95 Jeep Grand Cherokee Laredo cooling system

In the winter time my Jeep overheats and also freezes up even though there
is adequate antifreeze. Also, whenever I stop the heater gets cold
immediately, and the air conditioner doesn't work even though there are no
leaks. The speedometer also doesn't work until I turn on the defroster. I
have replaced the thermostat and it's housing, the fan is working, and the
fan belt is good. Can anyone tell me what else to look for?

Did you get the right water pump if your engine is a 4.0 early ones us
diffrent water pump maybe had the wrong one in the box must have R stamped
on inpeller

For starters, you are grossly underestimating the amount of antifreeze
if it freezes up. You need to fix that first.

A mix of 50% antifreeze and 50% 'preferably' distilled water sitting in
a jug on the ground will start going slushy around -32F. Once this mix
is in the vehicle, there is no way it can freeze up at any temperature
above that.

I am in Canada and use 60/40 or more so I have -50 or so protection.
The strongest allowed with the glycol or green antifreeze is 70/30 for
-60F protection.

It is easy to mess up the mix. When you flush the system with water a
whole bunch gets left in the block and heater core because most folks
don't open the block drain, just the rad drain.

So you have to know the capacity of the system. My Cherokee holds 11.4
liters or 12 US quarts. This means I need to add 6 quarts to get to
-35F protection, 7 quarts for -55 or so.

After a typical flush and drain, I add the 6 or 7 quarts of 'pure'
coolant first. I then add water if there is any room left. Normally I
can only get another 1, 2 or 'maybe' 3 quarts in and it is full. The
rest was trapped water in the block and heater core.

You cannot use the 'pre-mixed' antifreeze to fill it after a flush or
you will only have -0F or hotter protection..... The premix is only for
top ups.

The speedometer only working when the defroster is on likely means you
have lost a ground tag somewhere.

I would be checking the ground from the battery negative to the fender
for a corroded connection on the fender first. The other main harness
grounds are on a bolt near the oil dipstick on the 4.0 engine. I think
the engine has a mesh ground strap across one of the engine mounts. The
dash itself has ground wires on the circuit board. I know some of the
TJ's have issues with the dash ground and heater/AC controls, the wire
comes loose at the circuit board, not sure about the GC's.

Like someone else mentioned, make sure you have the correct pump, it's a
reverse rotation one for the serpentine belt, but if the pump hasn't
been changed, then no worries.

You also can check to be sure the heater lines don't run higher than the
radiator. This can cause air bubbles so you get very little inside
heat.

I have even seen, done and heard of folks parking the Jeep on a hill
with the nose in the air to top up the rad. This makes the filler the
highest point for sure and can help to get all the air out. I normally
let it heat up with the cap off after a fill to help get the air out.
You have to watch for gushers though when the t-stat opens and be ready
to cap it fast. Some gush fast, most don't.

Good luck!

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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birdshere wrote:
>
> In the winter time my Jeep overheats and also freezes up even though there
> is adequate antifreeze. Also, whenever I stop the heater gets cold
> immediately, and the air conditioner doesn't work even though there are no
> leaks. The speedometer also doesn't work until I turn on the defroster. I
> have replaced the thermostat and it's housing, the fan is working, and the
> fan belt is good. Can anyone tell me what else to look for?