Acura RL smoking only at high speed

I have a 2000 Acura RL, 160,000 miles. Recently, on two occassions, the car has begun belching white smoke from somewhere between the brake fluid refill tank and the engine block. This only happens when I drive over about 85 miles per hour. Otherwise the car runs perfectly, as it always has.

I’ve had the car inspected and it doesn’t appear to be losing fluid. I had a compression test done and my mechanic says the results rule out a head gasket problem. I assume if it were the water pump or a hose, it would be leaking all the time and not just at high speeds (timing belt and pump were done at about 50k miles ago).

I love this car, but just replaced it and now want to sell it. I want to make sure I’m not giving anyone a big problem - I’m guessing most people aren’t going to drive that fast in an older car, and at normal speeds, this car drives really nicely. Any ideas on what this may be?

At 85mph the engine must be around 3500 rpm. There isn’t any smoke if the car is in park and you rev and hold the engine at about 3500-4000 rpm? Did the smoke have a smell or could it have been steam? I hope you don’t drive above 85mph that often…

I can’t say I’ve tried to rev it sitting still. Might give that a shot. The smoke did not have much of a smell and I assume it was steam, yes.

So did you notice the steam/smoke after you had stopped or while going 85mph? It would have to be a ton of steam to be visible at that speed.

In both cases, about 2 weeks apart, I was in an unfamiliar area and had to accelerate to pass traffic and get off at an exit ramp. So I was slowing, and coming to a stop at the end of the ramp, and that’s what made the steam visible. In both cases I popped the hood, let things cool down, and the car was fine. After the first time I intended to take it to work and then right to the garage, but the problem didn’t come back (normal speed) so I took it to the shop before a road trip to have it checked for leaks, etc – nothing. So I went on the trip, same scenario, same steam, got home and have been driving for weeks with zero problem (normal speeds).

The car otherwise runs great, fluids/checks/etc showed nothing. As I said, it’s now time to sell or just take it to Carmax, and I’d rather sell but don’t want to pass on any major problems so I’d like to figure this out and either get it fixed or reflect the cost of fixing in the price.

Is this car an automatic? Is it possible that under the stress of going that fast it is spewing transmission fluid from somewhere? It wouldn’t take much to make a lot of smoke. (of course you would smell that—usually smells kind of like when you’re passing a Burger King)