99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
I know is it that common to get a bad tstat especially a OEM one
-
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cooling issue
- Thread starter 99VAXJer
- Start date
- Location
- Hammertown, USA
apparently you didnt reread the last 10 posts.
the front of the 4.0 is the highest point of the engine, which tilts down as it goes back. you get air trapped behind the thermostat. it insulates it from the hot water, and won't open until the air temp reaches the specified open temp - by which point the water has gotten a LOT hotter.
the thermostat is clearly doing its job, that does not mean its doing ti right or that it is at fault for failing to do it right.
the front of the 4.0 is the highest point of the engine, which tilts down as it goes back. you get air trapped behind the thermostat. it insulates it from the hot water, and won't open until the air temp reaches the specified open temp - by which point the water has gotten a LOT hotter.
the thermostat is clearly doing its job, that does not mean its doing ti right or that it is at fault for failing to do it right.
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
Ok well someone had said that if you park with nose up or something that it will burp itself is that all you have to do is just park the front end up and let it run
Your first post indicated your cooling problems started after replacing the radiator. In rereading this, is there anything else that was done at the same time? If your temps were in the normal range, why did you replace the radiator? Leaking?
David Bricker / SYR
David Bricker / SYR
- Location
- Hammertown, USA
it will.
if there is a way for air to get through the thermostat. which that little tiny hole doesnt really do very well a lot of the time.
if there is a way for air to get through the thermostat. which that little tiny hole doesnt really do very well a lot of the time.
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
But the air should come out if the tstat opens when it gets to temp I'm going to run out and do this now should I run it with the heater on or off
- Location
- Hammertown, USA
sigh.
make sure you get that nose up a good 30*. Keep checking the radiator and refilling it.
make sure you get that nose up a good 30*. Keep checking the radiator and refilling it.
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
So do I open or close the lever on the radiator cap it should pull coolant from the reservoir right
I measured between 30 and 55 degree temperature drop across my FFD radiator. These temps were taken at rest, after the engine had warmed up. The difference in temperature readings were based on other changes in the system, such as alternator replacement (which increased voltage to the electric fans), addition of shrouds, and so forth.
These readings were taken before I removed the electric fans setup, and went back to the stock mechanical and electric aux fan.
David Bricker / SYR
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
I just went out and ran it with it parked on a hill with the lever open and there was no change in coolant level and it got up to 210° while idling it is 100° outside though
souske
NAXJA Forum User
- Location
- The land of competition
anyone ever tried to incorporate an air bleeder valve like chevy used on their FWD's?
Throw that junky rad cap away and get a proper 16lb one. The ones with the release lever invariably fail to hold pressure.
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
Ok well everybody swore by the stant lever cap so i replaced it i had a regular one on it before and it was doing the same thing
Are you blowing any fluid into the overflow tank? Or is temperature just the issue? If you're not pushing fluid into the overflow, then the cap at this point won't make a difference. You've got bigger fish to fry (water pump, thermostat)
David Bricker / SYR
David Bricker / SYR
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
Nope coolant is staying the right level and two ?'s david will it bleed its self with the lever open and is a napa pump ok
A NAPA pump should be fine. I'd just avoid the Autozone stuff.
On the pump, be sure you get the right one for your year Jeep. V Belt drive run in the opposite direction of a serpentine belt drive.
The system will, over time, bleed itself whether the lever is flipped open or not on the radiator cap. The only thing the lever does is to relieve any pressure built up in the system.
There are a number of different ways to bleed the air out of the system, and each one has its merits. The way I have done it it to remove the return hose from the heater core and run water into the radiator. I put my thumb over the place the heater hose connected to, so the water is forced through as much of the system as possible.
There should be water flowing out of both the heater hose, and its connection. While the water is still running, I reinstall the heater hose. Then run the engine.
I fill the coolant recovery tank with straight anti freeze. If I need to add any more fluid to the system, I use straight anti freeze. Since my Jeep is in Death Valley, and I don't have a concern on freezing, I only run about 25% antifreeze for corrosion protection. I just keep track of how much I add.
David Bricker / SYR
On the pump, be sure you get the right one for your year Jeep. V Belt drive run in the opposite direction of a serpentine belt drive.
The system will, over time, bleed itself whether the lever is flipped open or not on the radiator cap. The only thing the lever does is to relieve any pressure built up in the system.
There are a number of different ways to bleed the air out of the system, and each one has its merits. The way I have done it it to remove the return hose from the heater core and run water into the radiator. I put my thumb over the place the heater hose connected to, so the water is forced through as much of the system as possible.
There should be water flowing out of both the heater hose, and its connection. While the water is still running, I reinstall the heater hose. Then run the engine.
I fill the coolant recovery tank with straight anti freeze. If I need to add any more fluid to the system, I use straight anti freeze. Since my Jeep is in Death Valley, and I don't have a concern on freezing, I only run about 25% antifreeze for corrosion protection. I just keep track of how much I add.
David Bricker / SYR
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
Well today I tore it down and put a water pump in it (original one was fine) also pulled the tstat out and drilled two 1/8 holes at 6 and twelve like recommend and was going to put a fan clutch (waiting for new radiator) in it but called radiatorbarn and they said they would send me a new one so I asked the to send me the 3 row instead of the 2 row and they just made me pay the difference will be here Wednesday will report back then
Honestly not sure if I'd go with the 3 row. Depending on the design of the radiator, three rows may not provide any more cooling, and may actually cool less efficiently than a two row. The reason for this is that the 3 rows do not allow enough air flow through the radiator. Unfortunately, I do not have personal experience to verify this.
I do know that the FFD radiator was intentionally designed as a wide spaced two row radiator to allow air flow through the unit.
Also, with a three row radiator, be extra careful that you have sufficient clearance for the fan clutch, especially if you are using the ZJ clutch. Some folks also grind or break off the tabs on the front of the ZJ clutch, to give a bit more clearance.
You have the heat to contend with where you live, but at least you have the humidity. My Heep lives in probably the harshest condition possible, with 120 degree temps and near zero humidity. So, you have a little more latitude to play with.
David Bricker / SYR
I do know that the FFD radiator was intentionally designed as a wide spaced two row radiator to allow air flow through the unit.
Also, with a three row radiator, be extra careful that you have sufficient clearance for the fan clutch, especially if you are using the ZJ clutch. Some folks also grind or break off the tabs on the front of the ZJ clutch, to give a bit more clearance.
You have the heat to contend with where you live, but at least you have the humidity. My Heep lives in probably the harshest condition possible, with 120 degree temps and near zero humidity. So, you have a little more latitude to play with.
David Bricker / SYR
Was there any contaminants in the water pump housing? Or did the flush you did clean things out well?
David Bricker / SYR
David Bricker / SYR
99VAXJer
NAXJA Forum User
- Location
- Louisa, VA
Nothing looked to have any contaminants in it everything looked pretty good actually im going with the triple core cause it will hold more coolant that and evrything has been replaced including the fans so hopefully it should be good there letting me keep my old 2 row radiator so if its to bad i can swap the 2 row back in i think i might take it to a radiator shop and have them take off the tanks and inspect the inside and fix anything thats bad so ill have a spare
