Hot!!!
Thread Starter
Intermediate
Joined: Sep 2004
Posts: 36
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From: Montello Nv
Hot!!!
My 91 , seems to be running hot. When I go up a long,long hill slowly, or drive slowly for a few miles. It seems to occur with all the road construction. What would cause this? Also the outside temperture is around 99 to 100.
patrisha
patrisha
Thread Starter
Intermediate
Joined: Sep 2004
Posts: 36
Likes: 0
From: Montello Nv
It gets to the almost boiling point. I have noticed it normally stays cool. But slow driving or mountains going slow the arrow goes all the way to the hot side. As it starts to raise, I cut off the air conditioner, hoping that will help....but it doesn,t seem to help.
patrisha
patrisha
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
A common occurance is that debris accumulates in the radiator
enclosure, sometimes rags/bags or whatever are drawn up into
the area ahead of the A/C condensor that is in front of the radiator.
Begin by looking up up underneath the front to see whether anything
obvious is blocking the air passage.
Next look under the hood into the radiator enclosure with a flashlight
and perhaps a mirror. Peer into the gap between the rad and condensor.
You are looking for signs of leaves, fluff, birds nests and so on.
Using a garden hose to flush water from the engine compartment
forward through the radiator one a year or more often depending on
your environment is considered prudent maintenance. If this hasn't
been done before, then it may be necessary to drain & remove the
radiator to clean the area with best results.
If you have an LT1/LT4 engine with the front mounted Optispark
distributer - do not hose the radiator in place. Water may damage
the ignition
Be careful with the radiator fins. They are easily bent by contact or
strong water pressure.
Time spent on your back with a jeweler's screwdriver straightening
fins bent by bugs and rocks pays dividends.
.
enclosure, sometimes rags/bags or whatever are drawn up into
the area ahead of the A/C condensor that is in front of the radiator.
Begin by looking up up underneath the front to see whether anything
obvious is blocking the air passage.
Next look under the hood into the radiator enclosure with a flashlight
and perhaps a mirror. Peer into the gap between the rad and condensor.
You are looking for signs of leaves, fluff, birds nests and so on.
Using a garden hose to flush water from the engine compartment
forward through the radiator one a year or more often depending on
your environment is considered prudent maintenance. If this hasn't
been done before, then it may be necessary to drain & remove the
radiator to clean the area with best results.
If you have an LT1/LT4 engine with the front mounted Optispark
distributer - do not hose the radiator in place. Water may damage
the ignition
Be careful with the radiator fins. They are easily bent by contact or
strong water pressure.
Time spent on your back with a jeweler's screwdriver straightening
fins bent by bugs and rocks pays dividends.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
main fan (behind the rad) to operate. (The optional front fan will
engage based on coolant temp alone.)
On the '89, the way to get the benefit of the main fan without
adding additional heat load from the A/C is to have the A/C on
but set the cabin temperature to max.
This also provides a modest cooling boost by using the in-car heater
& fan to shed heat. However, in the NV heat, it may be an unsatisfactory solution.
.
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Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
patrisha, be aware that for an '89, the stock activation temp for the
main fan is in the vicinity of 220ºF (226 on, 220 off?) The optional fan
is to actuate in the vicinity of 235ºF (225-236ºF on, 212ºF off).
If there are still cooling issues after ensuring that the current radiator
is able to breath and there are no other mechanical factors at work,
a replacement OEM or aftermarket radiator can make an improvement.
I installed a DeWitt radiator after cleaning and adding Water Wetter
proved inadequate to deal with idling in line at events, it made a
tremendous improvement. At least one member here maintains that
simply installing a new replacement radiator is a benefit on the basis
that it is difficult to clean the fins fully and scale accumulates inside.
Be sure to avoid using water only for coolant because this leads to
accelerated corrosion in the cooling system. Distilled water with
glycol changed annually or bi-annually extends the life of the system.
.
main fan is in the vicinity of 220ºF (226 on, 220 off?) The optional fan
is to actuate in the vicinity of 235ºF (225-236ºF on, 212ºF off).
If there are still cooling issues after ensuring that the current radiator
is able to breath and there are no other mechanical factors at work,
a replacement OEM or aftermarket radiator can make an improvement.
I installed a DeWitt radiator after cleaning and adding Water Wetter
proved inadequate to deal with idling in line at events, it made a
tremendous improvement. At least one member here maintains that
simply installing a new replacement radiator is a benefit on the basis
that it is difficult to clean the fins fully and scale accumulates inside.
Be sure to avoid using water only for coolant because this leads to
accelerated corrosion in the cooling system. Distilled water with
glycol changed annually or bi-annually extends the life of the system.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Oops. In a post above about fan actuation Slalom4me has erred.
tequilaboy has more detailed knowledge on the subject. I defer to
him on the matter.
Ken,
The fan info you provided is not correct. The main fan is controlled by
2 sets of fan on/off temperature settings.
The A/C 'On' fan on/off settings are used below 11 mph, independent of
the AC operation and at any speed above 11 mph when the A/C is on.
The A/C 'Off' fan on/off settings are used above 11 mph when the A/C
is off.
Factory tuning has both sets of on/off switch points set to the same
values (226 on/200 off ). So in practice, it makes no difference if the
A/C is on or off.
AC 'On' and AC 'High Pressure' below 35 mph will also command a fixed
100% duty cycle, instead of the variable duty cycle table, which is also
happens to be set to 100% with factory tuning.
It is not clear whether AC 'On' and AC 'High Pressure' alone will activate
the fan at 100% duty cycle below the AC 'On' fan on/off temperatures.
I haven't seen this happen, since it is unlikely with my present tuning,
but it may be possible.
tequilaboy has more detailed knowledge on the subject. I defer to
him on the matter.
Originally Posted by tequilaboy
Originally Posted by Slalom4me
I don't recall about the '91 but on the '89, the
A/C must be on for the main fan (behind the rad) to operate. (The
optional front fan will engage based on coolant temp alone.)
On the '89, the way to get the benefit of the main fan without
adding additional heat load from the A/C is to have the A/C on
but set the cabin temperature to max. This also provides a modest
cooling boost by using the in-car heater & fan to shed heat.
A/C must be on for the main fan (behind the rad) to operate. (The
optional front fan will engage based on coolant temp alone.)
On the '89, the way to get the benefit of the main fan without
adding additional heat load from the A/C is to have the A/C on
but set the cabin temperature to max. This also provides a modest
cooling boost by using the in-car heater & fan to shed heat.
The fan info you provided is not correct. The main fan is controlled by
2 sets of fan on/off temperature settings.
The A/C 'On' fan on/off settings are used below 11 mph, independent of
the AC operation and at any speed above 11 mph when the A/C is on.
The A/C 'Off' fan on/off settings are used above 11 mph when the A/C
is off.
Factory tuning has both sets of on/off switch points set to the same
values (226 on/200 off ). So in practice, it makes no difference if the
A/C is on or off.
AC 'On' and AC 'High Pressure' below 35 mph will also command a fixed
100% duty cycle, instead of the variable duty cycle table, which is also
happens to be set to 100% with factory tuning.
It is not clear whether AC 'On' and AC 'High Pressure' alone will activate
the fan at 100% duty cycle below the AC 'On' fan on/off temperatures.
I haven't seen this happen, since it is unlikely with my present tuning,
but it may be possible.
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Not directly, but a very dirty filter makes your engine run inefficiently and can cause premature wear. My son lives in Arizona and changes his filter every 6 months.
Last edited by BADDUCK; Jul 11, 2007 at 05:27 PM.
Thread Starter
Intermediate
Joined: Sep 2004
Posts: 36
Likes: 0
From: Montello Nv
Okay I think I understand: I can leave my air conditioner on. I don,t need to be concern if the arrow raises, as long as it doesn,t go all the way on the boil side. I can look for dirt and stuff near and under the car, and perhaps change my air filter every six months. So if it does actually over-heat, what do you all recommend that I do?
patrisha
patrisha
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Okay I think I understand: I can leave my air conditioner on. I don,t need to be concern if the arrow raises, as long as it doesn,t go all the way on the boil side. I can look for dirt and stuff near and under the car, and perhaps change my air filter every six months. So if it does actually over-heat, what do you all recommend that I do?
patrisha
patrisha
With your AC on, did you check to see if your fan(s) are running? This is real important....
Also, since you have a '91, you DO NOT have an Optispark, so you will be safe to hose out the radiator from front and back.....but avoid getting water on anything electrical like the distributor which sits at the rear of the engine.
Last edited by MikeC4; Jul 11, 2007 at 06:19 PM.
That is a good suggestion.....I will have to look into that.
I basically ,turn the engine on, wash, wax, pay for oil changes and wave.. I love waving.