1998 Jeep Grand Cherokee Laredo SE Straight V6 4.0L 4x4

My Jeep has recently had overheating problems, therefore my spouse and I
have changed the thermostat, radiator, water pump, spark plugs, and all
hoses, battery. It is running rough and vibrating still and will not stay
running. The vents are blowing cold air when the controls are set for hot,
even after the car has warmed up. The engine light does not come on, we've
even tried the computer code reader and it says everything passes. I can't
figure for the life of me what else is wrong. Can someone give any
suggestions?

Thank You,
Gor595Gee

I've heard on this NG about being careful when replacing water-pumps as
the 4.0L has a reverse-spinning pump..? Can someone else confirm this?

If you had overheating problems, maybe you've warped the head, and have
a gasket leak? Are the oil & coolant still their natural colors?

I'm no mechanic but it sounds like maybe your heater core could be
clogged.

It sounds like your heater core or the line going to it may be blocked for
one thing. This could explain why the car is running hot and the vents are
blowing cold air when the controls are set for hot. I don't know if that
could be causing the engine to run rough and vibrate though. When was the
last time you flushed the system?

Nat Man



"gor595gee" > wrote in message
lkaboutautos.com...
> My Jeep has recently had overheating problems, therefore my spouse and I
> have changed the thermostat, radiator, water pump, spark plugs, and all
> hoses, battery. It is running rough and vibrating still and will not stay
> running. The vents are blowing cold air when the controls are set for hot,
> even after the car has warmed up. The engine light does not come on, we've
> even tried the computer code reader and it says everything passes. I can't
> figure for the life of me what else is wrong. Can someone give any
> suggestions?
>
> Thank You,
> Gor595Gee
>
>

Five for five boxed incorrectly out of Pep Boys and Kragen:
http://www.billhughes.com/waterPump.jpg
God Bless America, ßill O|||||||O


Dave wrote:
>
> I've heard on this NG about being careful when replacing water-pumps as
> the 4.0L has a reverse-spinning pump..? Can someone else confirm this?
>
> If you had overheating problems, maybe you've warped the head, and have
> a gasket leak? Are the oil & coolant still their natural colors?

"gor595gee" > wrote in message =
lkaboutautos.com...
> My Jeep has recently had overheating problems, therefore my spouse and =
I
> have changed the thermostat, radiator, water pump, spark plugs, and =
all
> hoses, battery. It is running rough and vibrating still and will not =
stay
> running.=20

Check the plug wires and firing order... you might
have two reversed.

> The vents are blowing cold air when the controls are set for hot,
> even after the car has warmed up. The engine light does not come on, =
we've
> even tried the computer code reader and it says everything passes. I =
can't
> figure for the life of me what else is wrong. Can someone give any
> suggestions?

Exorcism?
__
Steve
..

The spark plugs are all fine. We still can't figure it out. Thanks

We flushed the system before we did the work, the line is not blocked, we
are going to check the heater core tomorrow.

We plan to check the heater core.

We have the water pump that says "R". We also have noticed air coming from
a certain part of the heads, and I do see some oil leakage, I will try
that as well (change the head gaskets), but the heads are fine, no
clanking noise (Pistons) while we let it run for 1/2 hour.

Thanks