Carbon Buildup with DI Engine

cbrsilv15 · June 29, 2017

http://www.gm-trucks.com/forums/topic/191007-anyone-had-a-valve-cleaning-performed-yet/

Knightfall · June 29, 2017

Just a thought, maybe the reason your engine temp creeps up when you gun it with these motors is to help burn off carbon?

Bxnanaz · June 29, 2017

Just a thought, maybe the reason your engine temp creeps up when you gun it with these motors is to help burn off carbon?

I think it's more due to the gauges actually being decent instead of most other manufactures putting in dummy gauges

mookdoc6 · June 29, 2017

Just a thought, maybe the reason your engine temp creeps up when you gun it with these motors is to help burn off carbon?

The GDI engines are designed to run hotter/more efficient is mostly the reason.....

mookdoc6 · June 29, 2017

Just learned that the 2017 F-150 has a new 3.5L Ecoboost that's also added port injection on top of the direct injection. Time to place bets on how long it's going to take GM to make the same change...

FERD is actually quite behind on GM in many areas.....Mainly do to the ecoboost fiasco. GDI is something FERD is following GM on. Many things have happened and since 2008 bailout somehow FERD came out as the "clear winner" The reality is not the case........

jono20 · June 29, 2017

FERD is actually quite behind on GM in many areas.....Mainly do to the ecoboost fiasco. GDI is something FERD is following GM on. Many things have happened and since 2008 bailout somehow FERD came out as the "clear winner" The reality is not the case........

I'm sure you're right, but in regard to the GDI carbon issue specifically both Ford and Toyota are now employing dual injection on their newest engines so that's something GM is behind them on.

I'd bet we'll be seeing the D4-S dual injection design from the Tacoma V6 carried over to the refresh of the Tundra V8 in the next year or two.

Edited June 29, 2017 by jono20

truckguy82 · June 29, 2017

I think it's more due to the gauges actually being decent instead of most other manufactures putting in dummy gauges

I'd bet it's just that the heat transfer from the block/head to the coolant is more effective.

To watch the water temp climb in the middle of a wot throttle run is impressive to me.

Nightcrawler · July 11, 2020

My experience with a 2011 Buick Lacross 4 cyl. with 83000 miles is making me nervous about my 2017 Silverado 5.3. The Buick started running rough last January (2020) at short intervals about once per 18 mile round trip setting a code PO300. first mechanic who had been Saturn gm certified replaced NO. 3 coil and all spark plugs with no improvement. Second mechanic found improved engine operation with MAS disconnected found engine air cleaner installed by another GM dealer last November with the corner of the filter missing and replaced engine air filter and MAS. No improvement. Third GM dealer ( the one that replaced engine air filter) replaced cyl. NO 3 injector. Some improvement . HE suggested a complete valve job if new injector doesn't help. Second dealer then suggested injector cleaning at $300 including oil change. I am now trying Techron solvent added to premium gas. with some improvement and driving car agressively (w/n speed limit) on state highways instead of low speed back roads. Next is spraying Motorcraft caburetor tune-up cleaner into intake air flow after MAS. I have spent $1200 approx. so far and a valve job if necessary will be $1500 approx more. hope solvent works and welcoming comments h_bvec @ hotmail.com

Bobbigboy · July 22, 2020

On 7/11/2020 at 2:08 PM, Nightcrawler said:

My experience with a 2011 Buick Lacross 4 cyl. with 83000 miles is making me nervous about my 2017 Silverado 5.3. The Buick started running rough last January (2020) at short intervals about once per 18 mile round trip setting a code PO300. first mechanic who had been Saturn gm certified replaced NO. 3 coil and all spark plugs with no improvement. Second mechanic found improved engine operation with MAS disconnected found engine air cleaner installed by another GM dealer last November with the corner of the filter missing and replaced engine air filter and MAS. No improvement. Third GM dealer ( the one that replaced engine air filter) replaced cyl. NO 3 injector. Some improvement . HE suggested a complete valve job if new injector doesn't help. Second dealer then suggested injector cleaning at $300 including oil change. I am now trying Techron solvent added to premium gas. with some improvement and driving car agressively (w/n speed limit) on state highways instead of low speed back roads. Next is spraying Motorcraft caburetor tune-up cleaner into intake air flow after MAS. I have spent $1200 approx. so far and a valve job if necessary will be $1500 approx more. hope solvent works and welcoming comments h_bvec @ hotmail.com

Feel your pain ! Wish you luck with the solvent.

Grumpy Bear · July 22, 2020

On 7/11/2020 at 1:08 PM, Nightcrawler said:

My experience with a 2011 Buick Lacross 4 cyl. with 83000 miles is making me nervous about my 2017 Silverado 5.3.

1.) Wife's Terrain has that same 2.4 I4 motor. Started using some oil around 100 K when the PCV orifice plugged rendering the system inoperable. Lot's of foam in the rocker cover. Manifold came off to clean out and the valves were in need of cleaning.

Cleared there was still to much crankcase pressure so the plugs were pulled and GM solvent, the same solvent used to clean the valves, poured in for 4 hours the evacuated and fresh plugs installed. A can of motor flush, Gumout, went in the crankcase and allowed to do it's thing then oil and filter. This restored enough ring function to a usable PCV system back and cut oil consumption down quite a bit. 2500 miles later dropped a can of BG ERP in the crankcase per directions and another dump and refill. Using very little oil now and runs quite nice. Still tracking oil usage.

That GM solvent is VERY aggressive and cleaned the valve quite nicely. The better the rings work the less oil gets in the manifold to cause this condition.

2.) 4.3 Ecotec3 GDI 122 K. It uses no oil and the valves are pretty spiffy so far. Makes better power now than it did new and gets stellar fuel economy.

These 2.4's in anything larger than a Verano work to hard. IMHO.

Conclusion: The problem has been forever a problem of ring seal not GDI. GDI just took the mask off the problem. The OEM's, all of them, have rings down pretty good. Motors that look like the photo above use oil. Motors use oil because of poor seal OR heavy load. Poor seal in a motor that had a good seal is an oil maintenance issue OR and operator use issue.

Manufactures that use both port and direct injection are attempting to make a pretty good system idiot proof. IMHO

Point of logic. If oil wasn't in the inlet tract then port injection would be redundant. No need to clean a deposit that never forms, eh?