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Robby New Reader
11/21/18 10:26 a.m.

In reply to kevinatfms :

They are the same part number for everything in between the the hubs from what I've seen on various GM parts diagrams. 

From what I've read the differences between the RS and normal Sonics is nothing too major. They have different gear ratios, rear disc brakes, different springs/shocks/struts, and some exterior/interior changes. Wasn't worth the money to me as I prefer the cloth interior in my LT and have since upgraded past all of that (or will have made equal in the case of brakes). 

I really wish it was more similar to the Fiesta/ST lineup, especially because Sonic RS prices weren't too far off of FiST prices. 

Robby New Reader
11/29/18 10:01 p.m.

Well, this past week I finally found the reason to replace my water pump. Every 3-4 months, my overflow tank would be slightly low on coolant. I had never seen a drop of it under the car and it was a super slow leak. All of a sudden, it started leaking a  lot more, so I figured I'd finally replace it. Then I learned the water pump on 2012-2014 Sonics have a service bulliten covering them for 10 years or 150k miles, luckily. So I dropped it off at my local Chevy dealership and got it done today. 

This makes my current non routine service records:

Trans @ ~30k miles (bearing whine) (warranty covered)

Battery @ ~50k miles

Coil pack @ ~60k miles

Starter @ ~65k miles

Water pump @ ~85k miles (warranty covered)



In a few weeks when this semester is over with and I have 5 weeks of break, I will be doing the brake swap on all 4 corners, replacing my coilovers, and possibly making a front tie bar. 

I will be making something similar to this. It won't cost much and will be relatively simple. I'm not entirely positive how much of a difference it'll make, but it seems to have good enough reviews to try. 

The car will currently oversteer before it understeers, so this might help make it a little more neutral. 

N7Prime Reader
11/30/18 10:16 p.m.
Robby New Reader
12/1/18 7:14 p.m.

In reply to N7Prime :

I've seen the Pierce Motorsports front x brace before. I think I'd rather attempt to make one for the price. I'll probably look into it after I do the front tie bar. I have not seen the Ultra Racing stuff before. Some of that is pretty interesting and doesn't look super complicated. 

Anyone have experience with adding a lot of bracing to a daily driver? Or even on a track car or autocross car? Can there be a point of too much bracing? 

Robby New Reader
12/6/18 1:00 p.m.

Today I ordered an intercooler, charge tubes, etc. from ZZPerformance. 

Stock core dimensions (inches): 24 x 5.125 x 2.5

New core dimensions: 23 x 6 x 4

I certainly didn't plan on ordering one anytime soon, but it was $300 marked down from $600 for a Christmas deal. I believe they were $120 more on black Friday. 

Daylan C
Daylan C SuperDork
12/7/18 3:32 p.m.

Posting to say I'm following your newsletter now to pass bad ideas to a friend of mine that just bought a '14 RS.

Robby New Reader
12/7/18 9:33 p.m.

In reply to Daylan C :

Haha, I'm full of horrible ideas. If your friend has any questions, feel free to let me know.

Robby New Reader
12/7/18 10:59 p.m.

To procrastinate studying for finals, I test fit the new rotor and caliper for the front. Excuse the filthy wheels

It appears the the rotor is closer to the back of the caliper. I have 3/8" wheel spacers like so:

Could I cut the spacer down to fit inside rotor hat to push the rotor out a bit? 

Robby New Reader
12/20/18 4:13 p.m.

Got the new front and rear brakes put on, bled them twice, but the pedal still goes halfway down before anything happens. I'm not entirely sure what to do with that...

I haven't yet put in the new e brake and will start with that tomorrow. 

I will also need to paint the new fronts to match my rears. 

Update: got the e brake cables on and working.  

Robby New Reader
12/30/18 2:26 p.m.

Brakes are completely done and feel great. The car stops super well now-way better than I thought it would. 

Threw on the new coilovers. The front passenger side had been making a clunking noise for a while now. I knew it was the mount on my old coilovers, but wasn't sure exactly what part of it. The strut bolt was stripped and took a Dremel to get the nut off. Probably shouldn't use a Milwaukee impact on any more strut mounts... 

I'm getting an alignment and corner balance on Jan 10th, I just need to play around with the ride height now. 

I'll be putting on my intercooler somewhat soonish. While I have my front bumper off for that, I'm going to be making brake ducts for the front. 

Robby New Reader
1/4/19 10:49 p.m.

I put in the new intercooler today. It wasn't a bad install and not too much went wrong. It did require some filing on the mount underneath the inlet, but wasn't bad. 

I also changed out the lower fog light housings to be able to make brake ducts. I used some materials from Home Depot to make the ducts; they're not great and I'll redo them with better materials and when I have more time. 

Robby New Reader
1/10/19 4:10 p.m.

Got the Sonic corner balanced and an alignment today. I had my spare tire in the car and a little over half a tank of gas. 

Before (without me)

After (with me in car):

Then went driving and hit 86,000 miles. Can't tell a difference between now and before getting corner balanced. The car just drives so well now and doesn't make a single noise that it shouldn't. 

Robby New Reader
3/11/19 1:42 p.m.


I have had the Sonic for 6 years now and have gone 87k miles. 

Was at a test and tune yesterday, and noticed after about my 18th or so run, that I was leaking brake fluid. It looks to be coming out of the brake booster, which seems kinda odd. I'm not exactly sure how to proceed. Whether I do the seal between the booster and master cylinder and hope that fixed it or do booster + seal and hope that fixes it. 

Also, it was reported to me that I blew out a tad of blue smoke at redline a few times. I will need to look into that as I don't think that's happened to me before. Not exactly sure what's going on there.  

I'm pretty busy at school with midterms and all, so it may be a few weeks before I can mess with it. 

81cpcamaro Dork
3/11/19 2:53 p.m.

Leaking out of the booster means the master cylinder is leaking, time to replace it.

As for the smoke, check the PCV system to see if oil is getting through it. That could cause the smoke you are seeing. If so then a catch can could help with that.

Robby New Reader
3/11/19 3:19 p.m.

In reply to 81cpcamaro :

Should I replace booster and master cylinder, or will fixing the master cylinder in a way fix the leaking from the booster?

The PCV system is an extremely common issue on these 1.4s. From what I'm seeing it could be the PCV regulator diaphragm, check valve, or the hose going from the intake manifold to the turbo. 

I have noticed in the past week or two my idle has been a little rough, which seems to point to the diaphragm from what I'm seeing. 

It certainly wouldn't be a bad idea to get a catch can and I probably will in the very near future. Thanks for the help, I greatly appreciate it. 

HotNotch New Reader
3/12/19 12:19 p.m.

I thought that was your car yesterday!  Myself and a buddy were driving the Desert Tan 85 Mustang with the teeth on the side.  


Your car was definitely smoking a little bit, but it appeared to only be on decel.  More than likely the PCV system, but could potentially be valve seals.  We have the same issue, but I would expect it with a junkyard 302 being ran hard.



81cpcamaro Dork
3/12/19 12:36 p.m.

It wouldn't be a bad idea to change the booster as well, the brake fluid eventually does a number on the diaphragm inside and the booster will fail. If the booster diaphragm is leaking, it could affect idle as well. You could plug the vacuum line to the booster to see if the idle gets better.

J1000 New Reader
3/12/19 3:43 p.m.

This is a cool car and I love what you're doing with it. I bet it is a riot to throw around at auto-x. I can't help but think that this car seems like it needs a lot of maintenance. Is that normal for the Sonic?

Robby New Reader
3/13/19 11:18 a.m.

In reply to HotNotch :

Oh, hey, that car was pretty cool. I haven't really seen to many foxbodies autocrossing, so was glad to see that. I'm going to hope for PCV and probably work on it over spring break in a few weeks.

Robby New Reader
3/13/19 11:26 a.m.

In reply to J1000 :

Thanks! It is rather fun, needs a LSD though.

Sonics do have some common issues that I seem to have developed about all of them. There's a bearing issue with 6 speed manuals from 2012-2013, PCV issues on all 1.4s, waterpump on I think 2012-2013. Other than those, I haven't had too many issues that I wouldn't call wear and tear considering how I treat this car. 

Daylan C
Daylan C UltraDork
3/13/19 6:19 p.m.

My anecdotal turbo Sonic evidence is my buddy's RS has had some water leaks pop up that he fixed pretty easy and the stock clutch was cooked at like 140k miles. Clutch seems reasonable to expect from a used turbo hatch that had a cold air intake and no other mods when he got it. His spends most of its time either sitting or hauling sound equipment.

Robby New Reader
3/14/19 9:15 p.m.

Picked this up today. 1994 with torsen diff and 116k miles. Came with two sets of wheels and a Snoop Dogg CD. It's super fun in a completely different way. I'm going to try to not spend a lot of money modifying it. 

Robby New Reader
3/31/19 9:11 p.m.

Got new tires and put the new top on the Miata. Went with Ohtsu FP0612 for $45 a piece. Took it to autocross today and was surprisingly impressed with them. I didn't want to spend too much on them and didn't want too sticky of tires where I can't slide around a bit on streets. 

Ordered all the parts for the Sonic. Went with a Camaro ZL1 master cylinder, which should help manage the bigger brakes without leaking. Also have an intake manifold on the way, which I'm pretty sure will fix my PCV issue. 

whiskey_business GRM+ Memberand Reader
4/1/19 2:38 p.m.

Just went through the PCV issues with my wife's '14 Sonic LTZ. The intake manifold check valve is the root cause of the PCV issues, but it causes the burst disc in the cam cover to fail and pull in unmetered air. Caused a light but noticeable misfire at idle, then a hard misfire after a couple days making the car undrivable. Replacing the intake should help, but the issue won't go away until the cam cover is replaced as well. 


It's unfortunate that the 1.4 intake check valve is inherently flawed and will fail again, once more killing the burst disk in the cam cover. If you plan on holding onto yours, you should look into some of the aftermarket solutions people have come up with.



Robby New Reader
4/16/19 5:11 p.m.

So I put on the new (ported) intake manifold on this weekend, didn't fix it of course. So I replaced the cam cover as whiskey_business suggested. Broke a plastic PCV hose in the mean time. $43 on Amazon or $79 at dealer...it's on its way here. Then we'll see if it's all fixed. Here's a pic before I cleaned up anything: 

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