Overheating

[Dani]

1950 Buick series 40 with 263. I have a custom radiator in it now since the originals are too hard to find in good condition. My question is if there is too much air at the top of the tank will this cause the engine to overheat? I don't have a line and am unsure how much air to leave. It's a 2 core radiator using the same hoses and everything, I think it will be fine in place provided I fill it with the right amount. Thanks guys-----

[JohnD1956]

I don't think air in the tank causes overheating. There are several things that could cause overheating. But the best idea to cure this is in that article in this months Bugle. If you haven't read this, it dealt with re-opening the coolant passages from the block to the head. If you have a new radiator and it is still overheating, I believe this should be high on the list of things to do.

John d

3757

[Dani]

The radiator I'm using now was used to cool a 289 V8 engine, I also used it to cool a 390 big block previously, and did so successfully both times. With it in the Buick, the engine still overheats. I just got finished taking the head off and clearing up the passages, I am now to add a super flush fluid and see what that does. Water pump has been rebuild, perhaps my timing is too far in advance? Some flushing and hopefully it will start to run cool. I havn't read the article yet, but hopfully well get a copy of the magazine soon. Oh, I forgot to mention, I was trying to clear out those 3 hoses that connect to the waterpump and 1 underneith the inlet. I shot water through one and came out another (nice rust colored too) until it was clear, then tried to shoot it down the last one and it just backed up, is this due to a valve in the line somewhere or is this a blockage that is perhaps causing my overheating??? Thanks-----

[Stripgear]

Dani,

I have a '48 super with the same motor. Take the freeze plugs out and get some long skinny screwdrivers and poke around everywhere you can reach.

You will be SHOCKED how much rust you will remove, particularly at the rear.

I removed almost a one pound coffee can of rust and scale about ten years ago. Now I can run it all day in the Texas heat with no problem.

I wish I could say the same!

Scott

[JohnD1956]

Just don't take out that freeze plug that Dani referred to in the other discussion on this board.

[Dani]

I've already cleaned the water passages of the block and head, probably removed just as much rust as you. Cleared all my heater lines, cooling lines all that good stuff. It now will stay cool for about 30 minutes idling, and slowly climb to hot thereafter. I still have to flush the system, hopefully I will get to that tomorrow. I have another radiator on the way, (it is as tall) but doesn't have the same length as the original, perhaps it is from a manual transmission car? Would this still cool the Dynaflow and 263? It's frustrating trying to fix cooling system problems! Thanks guys!!

[Buicksplus]

Dani:

Regarding your original question, air in the top of the radiator can definitely cause overheating -- if there is enough air so that the top of the radiator tubes are below the water level. When that happens, the incoming water goes just through just the tubes right near the water intake, and most of the radiator is bypassed. Make sure there is enough water to cover the top of all those tubes.

Has the engine been recently rebuilt on this car? These straight eights and any long stroke engine produces a lot of extra heat when they are tight with new bores and rings. Don't underestimate the need to thoroughly break in these engines -- I have had them overheat terribly until I drove them several thousand miles --then they cooled much better. Try to get some miles on it, I think it may help.

Check the timing too, if it is too retarded or advanced, it can cause heating problems.

Good luck!

Bill S

Albuquerque, NM

[Dani]

Thanks for the info. The engine has only 25K original miles on it so I figured it wouldn't need a full rebuild, just top end (due to closed coolant passages in the head). I'm the second owner and know the previous owner very well. He has told me that this car had cooling problems before it was parked in 77 even with this low milage. I'll double check the timing tomorrow, I think that this may be one problem that is causing some extra heat.

[Ron Green]

Beware of the old wives tale that buying a low milage vehicle will give you less problems. Having purchased a 5,748 mile 1967 car that was stored inside and appeared to be in excellent condition many problems surfaced when I started driving it. Sitting or little use is tough on mechanicals. 900 hours later and many of thousands of dollars it is starting to become reliable, somewhat.

[Smartin]

Heck,

My car had 67k miles on it when I bought it and I STILL had to pull the top end of the motor apart to replace head gaskets and all the seals, hoses, etc.

[Dani]

I just got a radiator (only it is for standard transmission so it isn't exactly the same dimensions) and it seems to cool the car now. I am wondering where the gauge typically points when the car is fully warmed sitting idle in about 70-80 degree weather? It was cool for about 45 minutes but then began to overheat again (I believe this time it was due to a leaking hose which I fixed, but lost some water).

[chub chub]

post if it still overheats after fixing the hose. post if it doesn't. we can take it frome there. best of luck.

[Dani]

Car is still overheating, but I found the problem. About 80% of the cores are closed on the top of the radiator (looking through the filling hole). It is some kind of brown stuff that is as hard as a rock, some kind of minerals built up? With a blocked radiator it is no wonder why the thing is overheating. Who knows how much more is clogged in the radiator. I am not ready to take it to a garage and have it flushed (which will probably open a few pin hole leaks on this old radiator), so anyone suggest a good liquid flush that will break this crap down?? Anyone ever take their radiator out and fill it with Drano??LOL..-----

[JohnD1956]

While determining the best way to follow up with the radiator, I would suggest an "in the top hose" filter.

I bought one from http://www.mako.com.au/auto for my 56 Super and it is great. I did have to cut the hose, but this is a hard plastic filter, with a screw cap that allows you to remove the stainless steel filter for cleaning. It's obviously not original, but so what! I had my radiator re-cored, increasing the thing to a three core radiator, and on the trip to Flint in 03 for the Centenial it started to overheat again. When I got home I found that same stuff clogging my new radiator and it had to be taken apart to rod it again. What a waste of $$$.

Anyway I put in the relatively inexpensive filter from Tony, and I can't believe the crap I filtered out of the car. Right now the guage runs just a bit higher than it used to 20 years ago but I haven't pulled my freeze plugs yet either to clean the bottom of the water jacket.

I heartilly recommend this filter product.

[Ron Green]

If the radiator is that clogged one has to wonder how much junk is in the cooling passages in the engine. It might pay to pop a freeze plug and take a look inside. A good radiator shop will be able to use your existing radiator tanks and install a new core for around $220. You may get some of the gunk out of your old radiator core but chances are its cooling capacity will be limited.

[Dani]

Must have been from the previous owner of the radiator, because I've already opened all my plugs and used air to blow all the rust out of the engine at various points (that's how I got screwed not being able to find that 1 freeze plug under the water pump!). This radiator is salvageable, it just needs to be freed from all that crap inside it. Once I am able to do that, I will purchase one of those filters, that is a good idea for this engine, I've used them before on a few other classic cars that have long been sold, but had forgotten all about them!

[Sgt Art]

I've run into a radiator that appeared to flowing well only to find out, after we did just about everything, that 2/3 of the lower passages were clogged. The radiator shop spotted it right off and I can assure you, they were correct because I helped them rod it out. There was a hard substance called silicon drop out (from the anti-freeze) that clogged the lower passages up. After rodding it out, the car ran fine without any further overheating issues.

That kind of situation will fool you, it did me.

[Dani]

My problem is I will never find anyone around me that will do rodding on this type of radiator. My first radiator-the original one, the tank has separated from the core and they didn't even want to touch it. They said "If I put a torch to that the whole thing will melt," this is a shop that's been repairing radiators for decades. They only like to repair the new type radiators, not the cellular ones. Perhaps I will just have to ship it to someone. I would love to have the original radiator repaired, like I said it is only separating from the tanks here and there, I was able to repair some of it but I just don't have enough skill to finish...

[Dani]

Okay guys it NOW seems that the car won't overheat idling while sitting with the hood off, but with it on- the heat builds up and the needle rises to H. Is this a common problem or just my luck..?