49 Chrysler Straight 8 Overheating

[bruros]

My 49 Chrysler New Yorker straight 8 motor continues to overheat. Hava a new radiator core, and have flushed/reversed flushed(through heater hoses) several times. The thermostat has been removed. The water distribution tube won't budge, and I am afraid to ruin it, as I do not have a replacement(for the straight 8 motor). Any thoughts on removing this tube? Anyone know where I might get a replacement water distribution tube for the straight 8? Looking into the installed tube(water pump removed) looks like it might be "necked down" but I cannot seem to spread it out. I am able to run a metal rod down the tube. It comes back with no sludge on it. The manual says to replace the tube to correct overheateng. I'd love to, but how to do it. Any other causes for over heating? How are the freeze plugs removed/replaced?

Thanks for any advice, up front!

[hchris]

Straight 8 has always been hard to cool at the back,some observations :

1.tubes typically corrode around valve seat areas & there`s not much alternative but make up a hook out of rod & pull it out in bits & pieces ( ensure it all comes out )

2.have heard of drilling thru back of block in line with tube & extracting from both ends ( engine out of course ) then fitting freeze plug after

3.removing thermostat only adds to problem as coolant rushes thru radiator too quick not allowing heat dissipation

4.run an external hose from heater outlet at back of block & make T piece to connect with inlet side of water pump, straight 8`s are known to percolate / airate coolant at back of block

[Guest imported_BaronvonR]

The best way to remove the water distribution tube is to make a strong metal rod with a hook at the end and pull it out. This MUST be removed in order to make sure your engine cools properly. Once you get the tube out you should then remove the freezeout plugs at the bottom of the block and power flush out the block. You will be amazed at the junk that comes out.

I have seen the tubes offered for sale on Ebay, and the freezeout plugs are easily replaced. NAPA should have those.

I cannot stress enough that the tube be removed and the block flushed, unless you do the car will always run hot.

BvR

[Sorensen_DK]

...or you could post your question at the P15-D24 bulletin board (choose 17-Forum): http://www29.addr.com/~merc583/mopar/framesets/welcomeframeset.html.

A ?40 Dodge owner recently had a similar problem ? turned out to be the radiator.

Good luck

Tom

[Guest dan.mining]

BaronVonR is right. I knocked out the welch (spelling) plugs last night and was shock by what I saw. Two and a half inches of muck! It completely filled the bottom of the cooling cavity. The sludge is thick and semi-hard. I cut 2 ft. off a Wall-mert sink snake (drain cleaner) and began the process of fishing the stuff out. The tool worked well as it is thin flat spring steel then will work its way around corners. There are no freeze/welch plugs on the manifold side so I plan to pull the distribution tube and either fish from there or continue working it from the casting holes. I'm open to suggestions.

Thanks Baron for the tip!!! I imagine this is really going to help.

I fished and flushed for at least an hour last night and figure another hour might do the trick.

Perhaps this is obvious, but I set the plugs back in the holes temporarily as I moved to the next to maximize water flow while I worked.

I took a pic of the sludge- maybe I'll try to post it later.

[c49er]

Hmmm...

Really old thread.

Anyway the straight 8 chrysler D-Tube can be removed from the back of the block as there is a 1-5/8" soft plug at the rear of the tube. Wont work with the engine in the car though! I made a precision fitting D-Tube removal tool for all 3 sizes of the MoPar flathead engines-23"/25" and straight 8's as I work on all of them.

Also it is a must to remove the soft plugs on the side of the block to see and and completely scrape out the coolant passages of sludge, then high pressure flush the passages with water till completely clean. It will make a huge nasty mess!

Correct thermostat, good distribution tube, timing correct and a good clean radiator- you should be good to go!

Edited August 10, 2011 by c49er (see edit history)

[Rusty_OToole]

Couple of points. If the water distribution tube is bad the coolant will stream right up the front of the engine and never reach the back. The front of the head will be cool while the back is overheating, this can be checked with an electronic thermometer or even your hand. Easy way to diagnose without tearing your engine apart.

I had a hard to find overheating problem caused by a mouse nest in the to rad tank. I only caught it after seeing bits of shredded paper towel floating in the rad. Cleaned out all I could reach, did not help much, finally took the rad out, turned it upside down and flushed it with the garden hose, eventually got out a pile of shredded paper the size of a football.

Can only surmise the previous owner drained the rad for the winter and left the cap off as a reminder and the critters moved in.

[Guest dan.mining]

I pulled the d-tube and it looked good, but mine appeared a bit different- it had round holes. The rear hole was probably 3/8 while the others were about a 1/4 inch. The one in your pic had longer slots that would allow more flow. Should I open them up? I'm working on a custom fan-shround now. I've been running her at idle foe up to 40 min. and she's no longer overheating, but at load I'm not sure yet what she'll do. I still need to set the timing. Thanks for the help.

[Rusty_OToole]

Are you sure it is an original Chrysler tube? If someone installed the wrong tube at some time there could be your problem.

The hole size and position were carefully worked out by the engineers after extensive tests.

[Guest dan.mining]

It's a 1941 straight eight (older design?). It lacked the retreival slot in the top, or I don't remember seing it. It was pretty clean and made of some alloy of brass. Fabrication?

Other question. Do the 5 rivets on the brake drums hold them to the hub. I can't figure out how to pull them.

[ply33]

It's a 1941 straight eight (older design?). It lacked the retreival slot in the top, or I don't remember seing it. It was pretty clean and made of some alloy of brass. Fabrication?

Other question. Do the 5 rivets on the brake drums hold them to the hub. I can't figure out how to pull them.

The drum and hub come off as one unit. You'll need the proper wheel puller to do it. Here is a link to the a repair that includes drum removal for a Plymouth which should be similar: 1933 Plymouth Rear Axle Oil Seal Repair

[Rusty_OToole]

Front hubs come off easily, easiest way is to leave the tire on and remove the center cap and take off the big nut. Give the wheel a wiggle and the bearing will pop out. Remove the bearing and set it aside, now you can pull the wheel and hub off as an assembly. If the brake shoes prevent the drum coming off you will have to back off the brake adjustment.

Rear hubs require a heavy duty puller. Get one that bolts to the wheel bolts, do not use one that grabs the brake drum, or you will bend it.

This has been covered in detail before, a search should turn up some further info.

[Guest Oldcartech]

New Old Stock Dorman water distribution tubes

I have new old stock water distribution tubes. I have Metal and Brass in most instances. If you’re motor needs one please send an email to Oldcartech@gmail.com

I will need the year, make, Mod, & eng 6 or 8 cylinders.

I cannot stress enough just how important it is for your motor to distribute water properly. It is absolutely a must that water is distributed around each cylinder as required by the motor manufacturer.

[August e. Bush]

I have a 49 NEW YORKER,  8, been in storage since 1972 , I have been trying to pull tube, unable to make it move, run 24" scale down each side and slide hammer to pull with vise grip. I'm finding that I am looking at pulling motor to get at back of block to remove a freeze plug??. I have seen a super type hook that will work, but don't know distance between the slots, any help on that.

  Any help in Idaho Lewiston area.Thanks for any HELP.

[Gunsmoke]

Hmmm... I am working on a '31 Chrysler CD8 Straight 8, first year for an 8 cyl in Chryslers. Head is currently off, and body is off car, so access to engine is easy. Have re-faced the valves and lapped therm in and checked condition of pistons, cylinder walls and lower end. Flushed out head this week (about 1/2-3/4 cup of debris, and planned to put head on this week. Now I read this topic and wonder what further steps I should take regarding flushing/cleaning water passages in block. Does the early 8 cyl have a distribution tube? Any suggestions.   

[Taylormade]

No water distribution tube in the early engines.  Not sure when they came in, but my 32 Dodge Brothers six doesn’t have one.  If your motor doesn’t have the full water jacket  (if you can see the shape of the cylinders on the side of the block) then you don’t have the tube.

[Spinneyhill]

I think CD8 is pretty similar to DC8 Dodge. No tube.

[Gunsmoke]

OK, so no tubes in my '31 Engine, what should I do to clean out water circulation/jacket cavities, use a snake of some sort, air pressure, water? I can do now while head is off.

[keiser31]

4 minutes ago, Gunsmoke said:

OK, so no tubes in my '31 Engine, what should I do to clean out water circulation/jacket cavities, use a snake of some sort, air pressure, water? I can do now while head is off.

Wire hangers.

[Taylormade]

Remove all the casting/freeze plugs.  Get a pressure washer.  Get the nozzle inside one of the openings and blast away.  Use a coat hanger to rod out any stubborn areas.  Blast in all the openings, in different directions.  You will be amazed how much crud will come out.  Keep blasting until the water comes out clear.  Wait a few minutes, rod out the passages with the coat hanger one more time, then blast again.  I’ve done it many times - 48 Plymouth, 29 Plymouth, 32 Dodge Brothers, 50 Dodge - works like a charm.  You really want to remove the plugs anyway as they tend to rust from the inside.

[r1lark]

3 hours ago, Taylormade said:

Remove all the casting/freeze plugs.  Get a pressure washer.  Get the nozzle inside one of the openings and blast away.  Use a coat hanger to rod out any stubborn areas.  Blast in all the openings, in different directions.  You will be amazed how much crud will come out.  Keep blasting until the water comes out clear.  Wait a few minutes, rod out the passages with the coat hanger one more time, then blast again.

 

This is exactly how I clean out water jackets. Besides coat hangers, long thin screwdrivers work well - you can get cheapies at Harbor Freight or similar places.

[Gunsmoke]

So your telling me I need new frost plugs. I assume they are available somewhere? I'll have to start searching. And can this be done with the internals still in place? Any concern of water getting into the cylinder walls/pistons/valve train area area? I can put oil pan on to protect the bottom end somewhat. Or is this procedure (pressure washer) only used on a block stripped of all the internals. Compressed air would avoid the water issue. 

Edited August 12, 2018 by Gunsmoke (see edit history)

[JACK M]

I wouldn't be afraid of water in the cylinders, or the oil for that matter.

The head being off may be a bonus for access with the wire or screwdriver.

This is a messy job so do it out in a yard where the junk will go back to the earth. (no coolant)

Just make sure that a good clean up and oil change follows.

[Rusty_OToole]

You can get new core plugs for a few bucks at any auto parts store. They are a standard fitting, used on many engines. Choice of cup or disc type, in various diameters.  Just get the same kind and size as the old ones.

[c49er]

I'd use the flat brass plugs... 1-5/8". I use a special miller drive tool for these plugs as I do so many.

I'd say carefully clean the block bore recess then pound them in with a blunt ended 1" steel round bar. The steel has mass to help drive the plug near flat and expand it enough.

The ball peen with another hammer works too  but IMO sometimes does not expand the plug enough and they can blow out.

Seal em with Permatex hardening # 1 .

 

[Gunsmoke]

Thanks for the good advice and tips, I will check around tomorrow to see if I can locate some proper frost plugs. This morning I stuck a hanger wire in each hole in top of block, scraped it around and then used a 3/8" magnet on end of a pointer and a few dozen pokes, pulled 1&1/2 cups of scale/rust out thru top of block! This only enabled access to perhaps 1/2 of the cavities or less, so I suspect there is at least another 1&1/2 cups still in there. Cheers

[Taylormade]

I did mine with the engines fully assembled.  It won’t hurt anything with the engine partly or fully disassembled, just make sure to dry everything off and leave no standing water.  Put down a tarp or other protection if you do this in your driveway- you’ll never get the rust stains out of the concrete, otherwise.  And you're blasting the water passages through the plug holes, not into the cylinders.  The mess will shoot out of the other open holes.  Take of the water pump, too, as this will give you a large opening at the front of the block to spray into.  Trust me, you want to replace the plugs at all cost - easy to do and cheap.  Any good auto parts store will have, or can get, the plugs.

[Rusty_OToole]

I have a special tool for installing core plugs, a wrist pin out of a WW2 radial aircraft engine. It is about 1" diameter 5" long steel and has aluminum plugs in each end.

 

If I don't have it handy I will put the flat face of a ball peen hammer against the plug and whack it with another ball peen hammer.

[philipj]

On 3/17/2012 at 2:51 AM, Guest Oldcartech said:

New Old Stock Dorman water distribution tubes

I have new old stock water distribution tubes. I have Metal and Brass in most instances. If you’re motor needs one please send an email to Oldcartech@gmail.com

I will need the year, make, Mod, & eng 6 or 8 cylinders.

I cannot stress enough just how important it is for your motor to distribute water properly. It is absolutely a must that water is distributed around each cylinder as required by the motor manufacturer.

Hello there,

 

Do you have a water tube for a 1936 Oldsmobile F-36? It could be the aftermarket Dorman WT-5, 26-3/4" long, also used in a 37-50 6 cylinder...

 

Thank you,

Philip

 

Edited April 11, 2023 by philipj (see edit history)