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overcooling question?

T

the_chief

NAXJA Forum User
Location
denver, co
i tried to search this, but couldn't find a definative answer.

Last year I replaced the stock radiator in the 88 xj 4.0 cheif with a 3 row unit.

Ever since it seems to take forever to heat up to temp, and usually runs halfway between 100 and 210. My heat sucks too. I can't get good hot air ever. From my searches, maybe an air pocket? The cooling system has been the biggest pita so far.

No mater how hard I beat on it, it seems like the cooling system runs in direct relation to environmental temperatures. ie, I can get better heat in the summer, but I'm sol in the winter. pls advise.
 
Yucca-Man said:
You have a thermostat, right? Make sure it's a 195* with the air bleed hole in the 12 o'clock position. Check out http://www.yuccaman.com/jeep/cooling.html and see if that helps any.

Jim
Click to expand...

yes, i do have a thermostat. thanks for the link I read the whole page and it is definitely helpful. I have drained and refilled a few times by my haynes, but it's a pita. I have never pulled the plugs from the block, but I'm told to avoid doing that.

Also, as mentioned in your article, I installed a cfs three row a short while ago.

I'm going to replace the t.stat tomorrow night.

1. jack up rear a little bit.
2. drain system via drain behind grill.
3. replace t.stat
4.. Add one gallon antifreeze
5. Add one gallon water
6. run and burp and fill until it runs right ( this step always takes me a while)

Any other suggestions. I know it's a simple task to be asking for advice, but the naxja guys always have a tendency to make things a little easier and better.

that reminds me, hang on, ok i have my visa in my hand, time to put my name in red, thanks guys!
 
Or, just use a 1/8" drill bit and make your own bleed hole and be done with it. Air pocket will pass on its own in short time, like a kidney stone, only less painfull! :)

Good luck,
Andrew
 
All of the local parts stores wanted to give me a tstat with no bleed hole for about 6.99 and sell me gasket at additional cost. the stealership sold me the correct unit with gasket for 10 bucks.

I installed it and my old thermostat could not have been more incorrect. hole at 6 o'clock.

Flushed real good and filled. runs good, has good heat. heat won't win any awards though, because the engine is still slightly overcooled ( according to the gauge in dash) heat seems to be in sync with the gauge.

Thanks to all, and to all a good night.
 
you might partly block the air flow through the rad in the winter..
(cardbord works..no doubt you could think of somthing that would look ok.)
 
When I lived in Wisconsin I just put a peice of cardboard behind the grill and left it there until the temp started to get above 20 deg in the spring. Worked good at getting the temp up a little quicker than normal.
 
this is what I did...

20051211095901_Picture 048e.jpg




Used that lining you use under mulch in your garden. Wrapped it around the back of the grill and screwed it down. It keeps the engine temps up around a more acceptable level now. You may need something alittle thicker being that it's a bit colder where you are.
 
I actually have a 1/8' plate of aluminum for a winter grille. I cnc'd one row of oe style vertical vents on both ends.
 
I'd have to say, it's due largely to the increased cooling capacity.

1. Run a higher temp T-stat
or
2. Block off part of the radiator


I don't understand why you guys jack up the back end of your XJ's to burp the system.

I take the heater hose off of the t-stat housing and fill the overflow tank until fluid comes out of the heater port on the t-stat housing. Doesn't air bind when I do that. Dunno.


Erik
 
Will having the bleed hole in another positon really cause overcooling?

I've had a 180* tstat since I changed to a GDI radiator 2 years ago. Since the mod, freeway temps were about 1 bar below 210 (97+ gauge cluster) in the winter and 1/2 bar below 210 in the summer. This summer, I replaced tstat (another 180* one) and water pump. Everything seemed perfectly fine during the summer and fall. Now in the winter, freeway temps are about 2 bars below 210. Just for reference, I think there are 5 bars between 100* and 210* on the gauge.

I just made something to cover part of the grill and haven't tested it yet, but now I'm thinking maybe I installed the tstat incorrectly.
 
Last edited:
MyJeepXJ said:
Or, just use a 1/8" drill bit and make your own bleed hole and be done with it. Air pocket will pass on its own in short time, like a kidney stone, only less painfull! :)

Good luck,
Andrew
Click to expand...

You've never watched a temp gage hit red and stay there have you (we really need a horrified smiley with something puckered up it's crack on this forum!)

I've got a similar problem after sticking a 3 row on my '98 this summer, using a Mopar thermostat and gasket. I started running my heater on recirculate in the A/C portion of the hvac panels and it heats almost as well as stock. I'm just glad I didn't try it 2 years ago, I'd probably have liquified anything on the inside and burned paint off the outside!
 
I looked more into my prob....I remember before I did the waterpump change and switch to dual electric fans, the temp on the freeway during the winter (around 20*F), would be around the green mark, but I noticed now it's at the red mark...

overcool1.jpg


I think the red mark is about 180* since that's when it seemed like the tstat opened (I have a 180* tstat). I let the car idle and kept feeling the radiator hoses until it seemed like the tstat was open. I also read another thread where someone said the temp gauge isn't linear, so this makes sense because it should be 155* at the red mark. Just for reference, non-winter freeway driving temps are usually somewhere between the green mark and 210* on the gauge.

I tried making something to cover up the grill.

overcool2.jpg


overcool3.jpg


I cut up a garbage can and zip tied it to the grill. It seems to help, in traffic my dual electric fans still keep it at 210*. When cruising on the freeway, the temps seem to keep higher, but I haven't had a chance to test it on a long drive.
 
I dont get why your complaining about your jeep not overheating, you should be thankfull. I would be more than happy to trade my overheating system for your overcooling system.
 
I swapped the open for the closed....Don't either under cooling or over heating problems...Depending on where you live maybe a block heater...or as some have posted partially blocking the rad...You sure you got a 50..50 mix runnin through the system?
 
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