1930 DC8 Overheating Woe's

[Guest WoodridgeDodge]

Hi Guys,

My name is Ben, I've posted here before but it was a couple of years ago now. I'm writing because I'm not sure what my next course of action should be. My grandfather has a 1930 DB DC8, it's not a show car, but it looks great in parades, so long as they don't last too long. The car seems to boil over after 10 minutes at a slowish speed. Motoring around on the roads, it will stay cool enough to avoid boiling over a bit longer, maybe 15 minutes or so.

We've pulled the radiator off and had it cleaned more than once (most recent was two winters ago). The radiator shop indicates that it should be working just fine. They did mention, for what this is worth, that the back 2 cylinders are running hotter than the rest.

Thermostat was fine at last check, according to grandfather, but at this, point for the money, I'm going to put a new one in anyhow.

I've been wondering if flushing the block may be a good idea. Is that a safe thing to do? Follow the normal flow of the water (bottom to top)? Or go backwards top to bottom?

Thoughts? Advice? Need more information? Thanks all.

[keiser31]

Make certain the timing is adjusted properly. Thermostat replacement sounds good, especially if the car sits for long periods of time. Always good to at least drain the water mixture and put new stuff in. Don't know about flushing with any amount of pressure, but you could certainly put a hose in there and see what comes out.

[Guest 1930]

Flushing out the block cannot hurt and would be a good idea, start from the top and run a hose thru it, see what comes out. Of course have your bottom outlet disconnected so the crap does not run back thru your rad.

[Guest Henry White]

Does that motor have a water distribution tube like the newer Mopars have? If so, maybe a bad tube?

[Guest WoodridgeDodge]

Does that motor have a water distribution tube like the newer Mopars have? If so, maybe a bad tube?

My grandfather mentioned the water distribution tube. He said he wasn't certain if it was in the 8, but he was aware of said tube in other models. Can anyone confirm for this model?

[keiser31]

I am pretty certain they did not use the tube that early. It will show in the instruction book if there is one. I don't see one listed in the Master Parts Book.

Edited June 18, 2013 by keiser31 (see edit history)

[Pete K.]

Good advice so far, maybe remove the thermostat completely and see what happens on a hot day.

[Guest WoodridgeDodge]

Thanks for the suggestions guys, I won't be able to try any of them until after this weekend (traveling), but I will be sure to post back when I do.

I plan to drop in a new thermostat, (and per Pete K, will attempt running without the thermostat on a hot day). I'm also going to flush the block, I plan on using some mesh to collect what does come out, just for examination purposes.

Again I appreciate the replies and will report back.

[JACK M]

Pop out the core plugs and go at it from all directions with a stiff piece of wire and water pressure.

[Guest 1930]

Pop out the core plugs and go at it from all directions with a stiff piece of wire and water pressure.

I dont think its gonna work like that on his engine, I would think that you should be able to jack the front of the car up and add a solution of possibly half and half muratic acid or something along those lines and let that sit and do its thing, this is just something that I have been contemplating and would not attempt until I looked into it further.

My own car 6 cyl has a removable water jacket drivers side, this feature was discontinued with the intro of DD-6 and DC cars but it sure makes this sort of problem easier to remedy.

My point to telling you this is that upon removal of the jacket on every engine I have fooled with there is gobs of crud blocking the passage in between the last cylinder and the outer casting wall, crap so thick a coat hanger poking away was tasking to clean it all out, I would not be surprised this is what you are dealing with as well.

I would consider my suggestion of getting something in there to sit and eat away/loosen what might be there, maybe molasses would work but that might be too slow, possibly coca-cola. Just thinking out loud.

One thing is for sure is that I would do it once and do it right so you do not have to keep screwin with it, take your time and experiment with what may work. In the meantime post some pictures of your car, its not often we get to see a DC-8 on this forum.

Edited June 19, 2013 by 1930 (see edit history)

[R.White]

I would suggest phosphoric acid rather than muriatic acid simply because it is less dangerous to use. Muriatic acid is hydrochloric acid and is one of the strong acids. Pool cleaner is about the right mix (about 30%) for this use but I must emphasise that you must always add acid never add water to acid - it will react violently and cause harm. Always neutralise any residual acid because it will continue to carry on working.

Before resorting to the acid treatment, I would go along with Jason's suggestion and fill the system with a solution of molasses and leave it for a while before rinsing out. Using a pressure washer or steam jet will shift quite a lot of crud.

Sometimes it is not just rust and sediment but lime scale build up and that depends on where you live. Is it a hard water area? Bicarbonate of Soda or something similar could then be the answer.

Best of luck,

Ray.

[hchris]

As others have said and the mention of rear cylinders running hotter, it is highly likely that there is a buildup of sediment in the cooling jacket at the back of the block, most of the Mopar 8 cylinder engines suffer the same problem. Unfortunately changing thermostats etc. wont cure the fault, you will have to bite the bullet and work on flushing or probing this area to remove the scale and crud.

Not sure of the freeze plug locations for the DC8, but any access into this area is the place to start; as regards flushing are there any heater hose outlets at the back of the head or block, this would be a good place to begin with. When you get it running again put a filter (even one of her nylon stockings) in the upper radiator hose to catch the remaing rubbish that will circle around for some time after the flushout.

[Aussie 8]

Ben.

I have a 1930 Dodge Brothers DC 8, now almost completely restored.

When I first bought the vehicle I stripped and cleaned the engine, repaired a piston, gave in a valve grind and re ringed it.

The rear part of the engine block was totally blocked up....Almost as if it had been filled with cement. The cylinder head was also badly rusted internally with the water galleries from the block to the head blocked up.

After removing the Welch plugs I cleaned this out using screwdrivers, welding rods, etc. then using a high pressure water blaster and compressed air to blast out the residue. I also used a hammer to tap the head to loosen heavy flakes of rust.

On reassembly and running there was a slight seepage from the block from the area of the casting seam above the rear two cylinder barrels. Above the starter motor. Initially I thought it could be repaired by welding, plating, or drilling and plugging. (metal stitching). On close observation and test drilling it was discovered that about 200mm (8") of the block wall was little more than paper thin. The block was beyond salvage.

I was lucky. I was able to source another block. They are very scarce!

The radiator core was also leaking and badly blocked so I had it recored using a new core from New Zealand.

There is no water distribution tube in the DC's block. This was a modification and an alteration to the castings in later series. A tube can not be fitted.

Last weekend, 15/6/2013 the car was driven to a car show. It completed the 20 Km round trip without any problems.

I hope this information assists you. Good luck with it.

Jim