Improving the cooling on our TJs

[MikeE024]

I can tell you that perfect rust free desert SBC 350s will give you a HEKKOVA time removing their drain plugs, luckily they’re external hex.

I didn't have that problem with my 2005 engine using a 8mm square socked. But, I don't envy the folks in the rust belt. Apply Mouse Milk and hope for the best.

I looked into the plug material stuff a little more and it looks like a brass plug should work if you keep the coolant maintenance up since the cast iron anode has much great mass than the cathodic brass. From what I read you shouldn't have a conductive solution (necessary for galvanic corrosion) until your PH drops to 7, so you could run test strips to confirm you stay near the 8-9 PH range. It's worth noting that some cooling systems tend to rust up more than others even when everything is done correctly, due to bad previous maintenance. Thermocure helps, but it won't prevent rust (that's sitting behind rust flakes) to become exposed and alter the coolant after flakes fall off into the coolant. Not everyone will have this problem, but I believe it's worth mentioning.

I'm doing flushes right now and just switched to a 304 stainless steel since I had two laying nice and pretty on the counter. I believe the SS material basically perfect because it's one slot more cathodic than nobel (since the plug was likely carbon steel instead of cast iron). Brass is four slots over on the chart. Just keep an eye on your PH and all will be good to go if what I've read is correct.

Sounds like a plan for the thermostat. Just don’t buy a Mr Gasket knockoff, additionally, test them in a pan before installing! I do this and never found a “bad” thermostat until I tried the Mr Gasket, looks like the same but in my case opened early. Maybe a fluke. But I bough 5 Robert shaws and watched them all open in unison …

I almost always boil my replacement thermostats to ensure they open. The PO had a 210* thermostat installed and didn't tell me...it was also stuck shut in the boiling water so I guess the rating didn't really matter.

 

[Ericshere03]

I didn't have that problem with my 2005 engine using a 8mm square socked. But, I don't envy the folks in the rust belt. Apply Mouse Milk and hope for the best.

I looked into the plug material stuff a little more and it looks like a brass plug should work if you keep the coolant maintenance up since the cast iron anode has much great mass than the cathodic brass. From what I read you shouldn't have a conductive solution (necessary for galvanic corrosion) until your PH drops to 7, so you could run test strips to confirm you stay near the 8-9 PH range. It's worth noting that some cooling systems tend to rust up more than others even when everything is done correctly, due to bad previous maintenance. Thermocure helps, but it won't prevent rust (that's sitting behind rust flakes) to become exposed and alter the coolant after flakes fall off into the coolant. Not everyone will have this problem, but I believe it's worth mentioning.

I'm doing flushes right now and just switched to a 304 stainless steel since I had two laying nice and pretty on the counter. I believe the SS material basically perfect because it's one slot more cathodic than nobel (since the plug was likely carbon steel instead of cast iron). Brass is four slots over on the chart. Just keep an eye on your PH and all will be good to go if what I've read is correct.



I almost always boil my replacement thermostats to ensure they open. The PO had a 210* thermostat installed and didn't tell me...it was also stuck shut in the boiling water so I guess the rating didn't really matter.

So, would you rather your block corrode with stainless or the plug corrode with brass ;-) … I literally don’t think it makes a lick of difference. Good maintenance is key. I did a Thermocure treatment, filled with fresh juices and added some RMI-25.

 

[MikeE024]

So, would you rather your block corrode with stainless or the plug corrode with brass ;-)

It's likely not going to corrode on me so I haven't given it a thought.

I literally don’t think it makes a lick of difference.

That was the point of my last post. I put a little more info in there than just our opinions. Both will be fine unless we don't maintain our systems.

Good maintenance is key. I did a Thermocure treatment, filled with fresh juices and added some RMI-25.

I flushed about 50 gallons through the heater core the other day using a tool that combines water and compressed air. I did so because bad stuff kept coming out so I kept going. The gun tool works infinitely better than just running water pressure.

Yesterday, my ECTs were 212* doing 93 mph on the highway with ambient temp at 92*...with Thermocure and distilled water in the system. I flushed the radiator and heater core again yesterday after dropping the Thermocure. I then added an in-line coolant screen after finding an option and configuration that works well for me.

I flushed the radiator a bunch more today because bad stuff kept coming out using the flush gun, then Thermocured it again I then dropped the Thermocure by running about 20 gallons of distilled water through the system.

My hope is that the ECTs will be pretty nice and sustainable moving forward.

Things are looking pretty good right now.

 

[MikeE024]

Edit:

I moved the coolant screen to the upper radiator hose after shortening shorter fittings I found and making the plumbing work.

 

[TexasTJ2004]

Yesterday, my ECTs were 212* doing 93 mph on the highway with ambient temp at 92*...with Thermocure and distilled water in the system.


View attachment 537382

I never ran my TJ at 93mph. Maximum was 82-83MPH.
On highway the coolant temperature always stayed under 210F.

 

[TexasTJ2004]

Additional info:

The coolant screen makes the water & coolant filling process much nicer because opening up the cap lets bad stuff out and helps reduce the air gap. Reducing the air gap results in the thermostat opening up way sooner, so there's no need for me to pull the thermostat to speed up the process when doing many flushes.

View attachment 537378

View attachment 537379

View attachment 537380

What is the PN for the coolant screen part?

 

[MikeE024]

What is the PN for the coolant screen part?

AF64-2043

I like it much better than the JEGs versions because those are know to leak.

 

[MikeE024]

It’s around 1/2-3/4 of an inch it hasn’t contacted anything so far it a derale 17919 fan and I’d say it similar in noise but a much higher arguably worse pitch it’s higher and more whiny but worth the performance improvement for me I also had to re drill the shroud to make sure it was centered correctly otherwise it definitely would hit somewhere.

View attachment 535890

Do you happen to know if the 18” version performs similar to the 19”?

(17918 vs 17919)

 

[Jcrubicon]

Do you happen to know if the 18” version performs similar to the 19”?

(17918 vs 17919)

I tried both bigger is definitely better in this case but the 18 was still a minor improvement

 

[MikeE024]

I tried both bigger is definitely better in this case but the 18 was still a minor improvement

Great to know thanks for that info.

I’m currently leaning towards doing the 19” Brushless Spal E-Fan install in August (that member Steel City wrote about). I like idea of taking some load off of the engine at highway speeds, being able to control the fan speed to my needs, and having a switch to run the full 4,000 CFM in idle or stop and go traffic.

 

[LJ-MXer]

The combo of 2791 with Derale 6 blade fan works perfectly fine. Meanwhile even when long idle the engine temperature stays under 210, more in the area of 204-208. This is in Houston Heat.
The transmission maximum when idling for 2 hours reached 178, and seems like derale transmission cooler kicks in and starts cooling.
I am still running autozone garbage radiator, so it seems like adding a better clutch (2791) with 6 blade fan works great

Having trouble sourcing 6 blade 18 or 19 inch fan. What make and model of vehicle should I plug in when searching?

 

[TexasTJ2004]

https://www.amazon.com/Derale-17918-Clutch-Reverse-Rotation/dp/B004XOO0FK?tag=wranglerorg-20 I used this one.

 

[LJ-MXer]

All the hard Parts should be here tomorrow is there by chance An issue With the actual switch itself I know the fan switch And the mode switch Will occasionally overheat and cause connection issues but have never heard of the actual temperature switch in the LJs being an issue.

 

[LJ-MXer]

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.

 

[Zorba]

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

That's great - it really is - but I never had any problems with my A/C with the lop eared 5 bladed fan, even back when I still had the stock fan clutch.

 

[LJ-MXer]

I have an aluminum 3 core radiator filled with Engine I've. There's enough cooling capacity there for a failing fan clutch to affect the ACs performance before the cooling systems. With the current combination I can idle, on pavement, in 100°F plus, and see engine temps swing from 203-219.

 

[KennethS]

Many times I refrain from posting since I know there are variations in 25 year old vehicle cooling systems. My ‘98 has the factory original fan, the original fan clutch and shroud, with an aftermarket Gates water pump and a parts store Murray radiator, and I have no issues driving in rush hour traffic in 115+ temperatures with the AC blowing 40 degrees. I haven’t done anything beyond replacing failed components with aftermarket replacements. It seems as if I can do this in 115 degree temperatures, then anyone in cooler areas should be able to do the same.

 

[LJ-MXer]

Many times I refrain from posting since I know there are variations in 25 year old vehicle cooling systems. My ‘98 has the factory original fan, the original fan clutch and shroud, with an aftermarket Gates water pump and a parts store Murray radiator, and I have no issues driving in rush hour traffic in 115+ temperatures with the AC blowing 40 degrees. I haven’t done anything beyond replacing failed components with aftermarket replacements. It seems as if I can do this in 115 degree temperatures, then anyone in cooler areas should be able to do the same.

I WANT to agree 100% but with cooling there are so many variables that don't show up on a forum. Same with the AC unless you have guages, a sniffer or can see your evaporator, with no knowledge of pressures, a lot of folks are out of their depth.

 

[KennethS]

Yep, having the right tools for the job makes things much easier.

 

[Ericshere03]

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.