Information on EGR system and intake Manifold Cleaning

If you shine a flashlight through the other opening, you should be able to move
around and see light through it.

 

I found this info interesting from the dealerships side of the coin. This guy has some good advice for diy'ers too.

 

Hi all (esp Mendel!)
Been through a whole lot of Prius chat about EGR and manifold cleaning that has been super informative. Tackled the EGR pipe and cooler yesterday on 2010 gen3 with 150k miles. Cooler completely clogged with soot. Chucked a straightened coat hanger in a cordless drill and managed to get the cooler channels clear after three rounds of that, followed by four or five with oven cleaner, then a pressure washer per recommendations.
My question concerns cleaning the intake manifold. I have it off the car, and I’ve taken a lot of oily gunk out of the EGR circuit, and run brake cleaner through the entire assembly per nuts about bolts on YouTube. However, there are numerous mentions on the forum about cleaning the EGR channels in the IM. however, the EGR ports in the IM appear to be blind and inaccessible. How can I be sure that the ports are clear? I’d be very grateful not to have to go through the entire disassembly process again, esp the blind nut under the cooler.
last question: the large intake manifold gasket appears to be in pretty good shape. Possible to reuse? Or false economy?
Grateful for any advice.
joe

 

There are small diameter EGR passages in the intake manifold, that branch off from that main EGR gallery, one per port:


^Thanks to @Mr. F for above pic.

I’ve had my intake manifold off twice now; second time I did replace all pliable gaskets, but orig did look good still. Still, only just past 100k kms on ours lol.

 

There is one hole for each cylinder. It's about the size of a .22 bullet.
I use a bore brush and gunk to clean them out. (using a drill) Yours appear to be completely
clogged.
You may have to use that coat hanger to open them up so you can completely clean
them out.

I would NOT reuse the gaskets unless you had no other choice. You can get them through
toyota inexpensively.

 

Here's the part no's I used, all the pliable gaskets interfacing with the intake manifold, ordering through Amayama. Prices are in Canadian dollars:



The metal gaskets between the EGR components and at exhaust manifold connection are metal: I wouldn't bother changing unless they're bent. Be careful not to drop the rearmost one, at exhaust manifold. If you can manage to extract the stud at EGR cooler's lower bracket, you can then leave the two rear studs on the cooler, and they will keep that rear gasket from falling.

 

I used gaskets from rockauto. If you replace the metal gaskets with ones from RA, the replacements may be quite a bit thicker and things won't line up very well.

 

Thanks to all for your advice and links. Sure wish I'd checked back here before reassembling everything this afternoon.
Secured new rubber gaskets for the IM from Toyota at 41st and Granville (resused the metal as they seemed fine) and reassembled after thorough cleaning all EGR parts. Or what I thought was thorough cleaning. Disappointed to see clacking somewhat reduced but still present... OBD now gives error code 304, which the internet tells me is the #4 cylinder. I'll take apart and clean out the EGR ports on the manifold more carefully as this still seems like the most likely cause of the issue. Not sure how I missed them as they are quite obvious in the picture posted by Mendel. I was convinced that the ports were somehow blind, inside the manifold!
At least I tried it out prior to reinstalling the wipers etc. Back to the salt mine.

 

Well, I’m in over my head now.

Pulled off the manifold again and confirmed that everything is clear, including the small EGR ports. Upon reassembly the motor started and ran for a few minutes with some clacking, still presumably from 304 misfire (sounds consistent with YouTube video in which someone pulls the plug off the #4 coil). Was going to pull the coil and swap with another cylinder, but I now get many warning lights and a “check hybrid system” error message. ICE now starts and runs for 5-7 seconds and then shuts down. Wondering if I’ve somehow run the traction battery down ( registers as very low) which is putting things into some sort of fail loop? Until I solve this issue I can’t really trouble shoot further. On the plus side, at least Priuschat is back online.

 

make sure that you've reconnected the pcv hose. It's easy to miss. It will suck in
alot of air and the engine won't start.

 

Thx ASRD. Will check PCV hose this evening. Also charged 12v battery overnight to rule that out. Refilled ICE coolant as it was low after taking off hoses to IM / EGR. Coolant doesn’t look milky and levels were steady prior to working on it so hoping the head gasket is ok. I’d have a look inside w a boroscope as Mendel suggests but I don’t have one on hand (nor had heard of one until Mendel suggested a chew days ago). Leak down also beyond my abilities.

 

Update: found hose to throttle body disconnected. Oops. That accounts for ICE refusal to start and corresponding error code (0309?) as presumably the HV battery was turning over the ICE without starting, which accounts for “check hybrid battery”… assuming it ran the HV pretty far down.
ICE now starting and charging HV battery, which is up to 3/4 full. Rattle persists. Cleared codes and got PO304. Swapped coil between 3and 4 and cleared codes. Error code PO 301 … Wth? Removed the spark plugs for visual inspection and replaced with new plugs (clutching at straws). Discolouration appears to be from rust on plugs 2,3,4 above threads. Sign of bad head gasket? (Pic below) Rattle somewhat diminished. Took a deep breath and drove around the block. Rattle returns. Goes away at higher rpms. Come back under load. Error code now back to PO304. Ordered $35 boroscope from Amazon that should arrive tomorrow to see whether cylinders indicate head gasket damage. Assuming one or more shiny barrels would be evidence of that? R

 

I think for DIY boroscope inspection, a good tactic would be to drive the car (which will build up pressure in coolant system), then let it sit overnight. Do the inspection the next morning, look for a piston top that looks cleaner than the others (due to coolant cleaning it), and/or tears of coolant, commencing at the head gasket seam.

Is your on-order boroscope capable of side-viewing?

 

Thanks for your advice, Mendel. I'm hoping that a mirror attachment included with the boroscope will allow for side viewing.
Wondering whether it would make sense to drive the car with the current rattle though ... twice around the block last night had me pretty concerned. Error codes now reduced to intermittent P301,P303, P304's, indicating roving misfires.

Detaching the EGR sensor made no difference in the rattle. Replaced the spark plugs last night. Is it worth installing new set of OEM coils to rule that out as well? They look to be original with 150K miles on them and pretty significant discolouration to water ingress. Corrosion at bottom of plugs is also appears to be on the coil springs contacting plug tops. All consistent with water ingress from above.

 

An alternative to driving (to pressurize the coolant system) would be to somehow tap into the cooling system, say by adding a T-connection to a hose leading to reserovir, and pressurize the system.

One way to do that is with an automotive-size fluid extraction syringe, coupled with one way valves. Here's an example, currently set up to apply-and-hold vacuum:



If you flip the valves, then it will apply-and-hold pressure.

All this is basically to increase the rate of coolant leakage. But even without pressurizing, you may see pooled coolant atop piston(s), and maybe a tear coming down from the head gasket seam.

 

This looks like a good spot to tap-in, for pressurizing:

 

Local auto parts stores should have a loaner tool for pressure-testing your cooling system: https://shop.advanceautoparts.com/p/powerbuilt-tools-loaner-tool-cooling-system-pressure-kit-22-piece-940427/9150049

 

This radiator pressure checker looks like it might be available for loan at Canadian Tire(!) assume that it woud do the job?

 

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