M20 Headgasket, Losing Coolant...

I believe I have to replace the head gasket on my 89 525ia @ 123,000mi. I am losing about 1 quart of coolant for every 50mi of highway driving. It does not appear to be leaking anywhere outside the vehicle either. At the same time, There is no smoke whatsoever coming from the exhaust which I have always thought was a tell-tale sign of a blown headgasket. Two questions:
1) Is there a chemical additive that I could try dumping in the radiator which might stop minor head gasket leaks?

2) Assuming that I do have to replace the head gasket, I know I have to order the set which includes all the other gaskets/seals which need to be replaced. I was wondering if there was anything else I should consider while the head was off? I think I will do the timing belt and water pump as well, is it necessary to change the timing belt tensioner?

Thanks,
Geoff

are you currently using the air conditioner? it probably wouldn't consume as much as 1 qt/50, but in my case recently, it was going out of the evaporator drain. also, how is your oil level? it doesn't have to be turning into milkshake for it to be mixing. is it rising as of late?

Quote:

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Originally Posted by ocampg

I believe I have to replace the head gasket on my 89 525ia @ 123,000mi. I am losing about 1 quart of coolant for every 50mi of highway driving. It does not appear to be leaking anywhere outside the vehicle either. At the same time, There is no smoke whatsoever coming from the exhaust which I have always thought was a tell-tale sign of a blown headgasket. Two questions:
1) Is there a chemical additive that I could try dumping in the radiator which might stop minor head gasket leaks?

2) Assuming that I do have to replace the head gasket, I know I have to order the set which includes all the other gaskets/seals which need to be replaced. I was wondering if there was anything else I should consider while the head was off? I think I will do the timing belt and water pump as well, is it necessary to change the timing belt tensioner?

Thanks,
Geoff

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Quote:

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Originally Posted by ryan roopnarine

are you currently using the air conditioner? it probably wouldn't consume as much as 1 qt/50, but in my case recently, it was going out of the evaporator drain. also, how is your oil level? it doesn't have to be turning into milkshake for it to be mixing. is it rising as of late?

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I have not been using the A/C consistently, it does not seem to have any effect on the amount of coolant lost. I checked the oil, still level, still clean. I am thinking it might not be leaking in that direction, rather it may be leaking into the exhaust passages? Even still, wouldn't I see some smoke coming from the exhaust?

a little coolent won't steam up the exhaust, if you are pumping it into the cylinder/s the cooling system will be getting pressureized by the combustion gasses

anybody ever try this stuff?

http://www.rxauto.net/