Coolant light on - can't see problem, random connector not connected

Hi

Well the 960 has been in the shop for a week getting some much needed
replacements for shocks and brakes, it's had its radiator done this year,
thermostat the previous year and the A/C system fully checked and a pipe
replaced.... But now we're getting the coolant light coming on - only at
startup and very rarely, we've topped up the coolant, but we can't see any
leaks.... I drove it for an hour to dry off the car (my dad washed it, so we
couldn't tell if the water at the bottom of the rad was a leak or water from
the car wash) then I let it sit for an hour and the car was dry, no
leaks.... Coolant level seems to be where we topped it off to. When I was
looking under the car tho, I noticed a cable and connector dangling
(protected by the plastic plate under the radiator), it was running parallel
to the wires which feed the horns.... The connector was near the miniature
radiator for I guess the A/C system as metal pipes were feeding into it, I
couldn't find a plug to stick the connector into tho. Does any one know what
that connector is for??


If my coolant level drops I know it could be a failed head gasket (if the
plumbing isn't leaking) - but I don't notice any white smoke even under hard
acceleration, temperature stays level at all times I haven't started
monitoring coolant levels but i'll be checking all this week and for a while
to come.

Another thing i've noticed is the rad fan isn't coming on, now it could be
because it is still 0°-3°C outside today, so I don't know if it would - I
tried turning the A/C on, but I don't think the ECC kicks on the A/C
compressor when it's that cold outside.

 

rob...check grounds...i think the coolant light comes on when the
curcut is grounded...is the plug "in" under the coolant bottle??

 

No, the plug is on the other side of the car (drivers side) the coolant is
on the passenger side hidden under the black housing of the ABS system
cover... This mystery plug travells with the wires for the horn and
terminates near the radiator A/C mini-rad (condensor? evap?)

I'll clean the electrical connections for the coolant sensor if the problem
comes back.

 

If the "mini rad" is underneath the radiator it is for cooling the engine
oil. This arrangement is used on 940 diesels as well. Perhaps it is for the
engine oil temperature or is one of the sensors which use air-con pressure
to switch on the cooling fan or even the thermal switch wiring for the fan.
There are two relays and three sensors involved in switching the fan.

Cheers, Peter.

 

Hmm could be for engine oil I suppose (i'm an electrical guy, not
mechanical/fluids type person).... Wasn't that warm when I touched it but I
let it cool off for a while... Is there not a cooler for the transmission
oil as well? (or is that built into the main radiator?).... How many rads
does this darn car have? I don't want to see how many a turbo model would
have (main rad, this mini rad, and an intercooler??)

Is there a manual way to switch on the cooling fan? I can't get it to come
on (and I drove the car HARD on the highway to try to get the engine running
hot enough... perhaps it had cooled down sufficiently when I stopped to
check it tho)

 

I think the car has three rads:
Engine coolant
Transmisson fluid
A/C condensor

I don't think it has a rad for the engine oil.

/Erik Lidén

 

Erik, the coolant and transmission fluid coolers are in the same radiator
unit. In cars with turbo, intercooler and air-con the three rads are
coolant/transmission cooler, Intercooler and air-con condenser. On Turbo
diesels with intercooler and air-con there are four rads with manual gearbox
and four with automatic gearbox. Without air-con there are three rads with
diesels. There is an additional small cooler which can be included in the
transmission cooler piping run on automatic cars.

Cheers, Peter.

 

The sensor that turns the low coolant light on is in the expansion tank
(where you top up and check coolant level). They often go bad in this
fashion. If the light disturbs you, pull off the wire on the sensor
until it's replaced. (Or for really cheap people, just leave it that
way.)

The miniature radiator is probably the engine oil cooler. Is it the
full width of the rad, and 2-3" high with one hose going into each end?

The rad fan only comes on when necessary to cool the rad and/or
condenser. Once you're going more than about 50 km/hr, there's very
little chance the rad fan will need to come on. The engine computer
controls the fan while monitoring coolant temperature, and with the
grill removed you will see a cluster of 3 switches in the bottom corner
of the condenser. These are set to 3 different pressures - the lowest
pressure turns on the fan at low speed, the middle pressure, high speed,
and the high pressure one turns off the compressor so the A/C system
doesn't blow up or vent the refrigerant. When the temperature is below
about 5 C, the refrigerant pressure drops such that the low pressure
switch on the receiver-drier stops the A/C from coming on.

If you want to see if the rad fan will come on, then let the car idle
for a while after it's warmed up. A piece of cardboard to inhibit flow
through the rad during this test will speed things up.

The dangling wire may be for an outside temperature sensor, if the
terminals are round. They often get removed during parking curb
encounters.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Excellent, THANK YOU for your post, you answered all I needed to know.

Yes that connector has round terminals, I was thinking it may be for a temp
sensor.... the 960's of 1993 didn't have a dashboard option for an outside
temp gauge as far as I know, but could this be the pre-wiring for one? - or
did some models have this? (We don't have the 'snowflake' light of the 850's
mentioned in our manual nor visible on dash, nor is there a place for a
thermometer).... Or is this sensor for the engine?

It was colder then 5C out, no wonder my A/C couldn't kick on, I was right
telling myself it was a smart system, and wouldn't kick on if it was cold
enough outside.

I let the car idle for 5-10 mins and it didn't kick in... I can't let a car
idle for very long - I don't think it's a good idea for the engine (I don't
believe oil pressure could possibly be being built up properly with only
idle speed), not to mention idling causing environmental problems.

I did check out those 3 sensors, that's what I originally thought was
leaking (turns out, not) - good to know what they do, now.

Cooler is exactly as you describe - nice to know this car has so much
cooling capacity! No wonder it never gave us trouble at 35C pulling a
trailer up the Cabot trail.

I topped up the expansion tank with a 50/50 mix of Volvo antifreeze and
distilled water, as per the recommendations on the bottle... I think with
the huge variations in temperature we have experienced in Southern Ontario
recently it may have caused some issues with the aging electrics.... After I
topped it off there have been no problems, and the level is where it was at
when I filled it up.

Thank you to all thos who responded, I think our ole' Volvo is going to be
just fine - I took her to work today (with her new suspension and brakes)
and she handled the winding roads as good as my much smaller Golf...
possibly better, even with it having its winter tires on!

 

yep Rob...the 940's are pre wired for the o/s air temp guage...i
poped one into my 940 for around $50...nice lieele extra feature...it
has the orange snowflake around freezing temps...just plug
and play.. ;-)

 

So I buy a sensor, then buy a little light cluster to go into one of the
"idiot light" blanking spots in the dash?.... How do you install that in
there? And where can I get it, the dealer?

Don't think I will get it tho, it would be on all winter, and i'd be more
interested to know exact temp, then just a snowflake - or is a temp gauge an
option?

 

There was a temp gauge option that fit in the lower left corner of the
instrument cluster (just to the left of the warning light row) for 88-
760s, 91- 740s and all 900s. It consisted of a little lcd display,
wiring harness and the sensor. I guess some of the later cars didn't
need the harness.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

rob...it will show the current o/s air temp (while the ign is on) and
when it dropps below freezing...the small, orange snowflake will
"appear"...let me look in my garage...i have either the small readout
window (that pops in the dash), or the other end...small sensor that
plugs into the wiring harness @ the front bumber...then pops into ths
small round hole "up front" in the plastic air damm, or mud barrier....

 

I Don't know about the US, but in Sweden the 960 does not exists as either
Diesel or Turbo.

/Erik Lidén

 

Yes that connector has round terminals, I was thinking it may be for a
temp

All of the 960's has outside temp guage here in sweden...
Maybe Volvo didn't think it was necessary for US to have those.

/Erik Lidén

 

I'm in Canada, and car had the cold weather package as standard (as all
Volvo's did, at least for a while up here).... Maybe it was a dealer
installed option.

 

Yes I now see where it would go.... something to look into for a project,
maybe...

 

it was part of my cold weather package...ie: heated seats, heated
mirrors, o/s air temp guage...
here in denver colorado.....i just checked my garage...i have an un
opened "sending unit"..the
part that plugs into the open wiring harness...and pops into the front
undercarrage...this has the sensor in it...
i will ship it to you for, say $15 freight included...if you want to
pay pal me $$...@

then, you would just need the other end, or part that pops into the
dash...there is already a small plate that
comes out (lower left of insturement cluster...behind the glass)...and
the read out unit pops in...it is lit for
night use also...you would want to order the part from >>

john sharisky @ boston volvo village


richard
colorado

 

Hmm, temping offer, but I think I'll have to take a pass.

Thank's tho!

Rob.

 

that's cool Rob...if anyone else want's it...it is
"in the box" and ready to go...