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Capacity / Air flow

R

robs

NAXJA Forum User
Battling for years

Issue:

1) Interstate is fine
2) Woods overheats (250F+) if >80F outside
3) Woods OK if under 80F outside

Known:

1) Small temperature drop across radiator. IR gun verified. When measured 240F hot side, 230F cold side (2 new sending units in back of head)

Radiators:

1) Stock
2) Radiator barn
3) CSF 3 core
4) Viston 1-1/2" aluminum 1 core (fan clutch ate it, but it overheated anyway)
5) Back to CSF

====

1) B&W Plate and coil tranny cooler (gage on OUTPUT line is 140F converter locked to 225F tops in woods). Have unhooked tranny from radiator, only made problem worse.

Flow:

1) High flow waterpump
2) High flow T-stat
3) NEW HEAD GASKET
4) Stock T-stat (Mopar) reinstalled to reduce flow
5) Spring in lower hose

Air cooling:

1) Stock mechanical w/ 3 different fan clutches
2) Stock electrical
3) 9" pusher fan in front of radiator in between two factory fans
4) Fan powdered hood vents

Question:

1) Anyone use Proliance 3 core?
2) Search turned up Zirgo fan.. .looks universal... any advantage over stock?
 
What year is it?Open or closed cooling system?
Do a cooling system pressure test...if you are not holding pressure it will over heat.

Make sure your system isn't "air bound"
It's helpful to have a small hole drilled at the 12:00 position in the t-stat flange to aid in letting the air escape from your system....

Is it possible you have a timming issue?Could be causing your motor to run hot....Pull plugs and look at the ground electrode,there will be a timming indicator(a difference in color) that should be right around the 90* turn of the ground electrode.Pm me for a chart that shows this.

Is your water pump turning in the right direction?

If your fans aren't putting out enough cfm it will run hot....From what you tell me it sounds like you have a low speed air flow problem


Do you have the spring in the lower radiator hose?(edit:noticed you have that)

Are your water jackets clogged with gunk?
 
Last edited:
Lean engines run hot. Injectors dirty? Air inlet temp sensor OK. O2 sensor or pluged cat? Try this mod.
Install a 10k ohm potentiometer in series with your air inlet temp sensor. Give it about 5k to start. This will trick the cpu into thinking it's colder outside and richen the mixtue a tad. Run the pot up till you feel like the engine is as peppy as it will get with this mod then back it down till the power just drops off and leave it. This may sound out there but it looks like you have tryed everthing.
 
95 XJ closed.

Low flow = good temp drop across radiator? High flow = poor temp drop?

Plugs look good. Normal temp. Only number 1 = oil fowl. Pulled head, everything looked good, hell, could see cross hatching on walls even after 175k miles...

Spring in lower hose.

Lean engines run hot. Injectors dirty
Click to expand...

Possible. I'm putting a supercharger on my Crown Vic and it's 24 lb/hr injectors will go into my XJ (direct fit)

O2 sensor or pluged cat
Click to expand...

Got a new O2 sensor. Not sure how to check the cat.

Install a 10k ohm potentiometer in series with your air inlet temp sensor. Give it about 5k to start. This will trick the cpu into thinking it's colder outside and richen the mixtue a tad
Click to expand...

Hummm.. haven't heard that before....
 
Plugged heater core?
 
I am more concerned about the lack of temperature drop over the radiator. You might be suffering the same thing I did with too much flow so not enough time to exchange the heat.
Do what I did and fit a restrictor as costs you nothing and a few minutes work to try. Worked out great for me. http://www.naxja.org/forum/showthread.php?t=915594
Let me know your results of the temperature drop over the radiator afterwards.
Also look at my site on adding a Taurus Fan. www.go.jeep-xj.info
 
Thanks GoJeep...

I tried something a little different... Didn't like the idea of an orfice... so I installed a ball valve tonight (yes, the maint guys said it ain't a throttle, but I did it anyway)...

Too earily to tell, but I did get a 30F drop across the radiator reving the engine in the driveway. I'll wheel this weekend and see what happens.

$30 worth of parts... (nipples from Graingers)

cool1.jpg

cool2.jpg
 
Last edited:
Wow, that is not doing it by half measure is it! Fully adjustable restrictor, I am impressed. ;)
You should be able to adjust the valve while using the temperature gun comparing each side of the radiator until you get the highest drop. :)
 
robs said:
Thanks GoJeep...

I tried something a little different... Didn't like the idea of an orfice... so I installed a ball valve tonight (yes, the maint guys said it ain't a throttle, but I did it anyway)...

Too earily to tell, but I did get a 30F drop across the radiator reving the engine in the driveway. I'll wheel this weekend and see what happens.

$30 worth of parts... (nipples from Graingers)

cool1.jpg

cool2.jpg
Click to expand...

Make sure you report back on how this worked.

Please
 
That looks pretty sweet, just make sure that it doesnt ever shut fully...I like the blue valve cover, you paint a spare one yourself?
 
Taken this long for follow up since I just NOW got back into the woods! ARGH! Needed the fix bad.

For control, just wheeled with the valve fully open... After 1/2 hour of fairly easy wheeling, I was at 240F.

hotthumb.jpg
(old pic, but was pretty close to this)

Sat for 1/2 hour to to cool off. In the real heat of the day, pulled the valve to 1/2 off. This is as HOT as it got after restricting the coolant flow. This happened after a very long uphill blast. If the valve was open, it would have easily been 240+F.

215.jpg



So. Everything I have done up to this point has focused on making it flow better and cool more (blue cover was when I yanked the headgasket). It did get worse each time.

Clearly now, I have to increase airflow so I can leave the valve open. I consider the valve simply a bandaid.
 
Last edited:
Why do you consider it just a bandaid? There is good reason for it too work as too much flow does not allow enough time for the heat transfer at the radiator to take place and also the restriction increases the pressure inside the block for better transfer for the cylinder and head as well.
 
Have you tried adding a surfactant, like Water Wetter?

A surfactant will reduce the surface tension of the water, making it "wetter" than normal. This allows for greater contact between the water and the metal surfaces in the cooling system, which allows for greater heat transfer into the coolant in the engine, and out of the coolant in the radiator.

I'd like part numbers and/or specifications on the "throttle" you used in your upper radiator hose as well, if you don't mind. It looks like the sort of thing that should be archived somewhere - and I'd like to contact you backchannel so I can get your contact and accreditation information (it's not my brainwave - I don't want to act like it is.)
 
Gojeep said:
Why do you consider it just a bandaid? There is good reason for it too work as too much flow does not allow enough time for the heat transfer at the radiator to take place and also the restriction increases the pressure inside the block for better transfer for the cylinder and head as well.
Click to expand...

I agree, many performance engines require some sort of artificial restriction in the cooling system. What temp thermostat do you have? I have seen engines overheat with a low temp stat, the water never stops flowing, much like your problem.
 
Some 20 years ago when I was a marine mechanic, we used to restrict the water flow from an engine block in order to get the engine up to the proper temperature. Of course the engines were sea water cooled and also not using a thermostat. The adjustable valve were the prefered item since it allow the driver to make adjustment when it become necessary. Using one in a modern (20 years or less) vehicle that has all the OEM parts make me think :dunno: :smoker: Hey, whatever floats your boat.
 
I've got a Mopar factory T-stat right now (replaced high flow one).

It's nice to have this in the line, but I'd really like to increase airflow to see if it's not needed. I can always fall back to throttling the coolant as needed. I might hook a cable up to it so I can throttle it from inside the cab...

Yes. THere's wetter in it now.

As for part numbers, I bought everything at Lowes except the hose nipples. Got the nipples at Grangers. We have a Grangers in town, but I think they've got mail order too. They were 1-1/2 if I remember correctly. Everything was like $30 total...

Pretty sure these are the nipples...

http://www.grainger.com/Grainger/items/3LZ95
 
Cool - so 1-1/2" pipe thread and hose nipples? 1-1/2" pipe ball valve as well.

Just checking - Grainger can be a little sticky about selling to people without a resale ticket (gotta get that done one of these days...) so having specs on the thing should help with alternate sources, if necessary.
 
Do you mind if I use your pictures and information in a write up along with my restrictor detail on my web site? Will credit you for the information provided.
BTW, I am guessing your are in Canada somewhere?
 
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