Hi everybody,

I just posted the message below to the general RWD forum by mistake, so I'll repost it here, with a postscript.
I have a '96 965, and back in August I saw the coolant warning light come on as I started up the car. It shut off after about 30 seconds. I was near a parts place, got some prestone to stave off what might be a really negative event, and put in enough coolant to bring it back up to the max level. Then I had my mechanic do a pressure test on the system and he found no problem. The car has since been driven about 2500 miles --including a 1500 mile road trip-- and this morning the light came on again; I repeated the top-off.
Here's the question --and forgive me for its' basic level and probable redundancy-- where is the coolant likely to be going?
Here's some other perhaps relevant info, perhaps it's just another problem. Seems I have a bit of an oil leak at the top rear of the engine block and, 2, the car seems to be producing less power than previously.
Thanks.

Since that post, I searched the archives differently, and got somer esults this time. It seems like I may have a headgasket issue. I'll look for oil in the coolant in the daylight tomorrow. Anything else I should check/have checked? Thanks again.

If your using prestone you may have a electrolis problem and it may have eaten
the heater core. Very common problem from what they tell me. Am replacing
mine now. Try bypassing the heater and see if it quits leaking.

I bet it is the upper rad neck. The are prone to cracking. Ergo, when the pressure builds, coolant as vapour escapes. But there is no coolant on the ground as when the engine cools, pressure decreases, and nothing leaks through the crack. Mine did exactly what yours is doing. Until one day there was a loud POP and the sweet smell of coolant drifted into the cabin. It was the upper rad neck. It had blown completely off. Thankfully, there was no engine damage. Rad replaced 4 years ago, no problems since.

A volvo tech friend says that these cars leak quite a bit of coolant through the resevoir cap - even the green one. Every 500 miles or so I have to add a bit to bring it up to full. I would replace the external heater valve, hoses (radiator,block to heater, oil cooler - it uses coolant) soon before you have a catastrophic leak. The heater control valve is made of plastic and metal and the plastic degrades and leaks over time.
--
92 244 lowered, Bilsteins, IPD sways, Unitek cam/header, TSW Revo 18x8's - 94 965 Niiice MONEY PIT! - 76 Datsun 280Z lowered, modified head, cam, headers, intake

Well there are a few basic scenarios I could imagine so lets start with the least expensive. My 960 does the exact same thing at about the same interval you describe. Every couple of thousand miles my low coolant light comes on. I just top it off and don't really worry about it. I believe mine is evaporating through the coolant reservoir cap. I remember reading somewhere that Volvo updated their reservoir caps for this exact issue. I think the newest cap is green. I have a gray cap and there also existst an older black cap. I could upgrade, but a bottle of coolant every couple of years is cheaper.
The loss of power can be a number of diffent things like dirty air filter, stuck hot air flap, worn out spark plugs. If your engine was digesting coolant I would imagine the level going down much faster. To be safe, you could have a mechanic perform a compression check. But I doubt the coolant is related to the loss of power or oil leak.
Good luck.
Justin

the coolant is either leaking or being burned. check the filler cap gasket and oil dip stick for a carmel coloring suggesting condensation from coolant and oil mixing. in addition to the water pump, check all hoses and clamps for leaks. it's either leaking or being burned. good luck.

pull the timing cover off and look at the bottom of the water pump. it may not be wet, but might have some residue from leaking and drying. it can also collect in the bottom of the back timing cover. good luck, chuck.

I don't know if you're able to detect this but a coolant leak into the combustion chamber will emit white smoke out the tailpipe. FWIW. You probably won't be able to tell if it takes that long to reduce the level to where the light comes on. Sounds like a head gasket to me . I'd be doing a compression check next, or a leak down test if you have access to one for greater accuracy. Good Luck.