'90 Honda Civic cooling problem, DIY radiator installation questions

OK, here’s the story.

About a month ago, I noticed that my 1990 Honda Civic DX (with
automatic transmission and A/C and ~75,000 miles) started getting hot
within 5 minutes after starting out. Almost to the red line on the
gauge. I was stuck in traffic when I noticed this. I immediately tried
to pull off a freeway exit. As soon as I got off the exit, I noticed
the temperature drop almost instantly on the gauge from the line below
the red to midway on the gauge. But then a couple of minutes later
through town, the temp went back up again, only to drop back down
later when going back onto the freeway. It did this on the remainder
of my freeway trip and ever since then. Doesn’t matter when or
where I start out (morning/noon/night, freeway/town), this pattern is
consistent. It continues this same pattern: a couple of minutes after
starting it would go to almost the red line on the gauge, a couple of
minutes later back down to midway on the temp gauge, back up to almost
the red line, back down, etc. etc. etc. Never overheated to where
steam was pillowing through the hood. As it happened during the
Christmas holiday season, I passed it off for fixing until after the
holidays, driving it all the while. I would put on the A/C just to
keep the fan blowing on the radiator.

I did a little research and concluded (rightly or wrongly) that my
thermostat was stuck. So I went to Honda last week to get a
thermostat. However, as soon as I was about to replace it, I saw the
cooling fins on my radiator were bad. They were disintegrating,
crumbling. Whether the thermostat is the root of the problem or not,
the radiator will most definitely need to be replaced (I intend to
keep the car for at least a couple of years). So I decided that I will
go ahead and have the radiator replaced.

My questions to you folk:

Do you think that the radiator is the root of the problem with the
symptoms I am having? Initially, I was hesitant to think the radiator
was the problem because if the radiator was that bad, wouldn’t
it lead to the car always running hot (i.e., not cool and hot like
it's running now)?

OK, more importantly, I am thinking that I will attempt to replace the
radiator myself and have some questions regarding this. I normally
would send the car to Honda, but right now I am trying to pinch
pennies as I just bought a new home and have a new child in the
family. BTW, I am not a mechanic, but I consider myself fairly handy
as I do regular maintenance on the car (tune-ups, oil changes, etc.)
and have done slightly more significant repairs to my previous car, a
’83 Honda Civic (water pump replacement, muffler replacement,
starter replacement, etc.).

1) Is the work involved too much for a “backyard
mechanic”?
2) Do I need any special tools the average “backyard
mechanic” would not have access to?
3) How much will a new radiator be (price range)?
4) Should I purchase a Honda radiator? I know that many times buying
genuine Honda parts, although more expensive, is always better in the
long run. However, I understand that Honda radiators are plastic and
am thinking maybe another type of replacement radiator (i.e., metal)
would be better in the end.
5) Can I do the job in a day? Will I need more than myself to do it?
6) Any other advice you can give regarding the specifics about
radiator replacement in Honda Civics of this vintage. As I understand
it, I need to undo all the hoses (coolant, A/C and auto trans.) and
fans (I think there’s two?) and brackets to get the old one out.
Seems pretty straightforward. And then just reversing what I did. I
also plan to put into a new upper and lower radiator hose and a new
thermostat at the same time.

Thanks for your time,
Chris

 

From your description it sounds like the car is cooling down when you
are going fast and heating up when stopped or in stop and go traffic. If
that is the case, most likely your radiator fan does not run, either
because the fan is bad or because the thermoswitch that turns on the fan
is bad. Do you ever hear the fan turn on?

 

From your description it sounds like the car is cooling down when you
are going fast and heating up when stopped or in stop and go traffic. If
that is the case, most likely your radiator fan does not run, either
because the fan is bad or because the thermoswitch that turns on the fan
is bad. Do you ever hear the fan turn on?

 

From your description it sounds like the car is cooling down when you
are going fast and heating up when stopped or in stop and go traffic. If
that is the case, most likely your radiator fan does not run, either
because the fan is bad or because the thermoswitch that turns on the fan
is bad. Do you ever hear the fan turn on?

 

When I had a few fins missing (areas about the size of the palm of my hand
in each half) and disintegration in progress ('92 Integra), I ran the car
for a month in 70-80 degree weather without any signs of overheating. I
guess it depends on how many fins you have left but I'd tend to say: no,
that should not cause the oscillations in temp you are seeing.

It's not that difficult - the difficulty is in figuring how to get things
out in the right order without interference with other parts.

Check www.hondaautomotiveparts.com and www.radiators.com

I got a Honda/Acura one though others have reported success with
aftermarket. Before you buy, check the make of radiator you have - Toyo or
Denso (should be scripted on the top) and specify that - I know that Honda
has two different parts because the fan shrouds have different mount points
between the two. The Honda radiators come with a new cap.

Yes and no respectively, though having a 2nd person to assist, for actually
dropping in the new one, can be handy to avoid gouging/damaging it. With
the radiator out, you'll also have access to many areas you'll want to
clean up for dirt & corrosion.

You shouldn't have to disconnect any A/C lines - once the top brackets are
off, they should push out of the way and allow removal of the radiator with
the main fan shroud still attached; the A/C fan shroud, I found, was better
detached before removing the radiator and left dangling - no clearance for
it.

Coupla tips: the electrical connectors can get stiff with age - a spritz of
silicone spray before wiggling, helps to get them off. Before you put the
new one in, cut pieces of the cardboard box it came in, which just fit in
the radiator frame and cover up all the fins - avoids gouges as you
maneuver it into place. This is especially important if you attach the new
bottom hose before installation, which *may* be necessary - the bottom hose
clip location is often inaccessible with the radiator installed... without
more, boring disassembly. Getting the new radiator into place while trying
to route the bottom hose is where that 2nd person helps.

Good luck.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

When I had a few fins missing (areas about the size of the palm of my hand
in each half) and disintegration in progress ('92 Integra), I ran the car
for a month in 70-80 degree weather without any signs of overheating. I
guess it depends on how many fins you have left but I'd tend to say: no,
that should not cause the oscillations in temp you are seeing.

It's not that difficult - the difficulty is in figuring how to get things
out in the right order without interference with other parts.

Check www.hondaautomotiveparts.com and www.radiators.com

I got a Honda/Acura one though others have reported success with
aftermarket. Before you buy, check the make of radiator you have - Toyo or
Denso (should be scripted on the top) and specify that - I know that Honda
has two different parts because the fan shrouds have different mount points
between the two. The Honda radiators come with a new cap.

Yes and no respectively, though having a 2nd person to assist, for actually
dropping in the new one, can be handy to avoid gouging/damaging it. With
the radiator out, you'll also have access to many areas you'll want to
clean up for dirt & corrosion.

You shouldn't have to disconnect any A/C lines - once the top brackets are
off, they should push out of the way and allow removal of the radiator with
the main fan shroud still attached; the A/C fan shroud, I found, was better
detached before removing the radiator and left dangling - no clearance for
it.

Coupla tips: the electrical connectors can get stiff with age - a spritz of
silicone spray before wiggling, helps to get them off. Before you put the
new one in, cut pieces of the cardboard box it came in, which just fit in
the radiator frame and cover up all the fins - avoids gouges as you
maneuver it into place. This is especially important if you attach the new
bottom hose before installation, which *may* be necessary - the bottom hose
clip location is often inaccessible with the radiator installed... without
more, boring disassembly. Getting the new radiator into place while trying
to route the bottom hose is where that 2nd person helps.

Good luck.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

When I had a few fins missing (areas about the size of the palm of my hand
in each half) and disintegration in progress ('92 Integra), I ran the car
for a month in 70-80 degree weather without any signs of overheating. I
guess it depends on how many fins you have left but I'd tend to say: no,
that should not cause the oscillations in temp you are seeing.

It's not that difficult - the difficulty is in figuring how to get things
out in the right order without interference with other parts.

Check www.hondaautomotiveparts.com and www.radiators.com

I got a Honda/Acura one though others have reported success with
aftermarket. Before you buy, check the make of radiator you have - Toyo or
Denso (should be scripted on the top) and specify that - I know that Honda
has two different parts because the fan shrouds have different mount points
between the two. The Honda radiators come with a new cap.

Yes and no respectively, though having a 2nd person to assist, for actually
dropping in the new one, can be handy to avoid gouging/damaging it. With
the radiator out, you'll also have access to many areas you'll want to
clean up for dirt & corrosion.

You shouldn't have to disconnect any A/C lines - once the top brackets are
off, they should push out of the way and allow removal of the radiator with
the main fan shroud still attached; the A/C fan shroud, I found, was better
detached before removing the radiator and left dangling - no clearance for
it.

Coupla tips: the electrical connectors can get stiff with age - a spritz of
silicone spray before wiggling, helps to get them off. Before you put the
new one in, cut pieces of the cardboard box it came in, which just fit in
the radiator frame and cover up all the fins - avoids gouges as you
maneuver it into place. This is especially important if you attach the new
bottom hose before installation, which *may* be necessary - the bottom hose
clip location is often inaccessible with the radiator installed... without
more, boring disassembly. Getting the new radiator into place while trying
to route the bottom hose is where that 2nd person helps.

Good luck.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

I have also found that it is also easier to remove the lower radiator
hose where it attaches to the engine, and wait till the radiator is on
the bench to remove the hose from the bottom of the radiator. bob

 

I have also found that it is also easier to remove the lower radiator
hose where it attaches to the engine, and wait till the radiator is on
the bench to remove the hose from the bottom of the radiator. bob

 

I have also found that it is also easier to remove the lower radiator
hose where it attaches to the engine, and wait till the radiator is on
the bench to remove the hose from the bottom of the radiator. bob

 

No, the temp going up and down is not related to speed. It can heat up
when I am going down a major hill out of the mountains. That's why I
suspect it's the thermostat. Also, fan comes on and stays on when I
put the A/C on. Even with the fan running, however, the temp gauge can
still head north, just to come down a few minutes later. Again, I am
thinking the thermostat is sticking and the coolant can't get back to
the radiator to cool. Thus my quest to see if this could be the case
from the gurus...

I do want to replace the radiator as well so there are no surprises
later...

 

No, the temp going up and down is not related to speed. It can heat up
when I am going down a major hill out of the mountains. That's why I
suspect it's the thermostat. Also, fan comes on and stays on when I
put the A/C on. Even with the fan running, however, the temp gauge can
still head north, just to come down a few minutes later. Again, I am
thinking the thermostat is sticking and the coolant can't get back to
the radiator to cool. Thus my quest to see if this could be the case
from the gurus...

I do want to replace the radiator as well so there are no surprises
later...

 

No, the temp going up and down is not related to speed. It can heat up
when I am going down a major hill out of the mountains. That's why I
suspect it's the thermostat. Also, fan comes on and stays on when I
put the A/C on. Even with the fan running, however, the temp gauge can
still head north, just to come down a few minutes later. Again, I am
thinking the thermostat is sticking and the coolant can't get back to
the radiator to cool. Thus my quest to see if this could be the case
from the gurus...

I do want to replace the radiator as well so there are no surprises
later...

 

You should check if your radiator fan and itsswitch are working fine.
Never changed a radiator on a Honda but did it on a Ford and a Nissan no
problem. It is easier than several other things you have done.I didn't buy
new radiators with my old cars. I bought refurbished ones instead. And you
should change the thermostat at the same time since you're not sure.
You might also want to plus a garden hose into the system and rinse
everything clean since you'll be changing the coolant anyway. They sell an
adaptor that you can easily install on one of the hoses and plug a garden
hose to rinse the system.

 

You should check if your radiator fan and itsswitch are working fine.
Never changed a radiator on a Honda but did it on a Ford and a Nissan no
problem. It is easier than several other things you have done.I didn't buy
new radiators with my old cars. I bought refurbished ones instead. And you
should change the thermostat at the same time since you're not sure.
You might also want to plus a garden hose into the system and rinse
everything clean since you'll be changing the coolant anyway. They sell an
adaptor that you can easily install on one of the hoses and plug a garden
hose to rinse the system.

 

You should check if your radiator fan and itsswitch are working fine.
Never changed a radiator on a Honda but did it on a Ford and a Nissan no
problem. It is easier than several other things you have done.I didn't buy
new radiators with my old cars. I bought refurbished ones instead. And you
should change the thermostat at the same time since you're not sure.
You might also want to plus a garden hose into the system and rinse
everything clean since you'll be changing the coolant anyway. They sell an
adaptor that you can easily install on one of the hoses and plug a garden
hose to rinse the system.

 

Chris,
I won't be able to answer all of your questions but can offer some advice
since I had a defective radiator on my car when I was a poor college
student. I compared the price of a new radiator at the car dealership and
a new radiator that was sold by a radiator repair shop located in that
town. Needless to say, the radiator at the radiator shop cost about half
as much as the radiator that the car dealership wanted to sell me. I also
shopped at a junk yard but did not find any cars at the junk yard that had
a decent looking radiator that would fit in my car. I ended up buying the
radiator at the radiator shop. I could have easily installed it myself but
the radiator shop owner installed it for about $20.00. He also installed a
new thermostat. I also advise you to replace the water pump at the same
time that you replace the radiator. The junk yards are now on a computer
net work and might be able to get you a really great radiator for a low
price. Some junk yards even provide a free guarantee on any products they
sell--they just replace any defective product.

 

Chris,
I won't be able to answer all of your questions but can offer some advice
since I had a defective radiator on my car when I was a poor college
student. I compared the price of a new radiator at the car dealership and
a new radiator that was sold by a radiator repair shop located in that
town. Needless to say, the radiator at the radiator shop cost about half
as much as the radiator that the car dealership wanted to sell me. I also
shopped at a junk yard but did not find any cars at the junk yard that had
a decent looking radiator that would fit in my car. I ended up buying the
radiator at the radiator shop. I could have easily installed it myself but
the radiator shop owner installed it for about $20.00. He also installed a
new thermostat. I also advise you to replace the water pump at the same
time that you replace the radiator. The junk yards are now on a computer
net work and might be able to get you a really great radiator for a low
price. Some junk yards even provide a free guarantee on any products they
sell--they just replace any defective product.

 

Chris,
I won't be able to answer all of your questions but can offer some advice
since I had a defective radiator on my car when I was a poor college
student. I compared the price of a new radiator at the car dealership and
a new radiator that was sold by a radiator repair shop located in that
town. Needless to say, the radiator at the radiator shop cost about half
as much as the radiator that the car dealership wanted to sell me. I also
shopped at a junk yard but did not find any cars at the junk yard that had
a decent looking radiator that would fit in my car. I ended up buying the
radiator at the radiator shop. I could have easily installed it myself but
the radiator shop owner installed it for about $20.00. He also installed a
new thermostat. I also advise you to replace the water pump at the same
time that you replace the radiator. The junk yards are now on a computer
net work and might be able to get you a really great radiator for a low
price. Some junk yards even provide a free guarantee on any products they
sell--they just replace any defective product.

 

(Seven) spake unto the masses in

<snip>


This does not sound like a rad problem at all. How's the coolant level? Has
it been bled properly using the bleed bolt on the upper rad hose?

Do you notice the reservoir level mysteriously going UP?

If the coolant level is fine, it sounds more like something electrical,
Like maybe the TW switch being bad, its wiring corroded or something else
electrical.