. 67 over heating problem

[Ruppstang]

My son Craig and I restored this 67 coupe a couple of years ago. He is studying in west Germany this semester. I would like to get this over heating problem resolved before he returns and my show season starts.
To start with the 289 2V runs absolutely great. We went to a show that was a 85 mile round trip [cool day] no problems. We went to another show 40 miles and on our return it got real hot but did not boil over, it was 90+ that day. Now we can drive 5-6 miles and it starts to get hot.
The engine was a low mile overhaul when we got it. When we first started there was a head gasket leak. We had the heads checked and resurfaced. We also used a new radiator. I have checked with a laser and it is not a gage problem. I was thinking of back flushing with a hose to see if there is a blockage. I thought some of you engine guys may have some ideas.
Marty

 

[franklinair]

I agree on the back flushing. Have the radiator checked for blockage. (Is it a 2 or 3 row radiator?) I use 3 row as a minimum, 4 row with A/C. Another likely culprit is the thermostat. Replace it. Hoses OK?
That's the way I'd start.

Neil

 

[66hcs-conv]

I had good luck putting on a fan shroud and using one of the cooling additives. Makes the water wetter - whatever that means. But it did lower the temp.

I also used a 3 row radiator, and now wish I would have used a 4 row.

Prolly wouldn't hurt to put the thermostat and a thermometer in hot water & see at what temp it is opening. I've seen brand new t-stats that don't work.

Have fun, Dave

 

[rvrtrash]

My brand new rebuild was overheating bad. Even though it was a new thermostat, I put another one in and the problem was solved. Get a premium one with the small bleed hole, or drill your own.

Steve

 

[Midnight Special]

My brand new rebuild was overheating bad. Even though it was a new thermostat, I put another one in and the problem was solved. Get a premium one with the small bleed hole, or drill your own.

Steve

...Ditto here with my son's new rebuild. Three thermostats before it was solved. Also did the heater core and added an overflow bottle w/ new radiator cap. All is well now...

 

[Russ]

Marty, The one thing not mentioned by everyone is the head gasket. As you know, the head gasket on a small block Ford goes on only one way, and if it is installed incorrectly (backwards), overheating is guaranteed. If everything mentioned checks out okay, I would suggest checking the head gasket. Hope this helps. Russ

 

[franklinair]

Apparently this is not a fresh rebuild, so something has gone awry recently.
Gotta go thru all the preliminary steps before suspecting engine problem. Worst case scenario here would be a blown headgasket (recently), but all the peripherals have to be eliminated first.

Neil

 

[GT/CS S Code]

Do you know how old the heater core is? Was it replaced at the same time as the radiator? Thermostat is likely first place to look, but maybe there was a blockage in the heater core that has migrated to the rest of the cooling system? Just a thought ...
Good luck with finding the culprit!
Al

 

[6t8-390gt]

Marty, The one thing not mentioned by everyone is the head gasket. As you know, the head gasket on a small block Ford goes on only one way, and if it is installed incorrectly (backwards), overheating is guaranteed. If everything mentioned checks out okay, I would suggest checking the head gasket. Hope this helps. Russ

The head gaskets should have a tab that sticks out between the head and the block; if this tab is on the front of the engine the head gasket is installed properly. You do not need to pull the head or engine to check it.

Danny

 

[Mosesatm]

The head gaskets should have a tab that sticks out between the head and the block; if this tab is on the front of the engine the head gasket is installed properly. You do not need to pull the head or engine to check it.

Danny

Well I'll be darned. That's cool! I never knew that.

Here is the tab on the bottom right. Note the bottom right portion of the gasket is squared-off while the bottom left side is curved.

 

[Ruppstang]

You guys are the best I knew that I could count on you for some great ideas. I'll you posted as I start to eliminate the possibiilties. Marty

 

[6t8-390gt]

Yeah, I found that tip out AFTER pulling a motor and the heads! I thought I would pass it along as it would have saved me hours of work not to mention the cost of new gaskets.

I chased overheating problems for a couple weeks; as noted I checked the hoses, thermostat, timing, heater core, head gaskets, and finally replaced the radiator. The radiator was not flowing to full capacity. With the old engine it was not a problem; but with a fresh tight engine it became a problem. Get your radiator flow tested before you tear into the engine!

Danny

 

[robert campbell]

Marty,
I worked in a radiator shop for a couple years prior to my government employment. Re-cored radiators and heater cores. Lots of remove and replaces. Lots of makes, models, of both cars and trucks and even heavy equipment stuff like bulldozers.

Always check any thermostat by boiling on the stove with a candy thermometer and see that it opens as specified. If you basically have a Sunday driver, then use a 180. If you are a “year rounder” I use a 195 in the winter at least. The bleed hole that Steve speaks to is a great add.

I wonder if you are suffering from initial timing being set to close to zero TDC. Your engine is recommended to be set a 6 degrees BTDC. This was the main culprit in Amy’s “satan” story. She started out with an extremely dirty system, but it was not the final problem. Her’s was retarded ignition timing. By the way, the head gasket story will kill a motor, but as bad as it sounds, it does not happen all that often in my experience. The are prominently marked “front” and most hobbyist do not make this mistake.

First I need to know more about your engine. Bone stock with a 2 barrel Autolite? Single diaphragm distrubutor?

I would check my timing and see where it is now hot idle with vacuum hose removed from distributor. If you are running the stock vacuum line and location out of the carb, which means you are using “ported” vacuum. Normal for that engine. Idle should be slow at 600 to 700 RPM when you check it. As said, normal setting is 6 degrees BTDC. Does it “ping” at all before it gets “too” hot under heavy acceleration? If not, then sneak it ahead (towards 10 degrees BTDC) 2 degrees at a time. As you do this you will have to reduce the curb idle each time. The engine will run “freer”. Engines love as much advance as you can give them and they generate less heat! And more power and better mileage. A win win win win!!! A bet this will solve you heating problem. You may end up adjusting your air mixture screws before this is all over. Another story.

We have Amy’s stock 302 around 14 degrees BTDC. It is cold as a cucumber now! Running on a old radiator I gave her that is ok, but not optimum as a new one. 6 degrees BTDC, as the recommend factory setting, is a conservative guideline back in the day that ensured no pinging on regular. Our gas today is totally different than in 1968! Each car should be tuned to the gas you run and its intended usage. If you run 87 then tune it to 87. All stock motors should run fine on 87 and putting 92 in is a waste of money if it is tuned to 87. The 92 gas will ignite slower and do nothing over the 87.

I tune my cars to run on the 92. I am out at 18 degrees BTDC on both engines. They have short advance curves and run at 38 total.

My favorite subject is gasoline discussions about then and now!! Don’t start me, I am warning you!!!

Rob

 

[GT/CS S Code]

Just for reference ...

Just to file it away in my little "pea brain" for future reference ... do all the Ford head gaskets have that tab? Is it the same on the small blocks and the big blocks? (Ours is "buried" in the garage for the winter or I'd go down and pop the hood and have a look at our 390.) Just a good thing to know about ...

 

[GT/CS S Code]

Also ...

I don't mean to "hijack" your thread Marty, but I'm also curious if anyone has any suggestions about how to install a radiator overlow container that still looks fairly period correct on our '68 GT/CS? Our 390 "throws" a bit of coolant out of the overflow hose onto the ground after you shut it off if the rad is nearly full to the top. It seems to settle down and not do that if the coolant level is about 2 inches below the filler, but then the core is showing above the coolant level. This car hasn't given us any overheating problems so far, but I'd prefer that the rad was full to be safe, and I hate leaving coolant behind on the ground especially if we're out for a drive. Any suggestions from anyone out there?

 

[Ruppstang]

Ok here is what I have done so far. I took it for a drive yesterday and pushed it hard could not get more than 1/2 the temp. range. It was about 38 degrees. Could see the T-stat open by the drop on the gage. Today I started it in the shop and let it warm up with the radiator cap off the T-stat opened at about 3/8 the range and could see a good flow through the radiator which is a brand new 2 core with a shroud. Next checked the head gaskets which are correct. Then we back flushed the block. It flowed very freely and had nothing extra in side. I decided since we were all ready that far we would replace the water punp. The old pump was a little rusty but ok but decided to replace it anyway. Put everything back together and ran it in the shop temp still about 1/2 the range. Rob it is a bone stock 302 with autolite 2100 and single advance. At idle it has 16-17 inches of vacumbe. Could not drive it because it is snowing to hard. It may be a while before it is warm enough in NE. to really test it. At least we know some of the things it is not. Marty

 

[Mosesatm]

Marty, does your bottom hose have a spring in it?

 

[Ruppstang]

Yes has the spring. Keep them coming. Marty

 

[franklinair]

You mean one of those flex hoses with the internal spring?? If so, get rid of it! Use a correct preformed hose (top & botom). The flex hoses have a tendency to collapse & block flow.

Neil

 

[Ruppstang]

Neil I have the preformed hose with the coil spring inside to prevent collaspe.