I have a 1999 1500 Express van with 5.7L Vortec engine. It has the
well known problem of leaking coolant at the intake manifold to head
I have browed lots of posts on this subject but would like more help.
My factory service manual says I need to remove both valve covers
which appears to require removal of the steering pump pulley and
moving the AC bracket.
My Felpro intake manifold gasket set only includes one valve cover
gasket so they seem to think removal of both valve covers is not
Why does either valve cover need to be removed?
If only one needs to be removed then which one?
Can the manifold be removed/replaced without moving the power stering
and AC mounting bracket?
Anything else special about doing this job on a G van?
No need to remove the PS pulley or the PS pump itself. Remove
the AC compressor and move it aside, unbolt the AC/PS bracket and
pry it forward until it's clear of the corner of the intake
manifold. IIRC, there are three bolts thru the bracket from the
front, and one bolt on the back side of the PS pump. Lots easier
than it looks...
Correct. I usually remove the drivers side valve cover, on a
van, passenger side might make more sense.
The valve covers overlap the intake manifold.
Your preference, I pull the drivers side. On a G van, it -may-
make more sense to pull the passenger side since that side offers
more room to work on a van.
No. The bracket overhangs the manifold and one bolt in the
drivers side front corner. But, the bracket is very easy to move
forward once a few bolts and nuts are removed.
No, just follow all the advice that Ian and I have posted over
Follow the torque specs EXACTLY, do NOT over torque.
Torque values are very low, make sure you use a torque wrench of
appropriate capacity (electronic is best).
Use blue loctite on the manifold bolts when installing.
NO Roloc pads when cleaning, putty knife and razor blades to
scrape the gasket surfaces, don't sweat the stains left on the
gasket surfaces, it doesn't have to shine, just be clean and flat.
New coolant disconnect while the manifold is on the bench (if
NO sealers required except the ends of the block/manifold
interface, I use "The Right Stuff" instead of the black RTV that
comes in the Fel-Pro kit.
Keep the injectors 'wet' which means cap off the fuel rail lines
There is a mix of metric and SAE fasteners so be careful before
you round off a bolt head.
Manifold bolts do not need to be replaced unless they are
corroded anywhere along the shank/threads.
Thanks for the advice. I spent an hour or more studying the problem
this afternoon after removing the engine cover, air filter, and
coolant reservoir, and could then see that the bracket obstructed the
front left manifold bolt. Good to have the confirmation that the
bracket has to move but that it can be done without removing the PS
The jobs looks to be quite awkward and I was tempted to have it done
at a shop. Trouble is I'm not sure I can get a reliable quote. Pep
Boys gave me a price but said no need to remove the AC compressor or
either valve cover. If required that would be extra. (I'm guessing a
Vans have their advantages but engine access is not one of them. :(
Valve cover and AC compressor removal (when required) is part of
the labor time for the job, where they come up with the 'extra"
is anyones guess. A brake and tire chain is probably not the
best choice for any type of engine work... they've already given
up clues that they probably are not all that familiar with the
job to begin with.
WRT the intake R & R, There are things that are easier to do on a
van versus a pick-up truck, the van is a little more awkward
compared to doing it hanging over the grill but it's not a
This thread has got my name all over it....I will be
doing this job on my '99 G30 -5.7 which has the mystery coolant
loss.....Just waiting for a little warmth and way less snow ;)
The only thing I can add may be obvious, but taking 5 minutes to yank out at
least one seat makes it way nicer to get into the engine bay in the truck.
Throw a mat or such on the protruding bolts and flail away !!!
Good luck with it.....
I can't comment on the accessing the engine in a G series...but I just
finished this job in a 99 Tahoe. After I finished the job...except some
distributor issues....I found a good write up on the procedure from another
group. I can clean it up, add my own comments and post if desired...please
advise. I also made a list of all the torque values, but I through it out
when I cleaned up the shop. Sorry.
Let me say that, in general, this is not a job for the week. If you have
good skills, patients, and time you can do it. There are no major technical
issues and no special tools required but the p/s pulley removal tool and a
light duty torque wrench. I've done a lot of repairs and such...and I was
quite proud of this one. I cleaned everything as I went along plus re-taped
some of the wire looms. The only evidence of me being in there is the fact
that the intake and valve covers are factory clean.
It is holding strong and as of day 4......has not consumed any coolant. (But
I'm still running a 7 lb cap. Next week I'll put the 15/16? lb cap back on.)
Note that I did send in a sample of the oil prior to the repair...and it did
show glycol contamination but no concentration values. There was no visible
evidence of water in oil...so it must have been seepage that allowed the
water to boil out and leave glycol behind. Hopefully no damage was done.
Also, thanks to Cuda, no more P1345 which cost me hours because I didn't
mark the distributor before I pulled it out. Was banking on just rolling to
1TDC and pokin' it in.
I would appreciate at least a link to the site you're talking about.
But if it's not too much trouble I would appreciate you listing your own
version. I think I'll be needing to do the repair to my Dad's 1990
Sierra soon. Thanks.
Updated by request....
----- Original Message -----
Sent: Sunday, February 18, 2007 10:39 PM
Subject: Vortec Lower Intake Gaskets for Dummies - requested in another
In response to a request to post a collection on the replacing lower intake
gaskets on Vortec CPI engines....
Comments and corrections appreciated.
My experience is on a 99 (old style) Tahoe 5.7. Your experience may be
different. No warranty expressed or implied. Quantities may be limited. Void
where prohibited. Offer may expire without further notice. Yadda yadda
You should look up all the torque values in your manual.
I bought the complete Felpro intake manifold set which was not complete at
all and very expensive. The Felpro design is great. I suggest buying the
gaskets you need and not the kit. I used the lower intake gaskets, the RTV,
and the fuel line o-rings...that was it. There was only one valve cover
gasket, but I took both covers off for cleaning. So I had to buy the valve
cover set. There is a part number for only one gasket, but at Pep Boys, it
was a dollar more than the pair and special order. The kit comes with the
upper plenum cover seal and the throttle body seal but no fuel line to
metering block o-rings so you are short if you need to take the plenum cover
off. I think it is also short 8 o-rings for the injectors, but I'm not sure
how those work because I didn't go there. Remember..this project is to fix a
coolant leak...not a air/fuel leak. The kit doesn't come with the thermostat
seal but your new thermostat should. No EGR gasket either. The EGR gasket
and thermostat are not needed to fix your cooling leak, but you should
replace your thermostat and clean your EGR ports while you are there. The
intake is more fun to work on at the bench than under the hood.
1. Disconnect negative battery cable.
2. Drain the engine coolant (if there is any left:) to at least a level
below the intake. If you have original coolant..drain it all and discard.
3. Remove the air duct from the mass meter to throttle body (cover the mass
meter opening with a shower cap or zip bag. Same for the TB or stuff with a
lint free rag.
4. Now is a good time to take lots of digital photos...in case you run out
of beer before you get it all back together.
5. Remove the upper radiator hose and three heater hoses. One of the heater
hoses has the quick disconnect that may crumble in your hands like powdered
Gatorade. Have a spare on hand if you don't want delays. The hose with the
quick connect can be popped out of its holder and folded back out of the
way. The aluminum bypass tube can also be loosened. I can't remember what it
gets in the way of...but some slop helps.
6. Remove the top radiator shroud and get it out of your way - especially if
you are going to remove the P/S pulley...discussed more later.
7. Remove the vacuum booster hose from the intake and rotate the check valve
in the booster so this hose is out of your way. Tuck it over by the booster
or down by the driver's upper control arm. This hose will constantly be in
your way if you don't.
8. Take the wires off the cap and INDEX THE CAP SOMEHOW WITH A SHARPIE.
Remove the cap. Mark with a Sharpie where the rotor is pointing - exactly.
Also index the distributor shaft housing
with the hold down clamp or intake with a Sharpie. You might need a small
mirror to do this. (CAN ALSO roll the engine to #1 TDC compression stroke
and line up the timing mark on the balancer with the indexer on the block.
With the cap off, you don't need to pull the spark plug. The rotor should
point "near" the cast "8" next to cylinder 1's electrode. You should mark
the difference between the rotor and the "8" so you can re-create it...else
you will probably throw a P1345 code upon restart like I did.) I used a 13mm
stubby combination wrench for the distributor hold down bolt. There is not
enough room for a full size wrench...there is to break it loose but not make
quarter turns. An old fashioned distributor wrench in 13mm would work good
too, especially if you can put a ratchet/torque wrench on it to set the
torque. The distributor housing is plastic. Be careful when you put the hold
down clamp back on it. It likes to be in every position but the right one.
Use a small mirror to see it in the right spot before you tighten it down.
Also, book says the cap's screws are good for one time use only. Maybe you
could just put on new thread-lock paste - not drops. The housing is plastic.
If you haven't changed the cap and rotor before, now is the time and you
will get new screws with the cap and rotor.
9. Disconnect all electrical connectors and the necessary loom clips. I
disconnected the alternator's plug but not the main battery lead. Do not
attempt to remove the big wiring harness. Just disconnect everything and
move the little pig tails out of the way to a safe area. Bungee cord the two
big looms over the middle so that they are suspended above the intake. I
didn't bungee.but should have. The intake will slide out from underneath the
wires...hence my later term "re-entry."
10. Be careful with the tangs and such on the electrical connectors.they may
be old and brittle. (I did find them to be in better shape than those on my
'99 Navigator.) Note one of these loom clamps near the EGR to intake
connection is a nut on a nutted-stud fastening the plastic upper intake. The
stud will probably turn when you try to loosen the nut and you can't back up
the stud with an open end wrench. See notes at end on what I did. Also note,
all the electrical connections are different so you don't have to mark them.
My looms were stiffened from the heat enough to lay back into their original
positions. There is a ground wire on the thermostat cover. It has its own
11. There is a bracket that holds the wiring harness at the passenger side
rear of the engine. Don't bother trying to get it completely out of the
way. Just unbolt it where it is secured near the coil and then just lift it
up and out of the way. There is no need to attempt to unbolt it where it is
secured to the rear of the head. (I had no problem with this bracket but
here is a tip others have noted.... You will note though that the bracket
has a small tab right where it intersects the cylinder head/manifold area
that sticks forward over the intake. You need to bend this tab out of the
way, before you re-install the intake, otherwise it can interfere with the
manifold as you are moving it into position.) Also with respect to this
clip....if you are going to take off only one valve cover...removing the
driver side cover my help the intake slip under this tang.
12. Remove the Evap line from the passenger side solenoid. Don't break the
clip like I did. Push on the one side of the clip with the nipple "into" the
slot and pull on the hose just after depressing the clip. The hose should
slide right off. I broke the clip which is not available from parts. The
entire hose with EVAP test port was twenty-something at GM. If you break a
clip, post a request and I'll sell you one for $10;)
13. Disconnect the throttle cable and cruise cable. One has a clip. The
other just slips in a stop and the cable wraps around. Then squeeze the
plastic casing locks out of the bracket and tuck the two cables out of the
14. Remove the drive belt.
15. Remove the four A/C compressor mounting bolts. DO NOT DISCONNECT THE
HOSE ASSEMBLY. When the time comes, you'll slide the compressor FORWARD to
access the driver/front manifold bolt. OR YOU CAN DRAG THE COMPRESSOR OVER
AND STORE IT ON THE BATTERY.
16. Disconnect the EGR pipe from the intake near the front and the bolted
hold-down bracket in the back. Don't remove the connection from the exhaust
line...that is not necessary and could lead to trouble.
17. Somehow disconnect the PCV valve hose. I pulled on the molded elbow on
the manifold connection so I could just swing the tube around and not have a
hole in the valve cover. When I did, it peeled apart like mozzarella cheese.
Replacement tube with valve was only $7 at GM. You might just pull the valve
out of the cover and remove the intake with the tube and try to remove it on
the bench. It is best to clear it out of the way for a smooth re-entry. Or
just buy the tube and valve the day before.
18. Disconnect the two fuel lines at the rear of the manifold. Do not remove
the fuel lines where they go into the upper plenum in the middle. Once you
have the distributor out, it's easy to disconnect the lines right back at
the firewall. You should replace the o-rings. One is big and one is small.
(The o-rings in the Felpro kit were black. I've never used black o-rings in
gasoline service. Usually, they are red. Hopefully black won't be a problem.
I should have picked up some red o-rings from GM like original and on my
'93. Black usually means Buna-N which is not the best choice for aromatics.)
19. Disconnect the electrical connector from the P/S pump if there is one.
My pump had no connector. There is a clip on the P/S bracket holding the A/C
compressor high pressure switch wire/loom. I delayed taking that loose but
eventually did and was glad. It allowed that entire pig tail with the A/C
clutch plug, temp plug, and ground to be cleared out of the way.
20. TWO OPTIONS:
OPTION 1: Remove the P/S pump pulley and loosen the P/S pump bracket nut and
bolts on the front of the bracket. BORROW TOOL FROM AUTOZONE. One bolt is
hiding way down at the
bottom. Don't remove the two pump fasteners behind the bracket. Leave the
longest bolt in three or four threads so the bracket doesn't fall off. I
forget which bolt is the longest but you will figure it out. Two are only
about 2 inches long. The long bolt is 4+. This will allow you to slide the
bracket and the loose A/C compressor forward to get to the driver/front
manifold bolt. The compressor bolts might not have to be removed but it
helps to get the compressor more forward than the bracket. THE PUMP WILL
STAY ATTACHED TO THE BLOCK BRACKET.
OPTION 2: DON'T REMOVE THE PULLEY. REMOVE ALL THE BOLTS ON THE FRONT YOU CAN
EXCEPT THE ONE BEHIND THE PULLEY. THEN REMOVE THE BOLT/NUT? BEHIND THE PUMP
THAT HOLDS THE PUMP TO THE BLOCK.....THE PUMP WILL THEN SLIDE OUT WITH THE
A/C BRACKET. BE CAREFUL NOT TO BEND THE P/S HOSES BEHIND THE PUMP.
21. The intake gasket kit ships with only one valve cover gasket. You have
to take off at least one valve cover to get the intake off. The cover lips
sit over the intake so there is no choice but take one off and slip the
intake out from under the other. I removed the intake with the passenger
cover tilted to the side but then went ahead and tilted the driver's side to
the side as well for re-entry. It just looked easier with more space...and
it was. Plus, I took both covers off and gave them a good cleaning. That
black patina sure looks better than gunk in all the crevices.
22. Remove the intake manifold bolts and remove the intake. You will have to
pull up on the wire looms and slip the manifold out the front. I did it even
with the coil and ignition module on. Four of my intake bolts where corroded
to an hourglass shape. I went ahead and replaced all 8 bolts.4 bucks each at
GM. (Yeah, only 8 bolts! I don't know how many bolts a legacy small block
V8 has, but my 4.3z has at least 12. 8 on the vortec...another dumb mistake
23. Clean the threaded holes where the intake bolts fasten. Clean the heads
and intake with a solvent saturated rag. If you scrape, be careful not to
scratch. Do not use abrasives, emery, stones, whatever, to clean the heads.
All the aggregate will fall into your valley/block and ruin your engine.
Before I started cleaning, I dabbed up all the antifreeze, fuel, and oil
from the valley area and cleaned the deposits from the low spots. Then I
cleaned the gasket areas on the heads and block. Then shop-vac'd the valley.
Then cleaned again with a lint free rag. Then I poured a quart of oil over
the entire valley to rinse any remains to the pan and leave a protective
coating. I covered the valley with heavy aluminum foil to keep the crickets
out while I slept. I also cleaned the manifold with solvent only. Maybe
there is a better way..like a cloth polishing attachment on a drill or roto.
It was pretty easy to clean even by hand. Plus I cleaned all the non-gasket
crevices just to make it look good and be clean. (I don't know if a shop
mechanic would do this .because I've never hired one. But I do it because my
dad taught me to. Yeah, he likes things clean.so I got to do the cleaning. I
guess scraping gaskets kept me out of his way. I'll be glad when my son can
scrape gaskets and chip welds.)
24. Check the intake faces with a straight edge like a nice level to be sure
they haven't warped.which is unlikely if you didn't overheat it. If you see
light along the straight edge, use a feeler gauge to measure and compare to
25. For most people, this job is to replace the lower intake gaskets to fix
a coolant leak. If you aren't having trouble with the upper intake, save
that job for another day. HOWEVER, there were a couple of bracket/loom hold
down nuts I had to remove that in turn loosened plenum cover studs. The
Felpro kit does not come with all the gaskets you need to remove the plenum
and the fuel pipes from the metering block. SO DON'T take all that apart
unless you need to and you have all the o-rings. Here is what I did on the
bench. Since a couple of the studs came loose, I went ahead a loosened all
of them one turn. Then took one out at a time, applied some loc-tite medium,
and returned that stud to near snug. After they were all done, I torqued
them in stages to spec in a crisscross pattern from the middle to the
outside. I did not replace the elastomeric gasket since I didn't pull the
cover.just loosened the bolts/studs. Had it been paper or such, I would
have. So far, so good.
26. With the intake on the bench, you might want to remove the EGR valve and
clear the carbon from the EGR passages. Buy the gasket the day before..it is
not in the set.
27. I pulled the intake off with the coil and module in place. They snagged
a few times on the loom so I removed them for re-entry. I went ahead a
removed the module from its holder and cleaned the heat sink with alcohol
and applied a thin layer of Ceramique heat transfer paste which is very
similar to what was there.unlike my 93 which had the remains of silicone.not
a metal/stabilized oil based heat transfer paste. Actually, silicone is not
a heat transfer compound at all.)
28. Remember to clean the threads of your intake bolts if they are not new.
29. Clean all the oil off the gasket surfaces with a light solvent like
thinner or alcohol. RTV won't stick if you don't. Follow the directions in
the Felpro box for applying RTV. They include Felpro brand black with the
intake gaskets. The gaskets have nipples on them to push into the heads so
they won't move around. The RTV is applied on the block and one-half inch up
the gaskets (both sides/both ends).
30. If you are re-using your intake bolts, apply loctite medium strength
threadlocker before you install them.
31. When you install the manifold you need to be able to move it into
position while keeping slightly above the gaskets and the RTV at either end.
Otherwise you can wipe the RTV off the ends and then you end up with a leak
after it's all together. One thing I might try next time is to put a small
stud in the passenger/front hole and a taller stud in the driver/second from
the back hole. The third bolt hole on the drivers side has a slot in it.
With the tall stud, you could index that hole to the tall stud then lower
the manifold indexing to the short stud on the passenger front. Then put the
other bolts in and finally swap the studs for bolts. The weight of the
intake is not very manageable when you're all hunched over.so either make it
fool-proof to install or get a helper or both.
32. Torque the intake in three to four stages in the proper order per the
33. By this time, you will be an expert and will know how and the order to
put it all back together. One thing to remember is to properly index the
distributor. If you miss it by more than plus/minus 2 degrees, you will
throw a P1345 code which means your camshaft sensor in the distributor is
not in sync with your crankshaft sensor. You will have to trial and error
adjust it clearing the code as you go or connect a scan tool with extended
data. Remember...no timing light required. The distributor does not control
ignition timing or advance.
Finally...before you start engine...change your oil and filter to get all
the crud out of your pan. If you are doubt about your cleanliness or didn't
drench your valley with a quart of clean oil..Drive your vehicle to Hooters
and back and change the oil and filter again!
What kind of damage can be done by this? My truck has lost about 2 qts of
coolant over the past 8 mos or so....I have changed the oil in that time
and it did not look abnormal....
If this has the potential for serious damage, I will move it way up on the
to do list....
Thanks for any comments..
2 quarts over 8 months is not much. But glycol or water in the oil is the
concern with contamination. Obviously oil is a better bearing lubricant than
glycol and or water. So if you get enough in your oil, you'll lose your
lubricating properties and ruin your bearings and/or rings. Go to
http://www.oaitesting.com/ and get a testing kit. It is cheap. Then you'll
know if glycol is going in there or not.
Thanks for the insight guys....
This repair is going straight to the short list....I've babied this truck
far too much to have some stupid damage caused by this....It's only got 60k
on the clock and I plan on driving it till the wheels fall off !!!
Am I to assume that a good gasket set (Felpro) will cure this problem for
Has anyone had this re-occur after repair ???
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.