Improving the cooling on our TJs

[LJ-MXer]

Yea ... I'm with Kenneth. Stock, everything is great, even on the surface of the sun I call home (Phoenix AZ). I've gone through 6 TJ/JL with the 4.0 and they ALL had reliable cooling systems and cold AC. Some of the crap hocked up as "upgrades" are anything BUT. The Problem is that we cannot get MOPAR parts as easily or at all ...

The Hayden severe duty will squeal the fan belt around 4000rpm, this is with all new belts, pullies, etc on a couple jeeps. MOPAR fan clutch seems just as aggressive but at the high end must slip a little more because they never squeal the belt.

Denso makes a fine replacement condenser that might just be the OEM part.

Water pump doesn't seem to matter much, but the Mopar always makes me feel better.

Radiator, They basically all have their issues, champion (3 and 4 core) , CSF heavy duty (brass), allow temps to creep a little but but Part store replacements are the worst. MOPAR just works, but those are NLA. I been running a "Cold Case" and it looks cools keeps cool, its a winner, but I cannot comment on reliability. I am about 2 years in with low mileage.

Hoses; Mopar is thicker and much higher quality.

Hose clamps... FOR THE LOVE OF GOD keep the spring clamps!!! you can get replacements at Bel Metric.

Fan; keep the stock metal, looks like a tractor fan but who cares, it works and has the ability to push enough air to squeal the fan belt.

Make sure you have a shroud.

I will add, sitting idle, you will experience the AC vent temps creep up a little but... you can raise the RPM a little bit or maybe consider an electric fan for when the AC is on ... that's probably the only cooling mod ill do... someday.

INSULATION and heat rejection for the interior is actually what most of us need. TJs/ LJs and prior are basically barns on wheels! We wouldn't expect our home A/C to keep a barn cool! Yes, we can get a certain temperature of air to come out of the vents but we won't RETAIN that temperature.
There's no "one size fits all" solution to that either.
You can't wrap your exhaust, in a wet climate.
Heat shields and heat barriers are nice but can obstruct views for diagnostic purposes and possibly come lose and rattle. Adhesive type insulation isn't always the best option for wet environments.

 

[Ericshere03]

INSULATION and heat rejection for the interior is actually what most of us need. TJs/ LJs and prior are basically barns on wheels! We wouldn't expect our home A/C to keep a barn cool! Yes, we can get a certain temperature of air to come out of the vents but we won't RETAIN that temperature.
There's no "one size fits all" solution to that either.
You can't wrap your exhaust, in a wet climate.
Heat shields and heat barriers are nice but can obstruct views for diagnostic purposes and possibly come lose and rattle. Adhesive type insulation isn't always the best option for wet environments.

Actually, yea… if we put the jeep TJ hvac system in a foam box, we’d freeze our butts off instantly… the TJ has got to be the worst insulated vehicle in modern times … YET I can eventually freeze my butt off in the TJ in AZ heat.

For exhaust, you can ceramic coat it … eventually, I’ll ceramic coat my exhaust manifold to control some heat under the hood… works like a wrap but also protects against wet environments/rust/etc … plus it can look really cool.

They make a lightweight foam laminated bubble paper that works well with heat. Eventually, I want line X my interior and I’ll throw new carpet with some insulation glued to the back of the carpet. But then I also have a soft top to contend with, which is a major heat gain under the sunny skies of the desert

 

[freedom_in_4low]

Actually, yea… if we put the jeep TJ hvac system in a foam box, we’d freeze our butts off instantly… the TJ has got to be the worst insulated vehicle in modern times … YET I can eventually freeze my butt off in the TJ in AZ heat.

For exhaust, you can ceramic coat it … eventually, I’ll ceramic coat my exhaust manifold to control some heat under the hood… works like a wrap but also protects against wet environments/rust/etc … plus it can look really cool.

They make a lightweight foam laminated bubble paper that works well with heat. Eventually, I want line X my interior and I’ll throw new carpet with some insulation glued to the back of the carpet. But then I also have a soft top to contend with, which is a major heat gain under the sunny skies of the desert

The matte surface and black color are about as bad as it gets for absorbing solar energy. I shot my top with an IR gun last week when it was 94 outside, and the top fabric was 148F! That's some serious radiation blasting down on you from the entire top side of the interior. I'd have a shiny white top if I could get past the look, or line the inside surface with polished aluminum if it wouldn't tear up and make a mess immediately.

 

[lBasket]

The matte surface and black color are about as bad as it gets for absorbing solar energy. I shot my top with an IR gun last week when it was 94 outside, and the top fabric was 148F! That's some serious radiation blasting down on you from the entire top side of the interior. I'd have a shiny white top if I could get past the look, or line the inside surface with polished aluminum if it wouldn't tear up and make a mess immediately.

If only they still made the white soft tops

 

[Moglocker]

CAN COMFIRM: Hayden SEVERE DUTY fan clutch and Derale HD 18in, 6 blade fan, got my A/C FROSTY! Cool front with a storm off the coast so ambient temperature was low 90s and this reasreadinf was at 89-92 F. Next week when SW Florida gets over 100°F with 100% humidity, I'll check back in. View attachment 635640

View attachment 635639

 

[Moglocker]

Does it heat up at idle?do you have a part number for the fan?

 

[Ericshere03]

The matte surface and black color are about as bad as it gets for absorbing solar energy. I shot my top with an IR gun last week when it was 94 outside, and the top fabric was 148F! That's some serious radiation blasting down on you from the entire top side of the interior. I'd have a shiny white top if I could get past the look, or line the inside surface with polished aluminum if it wouldn't tear up and make a mess immediately.

I had a Bestop twill top for a little bit (dumped it because it fit like a garbage bag) and it felt quite nice, it’s a great material.

BUT! Again, in the hottest part of the country, I can say I can be comfortable in a jeep with its factory AC… I have an LJ too with more interior volume …

Now, being heat soaked in the sun and getting going again can be rough for a min or two. But it could be worse …

It’s just a shame that black twill fabric doesn’t fit well at all… maybe when my NOS factory top deteriorates bestop will address the fit and I’ll try again.

 

[ironraccoon]

I used a black tablecloth, silver insulating bubble wrap, and a cargo net to insulate my roof against the Texas heat. Tinted the front windows. It gets COLD in there and cost about $20, plus I use the cargo net for a bunch of things.

 

[GoldenGorilla]

I think I replied earlier in this thread about how well my boom mat has helped with heat as well as sound. My TJ AC has always kept the interior frosty cold regardless of top used. As in too cold at full cold with the fan on 2.

I really like the shape of the unmodified TJ hood, but there is no denying an airflow/pressure issue exists in these engine bays. Vents placed in the top side do seem to help.

For exhaust, you can ceramic coat it … eventually, I’ll ceramic coat my exhaust manifold to control some heat under the hood… works like a wrap but also protects against wet environments/rust/etc … plus it can look really cool.

I think I'll go the cerakote route eventually too. In the meantime I intalled a heat shield I made from 1/4" fiberglass backed aluminum secured with some stainless zip ties when I installed my shorty headers in May. Was part of a bigger refresh job and average temps jumped 20F during that time so I don't have like for like IAT data to prove it. But I was getting IAT temps like 130°F when it was 30-40°F ambient and the highest I've seen lately was 135°F at 99°F ambient.

 

[LJ-MXer]

Does it heat up at idle?do you have a part number for the fan?

Read a few posts pack.

 

[JPHikr]

I have used Techline for 30 years.
First learned about them from NASCAR engine builders.
https://techlinecoatings.com/wp-content/uploads/Techline-book.pdf
The Thermal Barrier header coating is brushable and air cures then bakes on when you heat up the exhaust.
Use dispersant coating on all my Aircooled motorcycle and VW cylinders to remove heat.
Their internal coatings I have used on piston crowns to reduce oil temp,on pistons to reduce cylinder wall friction.

 

[LJ-MXer]

Does it heat up at idle?do you have a part number for the fan?

Just saw this. Did you read above and get the part number? Yes, temps still creep up a little at idle but thats more of an insulation issue in reference to the interior and just physics in reference to ambient temps

 

[MikeE024]

I think I replied earlier in this thread about how well my boom mat has helped with heat as well as sound. My TJ AC has always kept the interior frosty cold regardless of top used. As in too cold at full cold with the fan on 2.

I really like the shape of the unmodified TJ hood, but there is no denying an airflow/pressure issue exists in these engine bays. Vents placed in the top side do seem to help.



I think I'll go the cerakote route eventually too. In the meantime I intalled a heat shield I made from 1/4" fiberglass backed aluminum secured with some stainless zip ties when I installed my shorty headers in May. Was part of a bigger refresh job and average temps jumped 20F during that time so I don't have like for like IAT data to prove it. But I was getting IAT temps like 130°F when it was 30-40°F ambient and the highest I've seen lately was 135°F at 99°F ambient.

View attachment 637224

View attachment 637225

The heat shield you are using looks to be good stuff. Did you insulate between the intake manifold and exhaust manifold? After doing this, do you believe the 1/2” version would fit?

FWIW, I noticed no improvement in IATs after installing a ceramic coated JBA manifold, and I noticed no penalty when removing the lava wrap from the exhaust between the pre-cats and turbo.

Mild suggestion, to avoid an exhaust leak at the pre-cats (and heating up the engine bay), back off the fastener on the left in your first photo and go in more on the right (they aren’t evenly clamped). It becomes more obvious when you look at the threads. If interested, nickel based anti-seize works well on those threads.

 

[Ericshere03]

The heat shield you are using looks to be good stuff. Did you insulate between the intake manifold and exhaust manifold? After doing this, do you believe the 1/2” version would fit?

FWIW, I noticed no improvement in IATs after installing a ceramic coated JBA manifold, and I noticed no penalty when removing the lava wrap from the exhaust between the pre-cats and turbo.

Mild suggestion, to avoid an exhaust leak at the pre-cats (and heating up the engine bay), back off the fastener on the left in your first photo and go in more on the right (they aren’t evenly clamped). It becomes more obvious when you look at the threads. If interested, nickel based anti-seize works well on those threads.

Dang, I thought the ceramic coating would help a bunch … my guess is the air is moving too quickly to heat up much …

I thought about the American racing header and relocate the cats away from the intake manifold as well… I’m guessing the cats being 3 inches from the aluminum intake manifold may not be making much a difference …

Perhaps the engineers got it right when building these things

 

[Steel City 06]

If you do Cerakote, do Piston Coat rather than a normal color. Piston Coat is low emissivity and will help reduce heat transfer via radiation.

Even better if you do the intake header at the same time. Low emissivity = low absorbtivity, so even less heat transfer.

Doing both the intake and exhaust headers in Piston Coat bought me a lot of timing advance.

 

[MikeE024]

Dang, I thought the ceramic coating would help a bunch

Installing a hood louver did more for my IATs than the ceramic coated manifold and wrapping my exhaust.

Folks seem to underestimate the impact on IATs from a hot engine and a fan blowing hot air from the radiator all over the engine bay.

This is where the value of a Cold Air Intake comes in...not to be confused with a hot air intake that we wrongly label a CAI (I have an aftermarket intake that is not a CAI since it pulls in air from the engine bay).

The most common CAI method that I'm aware of is to pull air in from the cowl. For folks like myself who can't get air from the cowl and who don't want a snorkel, there's an older post showing that Blaine pulled air from outside of the engine bay through the grill near the passenger side headlight. I plan to employ the Blaine method if I ever go with highline fenders.

You could then wrap the CAI intake plumbing between the cowl/grill and the throttle body.

 

[Ericshere03]

Installing a hood louver did more for my IATs than the ceramic coated manifold and wrapping my exhaust.

Folks seem to underestimate the impact on IATs from a hot engine and a fan blowing hot air from the radiator all over the engine bay.

This is where the value of a Cold Air Intake comes in...not to be confused with a hot air intake that we wrongly label a CAI (I have an aftermarket intake that is not a CAI since it pulls in air from the engine bay).

The most common CAI method that I'm aware of is to pull air in from the cowl. For folks like myself who can't get air from the cowl and who don't want a snorkel, there's an older post showing that Blaine pulled air from outside of the engine bay through the grill near the passenger side headlight. I plan to employ the Blaine method if I ever go with highline fenders.

You could then wrap the CAI intake plumbing between the cowl/grill and the throttle body.

Being plastic, i would think wrapping the intake would NOT make a difference... but good idea relocating the intake box snorkel to pull from under the headlight... id suspect there will be a slight ram air effect as that grill is cramming itself through the air ...

hmm... things to ponder...

 

[MikeE024]

Being plastic, i would think wrapping the intake would NOT make a difference... but good idea relocating the intake box snorkel to pull from under the headlight... id suspect there will be a slight ram air effect as that grill is cramming itself through the air ...

hmm... things to ponder...

It makes sense that it would help with heat soak in a CAI set up that pulls cold air into hot tubes in the engine bay. A member I trust said insulating his plastic Windstar set up dropped his IATs about 10*.

If your IATs are low enough then none of the insulation talk really matters since the PCM won’t penalize you by pulling timing.

I wouldn’t expect a massive ram air effect since the air dam directs air flow to the radiator. We know the headlight isn’t sealed to the grill so there is air getting through, but I can’t say how much.

 

[Rickyd]

Being plastic, i would think wrapping the intake would NOT make a difference... but good idea relocating the intake box snorkel to pull from under the headlight... id suspect there will be a slight ram air effect as that grill is cramming itself through the air ...

hmm... things to ponder...

If you think you'll EVER do a river crossing, a grill mounted intake will hydrolock your motor when the bow wave is high enough. I've been there and done that.

I'll never have one again!

 

[jjvw]

It makes sense that it would help with heat soak in a CAI set up that pulls cold air into hot tubes in the engine bay. A member I trust said insulating his plastic Windstar set up dropped his IATs about 10*.

If your IATs are low enough then none of the insulation talk really matters since the PCM won’t penalize you by pulling timing.

I wouldn’t expect a massive ram air effect since the air dam directs air flow to the radiator. We know the headlight isn’t sealed to the grill so there is air getting through, but I can’t say how much.

My recollection is that the header tape I used on the Windstar canister and the remaining factory intake tube decreased the IAT temps about 10°F. The later addition of hood louvers decreased those temps another ~10°F.

Both of these were in addition to the sizable decrease in IAT temps from the Windstar cowl intake all by itself. The big tell from those early days was that I could no longer cook burritos on the intake manifold and the hood stopped getting uncomfortably hot to touch.