2005 Pontiac Aztek 3.4 engine overheating

[@countach711]

If they gave out medals for posting videos, you should get one. Thanks for sharing your extensive knowledge on cars. I could never have figured out this solution in a jillion years! I may investigate a similar issue on my Ford van and do this on my daughter's Aztek.

[@skrodgers68ify]

Thanks George...I am a retired master mechanic...1992...switched to wood working. This 05 Aztec has been driving me nuts. One local shop wanted 400 labor to install thermostat. . That is the I DON'T want to do it price. Thanks to your video i will tackle this myself for material cost....about 30bucks.

[@ricardogranados3112]

Indid thermostat in my moms aztek. 400 sounds reasonable now haha

[@ericrangelhernandez7048]

Thanks George V. McRae for not being selfish and sharing ur extensive knowledge.. u really surprised my mechanics..he was like damn..still have to pay for all the hours he spent checking everything..bit at least I know everything coolant plumbing wise is good.. your the man Sir..🎖️🖖🦾🏆🏆🏆🏆🏆🏆🏆🏆🏆🏆🍹🍹🍹🍹🍹🍹🍹🍹

[@CCMDVIP]

OMG, this video save my daughter a TON of money. Mechanic told her she needed a radiator $150 part and about $300 labor. Ran across this video, put a 1/4 brass fitting with an opening a little smaller than the 1/8th suggested. Stuck it in far enough so that I could get the hose on the nipple of the exhaust manifold. Locked the fitting in place with a clamp and then re-clamped to exhaust manifold. Temp is holding below half way mark. Thanks a bunch!

[@eltonmartin5623]

Just wanted to thank you so much! I have a Buick rendezvous 2002 with same engine. Wow I fought this problem for a few months. I replaced all the components that you have and still could not figure it out. Was just about to do the head gasket. I stumbled upon your video and wow I did what you said to do with nothing to lose why not. You are the man!! Never can learn enough. So all is well and fixed thank you so much. I am definitely a fan. THANKS again wow or wowed 👍👍👍

[@ericrangelhernandez7048]

How is ur car running..after u did this mod.

[@muspriky]

Still working??

[@muspriky]

I have an 2002 Buick rendezvous same thing would like to know if it's still working for you.

[@johngreen6643]

Thank you so much for sharing this! I have been scratching my head trying to diagnose a friend's 2001 Aztek, read hundreds of questions/comments on the same issue & they all changed thermostats, intake gaskets, head gaskets, heater core & whatever else only to still have the same problem. I was on the right track searching for a diagram on the flow of coolant on a 2001 Aztek. You hit it right on the money man! So cool that you can figure out what the GM engineers couldn't. Thank you again from Spokane, Washington!

[@gvmcrae]

John I'm glad it worked for you I think I might have it already and posted this in the wrong place but feel free to subscribe hope I can help you again have a good day!

[@johngreen6643]

Just got back in from putting this all to the test & works great! For anyone else with this problem I definitely would park the vehicle on an uphill slope or jack up the front while bleeding the air from the system. The heater core seems to be where the air collects so I just squeezed the hose while revving the engine a bit & could feel the air inside the hose. Then I opened the bleed valves a bit & back to squeezing the heater core hose & revving. I did this about five times until I could feel no more air in the hose & now it works like a champ. Originally I could never get any heat while idling & sometimes it would put out heat if I held the rpm's at about 2500. The temp gauge would go almost up to the red then back down below half & I'd get a bit of heat. As soon as it was back to idling the heat was back to ice cold & the temp gauge would start creeping back up. Now the gauge is steady & there is good steady heat at idle. Totally frickin awesome man! This gal is going to be so happy! And I get to retain my undefeated record! Lol. Thanks again & have a good one!

[@gvmcrae]

👍

[@andrewwatts4835]

Pl

[@jasonshupe9246]

Great job.Also , while you were doing that , I highly recommend turning the heat on full blast ​@@johngreen6643

[@skrodgers68ify]

Thank you for the info....been battling my aztec for a year. I am a retired mechanic but decided not to replace thermostat myself. Paid a shop 175 labor to do it for me. I did get mechanic to drill 1/8 hole in thermostat...at least he said he did. It worked fine for 2 months...now has mind of its own...sometimes overheats sometimes doesn't. I am going to try restrictor in intake return hose. If i drcide to change t-stat again i hope i find a hole in it. If not i will be upset. Thanks again.

[@keld0n84]

Mine did the same thing. Rarely overheated but it did sometimes. Fixed it today. It was the Temperature COolant Sensor. It was restricting the radiator fans from activating as well. Once we unplugged the sensor the fans blew on. Easy fix!

[@vljenewein]

Excellent ! Will share this with my GREAT mechanic, Robert H. and maybe we can get my daughter's 2003 Buick Rendezvoux SUV to stop random overheating. Replaced radiator, water pump, thermostat (2 times) and was thinking maybe head gasket. Will have to give this a try. ! Thank YOU!!

[@Texaca]

...thanks for making and posting this video, it's very helping, I learned some new things about this Gm 3.4L V6 engine. The things you pointed out about the coolant flow from the top Heater pipe 7:39 (the Thermostat Coolant bypass pipe), was very helpful. I have a 2004 Buick Rendezvous, which has the same engine, it's had overheating problems, but not severe. You explained the coolant lines far better than the service manuals do. Thank you. I'm going to try that modification you pointed out at 9:51

[@troywiler]

I'm somewhat confused regarding the placement of the 1/8" hole drilled into the thermostat... shouldn't the added hole be positioned at the TOP of the thermostat rather than at the bottom?

[@wesgreen2107]

I did what you did on my son's Rendezvous, worked like a champ. it was easier to bleed and fill. thank you

[@gvmcrae]

sylvaine it really doesn't matter I don't think OEM or parts store I had to drill 1/8 inch hole in the thermostat as described in the video and then restrict the flow in the hose as shown. you will see I made the restrictor out of a 5/8 piece of round stock and drilled a 1/8 hole in the middle of it so to restrict the flow down to 20% of normal good luck

[@danielgutierrez8263]

I want to thank you George the way you explain the flow pattern it made sense to me. In having similar issues on a Buick with a 3.4 Thanks again.

[@seanerobertson32]

Thanks for the post, I have been having the exact same issue with my 2001 Aztek. Sometimes I think the engineers that design these cars need to be smacked in the head so that maybe they can wake up! Next is fixing this issue and then tracking down my electrical problem. Thanks again and good job!

[@gvmcrae]

Good luck Sean

[@codymckey3620]

George we changed the thermostat drilled holes in it and installed the 1/8 inch piece. That fixed the problem of fluid backing up and out the overflow and it no longer overheats. However it still gets really hot enough to worry us. Not sure where To go from here

[@georgeblue1457]

Did you bleed the radiator of air.

[@TheBalloonBandit]

The bleeder screws release trapped air. Air in the system. Which causes the car to over heat. So if you loose coolant! Air gets in the system and needs to be removed. When you add coolant. As for drilling a hole in the thermostat it can help release trapped air thus making the car run cooler as long as the system is bleeded properly. As for blocking the bypass hose never do that. Results include blown head gasket, blown radiator, blown hoses or worse a blown engine.

[@hugoc677]

thank you so much for not being selfish with your knowledge. as soon as I saw the video I realized you were right .you helped me a lot.

[@borndiy5490]

Debating buyiing an '03 Aztek with 130K and worry of future cost & repairs. Consumer reviews great on the Aztek but complaints are also out there. Interesting to know about this plumbing on the Aztek. This is what I call a good Mechanic. Thanks

[@troywiler]

Please elaborate regarding the "5/8 piece of round stock". What is "round stock", what is it made of, and how long of a piece did you use please?

[@gvmcrae]

@@troywiler Troy all you need is a piece of 5/8 Steel the cheapest thing you can find take a 5/8 grade 2 bolt and cut it down to about a inch or so just so that you can put it in the hose and put a worm clamp over it to keep it from movin. If you shove it in there probably wouldn't move anyway. I recommend drilling on eighth of an inch hole in the center of it maybe you could go a little bigger if you thought it was necessary but I don't think any more than an eighth of an inch is necessary. You're just trying to restrict the flow so you don't develop an air pocket behind the thermostat

[@Shawtycuz]

Thank you, im having the same problem with my sister's 01 Aztek and you have clearly gave me insight.

[@jasonshupe9246]

The hose that goes underneath the manifold is actually one of the hoses that come off the heater core. And the other hose from the heater core goes directly into. The the Thermostat housing. That bypass pipe has 2 little. Male ends that attach to the manifold with a little piece of 2 inch. Long Hose and those are located Write above the thermostat housing. It is a very weird system and very difficult to work on this motor. No, you might just want to check the oil.The reason why the upper head gasket has a tendency to go out on these and It is possible that it has a pinhole through the gasket.And look , the coolant pressure will go into the oil. That is probably why you're having the problem that you are. But yes, it is something very difficult to explai.Wish I could attach some pictures for you. Thank you for your video.

[@maxxmasson4263]

good job man ,appreciate the input ,very well explained

[@ireuel357]

I drilled a hole in my thermostat too. Nice to hear from a pro that I did the right thing.

[@jasonshupe9246]

Actually i'm I'm changing. A thermostat out on My O2 right now and the new thermostat.Actually has a whole drill in Them now. It only took them how long.

[@stevewarnock1235]

hey George,,,was wondering how long is the five eights round stock with the one eighth hole you used ??

[@gvmcrae]

About one and a half inches just long enough so that you can Center a worm clamp over it and hold it in place

[@stevewarnock1235]

@@gvmcrae thank-you...gonna give a shot...change out the water pump...and thermostat.. cheers

[@ryanhanlan9652]

I have a 2001 aztek with 113k on it and the same problem as me earlier today my rad emptied into the reservoir and it started overheating so I removed the reservoir and dumped it into a pail... it was brownish in colour but I’m currently broke so I filled it back up with water till Friday... I will be trying the hole in the thermostat however with the rad emptying into the reservoir I think I have a bigger problem... any suggestions other than get a new car I love this car

[@blankczechz]

Exactly the problem I am having with my 2005 3.4 Pontiac Montana.

[@gvmcrae]

I'm glad the video helped!

[@ericrangelhernandez7048]

Hey George how long did that mod. Work on that Aztek.. just curious because I have a rendovous doing the same thing..but I want to see if after that mod. Should I trade it in or still keep it?

[@gvmcrae]

I'm really glad it worked out for you Michael!

[@jasondelombarde4406]

With the intake hose above the waterpump ask what do mean by putting a 1/8 inch hole? do you think need flush out too after you do that

[@gvmcrae]

The eighth inch hole is drilled into a plug that we put in the hose. So the plug would be like a 5/8 Bolt and drill a hole 1/8 inch diameter through the bolt so you are restricting the water flow from 5/8 down to 1/8 of an inch. This will slow down the water pump Scavenging too much water from behind the thermostat and making an air pocket.

[@gvmcrae]

don't trust your gauge use an infrared thermometer and check the temperature of the top and bottom hoses at the radiator make sure your cooling fan is coming on when it is supposed to. the temperature on your gauge should be just under half most the time if it's reading right. best way to tell it's really infrared thermometer to see where the heat is it may be that your gauge is not reading right or you could have a clog in the radiator also. don't forget to check the temperature on the hoses going in and out of the heater core. question do you have good Heat in the car?

[@skrodgers68ify]

George has the fix you used on the aztec still working?

[@jbayyley13]

I just bought this 2005 aztek and it ran fine for 2 weeks, the fuel and temp guage was not working so i replace the stepper motor in the cluster guage and it seem like when i put this all back together the temp cooling gauge light comes on and then it bubble just like you describe in your video.

[@gvmcrae]

the car we had if you took the time and got all the air out of system sometimes would go for a few days sometime would go for a week or two but every time it would restart cold it would push out just a little fluid to the point where it would create the air pocket I think you had the problem when you bought it try my procedure and I think it will be fine. truth be known they may have sold you the car because they could not fix it.

[@joea4501]

Great !! Thanks 👍

[@wesgreen2107]

One of the things I Figured out on changing the thermostat, take the throttle body off and use a moon wrench to remove the lower thermostat bolt. changed out a thermostat in 1.5hr. there is enough flex in the hard line (water) going to the Throttle body.

[@gvmcrae]

yes you're on the right track we got good at it too.

[@angryw4nderer]

Buick Rendezvous and these Aztecs can be purchased cheeeep if you have the stomach to fix them which could include a head gasket. Good times lol

[@gvmcrae]

Thanks for your kind comments John I hope it works for you too!

[@sandracrawn623]

I have my thermostat changed cuz it was running hot now that I have it change it still running hot and we can't figure it out I have a po171 code and a po128 code I have no idea what those are its things out the engine is doing worse after we change the thermostat that has new radiator hoses 205 Pontiac Aztek

[@sylvainelarose6858]

I have a 2005 Buick RendezVous that has just started acting up just like you describe. Do you recommend an OEM thermostat instead of a GM part? Do you have any theory as to why this would happen after 12 years (265,000 kilometers)? Thanks so much for your wisdom. I look forward to trying this.

[@gvmcrae]

If you have checked everything and verified none of the normal problems exist you may have a flow problem like I had hopefully the video will help you.

[@Jmoniz79]

I'm having the same prob with a 2001 aztek and changed the radiator water pump thermostat an blead the air out of it an still overheating I'm not seeing any signs of head gasket failure so fair to say I was stumped now I'm gonna try your method an see if that works thanks for the video

[@jbayyley13]

did you ever fix your problem'

[@gvmcrae]

James Bayley Yes if you watch the whole video you'll see what I did that's what fix the problem . It's a circulation problem unless you have something different going on.

[@jbayyley13]

Sorry George, I knew you had your problem solved I thought I was asking another person "Jeff" .. I did find a 7/16 socket that will fit right in the bypass hose and has about 1/8-3/16 hole. I think that will work could this be tried first before taking thermostat housing off again to drill holes 1/8 holes?... Again thanks so much for posting been working on this for weeks and your video is the only one that makes any sense

[@gvmcrae]

James Bayley you need to drill the thermostat first otherwise you will have a air pocket there that you cannot get coolant if you don't get coolant to the back of the thermostat the spring will not open the engine will get hot. Restricted in the hose will only help stabilize your heater and continue the flow properly

[@codymckey3620]

So we are having the same problem. We fallowed your instructions. And it fixed it.. it seamed. After the drive we decided to flush the system again and then it suddenly started overheating again. I am thinking we will drill 2 or 3 holes and try that. Maybe the one got clogged. We bled the air out of the lines also. Any advice?

[@gvmcrae]

cody mckey I think you're right I believe when you flushed it out probably some crap has circulated pluging hole im the plug or the hole in the thermostat.

[@gvmcrae]

Cody I was looking at some of these others and saw yours curious if you got it taken care of?

[@globbindabz744]

So I don't have the money for the part so I removed the thermostat and now it heats up going up Hill and cools going down hill and I have no cabin heat even if it is overheating

[@tybo-ug7pj]

what he means is it has the beginning signs of a blown head gasket

[@gristlevonraben]

Idk, I think the heater core is slowly clogged up with scale, some manufacturers put a ground wire on it for dash hook ups which makes scale build up quicker, ie. Jeeps and Dodges. As it scaled up inside, the bypass was used more and more, and allowed air pockets to develop. Odds are, there is air trapped in the engine block, or the intake itself. What it needs is redesigned, and what all cars need is a high point air valve to get the air out.

[@skrodgers68ify]

Added the restrictor in the hose.....6 weeks no more problems with overheating.

[@jackwild1111]

I've got a 2001 Pontiac Montana. 3.4 L , same problem. I've raised the bleeding apparatus so I can bleed higher than the factory bleed screws. That help for a while, but then the system overheats. I will attempt your fix. WHERE EXACTLY did you still the hole in the thermostat ??

[@gvmcrae]

I think I might have answered this already on a private message but you can drill the hole in the thermostat where convenient make sure the hole is towards the bottom so that coolant can go through and the air can get out because the thermostat won't open unless the bimetallic coil sees hot coolant. Don't forget the other part the return hose to the back of the water pump you need to put that restrictor in there so that the water pump does not scavenge from the back side of the thermostat.

[@jackwild1111]

George V. McRae McRae Wrecker Service I drilled 2 holes ( for a little more flow ) I put them on top. I'm still having problems. But when I 'milk' the heater hoses I get some success. I'm still screwing around with it. I wonder how critical it is to have the thermostat holes at the bottom ? Thermostat IS opening. But I am pretty certain I have a blown head gasket. I'm in the process of using Bars Leaks. I did restrict flow between intake and water pump. Also added a higher air bleed point above water pump. Lots of problems with cooling system locking up !

[@sevanson1]

as in most "rattle valve" designed thermostats, the vent hole should be located toward the top of the outlet during assembly, otherwise the hole you drilled, similar to any good "toyota" thermostat (see). rockauto.com/en/moreinfo.php?pk=481811&cc=1364633&jsn=392 will allow the coolant to pass thru prior to venting the air through.

[@maddog46036]

I have a 2003 Aztek doing almost the same thing. It's not quiet overheating but the gauge is climbing close to 3/4 of the way up almost to the red, then it starts cooling itself down it only has the issue at idle. For example when I'm in a drive thru, stuck in traffic, or at a red light. I think this may be my solution. My 3400 has 167k miles on it and had the heads and intake replaced around 110k. It seems like this may be my solution. Do you recommend attempting this fix even though the engine is not technically overheating?

[@nicho8218]

did you ever get yours figured out? im having same problem

[@sevanson1]

make certain your cooling fans are working properly. your auto's issue seems to indicate a cooling fan problem or a water pump volume supply issue.

[@raulgallardo5014]

Share, I got the exact same problem on mine. But my temp gauge goes just below the 3/4 mark and the fans start running and temp gauge goes back to barely over 1/2. Did u fix the problem? Thanks for any info.

[@raulgallardo5014]

Sharx, I got same problem. Did u get it fixed? Thanks for any info.

[@ericrangelhernandez7048]

Guys..I had my mechanic check my 2004 rendovous it was over heating and had the same symptoms as the astek. My mechanic was stump didn't know where else to turn..did compression test it came out good.. radiator good water pump good. Flushed and clean all good..bit still over heating..he called another mechanic that had a can with same motor doing the same thing..he replace head gasket and manifold gasket and it took care of the problem..my rendovous has 200000 mile and didn't want to spend 1500 to 2000 to do a head job or replace the engine ..stumble on this mod. And told my mechanic to go ahead and do it it wasn't gonna hurt anything than what it is already doing.. rendovous is up and running and hasn't overheated yet..going to drive it on a trip this weekend.. cross my fingers it doesn't over heat.. so far so good.. thanks George McRae for not being selfish and sharing ur knowledge..u deserve a 🏅 my friend..my mechanic was like damn..he learned something new..hehehe! They don't teach u that in school he is ASE certified on everything.. I will post later on how my trip went...

[@nicho8218]

would switching to a regular thermostat work by chance?

[@gvmcrae]

nich james I did not try that. But I don't believe it would because of the Scavenging from that pipe that goes directly to the water pump. That's the main problem in order for a thermostat to work it has to be submerged in coolant and a standard thermostat would probably work as long as you drill a hole in it to let the air go by. If you ever had an old-style cooling system that gave you a hard time and you discovered that by shutting it off letting it set that the thermostat would start to open. You can take an old style system fill the radiator to the top with coolant put the cap on start it up run it to temperature with your hand on the top hose and it'll still be cold. Shut the motor off and you'll feel it Purge. when you restart it you'll find that your coolant level has dropped down. Good luck!

[@nicho8218]

George V. McRae McRae Wrecker Service actually I'm just learning as I go now. Sick of mechanics that don't fix it and still get charged. Lots of Google and KZbin lol. So far so good but nothing too intrusive yet either

[@gvmcrae]

nich james did you read my response this morning to your question. I hope we can help. But I also hope that you can someday again have faith in a good mechanic there out there.

[@sevanson1]

or one might try this style 'stat. as in most "rattle valve" designed thermostats, the vent hole should be located toward the top of the outlet during assembly, otherwise the hole you drilled, similar to any good "toyota" thermostat (see). rockauto.com/en/moreinfo.php?pk=481811&cc=1364633&jsn=392 will allow the coolant to pass thru prior to venting the air through.

[@bigbear76095]

@@sevanson1 does that thermostat you posted fit the aztec?

[@christophermccray4866]

Love your name

[@gvmcrae]

I hate to say it but you have to take the thermostat back out and drill an 1-8 inch hole into it

[@gvmcrae]

John Green I'm glad I was able to help. feel free to subscribe to my little Channel and check some of the other videos to see if anything you're interested in. I have been held by KZbin in the past and I felt it was time for me to start contributing. take care!

[@gvmcrae]

Greg trust me it's my niece it didn't cost too much if you know what I mean

[@FLYNNER.]

Where exactly do you still the hole in the thermostat? I'm replacing mine June 13 2023 2002 Buick rendezvous

[@Texaca]

... drill the 1/8" hole in the metal part, underneath and away from the rubber seal (below as Mr McRae says). 6:33

[@jbayyley13]

Where your repair shop at? I am having the same problem on my 2005 Aztek and need a good mechanic.

[@gvmcrae]

James Bayley We are in Milton Vermont.

[@jbayyley13]

do you have any recommendation here in lakeland florida

[@gvmcrae]

Best bet is to just check with your family and friends see who they use and are happy with

[@jbayyley13]

All family are up north, I will keep working at it until it confirm that it is a head gasket. I feel it isn't. I did do the test with the blue liquid and if it turn yellow it was a head gasket.. it was hard to do cause antifreeze kept bubbling up from the radiator touching the test tube. So i went to the over flow and did the test there. I could not get it to turn yellow.. I already change the thermostat and now i replace water pump, I got the no spill kit so i can make sure all air bubble are out.. I am going to take a test ride tomorrow and see if it over heat or bubbles.. I am not sure what you meant or what you did on the return hose to reduce the flow.

[@gvmcrae]

Yes

[@gordongiroux1020]

engineered to not work properly and be a piece of shit...nice goin GM

[@gristlevonraben]

Wow.

[@americoreyes7953]

what you need is a FAILSAFE Thermostat

[@lwh7301]

Beware of mechanics winging it by drilling holes in the thermostat.

[@Texaca]

... 😂😂😂😂 sometimes Old time mechanics know the Best Tricks, that comes from Experience 👍🏼 But Mr McRae is 💯 on the money with this trick. These 3.4L v6 are notorious for overheating in these U-platform Vans and CUV's.

[@SixtyNinersclub]

Great video but I'm pretty sure she could have bought another one for the bill you gave her. I bought my Aztek for $1000 a year ago and haven't put a dime in it yet. Azteks are cheap. It's too bad she probably has no idea just how cheap you can pick one up for with 160k miles.

[@dennisadams1147]

How about pulling the block drain bolts to drain the block? You call yourself a mechanic 😅

[@Texaca]

... what drain bolts? 🤔 These engines are notorious for overheating, and Mr McRae is right, it's a very crazy coolant and plumbing system. I have a 2004 version in a Buick Rendezvous.