Is there any cooling system upgrade that really helps?

[spdrcr137]

So if i read the last post correctly you might know a solution for this guys problem but your keeping it to yourself?

[SilverXJ]

The trick is parking on an incline, running to temperature, opening the radiator and waiting for the gulping or scavaging to take place and having a gallon of 50/50 mix water/anti-freeze on hand to quickly fill the radiator as the engine pulls water and expells the trapped air.

The 91+ open cooling system does not have the same burping problems as the previous closed system. While it helps to put it on an incline to burp it, it would have worked itself out by now. I would also ASSUME that he has checked the coolant level a few times.

However, the thermostat or installation of it could be an issue. Does it have an air bleed hole or bleed valve? Is the hole/valve positioned at the top?

Since it cools down enough at idle (at least now) and when you turn the heat on I don't think you have a water pump problem. You also say the t-stat is good. One possibility is the lower rad hose collapsing at speed from suction of the water pump. Do you have the steel spring installed in it? Another is the radiator is clogged. Sometimes machine shops don't clean out the cooling passages that well leaving dirt in them which will be carried to the radiator. Have you back flushed the radiator yet? Also, what mix of coolant are you using? 50/50?

I don't think you need to upgrade anything. You say that it over heats at idle (or use to) and on the highway. You don't mention if the highway has a steep grade or not, but I would assume a flat section. A properly maintained stock system is sufficient enough to handle the cooling needs on a grade with, so it is able to handle the cooling needs of a stroker at idle or simple cruising.

If the Taurus fan mod helped perhaps the clutch fan wasn't up to snuff. I didn't think the flowkooler would help. I tried one once. I wasn't impressed first by the fact that it is just a stock pump with a plate riveted on the back. And I was 100% not impressed with the results. It made it run hot on the highway. I didn't investigate it much by playing with restrictions and the such. I just put a stock pump in and the over heating stopped. The theory is that the water wasn't spending enough time in the radiator for effective heat transfer. This was with a 2 core CSF as well. While the hood vents help with under hood temps and help with engine cooling a bit they are certainly not a fix.

[TAnderson22]

Yes I do - for proably everyone here, and if you don't do this first step, you are figting an uphill battle.

Get a factory service manual (yes, they are expensive! so are jeeps ; read it, there are 4-5 words in there that are the answer; its all chemistry.

There are too many give-aways in life - This is one of those things where you bring it to the shop for and you wonder how they did it.... why we make $$... so really - I am telling you how to do it - by first finding the information, then applying it.

[Missourian]

Get a Jeep factory service manual, read it, especially the cooling section, and you may be able to piece together the mystery; perhaps just stumble upon it and get a sense of accomplishment by solving the puzzle; For me; No one ever told me; I found out for myself.

I think you can do it too. It's all in the "chemistry" here...................

The trick is parking on an incline, running to temperature, opening the radiator and waiting for the gulping or scavenging to take place and having a gallon of 50/50 mix water/anti-freeze on hand to quickly fill the radiator as the engine pulls water and expels the trapped air.

So if i read the last post correctly you might know a solution for this guys problem but your keeping it to yourself?

He did give the answer. There is some assumptions made that most folks know to take these steps when replacing a water pump, radiator or just braking the cooling loop.

And to be real honest here, I learned the hard way and do own the OEM Service Manual... I read it like my bible.

[jbxx]

Remove the coolant temperature sensor when filling the system back up.
This will bleed the air out.
If you aren't going to answer the question, why post?

[Missourian]

Remove the coolant temperature sensor when filling the system back up. This will bleed the air out.

This does the same as parking on an incline and belching the system and keeping topping off the reservoir?

[jbxx]

This is where the air gets trapped, so removing the CTS removes the air lock.
On a couple of my vehicles I drilled and tapped an 1/8" NPT and added a small valve to do this.

[Missourian]

It makes sense, I never considered pulling the temp sensor.

Thanks for that tip, I am sure it will be faster than running the engine and adding coolant while parked on an incline.

[gonridnu]

I think the high altitude less dense air makes overheating easier to attain too.

Yes it does.

Yes I do - for proably everyone here, and if you don't do this first step, you are figting an uphill battle.

Get a factory service manual (yes, they are expensive! so are jeeps ; read it, there are 4-5 words in there that are the answer; its all chemistry.

There are too many give-aways in life - This is one of those things where you bring it to the shop for and you wonder how they did it.... why we make $$... so really - I am telling you how to do it - by first finding the information, then applying it.

This info has been available everywhere on the net and cheaper manuals for a couple decades. If someone is doing a their own engine build it is assumed they have a reasonable degree of mechanical skills and understand a basic cooling system.

Assuming your system is filled to capacity, if a stock engine is overheating under normal operating conditions there is a faulty component somewhere, a couple million XJ's in service is evidence enough of that. If you are operating in adverse conditions and/or have a larger displacement engine then you will likely need upgrades to your cooling system. It's a systems approach so a single component may not do the job.

I have only had elevated temps when slow crawling an extended hill climb at 6000 ft. I think it's safe to say that is an adverse condition. Kick the heater on and take a short break and she's back to normal. If not, there is another issue.

One thing I have not seen mentioned is who is and who isn't running a performance chip in their ride. If you advance the timing and lean the mixture (like chips do) then you are gonna have some additional heat to deal with. Everything comes at a price and cooling upgrades are one of them.

[Coffee Commando]

Don't forget to check your radiator cap. I've had that cause overheating while idling.

I think it's supposed to maintain 16 PSI in the coolant system. Mine was only at 9-10 PSI.

The more pressure in the cooling system the higher the boiling point of the coolant. With a bad cap your coolant could be boiling in your coolant system.

Since you've been overheating for a while the cap could possibly worn out of specs already, which doesn't necessarily mean that it was the cap that caused it. But it could be a problem after prolonged periods of overheating.

[robinsoncreek]

I am the guy who started this thread. My home email changed and I had to create a new login.
I have discovered some things about cooling that work and some that do not.
1) Water wetter does not help period
2) Flow kooler water pump did not help me at all. Stock water pump is not better than flow kooler either.
3) Tried 3 row and 2 row CSF radiators and I can't tell any difference in the cooling ability of either
4) Slowing down the water flow so that the water is in contact with this metal surface or that metal surface is NOT the right thing to do. Read this:
Look for coolant flow rate about half way down.
http://www.arrowheadradiator.com/14_rul ... obiles.htm

Things that did make a difference for me.
1) the Taurus 4500 CFM fan cured the cooling problem of sitting at a light on a 90+ degree day with the A/C running. I just hit the switch and the high speed fan brings the coolant temp down.
2) The hood vents definitely help at idle and at high speed. At idle (not moving) the high speed fan blows hot air directly out the right hood vent.

My main overheating problem is just any condition where you are using that extra horsepower. The worst place is the long grade on I70 where you are at 12,000 ft or so on a very long uphill grade. If I try to do 65 or 70 mph on that the needle just crawls steadily up. I use the heater to dump some heat when I have to. I know you can get a water misting setup to spray water on the front of the radiator for these extreme conditions when you need it. So I am going to install that before next summer. The other thing I am going to do very soon is install a transmission fluid cooler. I have not decided on whether to use a flat fin type or one of the Derale extruded aluminum tube units. I'll report back on what that does. The other thing I could try is a Hesco water pump but I have looked everywhere and I can't find an operating performance curve for that water pump or the flowkooler either. I expect to get a small noticeable effect from the tranny oil cooler but I need to make sure that the tranny oil cooler I pick is capable of cooling the tranny oil sufficiently.

[SilverXJ]

Put the transmission cooler some place other than in front of the radiator's air flow. Some people use a cooler with a fan on it by the from skid plate, some put them in the rear. C.A.T. also makes a high flow water pump for the 4.0L.

[robinsoncreek]

A fellow Jeep club member had one of these aluminum tube type coolers installed. I could mount one of these behind the front bumper and it would get some air flow from the Taurus fan while the Jeep is not moving. But I can't find any heat transfer characteristics for these or the plate and fin types. So I have no idea which would be more efficient. Thanks for the note about C.A.T water pump. I had not heard of that.
http://inet.derale.com/clientdocs/Deral ... g-2009.pdf

I'm going to install the largest Griffin 2 core aluminum radiator that will fit next spring. I'm tired of piddling with this thing this year and summer is almost over anyway. Once Sept gets here I don't have to worry about overheating in CO until at least next June.

[robinsoncreek]

I had a griffin radiator installed yesterday. The large capacity radiator has ended my overheating problems with my 4.6 liter stroker. If you have a stroker in an XJ, I would highly recommend this radiator. The taurus fan will not fit when the griffin radiator is installed since this aluminum radiator is thicker. You might be able to fit a taurus fan with the griffin if you removed the air conditioner condenser.

[hsalf]

Reading through this thread I didn't notice any mention of the fan shroud. It's been my experience people often consider this part optional or not necessary as it gets in the way of working on the front of the engine. It is quite important as it improves the fans ability to draw air through the radiator. Without the fan shroud in place much air will be drawn into the space between the radiator and the fan instead of passing through the radiator first. It can be over 40% of the total air moved by the engine driven fan in some vehicles.

Running an electric fan at highway speeds tends to reduce airflow through the radiator because the effective disc area of the fan blocks more air than it draws. In that case more fan blades is less flow than fewer blades.