Originally Posted by dezine2000us
Several months ago I noticed the coolant level in my '99 LT had dropped below the minimum mark. I added a little BMW nitrate free coolant. Now it's low again and I'm out of the BMW antifreeze. Can I add any other brand? The service manual says to use nitrate free. Must it be nitrate free? I've had trouble finding any that say "nitrate free."
Is it normal to find the level dropped like this within just 3,000 miles? What could be happening here? It hasn't overheated. It does often run way up on the temp gauge but the fans kick in and seem to do their job OK.
Thanks for any info/advise.
White Hall, Maryland
First, yes it does have to be what BMW specifies to avoid forming particulates in the coolant and, as I understand it, to maintain a desired film on the internal coolant passage surfaces (the film is one of the reasons is GM's so particular about not using a non-Dextron coolant in its engines).
The good news is that there are a lot more Honda dealers around than BMW, and you can use Honda's coolant if you can't find what you need at the local auto parts store.
Coolant use is not only unusual, it's virtually unheard of here. Four possibilities come to mind; look for dried coolant around each of:
1. Radiator cap -- worn out gasket
2. Overflow hose (from radiator neck to coolant bottle) -- age cracks
3. Coolant bottle -- cracked
4. Coolant pump-oil pump seal leak (worst case) -- look for coolant in oil, or oil in coolant.
The coolant pump and oil pump lie back-to-back in a common housing at the bottom front of the engine. There is a seal between the pumps. It was common on the early K-bikes for the seal to get chewed up and leak (either from solids in the coolant or corrosion of the pump shaft seal surface). BMW seems to have fixed this weakness, as current K's rarely ever have this seal fail -- but it remains a possibility which cannot be ignored, particularly on older bikes.