Hershey Trip

[Jim Stoltz]

Took a 250-mile round trip trek to Hershey PA in the old Allegro this weekend. It was probably the most hot, humid weather I've driven the rig in. 

I left early Saturday morning so ambient temps were cool (mid, low 70s). It ran fine up and down the Eastern-PA hills on Rt. 78. Coolant temp would creep up, but the stock clutch fan would kick in and I could see the temp drop immediately on the gauge.

The ride home today was a totally different story. It was mid-high 80s and humid. The temp gauge got right of normal (toward the hot) on the highway only about 10 miles out. With 125 miles to go, I was concerned. 

Not sure if the gauge is accurate, but it was flirting with the red zone pretty much every hill I climbed at highway speeds (60 MPH+). I slowed down to 55 MPH (in 65 MPH zones) which kept it out of the red but still high.

The last leg of my trip is about an hour of 35-45 MPH roads where it should have recovered. It didn't. Every time I hit a stop light the temps would shoot right up into the danger zone. 

The clutch fan is new, radiator is original it seems. What's interesting is that it appears to have "heat-soaked". At the beginning of the trip, it would recover fairly quickly from a hill climb. Over the 3-hour drive it was harder and harder to recover. The icing on the cake was the last 2 miles to my house. A long, steep climb where I tried to maintain 50 MPH. It shot up into the red zone on the gauge and I caught a red light at the top of the hill. There's a left where I turn onto the road to my house and the friggin left turn signal failed and I had to sit there through 2 cycles of the light. I had RPMs at 2,000 with the clutch fan roaring but it barely cooled down, though it did get out of the red.

It never boiled over, but it filled the expansion tank more than I've ever seen.

So the question is - are these things capable (in 1984 stock form) of staying cool at 55-65 MPH on the highway? If not, what can be done? The radiator appears to be custom, so I can look at having it re-cored.

It was a really stressful drive today that I'd like to avoid in the future.

[Lakota Wolf]

I have a question.... Is your radiator a 4 core?   Usually 4 core radiators are factory installed. I have had radiators re-cored with success  but I have also upgraded to Commercial 4 core radiators.

On all my trucks, I get around to upgrading to a commercial 4 core heavy duty radiator due to the fact I do at times push my trucks hard with serious weight behind them and thats one thing I dont want happening,,, the temp guage climbing in the red zone. I also hate factory temp guages and always install after market temp guage, with oil and generator guages. (I hate that normal range on the factory guage). because its a fine line from so called normal to blowing head gaskets time when it jumps to the red.

On the ole red diesel I have an electric actuator that closes vents over half the radiator to get the engine warmed up to operating temps, then it opens and I run steady at 185 to 210 , in the normal range, and with the commercial 4 core, it runs exceptionaly cool.

[Richard W. Cobbs]

I can only say what worked for me.  1976 M-500 440-3 727 trans.  On my first run after buying it, I was running right on the edge, had to keep engine running at gas station or it would boil over.  Had a two fan set-up and AC that didn't work.  Installed a small oil cooler and gauges on lines in and out of tranny.  Still ran hot.  Disconnected AC stuff, cleaned AC evaporator with alcohol and used it as an oil cooler instead of the small unit.  Hitched it up so oil from tranny goes into AC evaporator hot from tranny then to bottom of radiator.  I'm in hot weather all of the time, so I also threw away the thermostat.  Works for me!

[Jim Stoltz]

Thanks both.

I do have a trans cooler installed. I found that if I ran the heat it would help cool it, so I'm thinking it's a capacity issue.

I don't know what they install from the factory - I assume it's a 4-core rad but it's tough to tell. I looked at new ones online but this one has a neck on the side instead of the top. Tanks on the side. It's also square-ish versus the ones I found online that appear to be rectangular (with necks on the top). A new radiator certainly can't hurt - just don't know how/where to get one.

All in all the trip was good though. My mom and dad drove out there and hung out last night. My brother (whose camper burned to the ground on Friday) also came by and delivered some firewood. My mom said it reminded her of when I was young and they would take us camping.

We got home no issue. My kids, my girlfriend and her nephews never had any clue that there was an issue. The generator ran flawlessly the entire 3 hours and powered both front and rear a/c units, the fridge and everyone's electronic things. As I was sweating out the coolant temp issues everyone else was chilling in the back.

Back on topic: I need more cooling capacity. The 30-year-old radiator is probably not up to the task. 

[Lakota Wolf]

Jack made a good point,, I used laymens terms, as have always called them 3 or 4 cores,, meaning rows. sorry for any misunderstanding.

A radiator shop can show you options in the Standard Radiator and a Commercial version, (which is just a heavier duty unit for extreme conditions).

The difference in the thickness on my Ford diesel radiator is, the stock was only 3 inches wide and the commercial version is 5 1/2 inches and almost double the capacity in coolant.

[Jim Stoltz]

I always confuse the rows and cores thing too. I don't think it actually boiled, despite the gage being pegged on the hother sidea briefly on 2 occasions.. I'm going to invest in a real temp gauge next to see how hot it's actually getting. And I'm going to find a radiator shop. They're hard to find anymore since the Chinese ones are so cheap. No one rebuilds them around here anymore.

[So ska noname]

It's stressful when they overheat and you on the road in traffic. Friends added a trans cooler, or replaced or re did radiator. They had a similar problem. They go 55 from tullahoma, Tennessee
To michigan on freeway.

[Jim Stoltz]

It really is stressful watching that gauge creep up. Traffic is stressful enough without worrying about it overheating. Thankfully I didn't hit any traffic. What made it hot was highway speeds. The last 5 miles of the trip is 2 lane with stop lights. I kept it in neutral and about 2,000 rpm when stopped to let the fan do its thing. Just before the last big hill climb it looked like temps were finally edging toward normal. But that hill climb pushed it back to redline. I'm thinking that 31-year-old radiator needs rebuilt. I don't have a/c so there's no condenser blocking airflow.

My other paranoia is vapor lock when it gets that hot. It was a common problem with these things back in the early-mid 80s. It hasn't happened yet, and may never happen but it's always in the back of my mind. It appears as if it used to have an aux electric fuel pump but it was removed long ago.

[Jim Stoltz]

I ordered a mechanical (don't trust electric senders) water temp gauge today. And a 2 1/16" hole saw.

The Allegro has a nice Stewart-Warner air pressure gauge and an AutoMeter trans temp gauge next to it. Both are vintage with real glass faces and chrome bezels. The trans temp gauge has evidently never been hooked up to anything. So I'm going to hack another 2 1/16" hole in the dash for the new water temp gauge  and try to find a sender for the old AutoMeter trans temp gauge. It's too cool to remove.

I also called a "local" radiator shop today. Funny story - I grew up in a town called Roxbury. There was always a Roxbury Radiator shop, but it disappeared about 20 years ago. But....I used to drag race at Island Dragway in Great Meadows about 20 miles away. I would pass a radiator shop called "Roxbury Radiator" in that town. Yep - same family business - they moved. Talked to them and they're going to check out the radiator once I remove it (does not look easy but I think I can do it).

[Jim Stoltz]

Thanks Jack. Which is better/more important? Head or intake?

[Jim Stoltz]

I'm hoarding parts for this project now. The new water temp gauge arrived yesterday:

That's the hole where the trans temp used to be. It's an old school Auto Meter gauge:

It has apparently never been hooked up. There were no wires near it or attached to it. I'm thinking the previous owner put that in but never got around to hooking it up. I ordered a sender from Autometer for pre-1995 temp senders. It should work. So I'll put that gauge back where it was because it matches that air pressure gauge so well. I'll hack another 2 1/16" hole in the dash for the new gauge.

Now the back of the old trans temp gauge is interesting:

I can't find a part number on it anywhere. 2 of the 4 terminals are marked. One is ground, and the one with the red tag is for the sender. I assume the terminal on the right is for the hot wire (It's marked "I" which I assume is Ignition). Then there's that blade terminal on the top left. I assume that's for the illumination?

Also on the way is some Prestone cooling system cleaner and a flush kit. If that doesn't help I'll have to pull the radiator out and seek professional help.