I recently pulled my engine codes with an OBD-II reader. My Driver Information Screen tells me "Coolant: ---" and my cooling fan will stay on high, SOMETIMES. Then randomly it will read correctly... Anyway I pulled the P0128 code, which is pretty broad and undescriptive. I decided I'd be on the safe side and replace BOTH my thermostat (AcDelco Part Number: 131-158, and my engine coolant sensor (Part number: 9373). Since I do all of the work on my car myself and I refuse to take it to a shop to get Effed by ridiculous labor costs, I've been looking online for a good guide on how to go about replacing them.. That's only the second part of my "Question". Though out of order, my first issue is locating where to start. I see a lot of how to guides that say "to the left of the exhaust manifold". I know that means the header, but they don't specify driver or passenger side.. So my questions are:

1. How do I locate the Engine Coolant Sensor, and what's the easiest way to manuever my way around while working on it? Pictures would be the best thing for me if I can figure out where you are, so a few with maybe a circle drawn over the picture would be easiest for me.

2. Do I need to drain my coolant prior to working on my car (After letting it cool down)? If so, how do I do that, and can I reuse my coolant or will I have to buy more Dex Cool (And are there any additives needed)?

3. To replace my Engine Coolant Sensor, do I need any specific tools to remove the sensor? I know to lubricate the O-Ring with coolant.

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4. How do I locate the Thermostat, and where would be the easiest place to access it from (Under the car or on top)? Pictures would help as well!

5. True or False: I should replace my thermostat at the same time that I replace my Engine Coolant Sensor.

6. To replace my Thermostat, do I need any specific tools to remove, and are there detailed disassembly instructions involved (Whether I have to remove the entire housing or not)?

I know this post is long, and for that I apologize. I really don't post questions unless I've looked EVERYWHERE and searched every possible combination to find what I need. Thanks, and in advance I greatly appreciate any help I can get.

 

They are both on the drivers side; follow the lower radiator hose and at the end of it is the thermostat housing. there are 2 bolts holding it in if I remember correctly, they are 13mm if I remember correctly. When I did mine, I did the sensor and the thermostat in less than 20 minutes,I used my 3/8 impact and a 10inch extension, just popped them bolts out and pulled out thermostat then dropped new one in. The ECT sensor is on the back side of the head where the exhaust manifold is if I remember; just unplug the pigtail, remove sensor, install new sensor, plug pigtail back in.

Make sure you get ACDelco thermostat and sensor! I cannot stress that enough, I have had too many off brand parts fail too often. I actually threw a "standard products" cam sensor at my boss yesterday after I have told him multiple times to never buy parts from them. And I told him to put that **** on himself cause I ain't ****** doin it.

Also make sure you have new gaske t(actually its an o-ring) for thermostat and sealer on the threads for the ECT.

When you replace them, make sure you have fresh 50/50 mix of h2o/coolant, with coolant at the full mark, start the engine and turn on your heater full blast out of the dash vents and add coolant as necessary. Before you shut the car off, make sure the thermostat has opened fully and your entire system burps.

 

Is it safe to assume that this is most easily accomplished by jacking the car up a couple feet?

 

you dont even need to do that; everything is accessible from above. Unless you cant get a drain pan under your car for some herrafrush reason.

The issue with the 2.4s is that the gigantic chunk of wire loom going everywhere( between engine and fusebox) is almost right above where you need to get your hands in to deal with the thermostat and where you look to see the thermostat and the ECTsensor.

 

Yeah, I noticed that.. So I won't end up having to drain my coolant or anything like that?

 

Nothing is wrong with the sensor your Tstat is bad

 

Well I mean I have a new sensor, so if it's as easy as Verbatim said then it's kind of like "Why Not?". Really I enjoy working on my car (replacing sensors), so it's not a problem for me.

 

And Verbatim, are you suggesting that I flush my coolant and replace with the 50/50 mix? I don't know the last time it was replaced, the longest would be a year and a half. My car's lowered, but I can fit a pan under it if needed.

 

You will need to drain some coolant out if you want to keep everything clean and keep coolant off the ground. But at my shop, I have no ***** to give; So I just popped the thermostat out, popped new one in, shot lil water in the area and used my blow gun to dry everything off as much as I can.
...the floor in my shop is my drain pan, lol

Depending on the mileage, GM recommends that the entire cooling system is flushed at 100,000 miles. Your coolant system should already be very close to 50/50. When you replace the thermostat and/or the sensor you will lose some coolant, When you fill the system back up you need to try to get as close to a 50/50 coolant/h2o mixture as you can for efficiency. Don't buy the 50/50 mix, you will be paying the same price for half the coolant.

If you want to flush the entire system, take it to a shop that is priced decent(get several quotes) that will use a flush machine that has an external pump that sucks all the old out while pushing new coolant mixture in. I dont usually get into the pricing side at my work but I believe we charge 100$ and occasionally have coupons.

 

i had this problem recently. stupid me one day forgot to take shifter out of 1st when i started car and car violently jerked forward and stallled but this jolt fixed it maybe it was just stuck lol

 

Going to be doing a quick write up with pics on how to replace this sensor pretty soon..