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Head gasket in a bottle

Anyone have long term experience with the newer cooling system additives that are supposed to fix leaking head gaskets? Our 1996 Volvo 850 seems to have put about a pint of coolant into the oil sump during the past month/2000 miles. The car has about 140,000 miles on it and I would like to drive it another couple of years and 25,000 miles. I’d always understood that coolant in the oil was death to engine bearings and working surfaces. Is it extremely ill-advisable to try a gasket-repair-in-bottle product, as extensive engine damage could be visited on an otherwise decent car?

Have it double checked and likely have the head gasket replaced. Don’t make things worse with false hope supplied in a bottle.

It’s highly doubtful a bottle will fix your problem. Truthfully, it may do more harm than good. Your car is the right age and mileage to start to see such problems. And only a proper repair will last the 2 years and 25,000 miles your looking for. You are correct that coolant in the oil will damage the engine.

Those bottle treatments work by running polymers in a solution in coolant. Theoretically, the polymers harden when the coolant flashes to steam, which happens at a leak point. The polymers then ‘stitch’ a patch until the leak is sealed. However, those polymers are also dangerous to small passageways in the engine and radiator. Until the leak is sealed, flash points can occur in these small passageways, and the polymers will block them up. Most of these treatments require that you remove and flush the cooling system soon after the leak stops for this very reason. Left it too long, and they will block up all kinds of needed passages.

Also, a gasket leaks because it is losing it’s integrity, meaning it is breaking down. Even if the bottle treatment works, the gasket will leak in a different location sooner than later. You really want to fix this right if you intend to keep the car.

There’s only one way to repair a leaking head gasket; replace it. Miracle-in-a-bottle cures should be left in the bottle. Have a new head gasket installed and drive the car a few more years.