Sudden surge on engine temp gauge to 260 then back down - Cause?
 

I've got a slow leak in my coolant hoses which requires me to top off
the coolant levels every week (Until I can get it fixed). I've noticed
the engine to be running slightly hotter than 210 on average even
though its 20-30 degrees here in the Boston area. This morning I
refilled the coolant bottle, started up my car and went back inside for
5 minutes while the car warmed up. When I started driving the car I
noticed the temp gauge to be between the 210 and 260 mark. Since the
engine showed no signs of overheating I was puzzled. All of a sudden
the temp gauge surged to 260 and the "Check engine Light" came on. I
pulled over and waited for the steam to come pouring out of the engine,
which never happened. The funny thing was all the fans were working.
I turned off the car, let it sit for a while and turned it back on.
When the engine warmed up it was back to 210 again and showed no signs
of moving above that.

What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

Sounds like an air bubble in the system. I always open my flush kit
a bit to let the air out when it's running. It only needs to be loosened
for a second until coolant comes out.

G.Hombre@gmail.com wrote:
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?
>

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

Sounds like an air bubble in the system. I always open my flush kit
a bit to let the air out when it's running. It only needs to be loosened
for a second until coolant comes out.

G.Hombre@gmail.com wrote:
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?
>

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

Sounds like an air bubble in the system. I always open my flush kit
a bit to let the air out when it's running. It only needs to be loosened
for a second until coolant comes out.

G.Hombre@gmail.com wrote:
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?
>

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

You are describing a set of valve guide seals getting cooked due to
being steam baked. I personally have turned a perfect engine into a bad
oil burner that way and have seen others do it too.... Idiot light
instead of gauge eh...

When you have a 'small' leak, the coolant goes into the overflow bottle
like normal, but when you shut it off, it is easier for it to suck air
through the leak that to suck coolant up from the overflow bottle so
your engine top or head gets full of air.

You need to fill it from the radiator cap, not the overflow.

This air bubble turns to steam and spikes the temperature sender that
sits in the head area or at the top of the engine somewhere until the
thermostat opens and coolant starts flowing which will make the temp
gauge go lower.

Eventually this steam will also kill the thermostat too usually. On my
CJ7 that sprouted a small air leak last summer, it blew my thermostat
into fail-safe open mode. I at the time knew what happened so shut it
down quick and got fluid into the 'radiator' saving my valve guide
seals.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/in...?id=2120343242
(More Off Road album links at bottom of the view page)

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

You are describing a set of valve guide seals getting cooked due to
being steam baked. I personally have turned a perfect engine into a bad
oil burner that way and have seen others do it too.... Idiot light
instead of gauge eh...

When you have a 'small' leak, the coolant goes into the overflow bottle
like normal, but when you shut it off, it is easier for it to suck air
through the leak that to suck coolant up from the overflow bottle so
your engine top or head gets full of air.

You need to fill it from the radiator cap, not the overflow.

This air bubble turns to steam and spikes the temperature sender that
sits in the head area or at the top of the engine somewhere until the
thermostat opens and coolant starts flowing which will make the temp
gauge go lower.

Eventually this steam will also kill the thermostat too usually. On my
CJ7 that sprouted a small air leak last summer, it blew my thermostat
into fail-safe open mode. I at the time knew what happened so shut it
down quick and got fluid into the 'radiator' saving my valve guide
seals.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/in...?id=2120343242
(More Off Road album links at bottom of the view page)

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

You are describing a set of valve guide seals getting cooked due to
being steam baked. I personally have turned a perfect engine into a bad
oil burner that way and have seen others do it too.... Idiot light
instead of gauge eh...

When you have a 'small' leak, the coolant goes into the overflow bottle
like normal, but when you shut it off, it is easier for it to suck air
through the leak that to suck coolant up from the overflow bottle so
your engine top or head gets full of air.

You need to fill it from the radiator cap, not the overflow.

This air bubble turns to steam and spikes the temperature sender that
sits in the head area or at the top of the engine somewhere until the
thermostat opens and coolant starts flowing which will make the temp
gauge go lower.

Eventually this steam will also kill the thermostat too usually. On my
CJ7 that sprouted a small air leak last summer, it blew my thermostat
into fail-safe open mode. I at the time knew what happened so shut it
down quick and got fluid into the 'radiator' saving my valve guide
seals.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Aug./05 http://www.imagestation.com/album/in...?id=2120343242
(More Off Road album links at bottom of the view page)

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

I would go ahead and replace the thermostat.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

I would go ahead and replace the thermostat.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?

Re: Sudden surge on engine temp gauge to 260 then back down - Cause?
 

I would go ahead and replace the thermostat.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

G.Hombre@gmail.com wrote:
>
> I've got a slow leak in my coolant hoses which requires me to top off
> the coolant levels every week (Until I can get it fixed). I've noticed
> the engine to be running slightly hotter than 210 on average even
> though its 20-30 degrees here in the Boston area. This morning I
> refilled the coolant bottle, started up my car and went back inside for
> 5 minutes while the car warmed up. When I started driving the car I
> noticed the temp gauge to be between the 210 and 260 mark. Since the
> engine showed no signs of overheating I was puzzled. All of a sudden
> the temp gauge surged to 260 and the "Check engine Light" came on. I
> pulled over and waited for the steam to come pouring out of the engine,
> which never happened. The funny thing was all the fans were working.
> I turned off the car, let it sit for a while and turned it back on.
> When the engine warmed up it was back to 210 again and showed no signs
> of moving above that.
>
> What could be the cause? Clogged lines?