CRC GDI Valve Cleaner Trial - Before and After (Never Again)

My 2017 Kia Forte 2.0 GDI engine has been misfiring and running a tad bit rough on cold starts and its only got 31K on it. I figured it was due to the valves gumming on so I was going to scrub them clean but people kept telling me to try the CRC GDI Valve Cleaner that you spray into the intake while its running between 2500-3000rpm. I never believe these miracle in a can products and I love it when I hear from people, "You should see all the crap that comes out of your exhaust!!". My response question to them is, how is it getting past the catalytic converter?

So I decided to remove my intake, get video of the valves condition before the treatment, then remove the intake again and see the valves after the treatment. Well this stuff did more harm then good. Yes a "tiny" bit was cleaned off but they are still gummed up. The biggest problem with this method is the design of the intake manifold. Since my 4cyl 2.0 engine's intake drops low before the air moves back up and into the engine head, a lot of that cleaner pools in the intake regardless how slow you go or how long you wait between sprays. Once you hit the throttle to drive off, it sucks a bunch of that crap up and starts pinging away and smokes like hell. Sounds like the engines is tearing its self apart.

I tried to be as cautious as I could with this crap. They say to empty the whole can in one treatment. I did it in two treatments with a long drive in between with light throttle to get the pooled fluid to evaporate and get consumed little by little. Still had a good amount get consumed at once, once in awhile. I only sprayed the can for about 3-4 seconds at a shot the first treatment, and only about 1/2 - 1 second the second treatment, both times about 30-60 seconds in between sprays.

My thoughts.....I will NEVER use this stuff in that fashion ever again! It MIGHT be ok with 6-8 cylinder engines that don't have a valley in the intake manifold where the stuff can pool up. It also leaves an oily residue behind which I had to clean out of the throttle body I just cleaned. How I would use it, is by spraying the valves and pooling it up in the intake runner, scrubbing the valves with a wire brush on a drill and then sucking out all the fluid and rinse them down with some carb clean or with the same cleaner.

Also within 31K miles, my throttle body had a real nice carbon lip on the bore. I was very surprised as to how bad it was. After I cleaned the throttle body and gave the engine hell with the spray can I reset all the adaptive values.

So it didn't clean the valves and I will be doing it how I was planning on originally next time I get time. I have video and pictures I need to put together with before and after shots so be patient, I'll get them together.

I"ll be back with updates

The biggest problem with this method is the design of the intake manifold. Since my 4cyl 2.0 engine's intake drops low before the air moves back up and into the engine head, a lot of that cleaner pools in the intake regardless how slow you go or how long you wait between sprays. Once you hit the throttle to drive off, it sucks a bunch of that crap up and starts pinging away and smokes like hell. Sounds like the engines is tearing its self apart.

Well done being careful on that one. :ohmy: I had an ACDelco class where GDI carbon cleaning came up. Apparently, dealers have had issues with techs hydrolocking engines after a cleaning service. They dump the cleaner in at flat rate speed, hit the throttle on a test drive, and oops!

Yup and I certainly will be keeping a close eye on my oil level and condition for a little while. It never burnt oil before so hopefully it stays that way. Its under warranty still lol. No matter how careful I was it was still not careful enough. Never ever again.

Pictures are green cause I had to use night vision to see them.

Here is one of Cyl 1 valves before. I have all the others still in video just needing to find time. All other valves look the same though.


Here is one of Cyl 1 valves After. Same one. little hard to see since its open this time. I"ll get the other pics.

I never use those kinda cleaners. It's like you said. They're junk and crap.
We had a car in the shop a few weeks ago. Same problem. Gummed up valves. So I took the intake off and called this guy I know for some walnut blasting. Forgot to take pictures but I was pretty pleased with the result.

Ya walnut blasting is something I would like to get into eventually. I hear a lot of good things about the process.

Yeah that CRC stuff didn't clean much of anything. :blink: :lol: Probably made lots of smoke, though!

When I got my first car, I used to think I was cool for smoking my neighbors out by running a can of Seafoam though my brake booster hose. Now I know better. :blush:

It is sctually amazing how much water you can spray into a throttle body and the engine will still run the trick to use a finely dispersed spray.
However it reminds me of a friend back in the 1970s he had a Sunbram Imp a nice little car with very neat all aloy engine but very prone to head gasket failure. Of course the head gasket blew and he replaced it not realising the head had also cracked. For months afterwards he had to remove the pressure cap everytime he parked and take spark plug out to expell the water before he could start the engine.

Here are some pictures of the valves after cleaning them by hand. I did use the CRC Valve Cleaner as the cleaning solution. Spray the valves bores and let it sit for a couple min. Blew everything out with an air hose while keeping a paper towel over the bores to catch everything.

I'm very satisfied with the results. Wish I could have got it all but it took about 4 hours to get them this clean using nylon brushes.

Much better

Shiny. Unfortunately, this is probably gonna be a regular service on GDI's like this.

Yup. I am trying to find a good way of offering a maintenance service. I have a few ideas. Removing intake manifolds all the time will not be a good idea all the time especially some taking hours to remove on top of the hours to hand clean valves. For shops its fine...for me on the road though, not so good.

Just a FYI I learned from the last GM Class. Supposedly Ford has had issues with their turbos after using cleaners like this. Supposedly these cleaners burn really hot and end up melting the turbine blades in the turbos.

Tyler wrote:

The biggest problem with this method is the design of the intake manifold. Since my 4cyl 2.0 engine's intake drops low before the air moves back up and into the engine head, a lot of that cleaner pools in the intake regardless how slow you go or how long you wait between sprays. Once you hit the throttle to drive off, it sucks a bunch of that crap up and starts pinging away and smokes like hell. Sounds like the engines is tearing its self apart.

Well done being careful on that one. :ohmy: I had an ACDelco class where GDI carbon cleaning came up. Apparently, dealers have had issues with techs hydrolocking engines after a cleaning service. They dump the cleaner in at flat rate speed, hit the throttle on a test drive, and oops!

Sorry for digging this up, but I had the same thing. Learned it the hard way too. I have the current Mazda CX-5 with the SkyActiv-G, which has the same similar design of the intake manifold. I have done two treatments of this product on my Toyota Caldina 2003 with no issues in the past as it has a different manifold design. Thus, no pooling of the cleaner.

I made a grave mistake of flooring it after I had waited for an hour. It was accelarating fine until it hit the point, where there was enough suction to suck in all those cleaner in the manifold. Then, the engine knocked a couple of time while blowing a huge cloud of smoke. So, I took my foot off the gas and let it cruise before giving it a light gas. It was fine for the rest of the drive. But for a while, it would ping/knock if it exceeded a certain RPM until all the cleaner was gone.

The aftermath, I reckon the acceleration has decreased although further testing is needed to confirm this. The engine is definitely louder than before, but seems to run smooth while idling and driving. What sort of damages has been done to the engine? What would be the next step to take? Thanks in advance. Cheers.

On large marine 2 stroke diesels part of the morning watch juniors job was to spray water directly into the turbo for a few minutes.
I am wondering about how much effect introducing steam from wall paper or kitchen steam cleaner into a running engine would have.

PTCB wrote: The aftermath, I reckon the acceleration has decreased although further testing is needed to confirm this. The engine is definitely louder than before, but seems to run smooth while idling and driving. What sort of damages has been done to the engine? What would be the next step to take? Thanks in advance. Cheers.

Any trouble codes afterwards? I'm sure some got set during the treatment, but in the days since?

If it seems to run smoothly without misfiring at idle and under load, then I'd suspect that you probably didn't damage anything in the engine. The best confirmation of this would be compression and leak down testing on all cylinders.

No offense meant here, but are you sure the engine is louder and low on power? Because it's very easy to become hyper sensitive about such things after a service or repair goes wrong. Especially when you know expensive damage is possible.

Andy.MacFadyen wrote: On large marine 2 stroke diesels part of the morning watch juniors job was to spray water directly into the turbo for a few minutes.
I am wondering about how much effect introducing steam from wall paper or kitchen steam cleaner into a running engine would have.

I have also wondered if the induction of water steam would be a viable solution on a modern engine

Thanks for posting this. I'm super skeptical (in general) about these can fixes and haven mechanically cleaned valves before, it's hart to believe that brief contact with a chemical would touch it. I had an intake off of a Nissan Juke with like 11k miles and was surprised how much build up there was on the valves already. It was a short distance commuter, which would play a part. I do know that the new Altimas have GDI but also have a fuel injector that works the traditional way to combat this GDI issue. We will see how it works.

On LPG conversion especially on some Japanese engines it is quite common to add additional nozzles into the intake manifold to inject a lubricant to protect the valves

tinleytech.co.uk/shop/valve-savers-and-f...-valve-saver-kit-e2/

Steam cleaning & water spray test.

Only test vehicle to hand was a turbo diesel I tried using a steam wall paper steamer to introduce steam to the inlet downstream of the MAF and Turbo at the EGR this was followed by trying water spry combined the steam spray resulting copious water vapour exiting at tail pipe. When the vehicle was road tested with accelerator pedal to the floor under full turbo boost a considerable ammout of "something" could be seen coming from the exhaust.

This treatment didn't have much effect on baked on carbon at the EGR but removed some and most of any oil residue, interestingly the next day after any condensation on concrete where the car had been sitting had dried a considerable area around where the exhaust tail pipe had been was stained with a dark grey deposit.

How effective this treatment was on cleaning the inlet is in doubt but I am sure there was some cleaning effect on the combustion chamber, exhaust side of the turbo and the catalyst.

Seeing that reminds of what I learned from a seminar.
I had attended Automekanica a couple of years back and as per the seminar,
the host claimed that adding water can ruins the O2 sensors.
The biggest problem with GDI cleaning is that the carbon once built up
becomes too hard to dissolve.
The problem is if those chunks of carbon break off that they glaze or foul the catalytic converter. The host claimed that after studies nothing seems to work effectively but someone was working on a three stage chemical process that involved cold and hot fluids being injected.
I have not invested in any new cleaning equipment and have only done a handful
of intake spray type cleaning attempts on vehicles that develop idle issues.
I do offer it as a preventative measure only.
Customers don't like when you do not offer any positive assurances from the cleaning process so they either then don't do it likely go to a shop that offers
false promises.
It kind of leads me to needing to re examine some sort of chemicals or process that does work. I had believed that CRC would work provided the build up is not too severe and the cleaning is done frequently enough.
I also had my own experience on my own vehicle with it puddling in the lower intake and pinging on the highway . i was afraid it would bend a connecting
rod from hydraulic lockup. Not that I would be able to tell because
these vehicles have bottom end engine failures anyway LOL.
All joking aside I don't think I harmed it but will look to spray in the pcv
system or a stick a tube in a vacuum hose that does not go into the lower intake.
It is important though that it keeps atomizing and not puddling.
That is a tip that I got from a Peer who used to be my local BG rep.
Now in the current situation I might have some time on my hands to
re examine the process and chemicals.
I hope other members post if they find something that works well.
I tend to believe the best solution is removing the intake.