I just replaced the EGR valve in my 99 Suburban (K1500 - 5.7L) …
again. I am wondering if there is something else that I should look
at. I would imagine that the new valve could fail as well (because
there may be some other problem)
I was getting a P0404 code about 6 months ago (I have a code reader).
The car had typical EGR issues (rough idle, surging …) I removed the
old factory original EGR valve and cleaned the mounting area up (it
was not particularly dirty) and replaced the EGR valve and gasket with
a unit from Pep Boys. The brand was BWD I believe. The truck
immediately ran fine and the check engine light stayed out for the
last six months. The 99 Suburban uses one of those linear/electronic
EGR valves, and they are expensive (~$120 or more depending on which
part you buy).
A few days ago the truck turns on the check engine light again. It's
that good old P0404 code (EGR Performance). Indeed the truck is again
exhibiting EGR like issues (surging, particularly at lower RPMs). The
idle was not rough, but the truck was surging just like when the other
valve was bad.
I bite the bullet and buy a new EGR valve (since it did seem like the
EGR was bad). I removed the 6 month old EGR valve and cleaned the
mounting area up (it was still clean) and replaced the EGR valve and
gasket with an identical unit from Pep Boys. The truck immediately
runs fine again. I don't know whether the check engine light will
stay out … but the truck does run perfectly fine again.
I will search for my receipt for the old valve since I believe it is
still under warranty. However, I wonder if there could be something
else that could be causing the EGR valves to fail. Any thoughts,
cause this could be expensive if I have to put in a new EGR every 6
You need to clean out the passages in the intake. They are likely full
of carbon and crud, which is what is causing the problem. Pull the valve
off and use some stiff wire or cable to run down the passages. Once you
have it cleared out go get a can of SeaFoam or GM top cylinder cleaner
and run it through the engine. That will dissolve more carbon and allow
it to blow out of the engine through the exhaust. The easy way to use
either one is to pull the brake booster line off and allow the engine to
draw the cleaner in. Let it draw in about half the can or until the
engine stalls. Then shut off the key and let it set for 20 minutes or
so. Dump the rest in the gas tank. Now start the engine and take it for
a drive to burn off the cleaner and blow the crud out. It will generate
a LOT of smoke and spray soot and carbon out the tailpipe. DON'T USE IT
IN A GARAGE or enclosed area. Make sure the tailpipe isn't aimed at
anything that you don't want covered with carbon and crud.
Hey Steve... no Kleenscreen suggestion??
I put one in my 95 Blazer about 1 year/10,000 miles ago at your recommendation
and haven't had an EGR problem since..
Please remove splinters before emailing
I looked into the passages to see if there was any crud. I stuck my
fingers in there. The insides were black. However, there was no real
thickness to the black stuff, just a light coating. I have some
trouble believing that this would cause the problem ... but I suppose
it is possible.
OK, so it looks like Steve was correct. The new EGR valve fixed the
problem for two months .... WooHoo. The check engine light is on
again. A few days before the light came on, I was starting to feel
"EGR" like problems (a little surging, particularly at lower RPMs). So
it looks like those EGR passages need cleaning. I did not read the
OBDII code yet ... but I'm all but certain it will be a P0404 code.
I don't really want to run Seafoam or GM Top Engine Cleaner (TEC)
through the engine since I'm kinda worried that all that burning crud
could cause problems. I'm guessing that like it or not, I will have
to do the cleaning anyway.
From what I read, after running TEC through the engine I will need to
change the plugs and the oil. I am also kinda worried that it could
hurt the catalytic converter ... all that smoke going through the
converter does not sound good to me.
So as a preliminary fix I got one of those Klean Screen gaskets. I
will clean the valve carefully with carb cleaner (without getting any
cleaner into the electronic portion) and see if that buys me any time.
If that does not work, I'll get the cleaning done.
The gasket will stop the carbon chunks from getting into the EGR and
sticking it open.
The TEC won't hurt anything. It DOES generate a bunch of smoke when it
goes through but it won't hurt anything (provided you don't decide to do
the cleaning right after the neighbors put all their clothes out on the
clothesline, or in the middle of a BBQ with friends, then you may have a
Yes on the oil, The plugs wouldn't have to be changed unless one of them
bridges with carbon after the treatment. The reason for the oil change
is to flush out all the carbon that will go past the rings.
I do the treatment every other oil change on the 97 and the 02 just as a
prevention. Also do it on a lot of other vehicles. It really helps.
Steve turned me on to the Kleenscreen gasket a few years ago, and it stopped the
EGR problem completely...
I bought 2 so I'd have a spare and so far the first one is still working great..
Please remove [dot]splinters before emailing
So are you saying this screen gasket for the EGR valve stops the P0404 code
from being tripped? Wondering about that since that code indicates a misfire
on cylinder 4. It is interesting to see others having the same code though.
My '99 Suburban has done this for years, but only if it doesn't get a good
running every so often due to my wife using it as a daily driver. Get on it
a few times a month and it never throws the code when under stress during a
climb mainly at highway speeds. Don't get on it every so often and the same
code will throw and it will miss like mad for a few seconds until it clears
out and then go on about its merry way.
I've always attributed it to being a weak cylinder and getting deposits on
the valve(s). It has over 120K miles on it and keeps on going strong.
No idea about that code, sorry.. but the screen keeps carbon from getting TO the
EGR valve, so it doesn't bind up..
Our 95 blazer would get a "check engine soon" light and idle very badly and have
no power brakes at low RPM..
Had the EGR valve replaced and it the problem went away for a while, then came
I cleaned the little pin in the valve and the problem went away again but came
Steve recommended the Klean screen to replace the EGR gasket and the problem has
been gone for about 2 years..
OK, I verified that the code was indeed P0404. I bit the bullet and
did the top engine cleaning. I went to the GM dealer and tried to buy
TEC. They told me that it is not made anymore and gave me the "new"
replacement called "Upper Engine and Fuel Injector Cleaner" -
#88861802. I rigged up nice little funnel arrangement and slowly
poured the stuff in through the brake booster line.
Ultimately I poured the whole container in there and let the truck sit
for an hour. I started it up and it did the white smoke thing. I
decided to drive the truck rather than smoke out the neighbors. It
did seem to make a lot of white smoke. I also did some driving at
wide-open throttle. I forgot just how anemic the old 5.7 really is.
In any event, I can't tell any difference. . The engine still had
some EGR like symptoms … stumble/surge when you give it a little gas …
just off idle. Otherwise the truck runs OK ... not great … but OK. I
will change the oil tonight ... spark plugs seemed to be OK
Next, I took my previous EGR valve that I had cleaned with carb
cleaner … lots and lots of carb cleaner. I put that in with the Klean
Screen. I also cleared the P0404 code (so the check engine light is
out … for about a day or so). I can already tell that the "cleaned"
EGR valve is no good. The engine still stumbles/surges when you give
it a little gas … just off idle. So … I went to the store and bought
another EGR valve. I already know that when I put the new EGR valve
in the engine will not stumble/surge at all (since I have already done
this … twice before). .
My best guess is that none of this will have any long term effect. In
two months the new valve will be fouled. It would be great if the
cleaning and/or the Klean Screen solves this problem. Only time will
On Sat, 19 Apr 2008 16:02:16 -0400, firstname.lastname@example.org wrote:
Dan.. I had different symptoms, besides the "check engine soon" light, the real
rough idle and no power brakes at idle, nothing else was effected..
The truck ran fine except at idle, brakes were normal unless at idle, (and after
the first pedal push and release), and the fuel economy was normal..
I took the EGR valve out twice and both times the pin was frozen from carbon..
After putting the Klean Screen in, it's been trouble free for about 2 years
Hope yours is too!
Please remove [dot]splinters before emailing
OK, I put the new EGR valve in. Of course the truck runs correctly
now. No stumble/surge at any RPM. Idle is very smooth. Most likely,
by June 19 the new EGR valve will be fouled.
I believe that my engine is making lots and lots of carbon. This is
obviously what is fouling the EGR valve. I also believe the top
engine cleaning and the Klean Screen are most likely irrelevant. It's
not chunks of carbon fouling the valve. If this were the case, I
should have been able to clean my old valve (i.e., wash the chunks of
carbon out) and the valve would have worked again … but it didn't.
So my theory is that the gasses flowing though the EGR passages simply
foul the EGR valve … within two months. Whether the passages are
clean or not, those "toxic" gasses are going to flow through the valve
causing it to foul. I'm guessing that either i) the engine is
basically worn out or ii) there is something wrong with the way the
intake manifold is installed.
This truck has had a lot of problems (way too many). I bought the
truck new it now has 118K miles. It is pretty much always "broken".
It runs … it's just never right. The "service engine soon" light was
mostly on for the last 80k miles. No matter what I fix … it does not
last and that service engine soon light comes back on within a month
or two. For the most part the truck really never ran right. My wife
drives it most of the time and she does not really notice or care. I
usually hate driving the thing since it usually runs crappy. I went
through the whole random misfire fiasco … too much to detail here.
Anyway, once I got the injectors changed the engine finally ran OK and
life was good (for a few months). But then it started leaking coolant.
Of course it was not the water pump … again … this time it was leaking
coolant from the block, at the intake manifold. So the local mechanic
changed the intake manifold gasket and the leak was fixed. But its
been EGR hell ever since. I took it back a few times … again too much
to detail here.
So I wonder if it is possible to screw up the installation of an
intake manifold and cause all kinds of horrible fumes to flow into the
EGR passages. If this is possible, perhaps I need the have the intake
manifold done again (only correctly this time). In the alternative I
could try to make some sort of bulk purchase of EGR valves (since I
will need 6 of them every year).
Yes it is possible to screw up the intake gaskets. Do you notice and
white or blue smoke from the exhaust? If your not using coolant or oil
at a rapid rate I would guess the gaskets are OK.
It is also possible that the valve you purchased just failed.
The gasket is mainly to keep chunks of carbon from sticking the pintle
open. The top end cleaner dissolves the carbon and allows it to blow
through the system. It also cleans the valve heads, rings, and passages
where the carbon likes to build up.
Yep, I'm sure the TEC cleaned the combustion chambers. This is
certainly not bad. I'll bet there was carbon in there. But it does
not really make a noticeable difference when you are driving. The TEC
did not clean the previously fouled EGR valve and I was unable to
manually clean an earlier fouled EGR valve with carb cleaner (i.e., an
entire can of carb cleaner).
I installed a brand new EGR valve and of course the engine runs
"perfectly" … or at least as good as you could expect from a 1999
5.7l Vortec. The truck does not seem to be using fluids or blowing oil
smoke from the exhaust. It seems to run perfectly fine (with a new
EGR valve) … so I am a bit puzzled as to where all this carbon is
coming from. I should probably talk to the local mechanic. He spent a
lot of time on this truck (as did I). I mean, I bought a darn code
reader six years ago just so I could figure out why the service engine
soon light was always on. And I used that code reader a lot over the
years. The local mechanic fixed lots of problems over the years at
very reasonable prices. But this EGR thing has just sucked. He lost
a lot of money trying to fix this truck (cause I kept bringing it
back)… I'll be lucky if he agrees to work on it again (I wouldn't if I
I took a drive this morning and I actually enjoyed driving the truck.
If you press the gas pedal (even just a tiny bit) you feel some
acceleration. That is, the truck actually responds. Once the EGR
valve starts to go, you just don't feel the responsiveness and often
it is opposite of what you want (i.e., you depress the gas pedal and
the truck actually decelerates or hesitates or surges …). With the
new valve, the truck feels 500lbs lighter … it's like a whole
different vehicle. It can even go up hills without dropping out of
The drivability issues I have with this truck are kinda my fault. The
5.7liter engine was never really adequate for a vehicle this size. I
really knew this when I was buying the truck. I should have bit the
bullet and sprung for the 2500 with the 454 engine. Of course the
2500 is super major overkill for my needs (and gas mileage would
probably be worse than the 5.7l … if one could actually imagine that)
but at least I would have been happy with the power output.
So for now the truck is technically "not broken." Since it is garage
kept, it looks almost brand new. It took it to the car wash, cleaned
up the wheels and tires, cleaned all the glass and vacuumed the
interior. So if I left it in the garage for the next six months and
didn't drive it … it would be pretty and "not broken" for six whole
months. But alas, we are going to drive the thing. I will post an
update when I have something new to report.
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