Overheating issues

[47heaven]

I took the P15 for a ride up to the local mountains (Mt. Baldy) with a friend yesterday afternoon. The tempurature outside was about 88 degrees and even a little cooler as we proceeded up the mountain highway. I was watching the tempurature gauge as we climbed and noticed it going from 170 to 190. I figured that this was normal because most older cars are known for getting a little hot going uphill. Anyway, about three miles further, the gauge was registering about 200 and the power seemed to be fading, so I shifted up to 2nd gear and got a little more umfff, but the gauge started making it's way to about 205. I went back into 3rd and the car just crawled. By 210, I pulled over and shut off the engine. You could hear the radiator boiling and also hear the water spilling out of the overflow tube onto the dirt, but there was no steam coming out. I opened the hood and we let it cool down for about 20 mins. After it cooled to about 180, I decided to just go back down the mountain. The tempurature stayed at a safe 170 on the way down.

Today, it was hotter outside (about 95) and I took the car to show someone. It drove fine, but was getting up near the 200 degree range pretty quick. I then realized that it may be low on water, due to the overheating yesterday. I stopped at Pep Boys, got some antifreeze and poured about half of the undiluted flud in the radiator. I noticed on the radiator cap was some rusty looking sludge, which surprised me because I had the engine flushed last summer. Anyway, that seemed to do the trick and brought the temp. down to about 170.

Is it normal for these flatheads to heat up like that on a mountain upgrade or is this something to do with the cooling system needing another flush and maybe an electric fan or better radiator?

[Reg Evans]

Have you made sure the inside of the block doesn't look like this? No amount of flushing will get rid of this stuff without removing your freeze plugs. My 35 Dodge looked like this in the block and some of the water ports between the block and head had crusted over stopping the flow of water. A piece of coat hanger wire dug it all out and she runs cool now. Before I did this it would overheat after a short drive up or down hill. Was your radiator ever boiled out?

[De Soto Frank]

Wow, Reg... that pic is worth thousands of words about rusty-sludgy MoPar cooling systems !!!!

Thanks for posting !

De Soto Frank

[Norm's Coupe]

Wow, Reg... that pic is worth thousands of words about rusty-sludgy MoPar cooling systems !!!!

Thanks for posting !

De Soto Frank

My engine looked about the same (maybe a little better) when I removed the freeze plugs too, and it was running before that. I've helped take a couple of Flathead V8's apart too. They also had the same condition or worse. So, you'll see that in any old engine, and it should be cleaned out.

[47heaven]

Have you made sure the inside of the block doesn't look like this? No amount of flushing will get rid of this stuff without removing your freeze plugs. My 35 Dodge looked like this in the block and some of the water ports between the block and head had crusted over stopping the flow of water. A piece of coat hanger wire dug it all out and she runs cool now. Before I did this it would overheat after a short drive up or down hill. Was your radiator ever boiled out?

Reg...the pic is not showing here on my computer at work, but I can imagine that it's not a pretty sight. The radiator was boiled out about a year ago, but may have developed rust since than. Does removing the freeze plugs require lifting the engine out? Because if that's the case then I'm just going to have it rebuilt.

[Reg Evans]

No. The 3 main freeze plugs can be r and r'd from the drivers side. Remove the one near the rear of the engine first and if you find lots of sludge remove all 3. I used various lengths and shapes of coat hanger wire and gouged all the crud out. I also had a garden hose running down the inlet on top of the head and had removed the thermostat so the water would flow thru and carry all the crap with it. If you do find a lot of sludge behind the freeze plugs I would also remove the head and clean out all the water jacket ports.

Is your engine timing correct?

[47heaven]

No. The 3 main freeze plugs can be r and r'd from the drivers side. Remove the one near the rear of the engine first and if you find lots of sludge remove all 3. I used various lengths and shapes of coat hanger wire and gouged all the crud out. I also had a garden hose running down the inlet on top of the head and had removed the thermostat so the water would flow thru and carry all the crap with it. If you do find a lot of sludge behind the freeze plugs I would also remove the head and clean out all the water jacket ports.

Is your engine timing correct?

Okay...I see the crud now. Man, that looks pretty bad. I would like to hope that it isn't that bad, but I won't see until the freeze plugs are taken out. How about the water jackets? Do they need to be replaced, as well? I heard they were a real job to take out....sometimes coming out in pieces

[Don Coatney]

How about the water jackets? Do they need to be replaced' date=' as well? I heard they were a real job to take out....[/quote']

Darin;

Replacement of the water jackets is best not attempted at home. :D

However the water distribution tube is a different issue if that is what you are talking about.

[Reg Evans]

Well....in my old 35 that was all clogged up I didn't want to open Pandoras Box by afiddlin with the water distribution tube so I just used a long piece of hanger wire with a hook on the end and reached in there and scratched all around until the water was flowing through all the water jacket ports again. She runs cool as a cuke now.

[randroid]

Gents,

Living in the Rockies has given me the opportunity to hear many stories of over-heated engines, and the one remedy that works 95% of the time is to turn on your heater. It is nothing more than an auxiliary radiator and if you find yourself in a situation where a larger radiator wold be of benefit, use it.

I lived at 8000' when I rebuilt my '48 P-15 and there are some considerations to be taken at that elevation, including advancing the timing and leaning the carb. In mile-high Denver the atmosphere is about 10% less than at sea level, but when you get only a half-mile higher the density drops to 32% less than sea level, so you are effectively decreasing the airflow through the radiator by one-third.

I've been up that road on Mt. Baldy and am not surprised that the engine got hot. Next time you go up on a hot day roll down all the windows and use your heater. I expect you'll get a pleasant surprise.

-Randy

[Reg Evans]

That reminds me of an old truck I had that was prone to running a little hot in the summer months. I use to have a heater core I installed in the long hose running from the water pump to the heater inlet at the firewall. Instead of running the heater through the cab heater I just hooked the hose from the water pump to the back of the head inlet with that bare heater core in line swinging in the breeze. It helped.

[40phil41]

My favourite photo . A sample of the crud taken out of my freeze plugs (D24 engine in '40 Dodge).

Phil

[Reg Evans]

Ummmm Ummmm Good.