problem and tried a lot for years.
bigger radiator, additional fan drawing air out from under the hood, louvers, you name it...
my solution was a new radiator from http://www.alumrad.com/. that solved the problem forever. i paid about $200
hope that helps

 

[CanuckMariner/Nomad]

I would suggest rather than finding ways to cool your rig, you might try to find out why it gets hot. This is a very critical issue and should not be taken lightly (not that you are):

• Check the rad out at a specific rad shop who will do a test/check-up more than likely for free.
• Check out your rad to see it is free of debris like bugs, mud, silt etc. from all your wheeling trips. Having a thin coat of sediment on all the vanes in your rad, really impairs cooling.
• Check out the flow of fluid through your rad and that it is not blocked by some rust or sludge. This includes checking the water pump as it may need replacing.
• Check the thermostat as it may need replacing or changed out to allow for cooling more quickly - it maybe stuck closed too long and hence the heat issue.
• Check you rad fluid/coolant for proper mix of water/coolant should be 50:50 for all conditions.
• Check your fan to see it comes on and speeds up accordingly when the rad gets hotter, wouldn't be the first time the fan clutch is not working correctly - rad shop should be able to help here as well.
• Check with a dealership if there has been a recall to fix this problem. If not, the dealership may have already experienced this same problem with other customers and knows the fix.

Might want to install a really accurate or more accurate water temp gauge to monitor exactly how hot it gets and how fast as it may be the rather insensitive gauge (a common problem with stick gauges) that comes stock is giving you not accurate info.

I have heard about additives like Water Wetting, which with personal experience and testing, do nothing to control heating problems.

Lastly:

• you can turn on your heater, open windows and it will take some heat from the coolant system
• Gear down and slow down as this will cause you fan to turn quicker but less heat to the coolant system
• rather than coasting down hill, try gearing down and let the tranny help the fan do its job

Just some suggestions. Good luck with your hot engine problem as it can be quite serous if not address properly or correctly. :costumed-smiley-007

 

[jim65wagon]

When I put the 350 V8 under the hood of my 65 Nova, it ran hot, even with a 3 core radiator. Lifting the back edge of the hood worked quite well, at all speeds. Didn't matter if I was cruising downtown at an idle or freeway running at speed. It went from 220 degrees to 185 with just that mod. I used a pack of washers taped together in about a 3/4" bundle....probably the cheapest mod I've ever done....

 

[Black Dog]

I would suggest rather than finding ways to cool your rig, you might try to find out why it gets hot.

Thats a good call, several years ago on my 99 XJ it overheated on me and I managed to limp it home, then to a shop a couple days later. They said that there was a lot of sediment clogging up my radiator, enough that it couldn't adequately cool my coolant and enough that they couldn't flush it out. So I'd check to make sure that your flow is 100%.

 

[lamontagne]

How hot are we talking about?

210-225 degrees is normal operating temp for a 4.0 engine. 240 degrees I would start to be a little worried, 250 degrees I would be off to the side of the road.

Also what year XJ do you have? Do you have a Renix engine with the closed loop cooling system, or the Chrysler engine with the open loop? (hint, do you have a sealed overflow bottle or a vented one?)

After much trial and error in my old '94 XJ, the best solution for me in 120* Arizona heat was a stock brass 2-row radiator, 185* t-stat w/ enlarged weep hole, stock water pump (mopar brand, not a cheap CSK model), and installing a seperate transmission cooler.
While 4.0's like 210*, AW-4 automatics do not! Get the trans fluid out the same heatsink as engine coolant and both will be happier for it.

 

[Waytec]

Sorry I should have given a little more info. I don't have a engine over heating issue. I am running stock rad and a high efficacy water pump and I keep a close eye on the mix. Not my first time playing the engine heat game.
My issue is the engine compartment its self gets really hot to the point that you done want to touch the hood or fenders. On some trails every time we needed to stop I would pop the hood just to the safety latch and you can watch the heat rolling out.
A lot of people in this aria use Le Barren or Grand am hood vents but they now have been pretty picked over and hard to find. So that is why I was thinking about just raising the back. Cheap and the hardest part is realigning the hood after.

 

[preacherman]

I know several XJ guys that did this

http://www.4wd.com/productdetails.aspx?partID=41706

They just cut a hole in the hood and riveted them to the hood. The are printable if you desire a color match.

Hope that helps

 

[CanuckMariner/Nomad]

Sorry I should have given a little more info. I don't have a engine over heating issue. I am running stock rad and a high efficacy water pump and I keep a close eye on the mix. Not my first time playing the engine heat game.
My issue is the engine compartment its self gets really hot to the point that you done want to touch the hood or fenders. On some trails every time we needed to stop I would pop the hood just to the safety latch and you can watch the heat rolling out.
A lot of people in this aria use Le Barren or Grand am hood vents but they now have been pretty picked over and hard to find. So that is why I was thinking about just raising the back. Cheap and the hardest part is realigning the hood after.

Given your more complete description of the issue, perhaps your grill is blocked somewhat by lights, winch etc. and restricting the air flow through your engine bay.

 

[Azlugz]

Couple things said on here I want to address.

First off, being in the Phoenix/Mesa area, i feel your pain on the heat issue!!

If you are primarily trying to reduce engine bay temps while wheeling, the hood lift will work wonders, remember tho that you are blasting your windshield with HOT air and if you are cool and cozy inside with the A/C, this may cause issues. If your engine commonly runs 200* to 210*, normal range for the 4.0, then the hood lift should not cause you any issue on the hiway.

The 350 SBC mentioned earlier running 210-225*, this is norm for a SBC......225* is getting on the warmer side than they usually like, but still reasonable, 185 is too cold and you are losing performance. If it starts spiking up to 240 or more, then you have a problem. 225* could be too high or too low of water flow thru the system. Common mod in the SBC is to swap in a high flow short nose corvette water pump. This is usually not good on a stock motor and radiator as it puss the water thru the system too fast and does not properly cool. This will commonly make a stock SBC run at 225* to 235*. You should only go to a high flow waterpump system if you make the rest of the system able to handle it.

Water Wetter, Hy-per Lube Super Coolant, DEI's radiator Relief, 40 Below.....
All those coolant addatives work, they really do..BUT, they work for what they were intended for!!! They DO NOT work to cool an engine that is running hot due to PROBLEMS!! I spent quite a while as a Crew chief on various race vehicles from dirt track to NASCAR open wheel, to Speed Trucks. We relied on the coolant addatives to keep our engines down in the 210* range. The most common engine we had was a SBC pushing 700+Hp with lots of aluminum and lots of timing creating lots of heat when running on alcohol!! These were built engines that will run hotter because of the power being demanded out of them, not because the radiator is clogged and its not getting enough cooling. We used 40 Below and it kept engine temps manageble. Now, if your stock 185hp 4.0 is running at 250*, it is not because of the power you are demanding or the advanced timing for performance, it is because it has a problem that needs to be repaired and water wetter or 40 below is not the repair. It may mask for a short time, but does not fix it. So, the statement that water wetter does not work is a grossly misinformed statement. It just won't work for something it was not designed for.


All my rambling aside, I personally think the hood lift looks like redneck cooling and much prefer hood louvers or vents. If you are concerned with winter, make a cover for the inside that will let you block them in the winter.

For hood vents, you could also look for a set of vents from a 98 Grand Chero 5.9 Limited, I love the looks of mine and they work great.



Sorry for the long tiraid, just my .02

 

[Root Moose]

I personally think the hood lift looks like redneck cooling and much prefer hood louvers or vents.

x2

If there is a problem with the cooling system, fix it.

The OP's later post seems to imply it is more of a preference thing? These engines get hot... add some vents I guess.

 

[Azlugz]

These are the vents on my 5.9....

.

 

[Albin]

I know several XJ guys that did this

http://www.4wd.com/productdetails.aspx?partID=41706

They just cut a hole in the hood and riveted them to the hood. The are printable if you desire a color match.

Hope that helps

I did this for my '85 4runner, except I used a $4 heater vent cover from Lowe's, sorta qhetto, but it works. I don't have cooling problems, but I did it to make sure there were no cooling problems while exploring DVNP during the summer.