Pontiac Montana Thermostat Replacement

Had a van to work on and decided, what the hell I'll make a video.

[@motoozark4361]

I just did this job and it can be done much easier then all of the youtube videos I've seen showing you how to do it. You will need a 13mm VW carb wrench which can be bought on ebay. You don't need to remove anything accept the air box duct and lid Once thats all out of the way go under the crossover pipe with the vw wrench and get it on the bottom housing bolt, it helps to have a flat head screw driver above the crossover helping get the wrench on the bolt. Once that bolt is broke loose, use your index finder on your right arm still reached under the crossover bar and the flat head coming in from the top to back the bolt out. Go ahead and take it out and use a socket to remove the top bolt. Remove the housing and bad thermostat. Apply a thin line of silicone around the rubber o-ring on the new thermostat on the side that faces in the engine and position is in there. let it cure for 24 hours. Now prior to putting the housing back on, put the bottom bolt back in barely screwed in at all, by about one thread. Remove the two bolts on the on the heat shield at the front of the engine, you dont have to remove the heat shield removing these bolts will free it up enough to get the thermostat housing past it and the thermostat and onto the bottom bolt that is barely started into the block. You may need to use the flathead to help push the shield out of the way as you work the housing on. You'll have to come in from the top and it might take a couple of tries but its doable. Be careful not to knock the thermostat loose or you'll have to re-silicone it and wait another day, it should be pretty sturdy though if the silicone cured all the way. Once you got the thermostat on the bottom bolt, go ahead and start the top bolt to keep it in place then put the bottom bolt in the same way you took it out, right hand index finger on the bottom and flathead screwdriver on the top, then tighten with carb wrench.

[@frankleslie810]

Did you use the L or s shaped carb wrench?

[@cyoungso]

There is actually a special GM wrench for this job as you describe

[@shaedlifestylez8699]

Question is can it be done with a 13mm 3/8 1/4 etc 🤔

[@butchortner6572]

Thank you. Your video helps me see what I am getting into. Good job.

[@hairyliver1019]

This is a good video and somewhat easier than the usual removing the exhaust crossover pipe method. especially if you have a deluxe model that has additional AC piping and climate control pipes in the way of the cross over pipe. Just one thing I would add to this video - have a 13mm "s" wrench for the rear bolt on the thermostat.

[@euodow]

Thanks for the video! I'm all thumbs when it comes to this stuff. Your video made the replacement very understandable. I might try this one, myself. I have access to an iPad, which I'll keep at the car to refer to your video.

[@williamcarrothers6783]

Hate to say it. But it is totally possible to do this with out removing the throttle body. Upper screw can be had with a 1/4" socket and extension. Once the upper is done the casting / housing can be giggled to loosen Up the rear bolt to make it easier to break loose. Use a pivot head ratcheting open end wrench. For the back bolt Needs to be a pretty thin walled one to fit. My craftsman does not work as well as my off brand as its narrower. I will admit the back bolt was frozen on good at 201k miles. Needed some pb penetrating oil for that bolt in addition to little movement on the housing to get it loose. B

[@brandonstone6962]

He never said that you HAD to take all that off but the fact that it makes it easier to get to is all

[@markstrain4429]

What size wrench would I need

[@CaptainChrisMoore]

I'm about to attempt this repair and the auto part guy never mentioned a throttle body gasket -_- but now I know where the thermostat is thanks to this video.

[@brent-z3l]

you can get to it without taking half the engine apart

[@emmettturner9452]

1:45 ”Pull that hose the one that’s going at a 90° angle on top of it. Pull that out slowly. Old plastic will break. It’s brittle.” In my case it didn’t break but it’s almost worse: It came out intact on BOTH ends. I barely caught a glimpse of some rubber piece falling off the back end, deep into the engine. Hours later I found it by blindly feeling around the transmission area but it turns out that it was just a gooey rubber remnant of some grommet that is functionally useless in its degraded state… which is why it stopped holding the other end of the pipe in the first place. I spent hours trying to see or feel where it is supposed to go, but no luck. The van still starts/runs but it’s now breathing unfiltered air through that tube that no longer goes anywhere. Also, I doubt the hose was going where it was supposed to since I got the old van so who knows how long it was like that. I took the opportunity to clean my throttle body and MAF sensor with the appropriate products so I hate to see that effort go to waste. The throttle body gasket was stuck so tight that I spent way longer looking for another bolt than I should have! I hate to go through all this to replace my thermostat, thermostat housing (goose neck piece), air filter, etc just to end up taking it to a shop over this plastic freakin’ hose. It must go somewhere even harder to see/reach than the bottom bolt on that thermostat housing! Like you, my hands are all cut up. My thermostat housing even had a sharp protruding defect that shredded gloves and skin while flipping and turning that wrench on the slotted thermostat housing bolt. What a useless slot, seeing how the thermostat protrudes from the engine into the housing such that the housing can’t be slid off anyway. My thermostat was stuck open since I got the van a year ago so I actually got a “fail open” replacement (better than overheating). I ordered the replacement with a new housing so I won’t have to deal with that sharp defect next time but I was a little disappointed that the new bleeder. After refilling I needed a 7mm wrench for one bleed screw and 8mm for the other. The replacement included a new rubber O-ring that doesn’t seem to fit anywhere. I’m not talking about the flat ring gasket that’s part of the thermostat itself. It’s a slightly larger round O-ring. Maybe later versions of the 3400 engine have a groove for this ring? Mine didn’t. Rock Auto was selling them separately too so it must be a thing. I tried to replace my radiator petcock and fluid level sensor only to find that neither fit right. The petcock is completely different so I must have an aftermarket radiator. The coolant level sensor will not clip on and can pull right off. I actually had it replaced less than a year ago but the replacement didn’t work either. Now that I’ve confirmed it was bad maybe I should put it back in there and take it to the shop for warranty. All in all, this whole job has been absolute nightmare for many reasons I haven’t mentioned, but thanks for the video. I never would’ve got this far without it!

[@f0xentertainment387]

Thanks for making this, but you confirmed my fears that the thermostat is located in the most inconvenient spot. I am replacing one tomorrow on my mother in laws van. I was hoping it would be easy to access like this other van I did a few months ago (1997 Chrysler Town and Country) two bolts and boom its out! Wish you showed the process of removing everything but I can figure it out. Thanks again!!

[@wades623]

it's pretty straight forward but it is just taking the tb off and all of the stuff in the way of that. but it definitely is a crappy spot

[@glennbeadshaw727]

It's my opinion that those thermostats were deliberately designed for early failure

[@Quirk77]

Pretty good video, was a little hard to hear. And thanks for the tip about the throttle body gasket.

[@brandonstone6962]

I may have to be tackling this very same project on the van... So thanks for showing me exactly what I figured that I had to do.. So thanks for letting me know that I'm taking it to a shop to have them do it because fuck that shit lol

[@louisfrey]

thanks for the video. this info helped

[@josephbarron1186]

Ok I’m only going to add one then that’ll hopefully help some people the back bolt is slotted so if you pull the hose and the top bolt it’ll pop off with minimal effort

[@emmettturner9452]

…not with the thermostat protruding into the “hose” (thermostat housing). You have to back the bolt out almost all the way so the slot does absolutely nothing. Only use for the slot is if you just removed the thermostat to do a flush without a full warm up. :(

[@mlmcashbiz]

Great video thanks alot

[@lwh7301]

I got this far 3 years ago, and was able to put a wrench on the bottom bolt, and I declared victory in my head. Then the bolt head stripped. No way to get it off.

[@buzahall6451]

Just reach ur hand towards the back n hold the wrench upside down, use the box end of the wrench on the bolt... U do not need to take off throttle body, just air intake from the box to the throttlebody... Just got done doin it, lol

[@brodielucas9405]

What size are the bolts??? To the thermostat like so good at showing what to take off an all that but no metric or standard sizes

[@lwh7301]

They're 13 mm. The bolt heads are very thin, and of course the bottom bolt is in a very awkward position.

[@randylee2549]

@edmanwalkin1 was irt overheating or was it running cold, or too cool?

[@LasVegasLamar]

I like the funnel, what brand and what parts store did you purchase it from?

[@edmanwalkin1]

Got it off the Snap-On truck for about $25. Check online and local stores if you can, first.

[@grayslate219]

Geeeezzzz just to change a thermostat!

[@jefforo7035]

Thank You!

[@teben1990]

Stupid question......but, how does one get the video to play. It's just "blank" above the title. "Pontiac Montana Thermostat Replacement". All help is appreciated. Tks

[@edmanwalkin1]

***** Is it a black or green screen?

[@rahimd.1870]

Hiya, The 90 degree hose that you pulled out out the air intake hose that goes to the back.. what is it called, do you know? Mine did indeed break because it's -25 degrees Celsius here (-13f) - I need to order a new one. Thanks mate. Great video btw.

[@edmanwalkin1]

+Rahim D. It's basically a vent hose off from one of the valve covers to the intake hose. As long as you have an end to fit the hose and intake assembly you should be good. Should just be a 90 degree plastic tube.

[@rahimd.1870]

+edmanwalkin1 thank you for the info. i found A piece of pvc hose with a .5" ID to splice the 2 pices together. Only problem i have now is i cant get the "back" part of the hose to stay in anymore. It pops out at the slightest touch. Ill have to find a new one i think, but just can't find a part number at rock auto. Ill try a local wrecker. Thanks for your help.

[@emmettturner9452]

Mine is intact but I can’t even find where the other end is supposed to go. I recovered a melted gooey rubber grommet that fell off when it popped out but that only explains why the other end wasn’t attached to anything. It also means my throttle body is breathing unfiltered air, and who knows how long it’s been like that. :(

[@jevontaybrady3751]

how much is the thermostat. for the Montana

[@edmanwalkin1]

Depends on which store you buy it from. I go with Stant.

[@emmettturner9452]

Negligible. I paid nearly 3x for a premium “fail-open” one that included a new housing and gasket. Even then, I was under one Jackson (~18).

[@jodykay94]

my husband changed the thermostat and once he started the van it was running high do you have any idea why this happened?

[@edmanwalkin1]

Does it have the "Check Engine" light on?

[@laurieshaw1960]

how many hours does this take?? I just got my thermostat replaced and they charged me for 4 hours of labor. Just wondering if this is an average amount of time? Your video is only 12 minutes.. so that's got me really wondering if I got ripped off. Thanx for any info. Laurie

[@edmanwalkin1]

+Laurie Teat Basic coolant drain and fill is 0.6 of an hour, and took 45 minutes to replace, bleed, and test drive vehicle. I started working on the engine only once it was completely cooled.

[@jasonc.4472]

+Laurie Teat sounds about right, it is put in a lousy spot, and for some reason GM thought it was a great idea to run the exhaust pipe along the back of the engine instead of straight down. It was a real pain to do, hate this van!!

[@laurieshaw1960]

thank you for your replies edman and jason. Appreciate :-)

[@jeremyseward6973]

I'm having problems with my cooling fans on same vehicle. replaced fan still not working, checked fuses, replaces cooling temperature sensor still not kicking on. I'm hoping maybe the thermostat is sticking and maybe that's why it's not kicking on. Haven't checked relays yet. Do have a low coolant light on in the dash but is full and won't go off. I'm thinking thermostat on that. Any suggestions would be appreciated

[@edmanwalkin1]

I'd check to make sure the fans work. Give them their own voltage and ground. Having the A/C system switched on should run them (if still working properly). If they work, check and listen if the relays are kicking on. If not, find out what powers or grounds them.

[@richgwozdz8580]

It’s horrible to get them bottom bolts out

[@BURTBOYY1469]

I'm gonna be doing a heater core on a 2004 Pontiac montana is there any video's or opinions on how hard it is to do. thanks

[@edmanwalkin1]

+Robert Putnam That will be a big job. Getting to the heater hoses at the fire wall, and pulling the entire dash out. Be careful with brittle plastic and pulling old hoses. Also, be absolutely sure it's the heater core. Do you have coolant running into the floor? Have it pressure tested if you haven't already.

[@brendanlang3632]

Looks like a lot of time. I'm trying to fiqure out why my blower moter isnt going on got a new resistor and blower moter and nothing will turn on no air what so ever seems to be getting power to the resistor and moter

[@SevenX_]

Did you check the actual gang switch on the control panel?

[@SevenX_]

*fan no idea where gang came from

[@fbodkin1]

Man, I appreciate the video but way too much time talking about this sensor or that hole.

[@emmettturner9452]

I came here for that extra stuff. Plenty of GM3.4L thermostat videos that don’t show you the throttle body or the different holes. Heck, one of my rigid plastic hoses popped out on both ends and I need guidance on where it goes.

[@akimwilliams7907]

where is th chassy number on these cars?

[@brent-z3l]

you didnt need to do all that bro lol

[@austinashby736]

Hope you cleaned that tbi I didn’t watch all the video so maybe you did idk but lord it looked nasty

[@akimwilliams7907]

plzzz help me out

[@edmanwalkin1]

+Akim Williams I believe the numbers would be stamped individually on the major parts. Varies by manufacturer. Somewhere on the firewall, maybe. The engine should have a stamp. A set of numbers in the glove box. That should help to see if your vehicle has had any major work or changes. Other than that, the VIN should help with getting replacement parts.

[@allhopeandlove5076]

Clearly you’re not very mechanically inclined

[@emmettturner9452]

Clearly, you’re a… Nevermind.

[@jasonc.4472]

these vans are junk

[@jasonc.4472]

+Joe Hoe GM crammed everything close together, they only thing easy is the water pump. then there is unnecessary crap to take off just to change the battery, there is quit a bit of things going on with ours, and the engine they put in it is crap, weak 3.0. yeah some people may have it for 300k but after how many problems to fix in that time. Just very poorly designed, but it is a pontiac so no surprise there. And you just said it all in your last sentence.....bunch of repairs!!

[@jackoborne2988]

Sounds like someone doesnt have a basic understanding of working on vehicles especially mini vans. These are by far the best minivans on the market for 15 years. BTW, its a 3.1 then 3.4, not a 3.0

[@thayneheath8888]

The bottom bolt doesn't have to be removed. Just loosen it until it is about ready to fall out. When you take the top bolt out, you can wiggle the thermostat housing straight up and out because the hole on the housing for the bottom bolt is slotted.

[@dannyhampton711]

@@thayneheath8888 that was the magic words I wanted to hear! Cause I was dreading that bolt removal! Thanks Dude!

[@emmettturner9452]

@@thayneheath8888 that doesn’t help much when the difficulty is all in getting it that loose 1/32nd of a turn at a time. The thermostat protrudes into the housing so you can’t just break that bolt free and then wiggle the slotted housing out. :(