The Stovebolt Site Forums The Shop Area Engine Shop Needs new radiator pt. 2 ??!!

I didn't want to highjack Cmayna's post (as his problem is a little different than mine) So, once again here's the problem:

The vehicle: '49 1/2 ton Chevy. Stock driveline w/ '58 235 converted to 12 volts with thermostatically controlled (set to 180) electric pusher fan in front of radiator.

What I've done: back flushed block, new "fail safe" thermostat, all new hoses, belt, new water pump, boiled out radiator & heater core, new 4lb cap, overflow tank.

The problem: I can drive around town just fine even if it's in the 90's (with Missouri humidity!)It stays right at 180 on the gauge even sitting in traffic. My fan cycles on and off even. Once I get out on the highway and start running 50 or so the temp starts to slowly but steadily rise. In 10 - 15 miles it will be mid-way between 180 & 212. In 30 miles it will be right on 212. If I slow down to 40 or so it will drop back down. It hasn't ever boiled over or even smelled hot. I have checked the accuracy of the gauge in a pan of water vs. a candy therm. & it seems dead on.

Footnote: I should also add that I have checked point gap, compression, timing & valves. There is no indication of any other "related" problem. It starts very easily, has great power and will accelerate smoothly. What the H#@L is my PROBLEM???????? :mad:

Is your fan pushing the air the wrong way? It should draw air in and blow it toward the engine. Don't laugh, I've heard of it happening before.

Another thing it could be is that the lower hose is collapsing from water pump suction at higher rpm and pinching off flow. Make sure you run a nice new hose with a spring inside it to keep it from collapse.

4ontheFloor, Yes, it's blowing the right way. Puts out a heck of a breeze.......Hoses are all new, correct, molded.

I should also add that just for giggles I tried the old wive's tale of "distilled water only making a twenty degree difference" Bull pucky. Might work for flat top fiords but, it didn't help me.......

And.....the radiator flows good (top to bottom) if you fill it up (hoses off) and let it run out the lower neck. It just gushes out. No noticable cool spots (on the radiator, indicating lack of flow) when running.......either

Drill a small hole in the flange of the thermostat. This will allow for a small amount of flow even with the thermostat closed. It will avoid airpockets.

Are you saying you ONLY have the electric fan and NO standard fan? If so, your electric fan might just not have enough capacity at the higher speeds. I thought you ran those electrics in conjunction with the stock fan?

Your truck has the typical signs of a bad radiator, fine in town, heats up gradually on the hiway.I have had several vehicles with the same symptons and a radiator recore,or replacement always cured the problem.

Tony,

Thank you my friend.....Are you saying that even though it flow checks ok it could still be partially clogged? I've gotta get this fixed......Got a Serro Scotty to pull you know..........

I'am with Tony on this one, the radiator is bad. It can't cool the water fast enough. It must have build up inside. You might try some of the Water Wetter or similer product on the market. They do help, the water "sticks" to the metal and ransferers the heat better. My 37 wouldn't cool at all and water really ran through it. A new core cured it. Joe

The fan has nothing to do with cooling the engine at hiway speeds, they don't have enough air flow. Suspects are the radiator, water pump, or major engine problem such as cracked head, headgasket or cracked block.

Radiator - Did the shop rod it out? If so, did they have to block off any passages?

Water pump - Even if it's new, if it spins too fast, it can cavitate the water behind it, stopping the water flow. Cure is to put on a bigger pulley. Also inspect the impeller for damaged blades.

Cracks, leaks - Check coolant for bubbles or signs of oil. Also check oil for coolant. Inspect engine in the morning before it's started, looking for coolant around head.

I agree with Dr. Pascarella; time to either recore, rod out, or replace the radiator.

These are textbook symptoms of a bad radiator.

Stingray,
Everyone above has me convinced regarding new radiator time. Where's a good source for a good radiator? Your local radiator shop or those such as our many old chevy truck part suppliers ?

I'd love to hear how you set up your electric fan. Where did you install the thermostat, etc ? This could be a seperate thread, maybe.

First of all, nice truck! When I had my '49 1/2 ton stock drivetrain 50 mph ("...when I was out on the highway running 50 or so...") was 'wound out' or nearly w/ the 4.11 rear end, IF you're running shorter tires than stock this runs up (higher numerically) the rear end thereby making the engine work even harder. How far you pulling your Scotty and at what intended speed? All info. re: radiator above duly noted.

Gentlemen, (I'll use that term loosely)

Thanks for the input. I suspected the radiator all along (hence the name of the post) I just wanted to make sure that I wasn't missing something obvious. A guy can do that sometimes if you stare at something long enough you miss the details...... I just wanted reassurance before I spent the $$ for a new radiator.

To answer a few questions that popped up in this thread. My local radiator shop would not "rod out" my radiator He's a younger guy (more interested in race cars) he said it would be to hard to resolder the old honeycomb type core. He also suggested a new one instead of a recore because of the age of the tanks & necks.

Cmayna, I will probably be getting a new one from Jim Carter over in K.C. (in fact I'll probably just make a trip over to get it) a tank of gas will be cheaper than the shipping. As far as my electric fan.......I am in the proccess of putting one of those in all of my trucks.......now, I'm one of these "everything original" nuts but, I'll tell you what, we had a blade break on our '57 two years ago doing 60 mph down the highway. Luckily, it went straight down, bounced off of the pavement and hit the cab floor. Could've been much, much worse. I drive all of my trucks very regularly so, off come the 50 year old 4 blades. When I have 'em looking good enough to go into a museum I'll put 'em back on.

As far as what I use......I don't buy new ones. I'm lucky enough to have a local salvage yard that parts out the cars and shelves everything so, I just take my tape measure along and I've got about three racks of fans to choose from. $25.00 ea. (and I've got actual G.M. parts that way too)

Hey Joe,

Do you belong to the K.C. truck club? Are you going to the Show in Chillicothe this Sat? Gaileen told me there were about 13 or 14 from over your direction that were going.

When I took my radiator in they boiled itdeclared it d.o.a. Too much corrosion. My tanks were good, so they recored it for about $230.

I just picked up a new one for mine from Jim and it is a nice piece, but I had to wait a month to get it. Beware of that, they don't mention it in their catalog.

CMayna,

Last two rads I had recored ran about $230 each- one was for my '61 Willy's Pick-up , the other for my '59 Edsel wagon.

If you can, get a Heavy-duty Core....that extra row of tubes helps keep the engine cool, if the tanks are wide enough to accomodate.

Am looking at at a new rad for my '72 C-10....sprung a leak in the lowest cross-flow tube, and bar's leak ain't stoppin' it....local jobber can get another for $160 so I won't bother with recoring this one.

BTW: I have a 1964 Valiant w/ slant six that's doing the same thing as your truck: around town, it's fine. On the highway it's fine as long as I keep the speed under 55. Over 55, or on long hills, it begins to heat-up. If I add electrical loads such as lights or heater fan, it heats-up.
After new t-stats, new water-pump, new hoses, and several flushes, the local radiator guy took one look inside the core and said "this thing is choked!"...apparently, the original rad core is just big enough for that slant six, and when they start to block-up, they just don't have the extra capacity to keep the engine cool.

Good Luck.

4ontheFloor,

I just called J.C. yesterday and was told that they had both the O.E.M. and heavy duty 4 core units in stock.

They must have been out of stock when I ordered then.

BTW, get some 'water wetter', Redline makes a good one, and run it mixed in the radiator. It really improves the heat flow. I use it in my BMW in the summer when I'm using the A/C and it keeps the coolant about 10 degrees cooler in traffic. I put it in my truck too. It's basically a detergent that overcomes the surface tension of the antifreeze and it conducts heat better.

Stingray, the original Harrison radiators are very heavy, mostly copper construction and yes very hard to resoldier without an oven due to design. And yes they can be "rodded" out.On my 45 big truck,it could idle all day and never heat up but a long drive would have it boiling over , classic sign of a bad radiator.I pulled the radiator, hole sawed a few one inch holes in the top tank, took a choke cable inner wire and cleared the tubes. Most of the blockage is near the top of the tubes. I then CAREFULLY filled the radiator with a solution of half water and half muriatic acid.Let it sit for 10 minutes and then flushed out the radiator with plently of water.The acid thourghly cleaned the radiator.I then soldiered thin brass sheeting over the holes in the top tank.The radiator has performed no problem for the last 3 years.

Tony,

That sounds like a good idea. But, I just installed my new radiator last night! (picked it up yesterday afternoon) I will keep my old one though based on your fix and may try the acid thing.

I have to say those repros are pretty nice looking. Except for not having the #'s and name stamped in the back of the top tank they look pretty close to original (much lighter too), fit good as well. Only thing I don't like is that they do not have the solid overflow line running down the pass. side of the core. Instead they just have a nipple sticking out of the fill neck to connect a rubber line to. Looks a little too modern but, if it runs cooler I won't complain.

I have to run to the store this morning to get some new antifreeze. I'll post the final result of this endevor after a test drive.......stay tuned

Stingray,
What's taking you so long to get back. We're all waiting

Stingray,
Did you breakdown and now sit in the local no tell motel ?

I'm with you on the rubber hose overflow. You might be able to fab another metal overflow over the existing. For sure a radiator show could do it. Maybe you could unsolder/solder your old one?
Dennis

Stingray;
Sorry I didn't get back to you till now, but no I am not going to the show. I wanted to but I had to finish painting our house. It's one of those things that you have to force yourself to finish. Besides that my truck is apart right now. I am trying to get my three carb intake and header on. I had it started Thursday night but one of the base gaskets was leaking. I haven't been back to it yet.

Hows the radiator working out? Did you get to talk to Jim Carter when you came down? Joe

Hi guys,

Sorry it took so long to get back on this post! For some strange reason (which was not revealed to me) I lost phone service from last sat morning till about three this afternoon! Hence, no 'puter either!

Joe, If you lived closer (or if I did) I'd help you paint so you could get that truck back together. Didn't talk to Jim, he had already left for the day by the time I got there. I did talk to Mike almost till closing time though.

Well, it looks like the new radiator did the trick. The wife and I took a nice 40 or so mile drive over the weekend. I was a little concerned at first, as the needle on the gauge would move ever so slightly from sitting between the "8 & 0" to covering the "0" then back again. It took until we stopped at a stop light for me to figure it out. It was my electric cooling fan cycling on & off!

As for the overflow tube. I used a two foot piece of 5/16" fuel line, turned the lettering down so you can't see it, pulled it tight to the passenger side and down. I used small black wire ties to hold it in place. It's not quite original (and it will eventially bug me enough to take out the radiator and have the local shop put a copper tube on it) (winter project) but, on a casual glance it's not too obvious either. Main thing is it's back to the drive in this sat. night.

Now, who owns the dark green A.D. (looks subframed) that passed me on I-35 about 4:00 going north to the hwy 36 exit??

Maybe it was me. The misses asked me to go and get a quart of milk but I got lost.....

Anyway, keep us posted or send me an email during the next few days after you have been able to drive your truck a little more just to confirm if the new radiator has resolved this problem.

Be careful. If you fix all your truck problems too quickly, we won't hear from you again

Cmayna,

That milk is going to be pretty nasty by the time you get from N.W. MO to CA.!!

Fix all my truck's problems??!! That'll be the day.