Chevy Sonic overheating? It might be more than the Thermostat - watch this! 

chem dog you are so right my girlfriends car had the same thing now its a bad headgasket the echaust started smoking so bad it filled the whole block with smoke it was a nightmare now i have to deal with taking the bullshit car apart to replace one headgasket cause we were curious on why we had to keep adding water to it after all of that it never turned on the temp light on or the low coolant light it sucks this car just sucks in general

Yeah tell me about it, I'm 4000$ in debt from engine failure when it NEVER warned me of a thing and I still owe 7000$ on the car. Fuck Chevy for this, FUCK Chevy for this

That's why you have to check your coolant and not be lazy

@Al Dunn You are right about questioning why the fuse blew. Just replacing that fuse and assuming the fused failed because of "old age" is a BIG mistake. Fuses fail because of excessive current flow, not just fatigue. The next step, once the fans are working, is to throw a clamp meter on the fan wires to determine if the current flow is within normal limits.

Mine too. My Sonic is a little over 60,000. Im having the overheat issue right now. My mechanic was SURE he fixed the problem. Were gonna watch this video in hopes we can find the issue. Im not doing American cars after this. Honda or Toyota for now on!!!

agreed... 200+ comments ... 632 "thumps up"... to me means many folks have found this to be an issue.

I'm glad my video helped you.

I'm glad it helped. It seems this car has some pretty "special" issues..

John McGuinness -great to hear! I'm glad it helped you!

The coolant sensor is on the back side of the housing the sensor u showed is a heater for the thermostat

Mike R I'm glad this video helped you out. It's strange to see so many Sonics with the same issue. Thanks for the note

Fuses blow for a reason people. It’s usually means it’s time for a fan motor or their might be an intermittent short. Fuses are circuit protection. They do not just go for the hell of it.

Rick Dubois I'm glad it helped you. Thanks for the comment.

How much did it cost to fix it

@@Incrediblewash about 5 bucks for the fuse

@@russelmccombs Just solder a penny across that pesky fuse. I promise that 40A fuse will NEVER blow again. Sonics are easy to fix!!

A scantool or Torque app should be able to verify proper operation of the coolant temp sensor, without having to the place the coolant sensor itself. Always test fuses and relays first before replacing more expensive parts.

Great info.. thanks for posting. I'm glad this video helped.. this car seems that there is so much more than just the thermostat can go wrong... and the shops (I visited) didnt seem to know anything about the electrical issues.. .only to replace the thermostat..

I already replaced the all in one cheap plastic housing that cracked from the factory... It came wth the thermostat and temp sensor preloaded. Then replacement had better reinforced mounting, but still plastic against metal can cause issues. Of course after I changed the 40A fuse the alarm chime wouldn't stop until I disconnected the battery. But all seems to be working, for now. Thanks again.

Anthony Vara I'm glad the video helped

Thanks for the information

I bet they changed the block temperature sensor for $12 and didn't tell you.

Glad it helped!

What fuse size did you use? 30 or 40? Because my car is doing the same thing and the AC is doing the same thing and I change the thermostat but it’s still doing it so it has to be the fuse. And what fuse are you did you change exactly?

Great news! I'm glad my video helped

Yes, I've heard of that issue too. I'm glad you got it working

Glad it helped you

I'm glad it helped you... crazy car for sure

Cameron Brewer That is great to hear! isn't it awesome when you can fix a seemingly big issue with a inexpensive part :-) glad my video helped you

They do keep blowing get rid of that car

Sorry to hear about your issues. This is the reason I made the video. If all 4 items check out, you'll need to take it to a professional. But hundreds of folks have found the solution with the items I cover in the video. Good luck.

glad to hear, glad it helped you

Great to hear, I'm glad it helped you

I'm glad this video gave you additional options to check. I hope it works out for you. Good luck.

6y

Glad to hear it helped you

Sounds like maybe your fan died... you can use jumpers and connect the dan directly to the battery to test... just get the plus to plus ;-) good luck

DON'T BELIEVE EVERYTHING YOU READ ON THE INTERNET (like the above). Yes, adding antifreeze will raise the boiling temperature, but the big increase in the boiling temperature comes from pressurizing the system! Pure water at 15psi boils at 250 degrees whereas a 50/50 mix boils at 264 degrees. The is plenty. If one has a boiling problem, then it is likely due to air in the system which was not properly burped out. My guess is that replacing the coolant with undiluted coolant worked because in the process the air was burped out and did not work because of the pure mix. Using pure coolant in your car is actually bad, read about it on the internet ;-).

Glad to hear it helped. I have no idea why that fuse blows, but it's a great idea to keep a spare with you. There are a few unused fuses . And relays in that box that you could use in a pinch. Thanks for the note

I'm glad the video helped you. pick up some extra fuses :)

Miguel Juarez That is great to hear! have a happy New year!

Thank you! You too!

Not on mine.. use a tester to check the fuses.. by eye you might be able to tell

You're welcome!

haha, my son was stationed there and we were visiting. It's funny you caught that. I hope the video helped you.

I'm Glad it helped you

good luck. I hope its this simple issue. let us know what they say.

Deathbound I'm glad it helped you.. it's funny it took several days to figure out all I did.. even the service shops didn't have all of the info... again... glad it helped

I'm glad the video helped you. It's a strange car. Glad you got it fixed

I'm glad it helped you

@Revenant Touché Signed, She Who Admits She Needs A Man On Occasion 😉

This is my son's car, I have asked him how it has been running and he says all good. There seems to be issues with this system in the Sonic (from my searches), keep an extra fuse is a great suggestion... we kept an extra too ;-). And you are welcome, the shops where my son is wanted $150 to even do a code pull and he's in a state that doesn't allow auto parts stores to do it for free, so I hopped this might help others... glad it helped you.

You're welcome, glad it helped

Thanks for the great info. No one has been able to answer why the fuse blows in the first place... it does seem a model glitch... and maybe the Malibu solution you found might work here too. It's a crazy car for sure. Let us know

Russ M You're welcome. I was able to replace the relays a day after I commented on your video. So far, The Sonic seems to have stopped blowing the 40amp cooling fan fuse. I'm not 100% sure which relay may have been at fault, so I replaced both just for peace of mind and because the car has just over 100k on it. But if it helps anyone else who has a Sonic that keeps blowing the 40amp fuse and everything else checks out ok and is working properly. They may need to replace the low and high side cooling fan relays. If the relay/relays start to fail and will not hold contact to supply steady continuous power to the cooling fan, the constant kicking on and off may be causing enough of a power surge or if the relay is some how shorting out inside, it will blow the fuse. From what I gather, the Sonic 1.8 needs both the low and high side relay circuits to engage, cycle, and run/operate the cooling fan speed/speeds as needed by the cars cooling requirements. So its possible if one of these relays stops working properly, it could cause a excessive amp load on the high side fuse causing it to blow. If I understood the cooling circuit and wiring diagram correctly, the fan comes on on the low side first and immediately cycles to high right after , so instead of it going from fan off to fan on high, it has a very short two stage/step cycle to engage the fan on to high speed so there is no excessive amp load on the high side fuse. Low side is a 30amp, and the high side is only a 40amp, so its understandable why it transitions from low into high this way. Its easier on the fuse. I also believe that is why the 1.8 Sonic has the big resistor coil hide in the upper part of the electric cooling fan shroud. Its another attempt to try to ease/lessen the voltage and amp loads on the cooling circuit of these cars. I have seen that the Sonic with the 1.4 turbo has low, med, and high speed fan relays, and I have not seen many problems reported with fuses blowing on the turbo cars. There may be less of a strain on the cooling fan circuit because they have low, med, and high cooling fan relays and the fan is able to cycle from low, med, and high as needed. But I don't believe I would want to just pop in a larger amp fuse like the Malibu "fix". Because even if the wire size to the fan is increased, the rest of the circuit has not been upgraded and may cause even bigger problems down the road.

@@russelmccombs Thought I would give you a update. Its been over a month after changing the high and low speed cooling fan relays. We have had weather in the 90's here on and off and the AC is still working. Hope my information may be of some help to anyone with a 1.8 Sonic that blows the 40amp fuse from time to time after the car starts getting high miles on it.

@@russelmccombs Car has been ok for 5 months now.

I've been having same issue, so I'm going to try this out thank you.

that is great news! I'm glad it helped you!!

Agreed, I hope this video helped you though. it seems to be an issue that the manufacture might want to address.

@@russelmccombs unfortunately my thermostat housing was broken again. for the 3rd time in 80k miles. so i had to replace it. always seems to be perfectly outside the warranty of the part. this will be the last chevy i ever get after this.

@@jordanvilla8666 disappointing, it is a very bad design. I wouldn't buy one either ;-)

I'm glad it helped you.

Glad to hear it helped you.

how were you about to figure it out?! I’m having the same issue and the dealer is trying to charge me $2000 to fix

Trishelle Belisle so my issue was the 40 amp fuse. It doesn’t sound like that’s the problem you’re having, not if they told you they want $2,000 to fix it. I’m not too sure about the other solutions. I just bought a new fuse from a GM supplier and popped it in myself.

I'm glad it helped you. My son no longer has his sonic. He seemed ok, but like many other car brands, it had its issues.

The thermostat was the culprit. What kind of issues did to experience with your sonic? Was it a 1.4ltr or1.8ltr 4 cylinder engine?

I have to say, Ive never been called a wonderful soul. But I like it :) thanks for sharing your experience. I'm glad it helped you.

@@russelmccombs honestly thank you a hundred times bc i had to mechanic places (one was a gm dealership) wasting my money telling me they dont know and replacing parts tht didnt need to be replaced 🤦🏼‍♀️ Your video is truly saving cars n wallets 🚗💙

Great to hear! I'm glad my video helped.

Sorry, sometimes its going to be a fan motor... honestly.. not many based on posts... did you move any relays? There are a couple that are not used unless you have a tricked out model

I'm glad the video helped you

Sorry, never thought of that

I'm glad the video was helpful.

the AC has an "override" to run the fan.. so that makes sense... I would check the fuses... it could be that simple let us know... sorry for the slow reply.

@@russelmccombs actually I found there's two separate relays one relay seems to run the fan due to heat and the other relay runs the fan when running the AC. Anyways I think I found the problem, the little coil that the wires go into before they going to the fan it looks corroded

@@patrickmurphy8619 did you figure it out? My daughter's Sonic is doing the same thing. Fan won't come on unless it's on AC. I'm getting close but tired of throwing money at it lol. Thanks for any info you can provide.

@@2010ariez yes behind the plug on the fan housingthere is a sensor mine went bad it looks like a coil wrapped with green.there are two screws holding that down to the fan housing. Mine was badand I had to order a whole new fan housing in order to get that sensor included.

Beau I'm glad it helped you out

It's a 7 dollar relay

Hey, I don't suppose you would know if the thermostat rests in the open position? Like if you turn the car off, do the thermostat open?

@@keylay9453 the mechanical portion of the thermostat is temp dependent, so it will stay open on a hot engine, closed when the engine cools to a certain temp. The heater control circuit allows the computer to have more fine control of that open/close temp for better fuel efficiency and emissions related things

I'm glad it helped. Great info from you as well. Thanks!

Haha.. I think you've made a good decision... enjoy!

What do you mean the 40A instead of a 30?

you're welcome. I'm glad it helped you.

thanks for posting!

I'm glad it helped. Thanks!

I suggest starting with the fuse/relay check in the video .. a antifreeze flush would probably be a good thing. The battery dripping is not good, I suggest replacing. as I have said, I'm not a mechanic just a persistent person looking for an answer to the issue my son was having. I would rule out the system parts I talk about first and then take it to a reputable repair shop. let us know how it goes.

Yes, have a spare or two. Your dealer should be able to help you

@@russelmccombs I bought two 40s . When I first tested it , it sounded like the fan wanted to kick in but it didn’t . The engine was damn hot also. As soon as I put the 30 one in , the fan kicked in and the engine cooled off , and the AC worked even better. You helped me out . Here I thought I was going to have to spend hundreds of dollars. Thanks again! 👊

dreupen glad it helped! And thanks for the information.. I'm sure it will help too!

Thank you...and I'm glad it helped you. It's crazy how many people have had the same issue

Honest Cigar Reviews - the temp sensor is connected to the thermostat... the thermostat is a mechanical flow valve that opens to let the antifreeze flow through the engine. the temp sensor is a electronic switch that opens when it heats up... it makes the fan come on.... so one controls antifreeze... the other turns the electrical components on.

​​@@russelmccombsthe one on the thermostatic valve is not a temperature sensor.. It a thermistor plug that let the ECU open the thermostatic valve heating the wax inside the valve regardless of the coolant temperature

I'm glad it helped.. yup, those fuses are hard to see if they are blown

davyd slaybaugh perfect! Yes, there seem to me a few unused fuses... and relays in that box. Glad it helped

Great to hear it helped!

I'm glad it helped you

Try running 12 Volt's to the fan the way he explains it. Fan should come on instantly, if it doesn't the fan is definitely bad regardless of any other fuses sensors switches whatever.

Favio Escalon I'm glad my video helped you. It seems the Sonic has this issue a lot.. most shops seperate repair labor from diagnostic labor.. it's great to see people using this vs paying for expensive tests

there have been over 140 cars with the same issue... (just replying to this video). I think it's an issue with the model.. I doubt its something "broken"... I think it's "how it is"... if anyone finds the reason for the fuse to blow, let us all know :)

I'm glad the video helped.. sonics are interesting for sure

I'm glad it helped

Glad the video could help you.

Jesus ochoa-vega great to hear it helped you! thanks for the note

Glad to hear it

My son's had 2 speeds. Yes, I've heard of several needing a new radiator. Still check the fuses and relays first to be sure, but all of the issues can't be an easy fix. Sorry man. Good luck, and yes, this car is a peach.

I'm glad it helped