My daughter's C70 has been slowly loosing coolant. The coolant tank has some staining or something that looks wrong, and I suspect some problem of somekind before we bought the car.

After about 8 months I needed to add 1/4 to 1/3 gallon of distilled water (no Volvo blue coolant on hand). I thought that there was a very small crack in the top of the coolant tank, but was not sure, it was so very tiny. Ask for details if you want.

However, after topping off again, only a few ounces, it has not lost any coolant, and there seem to be no leaks, and the level of coolant is staying where it should after about 24 miles testing.

I do have a new coolant tank (genuine Volvo), and was looking for where the coolant or radiator drain petcock was, and it looked like there was a bit of water down in the frame, just below the lower radiator hose on the passenger side. However, the coolant level in the tank was exactly where it should have been. It had rained the night before, very heavily, and I can't get my hand down there to feel the liquid and see if it is coolant or rain.

Questions: Where is the coolant drain on the C70? What do you recommend I do? Continue watching carefully, replace the tank and inspect the hoses? Any other ideas?
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1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco

Are the Volvo hose clamps reuseable? Those are the original factory type, spring steel with what appears to be a way to clamp them open.

I am asking because I don't have replacements, and the usual worm-drive type at autoparts stores are not double-layer, like the older Volvo ones, to protect the hose from the sharp edges of the clamp, and the sharp edges of the slots for the screw threads.

Thanks,
Scott
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1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco

If you mean the small clamps with 3 barbs, yes they can be reused. If you are referring to the press fit clamp that looks like the worm drive, no they are not reusable.
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Keeping it running is better than buying new

In any case, I replaced the tank over the weekend because there was no doubt that the top of it was cracking, and had pin-hole leaks. There is a reddish-yellow area that you can see in the attached photo of the tank, and that is where the cracking is, and where there were very tiny pin-hole leaks.

You can also see the type of clamps that were on, and replaced on, the hoses in the photo. There have been absolutely no leaks from the hoses, or anywhere since the tank was replaced on Saturday, so I guess the clamps were reusable. PS: you can't see the big hose under the rear of the tank, but it has a bigger version of the same clamps you can see in the photo.


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1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco

Nothing wrong with reusing those clamps. Much. better than the hardware store type!

I am glad you found the source of the problem and fixed it.

Still sorry about Draco...
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Keeping it running is better than buying new

Seems that I have forgotten how to upload images to this forum, so pasting the link in the above post is the best I can do for now.
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1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco

You need to insert the entire HTML into your post. Like this:


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Keeping it running is better than buying new

Hi Scott!

What Klaus said and yes, the air guide must be removed to really get a good look at and access the radiator drain; 7-8 Torx screws (my reference is a pre-facelift P1 S40, so YMMV).

The other possibility to investigate is leaking at the heater core. As you may know, the hot engine coolant circulates through the heater core at all times, regardless of the climate control setting. There are two o-rings at the connection between the heater core and the fitting at the firewall. Eventually after so many heat cycles the rubber rings will give up and begin to leak. If you can get your head down in there to see them, it should be plain to see if they have been slowly leaking fluid.

Please whatever you do don't open that expansion tank unless the car is good and cool. While back a coworker burned himself rather badly when opening the system on his Chevy Cruze (bad head gasket).

-Will
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XC60 / Odyssey

You can only look for pressure leaks when the coolant is HOT and the engine turned off. First clean the plastic tank, remove the cap and clean that also. Then run the engine and get the coolant hot enough to turn the engine fan on (AC off). Get a clean white paper towel and go over the tank, the small coolant hose, the passenger side of the radiator (that's where the radiator breaks first).

Last time I looked, the drain is under the radiator, passenger side. It is black plastic. The air guide must be removed.

The hard top C70's are nice! Waiting for the pic of Draco.
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Keeping it running is better than buying new