Only code was for hydraulic fan solenoid & after realizing radiator had to be bled, fan came on full power. Took for test drive that night, started to get hot & stalled, barely got back home. Cranks but won't start today. Still air in cooling system or what? Computer reset. Still wont start.
Has the huge V8 with that fan. sure.
Ovetheated bad about 6 months ago been sitting since.
Ran ok at first. (sure all do that, till it overheats)
No signs of headgasket problem. bah,there are many)
1-compression test? bet top of list... )
compression at spec.?
2- oil/carbon dust, seen in rad neck cold or milky in oil pan.
steam at end of tail pipe, never hot engine.
3: see green "AF" at head gasket junctures, 4 sides x2 heads.
4: rad leak down test fails, i be you skipped that.
5: green/blue tester fails, finds exhaust in RAD.
6: antifreeze in oil pan?
7: antifreeze seen in ATF fluid of AT pan or dip?
8: gross engine misfire.
9: see green on spark tips.
10: rack back exh, mans, see green dripping from ports.
11: engine backfires and the GREEN lands in air cleaner,
ill end it here, there ARE lots of signs.
Replaced t-stat. (ok)
ID BET 100% the fan is a VICTIM !
Still overheats, Fan not coming on. (the fan must work on all engine, or it will overheat parked, in fact the FSM book that is the test.
ever read the book, factory service manual, its free, ask.
Now fan comes on after burping. but if there is air in the system , heat sensors fail, so air there is first. why is there air there.
answer you overheated it and it boiled out. cure, keep it full..
Overheat again.
but did the fan come on this time, MY OTHER SHOE DROPS HERE.!!!
http://jeepdied.com/overheated/overheated%20101.html
does it overheat parked?, this is the classic test, if yes , we fix this first and not drive a car that fails the parked test.
or risk warping heads.
the book is clear here.
the warm up, with rad and block full, side overflow tank 1/2 full, ignore it, now, and focus on rad neck full each time before starting a cold engine that is known to overheat, this is a RULE.
the book has you idle the engine, all engines overheat parked, (not in NOME Alaska) they will.
and as it reaches say about, 225F the fan kicks on, this is the test for the fan, and coolant actually full up. block and RAD.
if the fan fails this test stop now and fix this.
there is no other way here, the fan must work on all cars. unless you can drive it and never ever stop.
now my totally useless blind internet guess
this car has a coolant leak.
find this first.
my guesses btw, are like a broken watch
correct 2 times a day..
really. (why ask the blind how to fix cars)
find a live person to show you and win.
and point 2, making assumptions, with no tools
is wrong. you cant do diagnosis on assumptions.
only correct tests, and evidence.
why not get car serviced.?
http://jeepdied.com/overheated/overheate...
my guess is you do not know all signs of bad headgasket
or the fan never ever comes on,
chapter 7 cooling WJ
http://www.morris4x4center.com/knowledge...
read this yet?
posted over 300 times, and is free book.
4.7L has the hyda, fan, only it has this.
the book covers how to test this fan system.
read it and ask questions.
the fan has a solenoid, and relay the drive that. the PCM measure water temps using the main ECT sensors, if the ecu sees temps rise above (guess 225F and diffr, if A.C on)
the PCM sends a comment to the hyra. fan controller and it closes the relay and then the solenoid valve hand the PS pump pressure hits the fan hydra, motor.
this is how the fan works, it's not simple.
IF you scan the PCM (you didnt) it will flat tell you failures here.
DTC 1499.?
if the block is full of air the ECT goes daffy. THE ECT cant measure AIR !
so the fan does not come on e when you boil the block dry, yes before, no after.
see? this is how this works.
in the old days the fan had its own sensors
not now.(not yours)
if you scan the ECT and it read wrong,
block is dry (way low) or ECT is bad.
here is more quotes from the FRM
all very good. for knowing what to expect.
The hydraulic radiator cooling fan is controlled by
the JTEC. A PWM (Pulse With Modulated) signal
from the JTEC controls the fan from 0 to 100% of the
available fan speed. There are four inputs to the
JTEC that determine what speed percentage of fan is
required by the vehicle. These inputs are:
†Engine Coolant Temperature
†Transmission Oil Temperature
†Battery Temperature
†A/C System Pressure
By monitoring these four parameters, the JTEC
can determine if cooling airflow is required. If airflow
is required, the JTEC will slowly ramp up (speed up)
the fan speed until the parameter(s) are under control.
Once the temperature or pressure is reduced to
within operating parameters the fan will ramp up,
ramp down, or hold its speed to maintain the temperature
/ pressure requirements.
NOTE: Even if the JTEC is not requesting fan on
operation the fan blade will spin between 100 and
500 RPM when the vehicle is at idle. This is due to
a controlled minimum oil flow requirement through
the fan drive motor.
at a jeep dealer they can command on the fan.
I cant do that.
they do that and if that fails, they fix the fan first.
the book has no full set of tests in this fan
4.7L.
if the car overheats parked, and fan is dead or at 100rpm(min speed)
the fan is bad. or the PCM can not read the ECT or the ECT is bad, or the water level
is below the ECT sensor, rendering it useless. and the fan.
if car has overheating problems.
learn to check levels in the rad neck
before the first dead cold start.
learn to do that, it's same on a tin lizzy as is today.
the block must NOT be dry or low. (rad will be too, rad level matches block.)
never run and engine with a dry block.(or low)
never trust the side overflow tank,.! ask.
Make sure the cap is good,
The ECT sensor goes dead on dry blocks.
boiling and engine over, lowers the block coolant levels, or goes dry, if extreme.
if the rad neck level drops day by day
that means you have a leak, and is the true failure here, all else above is VICTIM .
this is what you do.
if you do have a leak, then find that, the leak is the prime directive.
and there are simple tests to find it.
look for leaks everywhere,
the whole engine.
the heater core in dash, or passenger rug.
the engine oil pan, milky. (change it? and look?)
the automatic pan, (dip stick milky)
the heads, look a the heads do they leak green? (4 sides each, look)
look at all hoses, are they leaking?
is the rad leaking?
if all this sounds alien, and hard
let your mechanic find it.
he will and fast, and usually in 1hr labor.
not much $, with the 2 tools of the trade.
1: mr,leak down tool.
2: mr, green/blue tool, finds exhaust ingress to the rad.
3: and mr, eyeballs, looking EVERYWHERE with due care, missing nothing.....!
all service tech.s, know that air can be trapped in any block. for sure if thermostat is installed wrong,(bleed hole wrong location)
they make every effort to get it full.(block , rad and all hose full)
so that you dont over heat the upper cylinders. like that. and warp them.
how is this done, well it depends on the engine, ever read 4.0L shop manual and the words, raise the front bumper, 3? feet high?
yeah, this car is pain. in the older Cherokee FSM books.
on some you need to remove hoses, to get it burped, top hoses.
and...
on thermostat changes, (trick of trade)
we fill the block there in the STAT PIT HOLE, with 50% AF. full up. to this point.
then STAT back correcltly not backwards nor
bleed hole down. bleed hole at high spot)
on some we must remove hoses (small) to get all the air out.
but on most cars, we fill it start it for 1min.stop and check level , its still cold engine, i keep it cold , with short runs.
and keep filling the rad.
on some, that are very stuborn, i fill it with cap off, and keep the cap off.
and keep filling it, as it runs.
if you see the level drop, stop the engine.
fill it more, and start it again.
and at some point it stops dropping, (good sign) and as the fluid heats up, it expands
and (physics) and i stop engine and cap it off
then i gun engine, and may drive around the block. come back and let engine cool off.
and check rad neck levels.
repeat until its stable.
if impossible, then the rad leak down test happens.
this answer is generic, some engines burp easy other not so. my 88/99 jeeps 4L were tough cars to burp of all air.
I learned that removing the 4L top pump hose
allowed it to burp very easy, not in the service book this trick,
for sure you can't just throw in the coolant and drive 100miles. or fail.
The pump fins are rusted to near nothing
rad core blocked inside or out
fan dead.
engine is eating coolant for lots of ways.
do you want to GUE$$ or TEST,, its your call.
×
You need to replace the head gasket and have the head machined flat
123 views
Usually answered in minutes!
Bled system with heater on idled at about 210, went for test drive, ran rough, got hot, stalled. Ran battery down trying to start today.
×