My 94 YJ was up on jackstands for a while. After I installed my new
Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
Wondered why it was dry, and how long it had been that way.

On the freeway run out to trailing Mojave this weekend, going sustained,
"pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
"check engine" light came on in a 3 hour drive.

I could smell coolant. The temp gauge showed a normal temp, and the
radiator was barely warm. Flipping the release lever on the radiator cap
cause to coolant to spew or violently gush out the side tank. A lot.

I would add water and coolant, drop the hood, and everything was fine
again for another hour of sustained driving. That was the first day.

Second day, no lights came on, but then, there was a lot of stopping and
resting. I and others in the group could smell the coolant, though.

When I got home after another "pushing it" drive, a decent amount purged
once I stopped and parked.

Do I have a water pump problem? Cracked block? Is my thermostat lying to
me? Did I not tighten the belt back enough? (feels pretty damn tight).
Almost 100k miles on this puppy, btw.

Any help would be appreciated!

 

"Cal Wheeler" <cal@whee.ler> wrote in message
news:bpc8ii$l84$0@pita.alt.net...
> My 94 YJ was up on jackstands for a while. After I installed my new
> Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
> Wondered why it was dry, and how long it had been that way.
>
> On the freeway run out to trailing Mojave this weekend, going sustained,
> "pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
> "check engine" light came on in a 3 hour drive.
>
> I could smell coolant. The temp gauge showed a normal temp, and the
> radiator was barely warm. Flipping the release lever on the radiator cap
> cause to coolant to spew or violently gush out the side tank. A lot.
>
> I would add water and coolant, drop the hood, and everything was fine
> again for another hour of sustained driving. That was the first day.
>
> Second day, no lights came on, but then, there was a lot of stopping and
> resting. I and others in the group could smell the coolant, though.
>
> When I got home after another "pushing it" drive, a decent amount purged
> once I stopped and parked.
>
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!
>

Make sure your lower radiator hose is in good shape and that the spring is
in there, it may be collapsing. Also pull the hose off and make sure the
inner liner of the hose hasn't separated from the outer. Both of these can
cause a coolant flow restriction that can do what you describe. You didn't
mention of the coolant is leaking out or not. Not likely, but you could also
have an air pocket somewhere in the cooling system. Some of these are tough
to get rid of. Sometimes you can bleed the system with the engine running by
cracking the hose connections (be careful!) or loosening the sending unit.
This can be a messy job, and please be careful with the hot coolant.

I'll be totally honest with you, this usually is a sign of compression
pressure getting into the cooling system. My preferred way of checking for a
cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
expensive, and you can substitute an air hose adapter that is available at
the parts stores. The hose will thread into the spark plug hole and connect
to your air compressor. When you pull the plugs, look for one that is
"washed" clean. This is another indication of coolant in the combustion
chamber, which normally shows up as whitish grey exhaust smoke, which you
didn't imply. Before you put the air to the cylinder, make sure the piston
is at TDC and have the radiator cap off. When you apply the air, you can
tell where you are losing cylinder pressure. You'll hear air hissing in the
tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
the coolant will indicate and head gasket or cracked block/head.

Chris

 

"Cal Wheeler" <cal@whee.ler> wrote in message
news:bpc8ii$l84$0@pita.alt.net...
> My 94 YJ was up on jackstands for a while. After I installed my new
> Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
> Wondered why it was dry, and how long it had been that way.
>
> On the freeway run out to trailing Mojave this weekend, going sustained,
> "pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
> "check engine" light came on in a 3 hour drive.
>
> I could smell coolant. The temp gauge showed a normal temp, and the
> radiator was barely warm. Flipping the release lever on the radiator cap
> cause to coolant to spew or violently gush out the side tank. A lot.
>
> I would add water and coolant, drop the hood, and everything was fine
> again for another hour of sustained driving. That was the first day.
>
> Second day, no lights came on, but then, there was a lot of stopping and
> resting. I and others in the group could smell the coolant, though.
>
> When I got home after another "pushing it" drive, a decent amount purged
> once I stopped and parked.
>
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!
>

Make sure your lower radiator hose is in good shape and that the spring is
in there, it may be collapsing. Also pull the hose off and make sure the
inner liner of the hose hasn't separated from the outer. Both of these can
cause a coolant flow restriction that can do what you describe. You didn't
mention of the coolant is leaking out or not. Not likely, but you could also
have an air pocket somewhere in the cooling system. Some of these are tough
to get rid of. Sometimes you can bleed the system with the engine running by
cracking the hose connections (be careful!) or loosening the sending unit.
This can be a messy job, and please be careful with the hot coolant.

I'll be totally honest with you, this usually is a sign of compression
pressure getting into the cooling system. My preferred way of checking for a
cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
expensive, and you can substitute an air hose adapter that is available at
the parts stores. The hose will thread into the spark plug hole and connect
to your air compressor. When you pull the plugs, look for one that is
"washed" clean. This is another indication of coolant in the combustion
chamber, which normally shows up as whitish grey exhaust smoke, which you
didn't imply. Before you put the air to the cylinder, make sure the piston
is at TDC and have the radiator cap off. When you apply the air, you can
tell where you are losing cylinder pressure. You'll hear air hissing in the
tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
the coolant will indicate and head gasket or cracked block/head.

Chris

 

"Cal Wheeler" <cal@whee.ler> wrote in message
news:bpc8ii$l84$0@pita.alt.net...
> My 94 YJ was up on jackstands for a while. After I installed my new
> Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
> Wondered why it was dry, and how long it had been that way.
>
> On the freeway run out to trailing Mojave this weekend, going sustained,
> "pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
> "check engine" light came on in a 3 hour drive.
>
> I could smell coolant. The temp gauge showed a normal temp, and the
> radiator was barely warm. Flipping the release lever on the radiator cap
> cause to coolant to spew or violently gush out the side tank. A lot.
>
> I would add water and coolant, drop the hood, and everything was fine
> again for another hour of sustained driving. That was the first day.
>
> Second day, no lights came on, but then, there was a lot of stopping and
> resting. I and others in the group could smell the coolant, though.
>
> When I got home after another "pushing it" drive, a decent amount purged
> once I stopped and parked.
>
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!
>

Make sure your lower radiator hose is in good shape and that the spring is
in there, it may be collapsing. Also pull the hose off and make sure the
inner liner of the hose hasn't separated from the outer. Both of these can
cause a coolant flow restriction that can do what you describe. You didn't
mention of the coolant is leaking out or not. Not likely, but you could also
have an air pocket somewhere in the cooling system. Some of these are tough
to get rid of. Sometimes you can bleed the system with the engine running by
cracking the hose connections (be careful!) or loosening the sending unit.
This can be a messy job, and please be careful with the hot coolant.

I'll be totally honest with you, this usually is a sign of compression
pressure getting into the cooling system. My preferred way of checking for a
cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
expensive, and you can substitute an air hose adapter that is available at
the parts stores. The hose will thread into the spark plug hole and connect
to your air compressor. When you pull the plugs, look for one that is
"washed" clean. This is another indication of coolant in the combustion
chamber, which normally shows up as whitish grey exhaust smoke, which you
didn't imply. Before you put the air to the cylinder, make sure the piston
is at TDC and have the radiator cap off. When you apply the air, you can
tell where you are losing cylinder pressure. You'll hear air hissing in the
tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
the coolant will indicate and head gasket or cracked block/head.

Chris

 

Cal Wheeler wrote:
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!

Let it idle for a while top it off slowly at the radiator until it's
full and the bottle is at the full hot line then get under and look for
a slow leak coming from the bottom of the water pump... You don't
actually have to top it off for this but it gives you something to do
while you're waiting for it to warm up completely and you'll also know
that it's cycling coolant before you get under it. The weep hole may not
actually be leaking coolant yet, but my guess is it will be soon enough.

I go through so many water pumps on my crew trucks at work (two in the
last month) that this has become old hat. Of course being kinda
pessimistic the first thing I start worrying about is a blown head
gasket... So looking for air bubbles/oil in the coolant/coolant in the
oil/gasket material or crud floating around in the coolant etc. is also
old hat.

 

Cal Wheeler wrote:
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!

Let it idle for a while top it off slowly at the radiator until it's
full and the bottle is at the full hot line then get under and look for
a slow leak coming from the bottom of the water pump... You don't
actually have to top it off for this but it gives you something to do
while you're waiting for it to warm up completely and you'll also know
that it's cycling coolant before you get under it. The weep hole may not
actually be leaking coolant yet, but my guess is it will be soon enough.

I go through so many water pumps on my crew trucks at work (two in the
last month) that this has become old hat. Of course being kinda
pessimistic the first thing I start worrying about is a blown head
gasket... So looking for air bubbles/oil in the coolant/coolant in the
oil/gasket material or crud floating around in the coolant etc. is also
old hat.

 

Cal Wheeler wrote:
> Do I have a water pump problem? Cracked block? Is my thermostat lying to
> me? Did I not tighten the belt back enough? (feels pretty damn tight).
> Almost 100k miles on this puppy, btw.
>
> Any help would be appreciated!

Let it idle for a while top it off slowly at the radiator until it's
full and the bottle is at the full hot line then get under and look for
a slow leak coming from the bottom of the water pump... You don't
actually have to top it off for this but it gives you something to do
while you're waiting for it to warm up completely and you'll also know
that it's cycling coolant before you get under it. The weep hole may not
actually be leaking coolant yet, but my guess is it will be soon enough.

I go through so many water pumps on my crew trucks at work (two in the
last month) that this has become old hat. Of course being kinda
pessimistic the first thing I start worrying about is a blown head
gasket... So looking for air bubbles/oil in the coolant/coolant in the
oil/gasket material or crud floating around in the coolant etc. is also
old hat.

 

c wrote:
> "Cal Wheeler" <cal@whee.ler> wrote in message
> news:bpc8ii$l84$0@pita.alt.net...
>
>>My 94 YJ was up on jackstands for a while. After I installed my new
>>Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
>>Wondered why it was dry, and how long it had been that way.
>>
>>On the freeway run out to trailing Mojave this weekend, going sustained,
>>"pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
>>"check engine" light came on in a 3 hour drive.
>>
>>I could smell coolant. The temp gauge showed a normal temp, and the
>>radiator was barely warm. Flipping the release lever on the radiator cap
>>cause to coolant to spew or violently gush out the side tank. A lot.
>>
>>I would add water and coolant, drop the hood, and everything was fine
>>again for another hour of sustained driving. That was the first day.
>>
>>Second day, no lights came on, but then, there was a lot of stopping and
>>resting. I and others in the group could smell the coolant, though.
>>
>>When I got home after another "pushing it" drive, a decent amount purged
>>once I stopped and parked.
>>
>>Do I have a water pump problem? Cracked block? Is my thermostat lying to
>>me? Did I not tighten the belt back enough? (feels pretty damn tight).
>>Almost 100k miles on this puppy, btw.
>>
>>Any help would be appreciated!
>>
>
>
> Make sure your lower radiator hose is in good shape and that the spring is
> in there, it may be collapsing. Also pull the hose off and make sure the
> inner liner of the hose hasn't separated from the outer. Both of these can
> cause a coolant flow restriction that can do what you describe. You didn't
> mention of the coolant is leaking out or not. Not likely, but you could also
> have an air pocket somewhere in the cooling system. Some of these are tough
> to get rid of. Sometimes you can bleed the system with the engine running by
> cracking the hose connections (be careful!) or loosening the sending unit.
> This can be a messy job, and please be careful with the hot coolant.
>
> I'll be totally honest with you, this usually is a sign of compression
> pressure getting into the cooling system. My preferred way of checking for a
> cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
> expensive, and you can substitute an air hose adapter that is available at
> the parts stores. The hose will thread into the spark plug hole and connect
> to your air compressor. When you pull the plugs, look for one that is
> "washed" clean. This is another indication of coolant in the combustion
> chamber, which normally shows up as whitish grey exhaust smoke, which you
> didn't imply. Before you put the air to the cylinder, make sure the piston
> is at TDC and have the radiator cap off. When you apply the air, you can
> tell where you are losing cylinder pressure. You'll hear air hissing in the
> tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
> air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
> the coolant will indicate and head gasket or cracked block/head.
>
Damn! Great advice. I will try this method and see what I see. Thank you!

 

c wrote:
> "Cal Wheeler" <cal@whee.ler> wrote in message
> news:bpc8ii$l84$0@pita.alt.net...
>
>>My 94 YJ was up on jackstands for a while. After I installed my new
>>Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
>>Wondered why it was dry, and how long it had been that way.
>>
>>On the freeway run out to trailing Mojave this weekend, going sustained,
>>"pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
>>"check engine" light came on in a 3 hour drive.
>>
>>I could smell coolant. The temp gauge showed a normal temp, and the
>>radiator was barely warm. Flipping the release lever on the radiator cap
>>cause to coolant to spew or violently gush out the side tank. A lot.
>>
>>I would add water and coolant, drop the hood, and everything was fine
>>again for another hour of sustained driving. That was the first day.
>>
>>Second day, no lights came on, but then, there was a lot of stopping and
>>resting. I and others in the group could smell the coolant, though.
>>
>>When I got home after another "pushing it" drive, a decent amount purged
>>once I stopped and parked.
>>
>>Do I have a water pump problem? Cracked block? Is my thermostat lying to
>>me? Did I not tighten the belt back enough? (feels pretty damn tight).
>>Almost 100k miles on this puppy, btw.
>>
>>Any help would be appreciated!
>>
>
>
> Make sure your lower radiator hose is in good shape and that the spring is
> in there, it may be collapsing. Also pull the hose off and make sure the
> inner liner of the hose hasn't separated from the outer. Both of these can
> cause a coolant flow restriction that can do what you describe. You didn't
> mention of the coolant is leaking out or not. Not likely, but you could also
> have an air pocket somewhere in the cooling system. Some of these are tough
> to get rid of. Sometimes you can bleed the system with the engine running by
> cracking the hose connections (be careful!) or loosening the sending unit.
> This can be a messy job, and please be careful with the hot coolant.
>
> I'll be totally honest with you, this usually is a sign of compression
> pressure getting into the cooling system. My preferred way of checking for a
> cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
> expensive, and you can substitute an air hose adapter that is available at
> the parts stores. The hose will thread into the spark plug hole and connect
> to your air compressor. When you pull the plugs, look for one that is
> "washed" clean. This is another indication of coolant in the combustion
> chamber, which normally shows up as whitish grey exhaust smoke, which you
> didn't imply. Before you put the air to the cylinder, make sure the piston
> is at TDC and have the radiator cap off. When you apply the air, you can
> tell where you are losing cylinder pressure. You'll hear air hissing in the
> tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
> air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
> the coolant will indicate and head gasket or cracked block/head.
>
Damn! Great advice. I will try this method and see what I see. Thank you!

 

c wrote:
> "Cal Wheeler" <cal@whee.ler> wrote in message
> news:bpc8ii$l84$0@pita.alt.net...
>
>>My 94 YJ was up on jackstands for a while. After I installed my new
>>Borla Headers, I noticed the coolant tank was bone dry, so I filled it.
>>Wondered why it was dry, and how long it had been that way.
>>
>>On the freeway run out to trailing Mojave this weekend, going sustained,
>>"pushing-it" speeds (depending on the grade) of 65-80 mph, twice my
>>"check engine" light came on in a 3 hour drive.
>>
>>I could smell coolant. The temp gauge showed a normal temp, and the
>>radiator was barely warm. Flipping the release lever on the radiator cap
>>cause to coolant to spew or violently gush out the side tank. A lot.
>>
>>I would add water and coolant, drop the hood, and everything was fine
>>again for another hour of sustained driving. That was the first day.
>>
>>Second day, no lights came on, but then, there was a lot of stopping and
>>resting. I and others in the group could smell the coolant, though.
>>
>>When I got home after another "pushing it" drive, a decent amount purged
>>once I stopped and parked.
>>
>>Do I have a water pump problem? Cracked block? Is my thermostat lying to
>>me? Did I not tighten the belt back enough? (feels pretty damn tight).
>>Almost 100k miles on this puppy, btw.
>>
>>Any help would be appreciated!
>>
>
>
> Make sure your lower radiator hose is in good shape and that the spring is
> in there, it may be collapsing. Also pull the hose off and make sure the
> inner liner of the hose hasn't separated from the outer. Both of these can
> cause a coolant flow restriction that can do what you describe. You didn't
> mention of the coolant is leaking out or not. Not likely, but you could also
> have an air pocket somewhere in the cooling system. Some of these are tough
> to get rid of. Sometimes you can bleed the system with the engine running by
> cracking the hose connections (be careful!) or loosening the sending unit.
> This can be a messy job, and please be careful with the hot coolant.
>
> I'll be totally honest with you, this usually is a sign of compression
> pressure getting into the cooling system. My preferred way of checking for a
> cracked block, etc. is to use a cylinder leakdown tester. These can be a bit
> expensive, and you can substitute an air hose adapter that is available at
> the parts stores. The hose will thread into the spark plug hole and connect
> to your air compressor. When you pull the plugs, look for one that is
> "washed" clean. This is another indication of coolant in the combustion
> chamber, which normally shows up as whitish grey exhaust smoke, which you
> didn't imply. Before you put the air to the cylinder, make sure the piston
> is at TDC and have the radiator cap off. When you apply the air, you can
> tell where you are losing cylinder pressure. You'll hear air hissing in the
> tailpipe for leaky exhaust, air in the carb/throttle body for leaky intake,
> air in the oil filler hole or dipstick tube for leaky rings, and bubbles in
> the coolant will indicate and head gasket or cracked block/head.
>
Damn! Great advice. I will try this method and see what I see. Thank you!