1987 Toyota Corolla FX16GTS - Revolution Sensor Issue?

STORMCROW

MEMBER
1987 TOYOTA COROLLA
4 CYL
2WD
MANUAL
135,000 MILES

Looking for an assist on an issue that arose recently.

On my way home from a trip. The AC was working perfect, then I noticed rather suddenly, no more cold air out the vents. The AC light was blinking.

When the AC button is pushed in at idle, the engine revs to over 2G, then it rapidly flucuates between 1500 and 2000 RPM. After this, the AC button light starts to blink. All this occurs in less than 10 seconds. While at speed, the light will just start blinking soon after pushing it.

I verified that the compressor is not engaging.

Others with the blinking light issue, had been directed to the revolution sensor. Though I hadn't heard mention of this odd idle speed issue in their cases.

I have located this sensor beneath the compressor. If this is the culprit, can I just remove the two bolts, remove it and Ohm it out? Or is this model years sensor under pressure?

Any help would really be appreciated.

4 Replies

STORMCROW

MEMBER
3 POSTS

Yesterday morning, I had cleaned up the underside of the compressor. Now I see that fresh oil accumulates. It drips right off where the sensor bolts in.

I had thought this leakage was PS fluid. Now, not so sure. As it is light weight and has no real smell to it.

Would this mean my compressor has blown a seal?

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Sunday, August 2nd, 2009 AT 3:47 PM

MMPRINCE4000

MECHANIC
8,549 POSTS

When AC is commanded the ECM will add fuel and air to increase RPM because of compressor load.

If no load then RPM will increase.

If you see a light oil under compressor, then you are right, the compressor has most likely blown a seal.

While you can still get R12, it is VERY expensive, so you will most likely be better of converting to R134a.

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Monday, August 3rd, 2009 AT 9:39 AM

STORMCROW

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3 POSTS

Thanks!

It appears the oill may be leaking out from where the sensor mounts. Wondering now if the whole issue is just that seal? Though, I'm not sure if that sensor is under pressure.

I am now trying to decide if I will evacuate the system and just replace the compressor and convert the system myself. Or, take it to a pro. I am afraid the total shop repair will exceed the cars value.

Thinking I may keep cost down doing what I can, myself.

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Monday, August 3rd, 2009 AT 5:43 PM

MMPRINCE4000

MECHANIC
8,549 POSTS

You can buy a conversion kit at most autoparts stores for $40.

Use a sealer with it and then if it leaks out again you will have to add a dye to pinpoint the leak.

If you see oil at the compressor, then that is most likely your problem. Depending on model a reman'd compressor can run $300 or so.

Really a hard call, only other choice is to buy a used compressor at a junk yard, but you never know what you are getting.

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Tuesday, August 4th, 2009 AT 12:06 PM