Overheating with A/C really PISSED

I am tired of fighting this, and spending money on it, if i cant fix it the ac comes OUT.

Heres the deal:

1995 XJ--4.6 stroker

new fan clutch
3-core gdi rad 2 yrs old
180 thermostat 1 yr old
water pump 1yr old
50/50 mix water-A/F new
newer style aux fan---seperately wired for when ac is off
hood vents
new rad cap
rad and ac heat exchanger have been cleaned(you can see right thru them)

and i built an adj. MAP sensor to deliver more fuel but with no good results(temp wise).

My junk will run around 180-200 with the ac off and aux fan on with 90+ temps.
With the ac on it's over 235 on the head and 210-220 on the block(aftermarket temp gauge).

If i make a run down the highway it'll hover 200-220(normal) as soon as i get off the highway and stop at lights it starts to rise over 220.

It has not boiled over yet but im not taking the chance!!!!!!!!!

I am at my wits end with this.
PLEASE help

Thanks STROKER

Last Resort maybe

Some suggestions:
Can you make it run a little richer, that usually brings temps down, leaner runs hotter. Need to find a balanced solution so as not to fry the cat and speaking of the cat it is possible that the cat is backing up heat thru blockage/starting to melt down. On a temp basis pull the cat and put in a straight pipe for a while, see if that changes anything.
Add two fans to the front of the radiator blowing into the rad for traffic.
You have hood vents, maybe fans under the vents to evacuate hot air faster.
Just some thoughts.

I like the cat idea. Maybe when you beefed up the motor the old cat couldn't take the extras and it burnt itself out...just a thought i aint a mechanic. But someone did post on here awhile back about fighting the same things and the last thing he replaced was his cat and muffler and POOF his problem was gone.

as others say just my .02

forgot to mention i have no cat. that was pulled 3 yrs ago. as far as being richer... i have had it so rich it almost stalled and not any better.

This is the exact same problem that I have had and I've done what you have. It's only overheats with the A/C on, during the summer I run 80% water to dissapate heat faster but it still gets hot. AND I have a CAT on mine and it's stock.

Ben, I'm no Mr. Goodwrench, but I had a couple of thoughts - take them as you will:

1. Is the A/C compressor turning ok? If it's starting to sieze (or dragging on something), could that be adding enough load to the engine at idle to build more heat?

2. You said that with the A/C off you do see the aux fan come on. Does it also come on when the A/C is on? I believe it should, unless your custom wiring has disrupted that function.

3. If you haven't disrupted the thermal switch for the aux fan (or the one that turns it on when A/C is on), perhaps there's some sort of voltage drop when A/C is on that is preventing the switch from turning the fan on?

HTH,

Rob

me too

I have much the same problem, Either running too hot, or almost too cold, depends on the a/c. Hope someone can give more ideas.

I Have a 180 thermostat, GDI 3core, 25% antifreeze 75% water. and I add Purple Ice, made by Royal Purple (supposed to increase surface tension of coolant to increase thermal transfer, seems to make a 10 degree difference)

Shhh, no cat either.....

Check you rad. Mine 3 row is 3-4 years old and clogged up bad. Already had it flushed once and it's still overheating. I'm switching to a two row soon. Hopefully the bigger tubes won't clog up as fast.

I can relate.

I am equally as PISSED about the overheating problem. I've installed a flowkooler waterpump, new 195* thermo, new 3 row radiator, flex-a-lite 110 fan on a manual switch which also turns on the factory aux fan. Banks header, throttle body spacer, K&N air filter. It couldn't have any more free air going though it if it was in a hurricane, but it still OVERHEATS on steep hills and towing. Now it just cools off quicker. Engine has been scoped and is clean. I've been told that the cat may be clogged and creating backpressure, but I doubt it since the miles are only 33K on it. Mine doesn't seem to be linked to the AC though, because it happens w/ or w/out AC on.

Radiator hoses?

This may seem to be out of left field but when did you replace your radiator hoses? It sounds like you are not getting enough coolant flow even with all those parts installed.

My guess is you have a lower radiator hose without a spring inside it. When coolant is sucked out of the radiator the hose is sucked shut and no or very little coolant flows.

This has been discussed before on here but is a last suggestion.

As previously posted in this thread other things I'd suggest replacing not already are:

* Make sure the engine is completely burped of air
* Thermostat 195F from the dealer - use the design temp thermostat, and if you get to 225 one time my radiator shop says you can damage the thermostat. You also may want to run without a thermostat to see if the problem disappears.
* Radiator cap - they get damaged if you over heat
* Fan clutch for the mechanical fan - they last about 5 years
* Have the cat checked for proper operation, if the pressure drop is too great heat can remain in the engine.

You may have already tried this, but I thought I'd post it just in case. There's a product called Redline WaterWetter that increases the cooling systems efficiency, in some cases pretty significantly. It won't directly address the cause of the overheating, but maybe it'll help. I went to Google and just typed in "Water Wetter". The following is part of their presentation. Good luck.

John
'95 Sport

Redline WaterWetter®
TECHNICAL INFORMATION

Red Line WaterWetter® is designed to provide improved metal wetting and excellent corrosion inhibition when added to plain water or a glycol coolant. The most poorly maintained system in an automobile is usually the cooling system. Maintenance is quite simple and only required once each year, but most vehicle owners never routinely change the coolant or replenish the corrosion inhibitors which are required for trouble-free operation.

Proper cooling system maintenance is very critical for most modern engines which utilize more aluminum. Aluminum has a very high corrosion potential, even higher than zinc, which is very widely used as a sacrificial anode.

The only property which enables aluminum to be used in a cooling system is that it will form protective films under the proper conditions which will prevent the uncontrolled corrosive attack of acids or bases.

Poor aluminum corrosion inhibition will cause the dissolution of aluminum at the heat rejection surfaces, weakening the cooling system walls and water pump casing and weakening the head gasket mating surfaces.

These corrosion products will then form deposits on the lower temperature surfaces such as in radiator tubes which have very poor heat transfer properties, causing a significant reduction in the cooling ability of the entire system.

Red Line WaterWetter® will provide the proper corrosion inhibition for all cooling system metals, including aluminum, cast iron, steel, copper, brass, and lead.

Water has twice the heat transfer capability when compared to 50% glycol antifreeze/coolant in water. Most passenger automobiles have a cooling system designed to reject sufficient heat under normal operating conditions using a 50/50 glycol solution in water.

However, in racing applications, the use of water and WaterWetter® will enable the use of smaller radiator systems, which means less frontal drag, and it will also reduce cylinder head temperatures, even when compared to water alone, which means more spark advance may be used to improve engine torque.

BENEFIT SUMMARY
Doubles the wetting ability of water
Improves heat transfer
Reduces cylinder head temperatures
May allow more spark advance for increased torque
Reduces rust, corrosion and electrolysis of all metals
Provides long term corrosion protection
Cleans and lubricates water pump seals
Prevents foaming
Reduces cavitation corrosion
Complexes with hard water to reduce scale

Here is my .02

I was not impressed with my GDI 3 core in my '98. Yanked that thing out after less than a year. Installed a new OEM aluminum twin core. The biggest improvement i noticed was at low speeds which is where your largest problem seems to be. Even here in Ogden Utah and south into St George with 115 temps had no problem with heating at any time. Never even made it to 215. I am sold on the UC rad. The quality of the piece was also totally excellent.

I know this bucks the GDI trend in this forum, but that was my experience....and i am accustomed to bucking trends.

Judd, Where did you get your two core radiator and how much was it? Thanks.

From the dealer i hate to say. I paid around $320. I know that is totally mucho bucks but personally i considered it worth it. I just did not want to deal with any overheating conditions whatsoever out West here. It's worked out great. I even had installed a switch on the elec fan so would not come on with the A/C unless running at low speed and need more air across the condensor. I just mostly keep it switched off even when 100+ here and still no heating at all....never hardly above 210 on the gauge just using the clutch fan. I also know the gauge is reading basically correctly because the engine feels like is running at that low a temp.

County Chrysler who is/used to be a sponsoring dealer here at gives good discounts to members. I unfortunately did not have time to get into that but had to order it locally in Va. Could also most likely get it from a Chrysler dealer through an on-line avenue to where you would pay jobber cost. Would be substantial savings that way too.

I know many cringe at the plastic tanks and all, but i have found them basically okay. The fit of this radiator was perfect, waaaay better than that old GDI. I was just amazed at the great quality too, esp after comparing to the cheapo GDI.

Do you run a stock box intake, cone set up or snorkel?
If you run a cone set up, box it off from as much engine heat as possible.

What injectors are you running?
I run 30lb ones from FoMoCo and thought I was running really rich. I just installed an Air/Fuel gauge and it appears I run very close to ideal. A/F gauges can be had relatively cheap. I would recommend one to see if you may be running a bit lean.

Ditch the GDI. IMnotsoHO GDI is CRAP. Go with a Modine 2-core set up. I think you will see a difference.

Bones :skull1:

This summer I had a radiator built.Used the metal ends from my old 1 row rad(96).
The new 2 row core has 5/8" tubes and is as wide as the end tanks.Look at the stock rad and you will notice the filler plates on the side of the core-mine now has none.Total cost was less than a Modine replacement rad.$180 or so.
Also replaced the lower rad hose with a Jeep replacement part.The NAPA hose on there with the GDI 3 core had a shorter spring inside.
If anyone is interested I will try to find bill and get core part # .
Temp still runs more than 195* but stay,s there during slow running on the beach or trail.
Wayne