Here is an odd situation with my 97 Miata. I have noticed that over the past few years an oil mark has been creeping up the speedo! Not thick or dripping but oil for sure. Anyone have an idea what could cause something like this?

 

That's a new one.

I have no idea.

 

Are you sure it's an oil mark, or are the faces starting to fall apart on the back? It can sort of give that same look. It's not difficult to check, you want to remove the plastic steering column cover, then pull the hood off the cluster by pulling it towards the steering wheel. Just get something to pry (without scratching), then pull it off.

After that, there are just a few screws holding the whole gauge cluster in, and you can take a small jeweler's screwdriver to remove the faces if you need.

 

Thanks Redcap for your theory. This really looks like a thin sheen of oil on the face from the 9 o'clock position down and around to the 3 o'clock position. Is it feasible that the speedo cable could be the cause of this leakage? I have never had to dash apart and am very reluctant to do so without good cause. All guages work just fine with no noise's.

 

That's certainly a possibility. I presumed they were sealed units, but they obviously could go bad... Here's a better step by step. If you don't want to go as far as removing gauges, you could just pull the hood and entire gauge unit, possible inspect the cable itself. That's not nearly as difficult.

revlimiter.net - NA Miata Gauge Face Install

 

If you are actually getting oil from the trans up there you would also be seeing lots of leakage from the front and rear seals of the transmission. That's why I think it is unlikely the trans would be the source.

 

Re-visiting this topic! The "oil" sheen has grown considerably on the black face of speedo! Not a wet sheen but a thin film of some sort. No signs of dripping anywhere else! Do I need to worry?

 

Hey, I think you should just try to remove the gauge cluster. It's seriously easy. Just buffer any prying tools with a towel or old shirt to prevent marring the plastic. 100s of ricers that changed to indiglo gauges in the 90s can't be wrong.

 

I have heard that getting the cluster cowling away from the dash can result in permanent damage to the cowling, ie. broken attachment tabs making it almost impossible to re-install it! If that isn't true then perhaps I will attempt that. I purchased the red plastic pry tools recently so that will help I'm sure. Once removed, how difficult is it to remove the clear plastic covering the guage face?

 

Any chance you clean the dash with Armor All, an interior detailer, windex or something similar that could have leaked down into the cluster?


While the cluster is dust tight, I doubt it's liquid tight.