cutlasssupremepizza Posted November 7, 2014 Report Share Posted November 7, 2014 1995 CS SL with 3100. Shop manual says basically "take it off", but there is some kind of aluminum shroud in the way of the lower bolt. Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted November 7, 2014 Report Share Posted November 7, 2014 That's probably the heat shield for the exhaust, you might have to take it off to get access to the lower bolt. Its not that hard to remove, just a few screws. The one closest to the O2 sensor was a bit troubling to get to if your back gets sore from being bent in an awkward position. Quote Link to comment Share on other sites More sharing options...
cutlasssupremepizza Posted November 10, 2014 Author Report Share Posted November 10, 2014 I think I must have some sort of special housing. The pic of the housing on rockauto shows 2 bolt holes, mine has 3. I took the heat shield off, but there is no way to access one bolt without taking the manifold or whatever off. Even with that off, there is a hard metal line going into the back of it. I would basically have to take the entire plenum, coil pack, etc off to get to it. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 11, 2014 Report Share Posted November 11, 2014 can you get a picture of this water outlet you have? there should be no reason for a 3rd bolt on there, there isn't anywhere for it to thread onto... Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted November 11, 2014 Report Share Posted November 11, 2014 Just to be clear, you are talking about the metal housing at the end of the upper radiator hose attaching to the engine block correct? Ive spent a lot of time looking at 3100s in my car and JY cars and Ive never seen a 3 bolt setup. Quote Link to comment Share on other sites More sharing options...
cutlasssupremepizza Posted November 11, 2014 Author Report Share Posted November 11, 2014 Correct. Maybe there is 2, but felt like 3. It's funny how the service manual just says to remove it, but there is no way to get a ratchet or a wrench on one bolt without taking the exhaust out. Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted November 11, 2014 Report Share Posted November 11, 2014 If you cannot get a socket on there get comfortable and weasel it out with a wrench, its slow going but it works. A set of those ratcheting wrenches really comes in handy on these I bet, I do things the hard way though. Now that I think about it I believe I removed my exhaust cross over to get better access and to see things better. The housing does get stuck on there, if two bolts are out tug on it a bit and it should come off. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted November 11, 2014 Report Share Posted November 11, 2014 i'm absolutely certain i didn't need to pull the crossover when i did it a couple of years ago. probably would have helped, but unnecessary unless your toolset doesn't have something that can get the job done. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted November 11, 2014 Report Share Posted November 11, 2014 All you need to do is loosen the bottom bolt. The thermostat housing is slotted on the bottom. Take the top bolt out, loosen the bottom enough to get the housing off, and your done. Quote Link to comment Share on other sites More sharing options...
cutlasssupremepizza Posted November 11, 2014 Author Report Share Posted November 11, 2014 There is also a piper connected to the rear of it. Quote Link to comment Share on other sites More sharing options...
white96supreme Posted November 21, 2014 Report Share Posted November 21, 2014 In case you're still looking for a solution for removing those pesky bolts, find a torque adapter (basically a box end wrench with 3/8 square drive on the other end) and an extension and take your time to remove those bolts. It took me about 5 minutes to remove the t-stat housing when I did mine last winter. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted March 5, 2016 Report Share Posted March 5, 2016 Yes, this is getting to be a stale thread. However, I have nearly finished with this job today--and I figured I'd describe my procedure. This way I don't have to start a new thread. In case you're still looking for a solution for removing those pesky bolts, find a torque adapter (basically a box end wrench with 3/8 square drive on the other end) and an extension and take your time to remove those bolts. It took me about 5 minutes to remove the t-stat housing when I did mine last winter. You are a better man than I, Gunga Din. I just spent five hours on this job. Most of that was trying to find a short enough wrench to access the lower thermostat housing bolt. The upper bolt was easy. Photos to follow...someday. I forgot to take pictures while I was working on this. I'll get a few after-the-fact. The thermostat and housing (water outlet) on Dear Old Dad's '98 Monte Carlo 3.1L is a pain in the azz to R 'n' R. They're sandwiched between the intake manifold on the right, the exhaust crossover pipe and heat shield on the left, the throttle body above, and the bellhousing/transmission below. Access to the thermostat housing is by removing the rubber air intake tube between throttle body and MAF sensor. Beyond that, there's very little working clearance. Install coolant drain pan more-or-less under the engine/transmission interface. Squeeze the spring clamp holding the upper hose, and slide the clamp up the hose. The hose will probably be "stuck" to the thermostat housing. A hearty twist, or a mechanic's pick slid between hose and housing will release the hose. Allow coolant to run into drain pan. Not a lot of coolant drains out--something like a quart. Maybe less. Not enough to make it worth draining the radiator. The thermostat housing is held to the intake manifold with two bolts. Access the upper bolt with a 13mm universal socket and a ~8--11 inch long extension (3/8 drive) Fairly easy. Access the lower bolt with...anyfuckingthing you can. I had to call the Snap-On man to get a stubby 13mm wrench. Since I am old and weak, my tools tend to have long handles for added leverage--and there's no clearance for wrench swing with a long wrench. As it turns out, I've lost my "ordinary length" Craftsman 13mm 12-point combo wrench, which might have worked. There isn't enough depth for a 1/4" socket and ratchet. The angle required to clear the exhaust heat shield is greater than a universal socket will accept. There's not enough room around the bolt for a "Gearwrench" ratcheting box-end. I don't see an alternative to a short-to-ordinary-length plain ol' 13mm combo wrench or, as said, a torque adapter (which my local Snap-On Man doesn't stock in a 13mm.) Small hands will be a bonus. Having removed the two bolts, the housing pops off of the intake manifold. In my case, the rubber seal of the thermostat stuck to the housing, making it impossible to remove the housing from between the intake manifold and the exhaust crossover pipe. I had to pry the thermostat off of the housing, back into the manifold, to sneak the housing around the thermostat and out. Then the thermostat and rubber seal can be retrieved. Clean-up the thermostat housing as required. Mine needed nothing but to have a few minor specks of corrosion (or possibly hardened sealer of some sort) wire-brushed off of the housing neck where the hose was clamped. The housing was still smooth--not pitted--under the corrosion/sealer. The surface that the thermostat seal touches was "perfect". The GM service manual is almost accurate. Error 1. The manual specifically states to install the thermostat into the intake manifold, then install the gasket and thermostat housing. There is no gasket. There is a rubber seal which is installed on the perimeter of the thermostat itself. This seal cannot be installed after the thermostat is in place in the manifold. The thermostat, with the rubber seal already installed, goes into the intake manifold, then the gasketless thermostat housing goes over the top. Error 2. The GM service manual says to use RTV sealer on the thermostat bolts. This is outright crazy. The thermostat bolts don't go into the water jacket! The bolts cannot wick coolant, because they're not exposed to coolant at any point. No sealant is needed. GM installed the bolts with no sealer. I installed them with anti-seize, as I am likely to do with any steel bolt that threads into aluminum. The thermostat housing lower bolt hole is slotted. This does not mean you can thread the bolt into the manifold while it's accessible and easy, and then slip the thermostat housing under the bolt head. I tried, and failed. Not enough clearance. Maybe I wasn't persistent enough. The slot seems to be there to allow more "angle" on the bolt while you try to position the bolt with one hand, partially-blind, by feel, because there's such limited clearance due to the close proximity of the exhaust crossover pipe heat shield. Install the thermostat housing over the thermostat/seal, install upper bolt hand-tight using the universal socket and extension (but no ratchet handle). Then you fight the lower bolt into position, thread it in by hand as far as possible, and then snug the two bolts evenly until appropriately tight. ASSURE THAT THE THERMOSTAT DOESN'T FALL OUT OF POSITION as you're getting the bolts in place. Shove the hose back on the housing neck, re-position the clamp where it was. For fukk sakes, don't throw the clamp away in order to install a worm-gear clamp. The GM spring clamps are wonderful, and easy to work with. Throw a floor jack under the right front part of the sub frame. Jack the right front of the car up a little, so as to get a little elevation to the radiator filler neck. You won't get a lot, but that's OK. Fill radiator with coolant. Have a beer. Beer should be considered a "Special Tool" . GM should provide an official GM/Kent-Moore J-xxxxxx part number for beer. I suggest "going medieval" with Steel Reserve. When the room stops spinning, top off the coolant again, and crack the bleeder screws. Top-off the radiator until you get coolant but no air at the bleeders, then close the bleeders. Assure that the coolant overflow tank is filled to the "Cold Full" line, and assure that the radiator cap holds pressure. Install cap. I really like the "safety lever" style rad caps, they are easy to release pressure. Fire the engine, allow to warm some. You need the water pump to churn the coolant, but you don't need it screaming hot...yet. Check the bleeder screws--purge any air you find. Shut off engine, release pressure if any, refill the cooling system if you get a lot of air at the bleeder(s). As the engine warms, assure that the engine doesn't overheat, and that the radiator fans work as intended. AFTER the engine cools again, refill the overflow tank as needed, and double-check the coolant level in the radiator. Hand the keys to the car to someone responsible, while you "polish off" the rest of your "Special Tools". Quote Link to comment Share on other sites More sharing options...
jman093 Posted March 5, 2016 Report Share Posted March 5, 2016 I keep one of these in my toolbox at work. Makes quick work of that pesky bolt. http://www.ebay.com/itm/Calvan-751-GM-Thermostat-Wrench-/172107221040?hash=item281263c830:g:ujcAAOSwNSxVGjoO&item=172107221040&vxp=mtr Schurkey 1 Quote Link to comment Share on other sites More sharing options...
Schurkey Posted March 5, 2016 Report Share Posted March 5, 2016 I keep one of these in my toolbox at work. Makes quick work of that pesky bolt. http://www.ebay.com/itm/Calvan-751-GM-Thermostat-Wrench-/172107221040?hash=item281263c830:g:ujcAAOSwNSxVGjoO&item=172107221040&vxp=mtr Kick-ass! Thank you! On my wish-list. I hope to live long enough to do this job again, someday. Quote Link to comment Share on other sites More sharing options...
Padgett Posted March 5, 2016 Report Share Posted March 5, 2016 Do you mean it is in here ? Gasket only has two bolt holes. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted March 5, 2016 Report Share Posted March 5, 2016 Yes, I expect that's the thermostat housing/water outlet. Doesn't look like the 3.1 I was just working on. Looks more like my 3.4L. Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted March 6, 2016 Report Share Posted March 6, 2016 Ive never seen that on either 3100 SFI models, maybe unique for the final year? Quote Link to comment Share on other sites More sharing options...
Padgett Posted March 6, 2016 Report Share Posted March 6, 2016 Is a 3.4 LQ1, guess they are different. Quote Link to comment Share on other sites More sharing options...
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