Buick straight 8 overheating - need some help here.

[Guest 1949 Roadmaster]

First off......hello. I'm brand new to the forum. I've read the posts for awhile but didn't join until I picked up my new find, a 1949 Buick Roadmaster. Anyway, the previous owner had the car running, but never registered it. I checked the anti-freeze...........full. Radiator seems to be in decent shape. I drive the car about 5 miles and the temp gauge climbs; however, it doesn't overheat until I shut the car off...then it pukes out about a quart of anti-freeze out the overflow tube. I checked the 160 degree thermostat and it opens at temp. The bypass valve has been replaced with the factory upgrade fixed oriface housing. my hoses are good and no leaks. I did notice the drain cock behind the distributor does not drain coolant when opened. I stuck a small screwdriver in there and no coolant flows out.

I could use some advice here before replacing the radiator or ripping the freeze plugs out to check for buildup.

Thanks is advance...........Rick

[rons49]

Welcome,Rick. Have you had a flow test done? A lot of sediment might have settled in the radiator and may be blocking the flow tubes. any good radiator shop will do this.They can rod out the tubes and free the radiator of that sediment. Also a good flush should be done as well. And consider joining the AACA if you haven't already. Ron Sotardi Life member

[Guest noncompos]

Nothing coming out of the block drain means accumulated junk in the water jacket inside..you can get a screwdriver in it?? (removed whole drain cock??).

Bend a little curve in a wire and fish around in there (you'll just be scraping cast iron) to see if you can't get stuff to flow out.

Rons suggestion good, but do a shade-tree flow test before spending $$$: pull the lower hose, pour water in the top, it should run out as fast as you can pour it in.

Could be crud in the block limiting the natural thermo-syphon activity when you shut it off, the block dumping residual heat into the block water putting it into slightly boiling.

Roadmonsters often seemed really warm when we used to open hoods on them. Good luck.

[Guest 1949 Roadmaster]

Thanks guys, anybody have any luck with those "back-flush" kits like the Prestone ones at the parts stores? I'll do a radiator drain check tonight, but was wondering if flushing the block myself would even be worth the time?

[Mark Shaw]

This is a very common issue. These monster engines hold a lot of heat when they shut down. Too much coolant will expand and cause about a quart to siphon out the overflow when you shut down. Add only enough coolant to cover the radiator core so it won't start the siphon.

[Guest 1949 Roadmaster]

Mark, so this is "normal"? Is it OK to run it a little low in the tank? I'll try just covering the tubes in the radiator core and drive it awhile. I can hear it "percolating" when I shut the motor off; it sounds like a coffee maker!

[Mark Shaw]

Yes, that is very common... Just check the level often since you will have little excess to make up for ordinary loss of coolant.

[john hanson]

had the same thing with my 1938. Tried ever thing i could think of

4 miles and would start to get hot. Finely pulled radiator and had tanks taken off

The top of cores were covered with stop leak. the guy that was to clean radiator just flushed it out. Put in a new core and the car never run better.

John Hanson

[Ben Bruce aka First Born]

John, agree with you. The radiator is almost always the major culprit.

Ben

[Guest 1949 Roadmaster]

I know this is an OLD thread, but I'm the OP.  It looks like I need to pull my head to rod out the block (water jackets).  Any advice to make this easier and more efficient?

Thanks.

[Ben Bruce aka First Born]

Did you pull the radiator and have it rodded out?  If not, that would be the first thing I would do. I would want to KNOW it is clean.

  There is no easy way to clean the water jacket on the block. Even with the engine out of the car, it is difficult.  I think, if your radiator is now , or will be, clean, I would put some kind of a filter between the engine and it after messing with the engine so junk is not re-introduced to the top of it.

 

  Ben

[fordrodsteven]

don't know if you're trying to keep it "bone stock" or if you are trying to make it something you can drive. It would be nice to get it sorted so that it doesn't burp after you shut it down. In the meantime you could add an overflow tank to catch the "burp" I had a car once that I could not get to stop spitting up a little after I shut it off. I added the overflow tank and never had the problem again.

[Guest]

Start by knocking out the core plugs and cleaning out the block.  Most of the crud collects in the block and pulling the head is not the way to clean the block.  You need big holes to get inside, not the water passages between the block and head.  There is really only one way to clean a block out and that is mechanically.  There is no particular mechanical talent needed.  Just pure dirty grunt work and a large dose of patience.  Don't stop with the job half done.  Dig out ALL the crud.

Buick straight eights were famous for plugged water passages in the block.  In the dealership I worked in in the 60's the mechanics pulled the rad and sent it to the rad shop to be boiled out and then they mechanically cleaned out the block.  Some engines had five and up to ten pounds of crud in the water jackets.

Go back to AACA GENERAL DISCUSSION and search "buick overheating".  There are 242 postings about this problem.  If you read them all you will see that owners did every possible thing to the rads, changed fan blades and in the end the only totally satisfactory way is through the core holes.  If you doubt where your engine is plugged buy and infrared thermometer and check all the areas of you engine.

The only reason the rad gets plugged is because little bits of the crud in the block circulate until the hit a passage that they cannot get through.  A clean rad will only stay that way if the block is also clean.

[Spinneyhill]

You can use a stocking "sock" in the radiator inlet pipe to catch the debris.

 

Just a note that the radiator water level should be about 3" below the bottom of the filler neck, covering the top of the tubes. If it is higher, it will expel coolant through the overflow until it is. You refill the rad., it expels the coolant and so on. The coolant expands when it warms. The expelled amount you mention sounds about right for 11 L or so of coolant expanding. 

[fraso]

If you're sure that your overheating issue is cause by scale and rust, my suggestion is that you chemically clean it.  I've used citric acid and it works quite well.

 

See Cooling System for more information.

[Bud Tierney]

"Owner had car running but never registered it"---if that meant it wasn't driven, or that the engine run for only a few minutes at a time, that the car mostly sat, you might ALSO shine a light thru the radiator, at night, to see if radiator partially blocked by insect nests, spider web caught debris etc...

[Pete O]

On 3/11/2017 at 3:29 PM, 1949 Roadmaster said:

I know this is an OLD thread, but I'm the OP.  It looks like I need to pull my head to rod out the block (water jackets).  Any advice to make this easier and more efficient?

Thanks.

I went through this exercise with my 263.   First bit of advice, use an engine hoist to lift the head off the engine.  The friggin thing weighs a ton!  Even with two guys it was hard to jackass that lump of iron off the engine.

I found that the water jackets in the back of the engine near the firewall were blocked up nearly halfway of it's depth.  I just used narrow screwdrivers to pick at it, then flush it out, then pick some more, then flush some more, ad nauseum   I had some wound cable that I chucked into a drill and used to roto-rooter  the areas that were harder to reach.  Patience and persistence.

Edited April 4, 2017 by Pete O (see edit history)

[Guest 1949 Roadmaster]

Thanks guys; I finally got my head gasket kit.  Historically, I did drop the radiator off at the shop.  The removed the tanks, rodded the core, and resoldered and pressure tested it.  Water drains FAST from top to bottom.  I'm gearing up to pull the head and pop the freeze plugs.  At the same time I'll check my water pump out.

[37_Roadmaster_C]

I would recomend NOT pulling the head to start.  Pull the manifolds and the block plugs.  At this point you can flush the block without flooding the cylinders and pan with water.  Several people here have mentioned making a tool for flushinh the block. It is described as a small copper tube (1/4 inch) fabed to a hose connector. This is used to "rod" the block by going in the plug holes and rodding with water pressure to dislodge the crud.  Very little is likely to be in the head or head passages. Either way, doing the block with the head in place will reduce the possibility of dumping a bunch of crud into the cylinders and pan.  If you feel the need, pull the head after the main rodding and flushing.  Do not forget that coat hangers  or welding rods also make for good scrapers and rods while flushing.

[Guest 1949 Roadmaster]

Ok, pulled out the freeze plugs and the jackets don't look that bad. How do I rod around the rear cylinders near the firewall?  I can only get a wire to go to the back of the block, not around it. 

[Rusty_OToole]

Dirt and rust always falls to the bottom of the water jacket. Best cleaned out through the core plugs and possibly the water pump opening. Do Buicks have a water distribution tube?

 

With the core plugs out you can wash out guck with a pressure washer, poke with a wire to loosen it up, reach in with an air hose ( use a brake line screwed to the end of the air blower). Wash it out as clean as you can then put in new core plugs.

[DonMicheletti]

Buicks do not have a distribution tube.

Sometimes you can use a length of speedometer cable in an electric drill to work around to the back of the water jacket.

[Larry Schramm]

On ‎8‎/‎15‎/‎2011 at 4:22 PM, 1949 Roadmaster said:

Thanks guys, anybody have any luck with those "back-flush" kits like the Prestone ones at the parts stores?

 

IMO, a waste of money. There are better things to use on old engines.

[Pete O]

On 6/20/2017 at 9:00 PM, 1949 Roadmaster said:

Ok, pulled out the freeze plugs and the jackets don't look that bad. How do I rod around the rear cylinders near the firewall?  I can only get a wire to go to the back of the block, not around it. 

The jacket behind the rear cylinder is more easily accessible with the head removed.  I understand the resistance to such a commitment, and the comments that junk and water can get into the cylinders.  But you can tape off the cylinders to prevent junk from getting in.  And by removing the head and inspecting its condition,  you may find another reason for it running hot- such as stuck or burned valves, excessive carbon buildup, head gasket failure, etc.

[Guest 1949 Roadmaster]

Finally solved the problem.  The radiator that I had taken apart and rodded out and re-soldered still wasn't flowing enough. I couldn't find a direct replacement, so I built my own aluminum radiator. Now it runs at 170° and rarely goes over 200 except when idling  in traffic.  My dad did the welding and it took one afternoon. Adding a coolant recovery tank next as a precaution. 

Edited August 8, 2017 by 1949 Roadmaster (see edit history)

[Bhigdog]

Nice TIG work. I've given up trying to TIG aluminum...............Bob

[Guest 1949 Roadmaster]

 It was tough at first, but I kept practicing on scrap aluminum and I got better as time went by. I didn't want to try the radiator, so my dad did. He's a certified welder.