Overheating on the Freeway - What Are Your Possible Causes?

You should stat with the shroud. It could make all the difference.

 

Thanks. Time to break out the timing light again and, this time, actually find somebody to rev the engine while I'm reading the timing. ou:

As far as the vacuum is concerned, I was measuring off of the distributor's vacuum advance which (I thought) is sourced by the vacuum connection above the throttle plate. (Is that ported vacuum?)

One thing I forgot to ask earlier. When I took my radiator to the shop to have it rodded out, not only did they clean it out thoroughly, but they also gave it a fresh coat of paint, which I was not expecting and thought I had no need for. Wouldn't the paint partially inhibit the radiator's ability to cool?

 

Just wanted to put out an update...

The cooling system is now completely cleared out thanks the the filter. I've gotten my timing closer to where I need it to be (still have more adjustments to make) thanks to the knowledge on this forum. I can now keep up with traffic in the slow lane (65-70mph) for a 40 mile run with the engine temperature averaging 195-200 degrees on level runs and 210 degrees on the uphill climbs. The system no longer threatens to boil over like it used to.

Thanks everyone. :TU:

 

Hey sir,

I've been reading this and I was wondering how your radiator and Skylark are doing now? I have a '64 LeSabre that occasionally the hot light comes on after trying to drive the car 75mph or the 134 or I-5. But if I keep it under 70 she runs like a champ with no overheating or boiling/gurgling coolant. I'm thinking my radiator is the original and the heater core is bypassed. I'm not sure whether I'm going to take it to Burbank Radiator to have it rebuilt or just get a new one at Champion with fans, a new shroud and call it a night. Based upon what you've gone through, what was your experience now that it is 2017 and this post was from 2015?

Thanks,

FG.

 

Had the original rad in my '65, still worked great held pressure but being so old the tubes were eroded so paper thin I got a leak when my finger touch the plastic blade on the electric fan trying to feel if the air flow was cooled down yet in line at the track and broke off one of the blades that barely touched the tubes in one spot ripped holes in a few tubes! Didn't hurt my finger at all but now I had to turn around and go back to the pits and didn't get to make that last run!

Was able to crimp the tubes with holes in them to stop the leaking and drive the car 60 miles home with the radiator cap on part way so it couldn't get pressurized. Good times!

I had a new '69 Camaro 3 row OEM style radiator sitting around that I got dirt cheap that I was able to alter to make fit, still works great.

I would say that an old radiator that isn't working the way it should work isn't always because it is clogged, could be because it is eroded VERY thin. The cooling fins between the tubes can corrode and not transfer heat as it should either when a radiator ages as well. GL


Derek

 

X2 on the 1 inch tube I had a champion 2 row with 3/4 wide rows, complete waste of money for my car. After doing this and that wasting more money it came down to the radiator was not big enough, at 60mph the car would hang at 190, at 70mph+ it would be over 200, on hot days 220. I took that out and put in a brand new aluminum Northern Radiator in with 2 row 1" tubes each. Cools the car perect on 95-100 degree days it stays at 180-190, after see a comparison of the 2 the champion is cheaper and looks cheap I also could not use the trans cool because the inlet/outlets would leak non stop on the champ. Also in the process of finding why my car ran hot I switched to the spal dual 11" fans and kept in with the northern aluminum, I also had those fans with champion.
Josh

 

It's been running much better nowadays. Ultimately, I had to:
1) Thoroughly clean out my radiator and heater core. (Both are still the originals.)
2) Catch all the remaining garbage that was still trapped in the system through flushing and an in-line coolant filter.
3) Add an overflow tank.

Since all that's been done, I've been running about 190 degrees in the mornings (before the sun comes up) on my way to work, even uphill. On the afternoon drive home, I usually run 190 on cooler days, 195 on warm days, and 200 on hot days. It'll go up to 200-210 on the uphill climb, but then drop down to normal on the downhill side and stay there the rest of the way home. These numbers are after I had put my hood back on. Prior to that, it was running about 5-10 degrees cooler.

Admittedly, I only drive at about 65-70mph, staying in the slower lanes. When I let it roar at 75-80 to pass, the needle will nudge up about 2-3 degrees a few seconds later before settling back to normal.

I'm really enjoying this adventure.