ACDelco GM Original Equipment 131-160 187 Degrees Engine Coolant Thermostat with Seal

This was a direct replacement for a 2011 Escalade. It has the same stampings on the outer rim as the original thermostat. Works great.

Exactly like OEM

It came and was presumably a genuine GM part. It's hard to tell since you can get any number of different packaging types that all technically fall under the GM brand (Yes, Delco is owned by GM). The 5.3 Vortec in my Tahoe (also the same as the Silverado 1500, Avalanche, GMC, and a few other models) call for this specific temperature, 187F (pressed into the thermostat itself it says it is an 86C which isn't exactly the same but close enough). Swapping it was easier on my Tahoe than it was on my old Jeep. On my model the radiator doesn't have a petcock at the bottom to turn and drain with, you need to take off the scrape plate underneath the engine compartment below where you are looking down at, it is a plastic chunk held on by 4 15mm bolts then squeeze the clamp on the lower radiator hose to slip it off of the lip of the housing inside of the hose and let everything drain from there. Place *multiple* pans underneath the area along with some old towels or absorbent material and disconnect the lower radiator hose that is plugged into the housing. As soon as you do that, coolant is gonna pour out of both the hose and the housing and it will simply drain wherever it feels to under the frame rail and all over the nearby belting and pulleys but stays primarily on the passenger half of the engine bay. Hold the hose for a while downward and ideally aimed at a pan until it gets to a trickle, take off the cap from your reservoir and it will start flowing again, draining the reservoir. If you don't do this it will just keep coming out of the reservoir anyway, albeit slowly while you try to work. Once that's stopped, there's 2 bolts, 10mm, one at the top and one at the bottom of the housing; they're basically a slight crank with a socket level of tightness. I thought that seemed kind of loose but then I came across multiple reports of people busting the bolts because they are aluminum bolts going into an aluminum engine so they are fragile and need to be able to expand so *do not* crank them when putting them back. They should be just a slight push past hand threaded. I believe the correct spec is somewhere around 9ftlbs which isn't even worth getting a torque wrench out for. Remember, you can always tighten it more if it leaks, but you will instantly regret it if you push it even slightly too far; I've experienced this with transmission bolts on this engine already. Anyway, take out the 2 bolts, the housing will come off with most likely the old one thermostat inside of it. It might fall out, but more likely you'll have to pull it out; just give it a good yank and wiggle, it will come out and won't hurt anything. the replacement fits in kind of loose, it's important to pay attention to the little breather valve on the rim and make sure you allign the gasket properly both with it and to the small notch in the housing that matches up with it. The gasket fits around the rim of the thermostat, not on top or under it. It goes in with the springs pointing into the engine, not away from. You can take this time to wipe off any excess coolant/dirt/oil from the area if desired but it isn't necessary like it would be with a cork gasket. There's no sealant needed but it isn't gonna hurt if you feel better using some anyway. Slowly put the housing back in place so as not to knock the thermostat out of the notching and insert one bolt, tighten it loose enough to hold the housing in place then let go and put the other one in. It doesn't fit flush to the engine (due to spring tension) on it's own so don't force it. Tighten each bolt a little at a time back and forth until slightly past tight. The bolts will push the spring tension to make the housing flush. You can swap out your hoses if you want to while you've got the system drained, they're really not that expensive but unless they are cracking or bulging around where the clamp goes there's not much need to; you can just rinse them out with a hose if you want then dry them well with a lint-free cloth or air compressor. I highly recommend you remove the rubber hose out of the reservoir tank to separate it from the system and rinse that out with a jug of distilled water (not bottled, not filtered, specifically distilled buy it at your local grocer). You most likely have debris in it that you don't want to stay in the system. I've heard some people will use de-ionized water instead but that doesn't necessarily make it free of contamination like distilling would. Once you've done any cleaning, reattach your hoses, fill up your reservoir tank, let it sit, top it off again, let it sit, do it again, then when it's relatively steady turn on your engine and let it idle while running the heat (not A/C) on vent mode and get back to your reservoir and keep filling it. By leaving the cap off, it becomes the high point for air to escape so as long as you keep filling it and not let it empty you'll get all of the air bled out. After the vehicle reaches normal operating temperature (for mine it is 210F) you should be mostly done with adding coolant. You can supposedly tell that at this point the upper radiator hose is hot because the thermostat has opened allowing coolant to flow through but the whole engine compartment feels extremely hot and I can never feel a flow through the tube or tell if it's any less or more hot than anything else. Turn the air off and the vehicle, let it cool and fill the tank to the Cold Fill Line. Take it for a spin and it will probably go down a little bit more but not much. Driving it will also help slosh things around and settle. Most videos I watched simply stated "about 2 gallons" is what is required but I must've drained mine more (I also originally had it filled all the way up) because I had to drive back to pick up a third which I needed about half of. So my suggestion is to buy 3 of the gallon jugs. The technical guide says it can take up to 16 quarts for a complete fill but that also includes draining the engine of coolant. GM recommends a 50/50 pre-diluted Dex-cool (orange stuff) but use whatever fits your application best. I would prefer to use a HOAT coolant as opposed to an OAT like Dex-cool as a HOAT is less harsh on the metals and lasts longer but I didn't build the thing so I'm gonna trust they know what they're doing after 100+ years. I live in one of the hottest parts of the country and tow so I usually run more like 20% coolant to 80% distilled water. Remember that it used to be just called anti-freeze because that's what it's for, if you don't live in a cold climate, you don't need as much of it. Heck, people used to just add alcohol to the water so it didn't freeze (don't do this, modern parts aren't designed for it).

This is an OEM thermostat, worked great, opened at the correct temperature. I purchased this unit because I had originally purchased a water pump on Amazon that came with a thermostat. Not using my brain, I did not test the non OE Amazon thermostat. what a mistake. I'll be doing that review next.

Put in as preventive measure when water pump was replaced. Works great! Stable engine temps.

My OG t-stat was having issues. Order this and it is a perfect replacement. My tahoe 5.3 gague would sit straight up at 210 all day. This one is the same. Went thru 2 others until I got the OG which gave me what I wanted. This is the one.

It’s a thermostat, it’s what GMC, Chevy and Cadillac recommends. A little pricy compared to the competition, but it’s for piece of mind. No complaints and the build quality is no better or less than the others.

Good OEM replacement!