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howardc64
03-29-2010, 10:17 PM
2001 V70XC 93k miles.

Have been adding some coolant to the reservoir a couple of times (adding about 3/4 inch on the reservoir level) the last couple of months because the level got lower than than the level sensor during cold startup and getting the urgent shutoff engine message from the low level sensor reading.

Now where is the coolant going... thats an interesting mystery.

During this time period, my dash temperature meter is not reading the same temperature when the car is warmed up. These cars are suppose to have the temp read with the needle at just about middle of the gauge. However, mine has been reading 1/2 tick to 1 tick to the left (cooler) and varies even after car is warmed up. It used to be almost dead centered (just to the left) and never ever moved once the car was warmed up.

Coolant and thermostat changed at 60k miles.

Thinking through my high school chemistry, I remember the formula

PV=nRT

So if the coolant system has a leak and the pressure drops, the temperature will read lower from this formula (until there isn't enough water to cool the engine anyways) Seems like this observation would suggest I have a pressure leak somewhere in the coolant system. The temperature movement would suggest a minor leak with varying amount of pressure leak.

I looked everywhere on the coolant flow connections in the follow diagram and can't find any obvious signs of leaks.

http://www.eeuroparts.com/Main/DiagramPopUp.html?http://data.eeuroparts.com/Images/diagrams/lg_7a3f6f3e-f1c4-41f0-91c9-4cca09779201.gif

The only place I could see is a film of oily wetness on the radiator housing just above the intercooler's charged air outlet. I looked at the obvious coolant reservoir overflow hose connection on top of the radiator (where hose 3 connects to 1 in the diagram) and saw nothing that indicated a leak (it is hard to see without disassembly tho)

Engine oil has no sign of brown foam and runs fine
Transmission shifts fine, ATF looks nice and red
Interior has no coolant smell, carpet not wet, windshield not fogged up
no coolant on the garage floor

These would seem to rule out headgasket, transmission cooler leak, or heater core+connections.

Anything else I can do before a coolant system pressure test to confirm a leak exist?

Anyone know if these radiator have common leak problems?

RockitShip
03-29-2010, 10:56 PM
Howard, the next step is indeed having someone (garage) running a dye through the system and double-check the entire system (and radiator) just to be sure. It sounds like you've pinpointed the problem to the radiator, but I understand your need to absolutely correct when it comes to a job like this.

kamiar
03-30-2010, 11:49 AM
Howard,

God forbid, if it is head gasket, it might also leak to exhaust or intake, right?

wgriswold
03-30-2010, 11:50 AM
PV=nRT is an equation that is good only for gases and will not apply to the liquid in your cooling system.

RockitShip
03-30-2010, 06:57 PM
Howard,

God forbid, if it is head gasket, it might also leak to exhaust or intake, right?

If it's leaking into the engine, he could give the tailpipe a whiff for the tell-tale sweetness of coolant, or look at the oil for the goopy white-ish brown oil coolant mix (also look at coolant tank).

Chilled Man
03-30-2010, 07:14 PM
If it's leaking into the engine, he could give the tailpipe a whiff for the tell-tale sweetness of coolant, or look at the oil for the goopy white-ish brown oil coolant mix (also look at coolant tank).

would also get misfires and such if there was such a leak

I would put my pennies on the Radiator

RockitShip
03-30-2010, 07:19 PM
Agreed, radiator.

howardc64
03-30-2010, 09:40 PM
Thanks guys.

I'll drop some dye into the coolant this weekend and see if I can find this minor leak.

And indeed, PV=nRT doesn't work for liquids... its been too long :) I however, do get 1/2-1 tick lower reading on the temp gauge for some reason.