HD Coolant Pump Install for the LT-1/4
Let me begin with my
situation before I started this upgrade. I have a 92 LT-1 convertible with
the 6 speed tranny. I had an oil leak coming from the driven shaft seal
of the water pump. After removal of the water pump I saw that it was
leaking coolant out of the weep hole right onto my opti-spark. After I
removed the opti-spark and disassembled it, I found rust, coolant, and a
lot of dirt inside. It was ready to leave me on the road; dead. Sound
familiar? Instead of just replacing the OEM coolant pump, I did some
research and found that electric water pumps work better than OEM pumps,
especially on LT-1/4s, and they eliminate one possible source of an oil
leak, while also eliminating the �weep hole leak� on to the opti-spark
syndrome. Theoretically, you even get a few extra ponies.
article talks about installing the Meziere HD Coolant Pump and all the
things I found necessary to do on my Vette along this trip. This project
can include changing the opti-spark, wires, seals in the timing cover, and
if necessary, the timing chain. This project will also eliminate possible
oil leaks on the front of the engine, which was a problem for me. Now
there is an argument for not removing the driven shaft that drives the OEM
water pump. I personally don�t like the idea of something spinning around
in the engine when it is not supported as designed. Too much chance of a
future oil leak or worse a piece coming loose inside the timing cover for
To start out, let me say that I used the Helms Service Manual
for much of the procedures. For example, the service manual has an
excellent checklist for removing the oil pan. I just added information
that I had questions about and came up with solutions. Other tips came
from you guys. So, use the manual and refer to my tips. Let me know if you
find a better way to do something and I\’ll update the article. I guess
I should come up with some \”grocery list\” of things to buy before
starting the project:
The Meziere HD coolant pump, 10 gauge wire,
14-16 gauge wire, terminals, 20 amp fuse holder with a mounting tab, a 30
amp relay with a mounting tab, Gaskets for the oil pan, timing cover,
water pump, water pump O-ring (inside inspection plate), oil filter
adapter (both gaskets), GM silicone sealer, GM assembly adhesive,
serpentine belt (if needed), seals: timing cover crank and opti seals.
I�d also, line up the ability to rent or borrow a Kent-Moore LT-1 hub
puller/installer kit, J-39046 and a driven shaft remover might be needed
(J-39243), but sometimes not required. Oh, about a 12 pack of your
favorite adult beverage.
First, I disconnected the battery. Next,
drained the anti freeze coolant by removing both knock sensors and opening
the radiator drain.
Removed the air cleaner assembly, all of it.
Removed the serpentine belt, I have the long tool designed for this,
cheap at Pep Boys or so.
To increase the working area in front of the
engine, I removed the power steering pulley using a Lisle puller. I also
removed the tensor; just one bolt holds it in.
Disconnect the upper
radiator hose at the coolant pump and use a bungee cord to hold out of the
way. Also disconnect the bottom hose at the pump and move aside.
Carefully disconnect the plug from the water pump sensor. Don\’t
break the clip that holds the plug in.
Now, you should have a good
view of the coolant pump. You have 6 bolts to remove not 4. Once they are
removed, pull the pump assembly off. It has two pins for alignment
purposes. Put the bolts together (I used a coffee can and soaked them in
solvent). There is a coupler that connects the pump drive to the driven
shaft assembly that is inside the timing cover. Look carefully at the seal
around this shaft in the timing cover, any sign of oil leaking here? If
so, you\’ll have to take the driven gear assembly off and plug the hole
in the timing cover, but that\’s later. Some guys just leave it in and
if it doesn\’t leak, okay, but I don\’t think this is a good idea for
the long run. I removed mine. That means removing the timing
Now for the not so easy task of removing the damper. You
need to remove the damper to gain access to the opti-spark. There are 3
bolts that hold the damper onto the hub. I marked the damper so I could
reinstall it in the same position on the hub, and it only goes on one way.
After removing the 3 bolts, you\’ll probably have to get under the front
end and using a soft drift pin or a wooden dowel (1 1/2\” dia by 12\” or
so) and a hammer, loosen it from the hub. Don\’t just hit one part of
the damper; try to hit it all around so it doesn\’t bind. This is a
PITA. Once it comes free it is time for your first beer; you\’ve earned
Voila, the dreaded opti-spark is now in view. Mark each spark
plug wire so you know where they go when it\’s time to reconnect. The
opti-spark has the terminals marked and I made it easier to see by using a
Sharpie marker. Pull the plug wires out of the opti-spark. Remove the coil
wire as well. Now would be a good time to replace the plug wires if you
want to. Remove the 3 bolts that hold the opti to the timing cover and
soak them, too. Unplug the connector going to the opti (11 o\’clock
position as you look at the engine hope you don\’t have a digital
watch). Carefully pull the opti off the timing cover and from this point
on DON\”T TURN THE ENGINE OVER, until we put the opti back on. If you are
not replacing the opti, doesn�t turn the little gear that came out of the
timing cover, this will make it easier to reinstall later.
for one of the hardest part of the project IMHO. Hub removal. This is not
like any other hub removal I\’ve done. GM has a special tool kit just
for the LT-1/4 it is \”J-39046\” it is worth its weight in gold. Time
for a beer and enough for today.
The next morning, I tackled the
hub pulling. Using the Kent-Moore LT-1\’s instructions made it easier
than expected. I did disconnect the hydraulic line going to the rack for
better clearance. No, I did not have to raise the engine. Oh, before you
pull the hub, make a mark on the timing cover and hub that matches so you
can reinstall the hub in the same position. The Helm\’s manual makes a
big point to make sure the damper is positioned back on the crank in the
same position. Some say it doesn\’t matter, but I went with the manual
and marked it. If your hub and damper were like mine they were pretty
rusty, so I cleaned mine up and painted very lightly. Time for a beer
If you are going to take the timing cover off, you
have to remove the oil pan. So, the next thing to do is drain the oil and
remove the oil filter. My Helms manual had a good checklist to follow as
far as removing the oil pan. One of the items to remove was the
driver\’s side cat. I did it and found that it gave me lots of room to
work. Just do it. It also said to remove the oil filter adapter, the part
that the oil filter screws into. It has two gaskets to replace and this
eliminates a possible oil leak down the road. Also, remove or at least
raise the oil dipstick holder as it interferes with the oil pan gasket
removal and install later. Remove the shields that go around the knock
sensors if you haven\’t already done so. Remove the oil level sensor.
The plug is a weather pack connector and using a small flat blade
screwdriver, carefully disconnect this plug before unscrewing the sensor.
Next, remove the starter, it\’s only two bolts and two wires and it
probably needs to be cleaned anyway. Now remove the clutch inspection
plate. I used my 1/4\” drive set to remove the oil pan bolts as it seemed
easier to work with. Here\’s another tip for you concerning the pan
bolts and their positions, I used a shoebox top and punched holes in it
similar to the oil pan\’s bolt pattern. This way I didn\’t loose any
and I knew where each bolt went. I then loosened the oil pan and jockeyed
it off. Later, I found that raising the engine just about 3/4\” would
have made this much easier. How do you raise the engine? On my LT-1 (92)
there are two nuts that hold the motor mounts to the 45-degree cross
members. Remove those nuts. The stud is just about 1\” in length so you
can judge by that how high to jack. Where to jack from? I have a 6 speed
and I used a block of wood on my axle jack and raised the drive train from
the bell housing. Remember, just 3/4\” is all you\’ll need. After you
get the oil pan off it might be a good idea to take a break.
Timing cover removal is next. With the oil pan off, you can now
remove the timing cover. Just remove the bolts (use the same shoebox
method of saving the bolts). I had to LIGHTLY tap the bottom of the timing
cover from under the car to break it loose. Clean the timing cover and oil
pan and also start cleaning the mating surfaces on the block. Once I had
the timing cover cleaned, I went to my local precision welder, Truecraft,
and had him weld a piece of aluminum into the hole where the coolant pump
drive came out. He did a great job, as you can\’t tell there was ever a
hole there. He even polished it! This is the point of no return for this
project. Oh, the price, $30.
Cleaning the mating surfaces on the block
was a long, tedious job. (At least two beers worth) The hardest surface
was the water pump mating area. I went through several razor blades and a
can of gasket remover.
Lets take a look at the instructions for
installing the Meziere Pump. It\’s just one page and seems easy. Take
the water pump you took off your engine and remove the six bolts that hold
the inspection cover on. Clean the mounting surfaces. Now, it\’s time to
remove the \”guts\” of your old pump. Some guys beat it out with a
hammer and a punch. I didn\’t like the idea of beating on a piece of
aluminum, so I went to a machine shop and had the impeller and bearing
assembly pressed out. Bring the Meziere instruction with you to the
machine shop as it explains how to press it out. Once he has it pressed
out, take a look at the inner seal right next to the bearing. Mine was
cracked and coming apart, no wonder it was leaking out the weep hole.
Definitely the weak part of the pump. While you are at the machine shop
have him press in the freeze plug, supplied, into the hole where the
bearing was seated. It\’s in the instructions and don\’t forget to use
the Permatex Form a gasket. The instructions talked about plugging other
holes, but the only hole to plug was the weep hole in mine and that is on
the other side of the freeze plug. So, I disregarded that issue. Now, you
should have a pump housing with the freeze plug installed. Some guys put
an extra layer of sealer around the backside of the freeze plug. The guy
in the shop had some sealer and put it on just before pressing the plug
into position. Good seal.
Ready to put the timing cover on?
Install the new crank seal and opti seal into the cover. I used a little
GM Assembly Adhesive pt# 12346141, around the outer edge of each seal.
Now, the manual didn\’t say whether to use gasket sealers or not so, I
used Permatex\’s Aviation Form-A-Gasket, LIGHTLY, on both sides of the
new timing cover gasket and placed it on the timing cover. Make sure there
is a little grease on the inner part of the crank seal. Place the timing
cover in position on the block and torque the bolts to the setting in the
Helm\’s manual ( 11N*m or 100lb. in.). Done, beer?
Now for the
oil pan. Did you really clean it up and maybe paint it? I did, Chevy red.
This is a tough one and two people might make it easier, but I did it
myself. First, I used GM Silicone sealer pt# 12346192. I used it to glue
the oil pan gasket to the oil pan. Let it set, for at least an hour. I
used it heavily on the end, where it mates with the timing cover. To hold
it in place while drying, I used a 2-liter coke bottle filled with water
as it was close to the radius of the pan. Go eat lunch or dinner as the
Once the gasket is firmly in place on the oil pan,
it\’s time to jack the engine up again, remember just about 3/4\”. The
manual describes where a bead of GM pt# 12346192 must be put to ensure a
good seal between the joints at the corners. I chose to put the bead on
the gasket just before I put the pan on. It just seemed easier and neater.
CAREFULLY, jockey the oil pan into position. The place to watch is the
front part of the oil pan gasket where it mates with the timing cover.
Tip, I made a few trial fit tests with the pan before I put the bead of
sealer on the corners. If you have to rotate the engine so you have
clearance, remember to mark the crank so you can get it back for the opti
and hub install. Okay, hopefully, you got the pan in place and you started
a few pan bolts to hold it in place. Before you tighten it down, recheck
the mating around the timing cover. Put the rest of the bolts in and
torque (corners to 23N*m or 17lb-ft and remainder to 11N8m or 101 lb-in).
I hope you didn\’t forget the reinforcement strips like I did. No
problem, just do one side at a time. It is time to put the oil filter
adapter back on with its new gaskets. These go on dry. Make sure the
O-ring gasket is correctly in the groove. I used a little Vaseline Jelly
on the O-ring. Check the manual for the torque setting (23N*m or
17lbs-ft). Lower the engine and reinstall the engine mounting nuts. Time
for a break.
Let\’s finish up underneath the car. Put the cat
back on. Put the knock sensors back in. Put the oil level sensor back in
(22N*m or 16lb-ft) with the plug and install the clutch inspection plate.
Install the starter (take a look at the # 8 plug it might be easy to
change before installing the starter depending on your headers). Recheck
everything under the car making sure all the wires are connected. Close
the radiator drain on your way out.
The hub installation is next.
. Just a word I should have talked about before, if your hub has a wear
spot around where the seal would ride, you might want to replace it or buy
a sleeve that goes around it. Mine was fine, and I just cleaned it up and
put a little grease around it before installation. Get out your
Kent-Moore LT-1 hub installation tool. Read the instruction and line up
the hub to your marks you made previously. Using the installer push the
hub into position, watch that the seal slips nicely around the hub.
Remove the installer and put in the hub retaining bolt torque to 95N*m or
70 lb-ft. If you removed the hydraulic line going to the rack, replace
Time to install the opti-spark. Before you install the opti,
some guys, including myself, put a bead of silicone around the edge of the
cap for a better seal against moisture. Notice on the spline shaft gear
(connects the opti to the cam) that there is a small \”keyway\” so it
will only install one way. I greased the seal part and inserted it into
the cam through the timing cover. Don\’t try to hammer it in. It will
slide in when positioned correctly. Now, you have to line up this gear
with the opti gear (same \”keyway\”) as you position the opti in place
on the timing cover. Be patient and don\’t force it. Once it slips into
place, have a bolt ready to go to hold the opti in place. Put the other
bolts in place and torque to 11N*m or 8lb-ft. Reconnect the plug wires and
the coil wire. Don\’t forget to plug in the distributor connector. I put
a seal of silicone around this connector so water won\’t be able to
enter the opti from here.
Now you\’re ready for the damper. Just
install using the three bolts torque to 81 N*m or 60 lb-ft.
Coolant pump install. Before you install the housing, do you want
to change the thermostat? Now would be a good time. I installed the
mounting housing first and then installed the Meziere pump. To install the
pump housing, I used Permatex Aviation Form-A-Gasket on both sides of the
water pump gaskets. Slide the housing into position and push to seat.
Remember there are two alignment pins to help out. I put Permatex sealer
on the bolts as I put them in and torqued to 41N*m or 30 lb-ft. Finally,
we\’re ready to mount the Meziere HD coolant pump! I bought a new O-ring
gasket to fit around the Mez pump where it fits into the housing. My old
one was flat and a little hard. I hope you didn\’t lose those 6 little
bolts that held the inspection plate on. These hold the pump in place.
Don\’t over tighten. I didn\’t have a torque for them so be gentle.
Oh, I had to loosen the A/C accumulator to make room for the Mez pump.
There, ain\’t it pretty? Now reinstall the belt tensor. Put the power
steering gear pulley back on and put the serpentine belt on. Reattach all
the hoses. It\’s definitely time for a brew.
All that is left is
the wiring. Meziere didn\’t give us what was really needed to wire this
pump up correctly. So, you need at least a 30 amp relay (Radio shack has
one, but a good electric fuel pump 30 amp relay might be better as far as
lasting longer). Another product that might be better is the Painless
brand electric water pump relay kit from Jeg\’s. I just didn\’t know
the amperage of the relay and it was $30. Also, I bought a 10-gauge wire
20 amp fuse holder with a few feet of 10-gauge wire. Some 10 – 12gauge
terminal ends, Insulated female receptacles to plug into the relay, butt
connectors to connect to the fuse holder and I eliminated the Mez plug
connector and went with butt connectors. A better way would be to use a
quality weather pack plug. Also, get some ring end terminals to connect
to the \”jump-start junction block.\” In case you don\’t know what a
relay is for let me explain. The relay is a switch that keeps the high
drawing amperage components away from areas that shouldn\’t have high
amperage. The relay has a signal circuit that energizes the relay and
makes a high amp connection. The Mez pump is a high amperage draw and we
need a relay to turn it on. Where does the signal circuit get its power or
signal? I chose to use the \”run-on, bulb test, crank\” circuit which is
the one that is powered when the ignition switch is on. Where did I get
the power to run the pump? From the \”jump-start junction block, which is
basically a direct shot from the battery. Okay, enough of electrics 101.
There is a block or junction of electrical wires connecting to one source
(a bolt with a nut) right behind the battery. This is 12 volt all the time
power. Put a ringed end terminal on it and run the wire to the relay you
bought. One of the tabs should say 12volt in. I mounted the fuse holder on
top of the ASR with the bolt that holds the cover on. I also mounted the
relay just under the ECM, there is a small plastic tab that sticks down
and I drilled a small hole for mounting the relay. Continue the wire from
the relay where it says 12volt out to the fuse holder. Connect the other
end of the fuse holder to the BLUE wire of the Mez pump. I dressed it into
the harness right along the edge of the fender. I used a butt connector
instead of the supplied plug (too cheap). Run the black wire from the pump
to a ground, I used the ground bolt just under the fan relays. Secure that
wire from the pump to the fan braces via tie wraps; don\’t want to have
it tangle with the serp belt. Now for the signal circuit. In my 92, the
run-on circuit runs to the fans and it is pink with a black stripe. You
can find it by tracing back from the cooling fan relays to a point where
you can make a splice. If you have any pink wire at the store, you can
keep the color correct for your circuit, or just use any 14 -16 gauge
wire. After making the splice, run the wire to the relay and connect to
the \”on/off switch\” tab. Run the remaining tab to ground. Again, I ran
it to the same bolt under the fans for ground. Recheck your connections
and that is it for the wiring. DON\”T TEST IT YET UNLESS YOU HAVE
REFILLED THE COOLING SYSTEM. The instructions say don\’t run dry. If you
followed the wiring exactly, your pump will turn in the correct direction.
Blue gets the power and black goes to ground. Did you reconnect the
Refill the oil and cooling systems. I don\’t use
DEXCOOL; I just use the GREEN STUFF and distilled water. After you have
coolant in your system turn the key on and look inside the expansion tank
to see if it is flowing. Hopefully it is. This makes it easy to top off
the system with the pump running.
Take one more look under and through
the car before you give it a test drive. Bring an extra fuse and a jumper
wire in case the relay fails. You can just pull the two 12 volt wires off
the relay and connect via a jumper wire with blade terminals on it. This
will get you back home. Most guys carry an extra relay, just in case.
Don\’t give Murphy a chance to strike.
That\’s it. One thing that
made this project easier was my Kwik Lift. It\’s a drive on ramp that
you jack up. Gives you about 20 inches under the car. And it makes things
safer. Hope this helps.