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Discussion Starter · #1 · (Edited)
19840
The oil pressure switch on the Ecotec engines has been a source of oil leaks over the whole 4 cylinder engine range as far as my experience with them has been. Many times leaking oil right onto the starter. Ending up ruining a perfectly good starter. Or at least significantly shortening their life.

As I had been replacing wire loom on the engine wiring harness, I noticed the oil pressure switch had started to seep oil. Not really leaving a lot of oil, but it was getting ready to start leaking onto the starter. I can afford a $15 pressure switch, but don’t really want to be replacing the starter any time soon if I don’t have to. Although it looks original, at 136,400 miles.

I have taken some pictures and have the part numbers of the part and socket to use.

I have used an AC Delco D1849A oil pressure switch, it was about $15. Depending where you purchase it, it should not exceed about $25. But I recommend using the AC Delco since fit and function are going to be exact. Also they install quite a bit easier than aftermarket versions due to the shape of the threaded portion as well as the unique crush washer that will not fall off the threaded end! The job with the AC Delco part will take less time since it is easier to find the hole compared to the aftermarket one. Look at the picture below and you’ll see what I’m talking about. I assume the part will also last another 10-15 years as the original is the exact same part.

I like to use a regular length ratchet to break the part free. Then use the small length ratchet to spin it the rest of the way off due to there not being a lot of space. I use a combination of 3/8 extensions. A 3” and a 1.5” to get the ratchet into just the right position. There’s just not a lot of space to swing the ratchet otherwise. Trying to use other methods with a swivel is more difficult, especially when initially breaking the part lose as a swivel will reduce the amount of torque you’re able to apply to breaking the part free.

The oil pressure switch/sensor socket to look for is usually available at any auto parts store. Generally it will be priced between $15-$20, for instance $14.99 at Advance Auto Parts. The one I have was purchased at O’reilly Auto Parts, I’ve had it for many years. It’s a Performance Tool W80590. OTC also makes one, part number 25254.

Also after removing the the connector, I like to take the green seal off and clean it. Pay attention to which way the seal was originally installed. It may be difficult to push the connector back onto the oil pressure switch if installed backwards. I’ll spray a paper towel or rag with brake cleaner and wipe it down. Can also use degreaser like 409 or Fantastik. I recommend only wiping the seal and not directly spraying it with cleaner. Also after the seal is removed I spray the connector with brake cleaner. Letting it dry off. You can blow it off with compressed air to dry it faster.

As far as removing the oil pressure switch, pay attention to where it’s located. This will help when reinstalling it because you can’t actually see the hole it goes into. Maybe even take a picture as I did so lining it up is a little easier. I found threading the AC Delco part much easier compared to when I’ve used a part made by Borg Warner or Standard. Both of which are just fine to use though, but are harder to install. Also the crush washer on the other brands sometimes will fall off while trying to reinstall the part. The AC Delco part uses a washer thats triangular like in shape and holds onto the sensor.

Reinstalling, cleaned the socket out with a paper towel since there was oil inside from the old part I removed. Cleaning the socket out can help the new part not slip and slide while trying to put it back into the engine. Also I like to keep my tools clean anyways. Basically you can’t actually see where the part threads into, unless you’ve got a mirror. If you aren’t familiar doing this type of repair it might be a good idea to get an inspection mirror in case you have trouble lining the part up with the engine. I had a fairly easy time lining the part up with the hole. Although I had to sort off feel around for the hole. I sometimes will spin the part counter clockwise, as if I’m removing it, while finding the hole it goes into until I find the hole. This way I can find the hole and not cross thread the part. Then once I’ve found the threaded hole I’ll spin it clock wise. Always start screwing it in my hand so you don’t accidentally cross thread it. You should be able to turn it in most of the way by hand until it touches the crush washer. I tightened the part without using a torque wrench. But you will want to be careful to not over tighten it if you’re familiar with installing spark plugs, it’s going to go about that tight. Has to be tight enough to crush the washer. I don’t have torque specs, but probably about 15-20 ft lbs and no more. Not like you can get much torque on it anyways. I’m sure someone has stripped one before though. So if you’re unsure, take it to a mechanic!

This repair was done under the hood. The car doesn’t need to be raised and done from underneath. Now if you really want to clean things up under there, you’ll have to remove the starter. It isn’t necessary to remove the starter for replacing the oil pressure switch. Although I’ve seen people do it before because they didn’t realize you can get to it by opening the hood.

Here you can see where the oil pressure switch is located under the hood.
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Here is the connector removed off of the part. You may want to attach a piece of tape to it because it may fall down and become difficult to see and locate.
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Here is the old sensor attached to the engine.
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You can see the part is oily. It may leak around the base where the plastic meets the metal. It also may leak through the electrical connection and get into the wiring connector. This was the case with mine.
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Cleaning the seal is recommended by myself. But make sure you don’t lose it. Leaving it oily can cause it to swell and not fit correctly or even disintegrate over time.
19833
 

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Discussion Starter · #2 ·
This is the genuine part that can be purchased at the dealer or online. I got mine locally from an auto parts wholesale.

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You can see the shape of the threaded portion. This makes it easy to install
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Also this unique crush washer ensures it doesn’t fall off of the part during installation.
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These are the tools needed to quickly do this job
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I need to dig into my car more because it's either this leaking, or actually the oil filter cap.
 

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81, are you giving any odds on the sender leaking? With all the work on your cars you do, I don’t think you left the cap loose and would notice a bad cap gasket
 

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I've actually leaned towards the filter cap leaking for a while now. The car never started leaking oil until I had a weird incident (back in 2014) where I did an oil change...and didn't remember to fully tighten down the filter cap. I added a quart about four days later because it had leaked that much out.

Ever since then, I've always had an oil leak. That happened about 2 months before we moved, so ever since then, I've just never gotten around to fixing it - one of those things that's minor enough where it's easy to forget or ignore.

There always seems to be a small pool of oil in the little "trough" near the filter cap, but overall it's hard to see due to the supercharger being directly on top. So that's why it's just my guess as to that potentially being the issue. With the supercharger (and enormous intake manifold) in my way, I'm not entirely sure I can see the sender, or feel it with my finger.
 
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