gofra
New Member
Hi,
a few weeks back, my Civic 1.5 started overheating out of the
blue. As many before me, I suspected the thermostat first, but it
wasn't it. I checked the coolant level, was ok. Bled the system,
checked the fan...even changed the water pump. Still overheating.
I began loosing my mind as it allready cost me a lot of time and
nerves. I came to a point where I dont see what to do anymore...
Here's how it went (a bit long, but please bear with me)...
The car I bought in February, is a Civic 1998 Aerodeck with the
E-Vtec, 1,5 LS i 16V engine. It was in good general condition and
with a fairly good service history (not official unfortunately).
It was running like a dream until...
Pinking / rattling sound under slight load
..it started sounding like something was loose when it was warmed
up and under moderate load. The sound disapeared with throttle
pressed or decreased a bit. I did next things:
- oil + filter
- fuel filter
- spark plugs
- spark plug wires
- distributor cap
- distributor rotor
- air filter
- timing adjustment
The problem was still there. As Im a person that has to fix
things, I decided to check the:
- valve clearances
Nothing changed. I tried different fuel - no evident difference.
Failing to find out what the problem was, I decided to just keep
driving. It progressivly got worse (more enhanced, louder) but
everything else was ok so it didnt bother me. After one seriously
quick 1 hr drive on the highway, the car started...
Overheating
As soon as I stopped at the traffic lights, gauge started
climbing dangereously close to the red zone. When I drove back
home I had no issues. A few days later it started again. This
time I decided to check whats going on:
- I replaced thermostat 2 times
- topped out coolant
It was still overheating
I decided to give a go with yet another thermostat (ended up with
three fully working ones - gave them a test). Time for..
Big service - water pump
- replaced all the belts
- replaced the tensioners
- replaced the water pump (btw, all the stuff I took off was in
mint working condition)
- took off the radiator, cleaned it, pressure tested it
- checked the pipes where I could for leaking
- adjusted valve clearances and timing again
- replaced all the coolant and bled the system
I was almost sure this would be it - but no. It still overheats.
I did manage (had looots of time) to find out next:
- when starting from cold and running the engine with car parked,
all works ok. Fan kicks in, temp. gauge never climbs over 1st
third of the scale even with my girlfriend in the cabin, pushing
the throttle down for 30 minutes (around 3K rspm).
- when I drive off and the gauge starts climbing up, I park the
car, engine running, fan not working.
- most of the times, increasing the rpm while driving will cause
temp. to drop, but not allways
- sometimes temperature jumps up or drops down (again, while
driving) from no apparent reason > driving constantly the same
- if I jump-wire the thermo switch located on the thermostat
housing, fan works ok, so relays and fuses shouldnt be an issue
- the plastic reservoir is all wet around the top eventhough I
made sure its tightened correctly. Also, the coolant level in the
reservoir gets way too high after a while...
- thermostat works ok as the lower pipe gets hot in time
- temperature gauge (sensor and sending unit) work - when the
gauge shows its hot, it is hot indeed
- there are some air bubble in the system when running idle, but not a single one when I increase the revs and hold them there...
Now, Im a DIY guy, but still have some questions regarding all I
wrote up:
- could it be that thermo-switch isnt functioning ok and it
sometimes works, but fails too when it really gets hot?
- could it be the reason is failed ECT sensor located under the
distributor housing?
- does the ECT sensor send data to ECU and then ECU adjust the
fueling mixture, meaning a failed one might cause ECU to "create"
a mixture too lean and thus engine would get too hot? This would
also make sense in corelation with my "pinking" (= preignition?)
problems...
- could the reason for both problems be a carbon build up inside
the engine, causing it to run too hot even for a flawless cooling
system to cool down?
- could the cap of the radiator be faulty and "let" the coolant
run into the plastic container before it hits 1.1 bar > the
pressure in the reservoir of course would be too high and it
would leak through the cap?
- could the reason for all that be a radiator not in top condition? Its not leaking but some of the cells have been smashed in the bottom...
- I bled the system twice, but could a bigger air pocket trapped in the system be causing this?
- is the cooling fan on the Civic a two or a single stage one?
I know, many questions but I really dont know what to do anymore. I bought this car to be a low budget transportation device so an idea of visiting a Honda garage scares the **** out of me...Any ideas what else might be causing it?
If everything fails, Im gonna go to a mechanic and test the compression and A:F ratios and see from there on...
Many, many, many many thanx for help guys!
Best,
F
a few weeks back, my Civic 1.5 started overheating out of the
blue. As many before me, I suspected the thermostat first, but it
wasn't it. I checked the coolant level, was ok. Bled the system,
checked the fan...even changed the water pump. Still overheating.
I began loosing my mind as it allready cost me a lot of time and
nerves. I came to a point where I dont see what to do anymore...
Here's how it went (a bit long, but please bear with me)...
The car I bought in February, is a Civic 1998 Aerodeck with the
E-Vtec, 1,5 LS i 16V engine. It was in good general condition and
with a fairly good service history (not official unfortunately).
It was running like a dream until...
Pinking / rattling sound under slight load
..it started sounding like something was loose when it was warmed
up and under moderate load. The sound disapeared with throttle
pressed or decreased a bit. I did next things:
- oil + filter
- fuel filter
- spark plugs
- spark plug wires
- distributor cap
- distributor rotor
- air filter
- timing adjustment
The problem was still there. As Im a person that has to fix
things, I decided to check the:
- valve clearances
Nothing changed. I tried different fuel - no evident difference.
Failing to find out what the problem was, I decided to just keep
driving. It progressivly got worse (more enhanced, louder) but
everything else was ok so it didnt bother me. After one seriously
quick 1 hr drive on the highway, the car started...
Overheating
As soon as I stopped at the traffic lights, gauge started
climbing dangereously close to the red zone. When I drove back
home I had no issues. A few days later it started again. This
time I decided to check whats going on:
- I replaced thermostat 2 times
- topped out coolant
It was still overheating
I decided to give a go with yet another thermostat (ended up with
three fully working ones - gave them a test). Time for..
Big service - water pump
- replaced all the belts
- replaced the tensioners
- replaced the water pump (btw, all the stuff I took off was in
mint working condition)
- took off the radiator, cleaned it, pressure tested it
- checked the pipes where I could for leaking
- adjusted valve clearances and timing again
- replaced all the coolant and bled the system
I was almost sure this would be it - but no. It still overheats.
I did manage (had looots of time) to find out next:
- when starting from cold and running the engine with car parked,
all works ok. Fan kicks in, temp. gauge never climbs over 1st
third of the scale even with my girlfriend in the cabin, pushing
the throttle down for 30 minutes (around 3K rspm).
- when I drive off and the gauge starts climbing up, I park the
car, engine running, fan not working.
- most of the times, increasing the rpm while driving will cause
temp. to drop, but not allways
- sometimes temperature jumps up or drops down (again, while
driving) from no apparent reason > driving constantly the same
- if I jump-wire the thermo switch located on the thermostat
housing, fan works ok, so relays and fuses shouldnt be an issue
- the plastic reservoir is all wet around the top eventhough I
made sure its tightened correctly. Also, the coolant level in the
reservoir gets way too high after a while...
- thermostat works ok as the lower pipe gets hot in time
- temperature gauge (sensor and sending unit) work - when the
gauge shows its hot, it is hot indeed
- there are some air bubble in the system when running idle, but not a single one when I increase the revs and hold them there...
Now, Im a DIY guy, but still have some questions regarding all I
wrote up:
- could it be that thermo-switch isnt functioning ok and it
sometimes works, but fails too when it really gets hot?
- could it be the reason is failed ECT sensor located under the
distributor housing?
- does the ECT sensor send data to ECU and then ECU adjust the
fueling mixture, meaning a failed one might cause ECU to "create"
a mixture too lean and thus engine would get too hot? This would
also make sense in corelation with my "pinking" (= preignition?)
problems...
- could the reason for both problems be a carbon build up inside
the engine, causing it to run too hot even for a flawless cooling
system to cool down?
- could the cap of the radiator be faulty and "let" the coolant
run into the plastic container before it hits 1.1 bar > the
pressure in the reservoir of course would be too high and it
would leak through the cap?
- could the reason for all that be a radiator not in top condition? Its not leaking but some of the cells have been smashed in the bottom...
- I bled the system twice, but could a bigger air pocket trapped in the system be causing this?
- is the cooling fan on the Civic a two or a single stage one?
I know, many questions but I really dont know what to do anymore. I bought this car to be a low budget transportation device so an idea of visiting a Honda garage scares the **** out of me...Any ideas what else might be causing it?
If everything fails, Im gonna go to a mechanic and test the compression and A:F ratios and see from there on...
Many, many, many many thanx for help guys!
Best,
F
Compression test follows..