Coolant Leak but No Puddle

My 1996 850R's coolant level goes down slowly and steadily but there is
never a puddle in the garage underneath the car. I have to add probably a
quart of coolant every couple of thousand miles.

Is this something I should be concerned about? What could be happening if
there's no coolant collecting underneath the car when it's parked? Maybe
it's leaking too slowly for it to collect? Does 50/50 anti-freeze/water mix
evaporate such that if it leaks slowly enough onto the garage floor it
evaporates before I see it? Or does it only leak when the car is running,
moving, and coolant is flowing thru the system and that is why I never see
any coolant collecting?

Thanks.

 

It's likely leaking only when under pressure. Get an old coolant cap, drill
a hole and put a tire valve in it. Pump it up with a hand pump to pressurize
the cooling system with the engine cold and see where it drips.

 

Check your Transmission. Is it over full?
The coolant can be leaking out through the trans cooler in the radiator.

50/50 should leave residue

Al


Had
79 245 D,
81 240 D,
86 240 320,000mi and running fine when traded
94 944 Green 257,503 mi CRUNCH Parted out
Have
94 944 White 149,000 The New one
94 944 Maroon 135,000 mi

 

That's an interesting idea but the system is still pressurized after I stop
the engine for at least a few minutes, right?

 

On the 200 series motors, there is a curved hose that allows flex between
the motor and the heater entrance through the firewall. This hose likes to
crack on the underside, spray only onto the hot block, evaporate leaving no
trace and a constant need to refill coolant. The first time it was a bear
to find, the second took seconds since I knew where to look.

Not having an 850 around to look at, is there a similar hose some where at
the back which create a similar situation. Look for a whitish residue on
the block and a wet feel on the underside of the hose. Do this on a cool
motor.

Look at the tranny level,( although after a while adding more than a gallon
of fluid would push the tranny fluid to a level that i probalby would dump
it out the breather and you would be concerend about a tranny leak)

Also look at the exhaust pipe. Any whitish vapor "after" complete warm up?
Look at other completly warmed up autos idling exhaust and compare it to
yours. If yours is visible or denser than theirs, you may have a head
gasket problem. A compression check would comfirm a head gasket problem
with the exhaust visibilty test just something that points to a problem.

Duane

 

<snipped>
:
: That's an interesting idea but the system is still pressurized after I stop
: the engine for at least a few minutes, right?
:
Assuming that your pressure cap is OK and don't forget you will be much less
likely to see hot coolant leaking as it evaporates quite quickly.

Cheers, Peter.

 

No, probably you have a head gasket going bad. The coolant is being pulled
into the combustion chambers and vaporized. If there is no leak in the car,
from the heater core, then it has to be going somewhere. How is the engine
performance? You are losing compression with this leak, so it should be a
bit down from normal. Either that or the coolant is mixing with the oil. How
is that level? Is it too high or foamy?

 

I had the same thing with my 960. It was crossflowing to the tranny and
fried it (shorted out the electronics).

 

check tranny fluid for foam as well

 

Just changed oil this past weekend. Totally clean.

I will check tranny fluid before I drive it the next time.

Thanks.

 

I had an interesting issue like this on an old 740 I had. The water
pump would weep only while warming up/cooling down. When cold it
wouldn't leak a drop (no pressure?) and when hot it was tight
(expanding seal?) but while the car was cooling down one day I saw a
couple of drips under it, sure enough the pump shaft was slowly
leaking. Checked again hot and cold, nothing.
Good luck
Dave Shannon
daveshan@DIE_SPAMMERScox.net (Spring Valley CA)
1984 245DL 200K
1984 245Ti 190K
1988 240DL 190K
1992 745 Ti 170K
'01 Jeep Sahara 15K
www.volvo2.homestead.com

 

I would think two things....
firstly you should have a green expansion tank cap..the older ones
could lose the seal after a few years and a newer one was issued.
secondly the heater matrix could have a small leak....does the car
smell of antifreeze first thing?

 

I would get an oil analysis done ASAP on the motor oil to check for oil
getting into the engine. $20 from http://www.blackstone-labs.com is well
worth it just to make sure.

John

 

Well, I have had a leak ever so slightly through the heatercore and it has a
drip tube going through the body right over the exhaust, this is where I
would suggest you might consider, especially if the 850 is same set up as my
240 DL?? I am considering a quick fix bars leak cube! I don't need the
aggravation of taking apart dash, heaterbox, took 12 hours of back breaking
close quarters poor access to nearly every screw even with the seats out,
steering wheel off too! And I did two of them (blower motors I mean) Could
kick myself in the ass for not doing heater cores too!, I really don't
believe that BARS leak, or any other additive crap is good for any engine or
car other than frequent oil changes, grease jobs, lubricating caliper
sliders, wheel aligning, waxing, polishing cleaning. I work in a local CTC
store in autoparts department and do a lot of Service writing/advising for
the Canadian Tire store as well. I get guys coming up to every shift asking
what is the best fuel injection additive, or oil additive, hell I am
supposed to bullshit my way through and tell some poor sap how is going to
make his jalopy with 300,000 klms drive like a new car? What's with that? I
take the approach every and some get offended that I will not stoop low
enough as to recommend what I truly don't believe in, tell LIES about
additives!/! give me a break?

Well enough said!


Dan in Toronto, Canada

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