4th cylinder coolant mod **KIT**

[acannell]

Get the 4th cylinder cool modification done for only $65 (thermostat version), $50 (heater version), or $35 (adapter + oring only) shipped, with no drilling, tapping, or modification of the head required.


This kit creates a path for stagnant, hot coolant on the #4 cylinder side of the engine to flow. The stock design locates the thermostat housing between cylinders 3 and 4, so hot coolant around the #4 cylinder has to change direction in order to reach the radiator, which causes poor flow and allows hot spots to form. By connecting a tube from the #4 cylinder side of the head to the thermostat housing, or the heater bypass, that coolant can flow continuosly in one direction through the head, greatly improving cooling ability.

There are some things you should check before buying this kit:

- The surface of your head around the freeze plug hole must be clean, flat, and free of any nicks, pits, scratches, or other physical imperfections. If you see some kind of blemish, the oring may still seal if its not in the oring sealing zone, which starts approximately 0.050" from the edge of the freeze plug hole, and extends out to approximately 0.19" from the edge of the freeze plug hole. However, you will still need to remove any protruding burs from the surface of the head so that the adapter can sit flush with the head.
- The bolt holes must be clean and have strong threads in them still. If your threads are eaten away or stripped, then you wont be able to tighten the bolts enough to seal the oring properly.

There are TWO versions of the kit, one which connects to the thermostat housing, and one which connects to the heater bypass.

Installation of the thermostat version is:

Remove bleeder plug on top of thermostat housing.
Drain coolant.
Remove valve cover.
Install 90 degree fitting into bleeder plug hole.
Install other 90 degree fitting into adapter.
Remove bigger freeze plug from #4 side of head.
Loosely install adapter in freeze plug hole.
Figure out the angle both fittings will need to be rotated to so that the hose will fit without kinking, to your liking.
Remove adapter.
Clean and remove any burs from oring mating surface on head around freeze plug.
Install oring in adapter, and install adapter onto head.
Figure out length braided hose should be cut to, and cut it.
Install hose fittings onto braided hose.
Install hose onto adapter fitting only.
Refill coolant, keeping hose above level of head (otherwise coolant will come out of it).
Install hose onto thermostat fitting.
Reinstall valve cover.

Installation of the heater bypass version:

Drain coolant.
Install brass 5/8 barb to 3/8 npt fitting into adapter, pointing towards the front of the vehicle at approximately 45 degree from level.
Remove bigger freeze plug from #4 side of head.
Clean and remove any burs from oring mating surface on head around freeze plug.
Install oring in adapter, and install adapter onto head.
Remove large fitting and/or pipe on bottom of thermostat housing, which heater bypass hose is connected to.
Tape and install included plug into the hole on bottom of thermostate fitting.
If needed, cut a short amount off the end of the heater bypass hose to get to fresh undistorted hose.
Connect hose to brass fitting in adapter, and secure it with a hose clamp.
Refill coolant and bleed system properly.

The kit requires an intermediate level of skill and tools to install. The ability to do the following are required:
-remove and reinstall the valve cover (for thermostat version)
-remove the freeze plug from the side of the head without scratching the surface of the head
-correctly install AN and/or NPT fittings, which requires the ability to torque, tape, and rotate them correctly as required
-figure out the correct angles and hose lengths for your particular setup
-cut a piece of braided hose correctly, twice (for thermostat version)
-install a piece of cut braided hose into hose fittings (for thermostat version)
-carefully locate the adapter onto the freeze plug hole without damaging the oring or head surface, and making sure the adapter boss is seated in the freeze plug hole
-drain and refill the coolant, and bleed the system of air

The parts included in the thermostat version of the kit are:
-one foot of uncut 8AN size stainless steel braided hose
-two straight female 8 AN to hose fittings (black)
-two 90 degree male 3/8 NPT to male 8 AN fittings (blue)
-one machined 6061-T6511 aluminum adapter plate with 3/8 NPT threaded port and oring groove
-two viton fluorelastomer orings (one extra)
-two black oxide flange head bolts with extra thick washers

The parts included in the heater version of the kit are:
-one brass 5/8 hose barb to 3/8 npt elbow fitting
-one machined 6061-T6511 aluminum adapter plate with 3/8 NPT threaded port and oring groove
-one galvanized steel 3/4 NPT plug
-two viton fluorelastomer orings (one extra)
-two black oxide flange head bolts with extra thick washers

The price for the thermostat version is $65 shipped.

The price for the heater version is $50 shipped.

The price for just the adapter plate and an oring is $35 shipped.

Just PM me and I'll send you my paypal info. You can also pay by money order if you like.

If you have any questions please feel free to ask!

[stewdaddy23]

Oooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooo!

[Khajjathefang]

Now that's damn interesting. Why not go in an "L" shape with a little extra material reaching down to that ground/support bolt at the bottom left on the back of the head? It's more metal but would alleviate any concerns over losing seal over time. Great idea!

---------- Post added at 10:26 AM ---------- Previous post was at 10:24 AM ----------

Or hell, the bolt on bottom right. Is literally right there....

[acannell]

Now that's damn interesting. Why not go in an "L" shape with a little extra material reaching down to that ground/support bolt at the bottom left on the back of the head? It's more metal but would alleviate any concerns over losing seal over time. Great idea!

---------- Post added at 10:26 AM ---------- Previous post was at 10:24 AM ----------

Or hell, the bolt on bottom right. Is literally right there....

That could be done, I thought about it but figured I would just keep it as simple and small as possible so it would be as compact to install as possible and interfere the least with whatever might be bolted into the head on custom setups. The one in the picture is leak free after driving around town for an hour and about 10 WOT pulls at 20 psi, and the one for sale is about 100 thou thicker to clamp the oring even better, so I think its okay.

[turbovanman²]

Nice job,

[johnl]

Interesting; nice execution too.

[cordes]

I bet these will sell.

[4 l-bodies]

Nice product. I would vote for the two holed one if given the choice. What might not leak in nice warm SoCal might not cut it at -20°. I've seen so many plastic end tank radiators weap badly during Winter months. Seal perfectly during summer months. Something to consider anyway. Rear air cleaner bracket hole would work/look good as second attachment point.
Todd

[turbovanman²]

I don't think it will leak but I would make them thicker so they can't flex and snap off.

[acannell]

The version in the picture is about 0.143" at the thinnest part (through the oring groove). The one that the auction is for has been improved and is 0.248" thick at the thinnest part. Since stiffness goes up as the fourth power of thickness, thats about 9 times stiffer. And since this 6061 has close to the same tensile strength as mild steel, I don't think it will be snapping off. The oring it comes with is Viton fluorelastomer, which is rated to -15F.

[GLHS60]

I liked your original version better.

Thanks
Randy

[acannell]

I liked your original version better.

Thanks
Randy

That one does have some advantages, buts its harder to machine properly and requires a very nice oring surface in the freeze plug hole, which I have yet to not scratch removing the freeze plug.

[rx2mazda]

I don't think it will leak but I would make them thicker so they can't flex and snap off.

You know how much pressure would have to be in the cooling system to make that aluminum flex? Lets just say, if you have that kind of pressure in your system then you have bigger problems.

[boostman]

Pm'd you about your kit.

[The Pope]

You know how much pressure would have to be in the cooling system to make that aluminum flex? Lets just say, if you have that kind of pressure in your system then you have bigger problems.

Just buy the one I had him do for me then



there isn't much side force support on the O ring with one bolt, with 2 on there there is a ton of support. I am not a fan of how he runs that hose though but no matter. Running this to my heater, then constant flush of coolent through the head.

[MNmopar]

Nice product. I would vote for the two holed one if given the choice. What might not leak in nice warm SoCal might not cut it at -20°. I've seen so many plastic end tank radiators weap badly during Winter months. Seal perfectly during summer months. Something to consider anyway. Rear air cleaner bracket hole would work/look good as second attachment point.
Todd

Agreed, I was thinking the same thing when looking at it. Us "northerners" think in terms of seasons, and I wouldn't feel great about having that on in the winter. I suppose that once the engine warms up the seal would get nice and warm and soft, but it just looks like trouble in a Minnesota winter when it's cold.

I'd buy a two bolt one, and thanks for making them whether you go two bolt or not! This is one of the things I really like about our community, people being creative and making these cars better than they came from the factory.

[Khajjathefang]

Just buy the one I had him do for me then



there isn't much side force support on the O ring with one bolt, with 2 on there there is a ton of support. I am not a fan of how he runs that hose though but no matter. Running this to my heater, then constant flush of coolent through the head.

That would part me with my money

[acannell]

Pm'd you about your kit.

Got it! I PM'd you back.

---------- Post added at 04:31 PM ---------- Previous post was at 04:30 PM ----------

That would part me with my money

The kit has been updated to include the thicker two bolt "Special Pope Edition" version. Check out all the details in the updated first post of this thread. I would be happy to machine a Pope-style adapter for you.

[acannell]

I am not a fan of how he runs that hose though but no matter. Running this to my heater, then constant flush of coolent through the head.

For anyone who requests it, I can modify the kit to have a different length of hose or to change the style of the fittings, i.e. to straight fittings or one with a hose barb. This can make it possible to connect to the water pump housing or the heater hose as the Pope describes. I haven't attempted those styles though, so you will have to tell me what you need. If its just changing a fitting there should be no cost (i.e. from elbow to straight, or one with a hose barb instead of threads, etc..). For longer hose, its $5 per foot add'l, plus another one-time $5 for increased shipping costs because it wont fit in a small flat rate box.

---------- Post added at 05:14 PM ---------- Previous post was at 05:05 PM ----------

Agreed, I was thinking the same thing when looking at it. Us "northerners" think in terms of seasons, and I wouldn't feel great about having that on in the winter. I suppose that once the engine warms up the seal would get nice and warm and soft, but it just looks like trouble in a Minnesota winter when it's cold.

I'd buy a two bolt one, and thanks for making them whether you go two bolt or not! This is one of the things I really like about our community, people being creative and making these cars better than they came from the factory.

I wish I could test it at extreme low temperatures, but it hasn't gotten below about 38F here in SoCal. The oring is Viton fluorelastomer, a very common material for automotive seals, rated -15F to 400F, and the gland compresses it about 30%, the industry standard for face seals of this type. It requires about 100lbs of force to compress the oring this much, so coolant system pressure changes are relatively minor compared to the static forces the adapter and oring are always experiencing.

For the first person to be a cold weather pioneer, I can upgrade the thermostat housing fitting to be a swivel type, so that you don't need to remove the valve cover to install the kit! Thats a $15 fitting! I can only do this for one person though, because I only have one fitting. Just make sure to specifically request the fitting upgrade, and I will confirm you are getting it. And you need to be somewhere 5F or colder please!

[Khajjathefang]

Pm sent!