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Radiator Problem - Overheating

Started by racertb, April 15, 2012, 10:57:18 PM

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racertb

Well, now that the car is driving well and the vibration in drive shaft is gone, the car is seriously overheating.  It actually started running hot at the Thanksgiving show in Ormond Beach and when I got home, I parked the car for a few months because I wasn't going to be able to work on it.  Just fixed the drive shaft issue most recently, so now time to tackle this.

Here's the scoop:  After just 2-3 miles, the car overheats badly.  Looks like a steam locomotive going down the road.  I believe there is some sort of blockage in the radiator;  there are some cold area(s) on radiator and I think the water/coolant is just not circulating properly.  It was suggested to me that I back flush the radiator to see if that helps.  I would like to try this or any other suggestions before I pull out the radiator and take it to a local shop.  A couple of guys in the Model A club suggested some places in town I could take it to.

So, thoughts on this one?  What's the best way to back flush this thing?  Should I circulate some sort of radiator flush prior to back flushing (the Model A guys said I should)?

As always, thanks for your help...

Tinkeys

I have used radiator flush on my 30u Plymouth it did clean a little but worst of all radiator started leaking in multiple places so I would not recommend to use a flush !
And eventually when I cut radiator open it was still more tan 50% blocked anyway .
My suggestion is take it out start fresh and also flush out engine block as you don't want to have rust scale going into new radiator core !
Cheers Tony

SDGlenn

I think Tony hit it on the head.  I had  to remove the soft plugs on my 39, there was so much crap inside the block I found it hard to beleive. The bottom plugs still did not drain until I pocked a screwdriver thru the crap.The only way to really clean this out is pulling the soft plugs.  I have back flushed old radiators also, almost every time there were more holes. lol  It was a good time to find those holes thou, you might luck out, maybe worth trying, can't hurt.
SD Glenn
SDGlenn

racertb

I think I'd like to try the back flush part first...just the radiator and circumvent the engine and then see what happens.  It may be a simple blockage or something more severe.  If this doesn't work, then I can take the radiator out and have it properly rodded and cleaned.

I was just wondering if anyone had done this (back flush) before and if there were any tips on how to do it.  I know the general idea, but was looking for experience.

1929luv

You can not rod a honey comb radator to my knowledge,  But back flushing might work.  There are tools for this.  I use a tool that use water and air.  This tool allows you to use water then shoot air into it.  It is coned for different size hole and then has an air inlet too.  Or just use water with a cone to back flush it. But the air with it works best. Most of time you haft to get new core if thats the problem.  Good luck Craig

p4jim

Be real sure its a radiator problem.  My 30U was over heating because of retarded timing.  jim

wellery

Suggestion have you pressure tested the coolant system with a pressure tester also while doing this you can do the radiator cap (sometimes it can be a cap, cap seal etc. etc. which is faulty), this will pick up any leaks in the system, also the external grill (fins) of the radiator are clean and not blocked.

Also I know this sounds really dumb but is she completely topped (also check for air blockages) up as Thermo Syphon systems have to be full to operate correctly that's why when you are using these types of systems they heat up relatively quickly when you loose water as the system starts to become inoperable (In some situations the flow of liquid may be reduced further, or stopped, perhaps because the loop is not entirely full of liquid. In this case, the system no longer convects)

Simply Put - Convective movement of the liquid starts when liquid in the loop is heated, causing it to expand and become less dense, and thus more buoyant than the cooler water in the bottom of the loop. Convection moves heated liquid upwards in the system as it is simultaneously replaced by cooler liquid returning by gravity. Ideally, the liquid flows easily because a good thermosiphon should have very little hydraulic resistance.


Tinkeys

Correct me if I"m wrong ! These are an open system which donot pressurize , My 30u is this way also 34 Dodge
what the other boys are saying is correct , Airflow, enough water,timing , head gasket , buildup of gunk in block and radiator. just some of thinks to look for.

wellery

Flushing the radiator is relatively easy you need to use a mixture of air and water (as Craig suggested) - instead of using these new types of products (as they can be quit harsh on the old girls) use a gallon of vinegar and top the rest with water - let it sit overnight and drain. Make sure when you drain the radiator it is not on your driveway as the rust and so forth can be a bugger to get rid of and can stain. Also if you are worried about the acidity of the vinegar you can do a flush with some baking soda to neutralise it.

Reverse Flushing Radiator

Disconnect the hoses at the engine
Put radiator cap on tight
Clamp the flushing gun in the lower hose with a hose clamp
Turn on water and let it fill the radiator
Apply air pressure (6 lbs. max.) gradually to avoid radiator damage
Shut of the air, again fill the radiator with water and apply air pressure – repeat until flushing stream runs clear
Clean and Inspect radiator cap

To Clean the radiator grill (fins) it is best to direct an air blast directed at the backside (engine side) of the core and passing through to the front of the car (there are solvents that you can use for this but try first without them)

Engine Block flushing can be done as well but try the radiator first.

Are you using coolant/antifreeze?

Does you cap have a pressure rating on it?

Contrary to popular believe, an engine produces more energy (and heat at the same time) at high speed (freeway) than at idle or slow speed. So more adequate / perfect cooling is needed. Pressure loss often happens in that condition.

Try this and if it doesnt work we can take it from there

Cheers

Wayne

wellery

Tony

They can be pressurised - Can I answer this later as i have to get the young bloke from school??

Cheers

Wayne

chetbrz

Quote from: Tinkeys on April 18, 2012, 12:08:44 AM
Correct me if I"m wrong ! These are an open system which donot pressurize , My 30u is this way also 34 Dodge
what the other boys are saying is correct , Airflow, enough water,timing , head gasket , buildup of gunk in block and radiator. just some of thinks to look for.

You are correct a Thermo Siphon system should not be pressurized under normal conditions.  Once at working temperature the excess water is expelled through the overflow tube.

Chet...
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

racertb

Thanks for all the feedback...I'm going to start with checking out the radiator.  When it's hot, it's steaming out the top.  I use 50/50 mixture of coolant and distilled water.  There are parts of the radiator that are cool to the touch when this is happening, so I'\m going to assume there is a circulation problem in the radiator (?)  If flushing isn't successful, I'll probably have it removed and checked out locally.

Not sure how soon I can get to it, but will update when I do...thanks again.

chetbrz

When working correctly the top of the radiator should be hot and the bottom should be cool.

Clean out as much crap as you can to faciliate good water flow.

I have had my car out in 95 degree weather without any issues. 

Chet...
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

racertb

Thanks Chet...that's what I want to do...start first with the radiator making sure it has no "issues" before moving on to anything else.

Rusty

This is what mine did.  The block was rebuilt so at that time I had the freeze plugs out and flushed the block.  Mine would go about 3 miles like clock work and over heat.  It could idle for 15 minutes and not over heat but exactly 3 miles , boom.  I had it checked by a local radiator shop ,twice, both times they checked it and said it was ok.  I got a new core and that fixed all problems.  I think that on a thermo sipon system, it really needs to be clean and not blocked as there is no pressure in the system ( no water pump ).  I also had tried two gallons of vinager in the rad and ran the engine for 10 to 15 minutes.   Did not help.
Rusty.