Mr Martin,

Can you provide some advice toward diagnosis a headgasket vs automatic trans cooler? The radiator cap area has a small amount of oil goo. There doesn't appear any pressure. I cleaned the radiator today, but remember something similar last coolant change~ 2 years ago and 15,000 miles. One of the fittings on the automatic cooler seeps trans fluid externally. 160,000 miles.

Hey J I responded to your advice about disconnecting one of the 2 connections to either the low vac switch or the brake stop switch( on top of the brake valve under the MC). This was regarding diagnosing my brake lite coming on with the combination of low pedal and no oomph on the brakes at all. So disconnecting the brake stop switch/sensor turned the lite off, and you suggested that that would mean my 3 year old MC is faulted. Do you suggest I swap out the booster also? That thing is 6 months new. Thanks by the way. Ragu

Well, I would think it depends on how the compressor failed. If it just wore out, and the find debris would clear the expansion valve and get trapped in the drier, then I'd do as they say. If it shelled out something and sent metal particles into the system, then you're looking at call backs if you don't flush it out. You could hold off on replacing the expansion valve, but it's so inexpensive that a failure chance of 20% or less would pay for it on average. (assuming Mark's quote is reasonably accurate.)

I'm not exactly a refrigeration tech. My main strength in design and maintenance consulting is matrix analysis, ie making sense out of the options, or sorting out the clues to arrive at an accurate diagnosis. I get beat down by experts all the time. Goes with the territory.

Was relying back to your comment on my post about the r12 to 134a. When you say clean up the carnage are you meaning flush out? Didn't want to post any of the suggestions I have gotten from fellow techs who are hvac service techs in my trade and they all say if I were going to stay with r12 just do my compressor change out, along with new filter drier and that is all. Vaccum system and refill with r12. Don't remove the expansion valve or anything. Your thoughts?