I posted a couple months ago that since porting and shaving the head I have been having cooling problems. yesterday I took the Valiant on a 140mile round trip drive to Jersey to sell a front disk setup and on the way it would get almost to the top of the normal area, then suddenly drop to about 2/3's. on the way back I stopped at a rest area and pulled my 180super stat(which was wide open) the water looked like thin mud. I have used cooling system flush 3 different times this summer and drained and re-filled the system3 times after each flush. after each flush the rad would fill more quicky than the last time and would seem to work better for a week or 2 then back to getting hot at highway temps. the rest of the way home the temp gage never got above 3/4s but I think that is still to high when there is no thermostat at all. I'm going to drain the system today and start looking for a rad. I have seen a couple at a yard thet seem to be really large single core rads I guess I'll try since I cant seem to find a 3 core anywhere.
what do you guys think of my situation, does anyone have any comments/suggestions/input?

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Have you checked the heater core? Also, pull the water pump, engine coolant gallery drain plug, and maybe even the freeze plugs to make sure those passages are clear.

after doing my engine, the block seemed to have loose material inside from hot tanking at the machine shop. this stuff filled up my radiator, over a few months and the system got worse, eventually it got into my heater core and caused a leak, so i bypassed it and installed a different radiator (late 70s Volare 2 core) now it runs just below the 1/2 mark .. still have to flush a few more times to get the junk out of it...

Maybe the long drive and extended heat loosened up some gunk
in coolant passages and now it is finally coming out and maybe
more might be coming out. Constant monitoring of coolant
and regular flushes will get it all out.

Phil,

Here is my thinking, for whatever it's worth. Highway speed is not the time for a cooling system to struggle? No car I've owned has ever had heat problems (only) at 60mph. The boil-over usually looms in traffic at an idle when air and circulation are worst.

I propose you are seeing the results of a lean open throttle mixture and not enough ignition timing? Perhaps in part due to your RPM range on the highway and how it has changed due to your rear end gearing.

How wide open is the throttle at the high heat speeds? Are you getting any vacuum advance at that throttle position? What is your total advance? Have you tried adjusting the carb to supply a little more fuel at that range? How is your mileage on the highway?

You know I'm not an expert. I'm just offering some suggestions and discussion.

Finally, have you checked on the cooling of your transmission? It doesn't seem like it could be causing the heat problem, but I've been told they are more sensitive to heat than the engine.

Paul

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1980 Aspen 225 super six

Today I adjusted the valves(I had the rocker cover off anyway so i figured while I was there...) , retorqued the head bolts(just in case they were a little loose and allowing a small compression leak, the most any would turn was about 1/8 turn), backed the timing from 8* to 5*(It had started to ping occationally), and raised the metering rods all the way up(to possibly richen the mixture if being lean was causing exsessive heat build up).
None of this helped. it is still running way up in the normal range after 8 miles of speeds over 60mph. also once it is hot it takes a long time to cool down while running.
lastly do these plugs look normal to you folks?

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I was surfing the net looking for head porting tips, when I hit some info which might apply. This guy was offering 3 different types of porting mild, medium and HOT. He clearly warned that the HOT ported heads would give the most power, but would not be very suitable for street driving due to overheating.

My Aspen gets very hot, very quickly with what I would call a mild port job and .060 off the head. Maybe the extra flow and high compression are enough to tax the stock cooling. I'm surprised that it's not a more documented side effect if that's the case.

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1980 Aspen 225 super six

I did 2 things since it got hot(but not to the point of overheating). I pulled the thermostat and backed the inital and vacuum advances. I havent really had the chance to drive very far since the timing changes but pulling the t-stat helped(it didnt go over 3/4 on the temp gage). I really think I just need to back flush or get the rad rodded out.
I still have to get those tires put on my slots. the rear end is all over the place now that both tires break loose i the rain.

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The plugs look great. Get a new 180 or 190 degree thermostat and install it. Your car will run cooler with it. I run my Valiant with no fan all summer. As long as the car is rolling it never even close to overheats. If you can change the thermostat without getting scalded it is not overheating.
Make sure your gauge reads right. Our Valiants gauge always reads too hot,,,and the fuel gauge reads high . That is an electric problem not a cooling problem.
Your porting job is not likely to change your cooling significantly. How well your valves and timing are adjusted will. This is a good time of year to adjust valves, choke and idle mix. Check belt tension and antifreeze levels.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I am going to replace(put it back in) my T-stat soon. The weather is getting a little cooler and it takes too long to warm up right now. The gage read accurately because out at Carlisle the fan wasn't coming on in town and she puked all over the place once the needle hit the red zone.
I really need to get a total advance light and see what kind of advance I end up with around 23-2800rpm.
valves were adjusted in the last week or two and it has a manual choke. those arent the problem.
I dont think it is the porting but probably the 0.100" taken off of the head+too much advance+ half clogged radiator= running hot.

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Good diagnosis!

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Yeah....Im the one who destroyed this rare, vintage automobile.....

70 Valiant;


I think you have a clogged-up radiator.


I've been dealing with the same thing for three years now with my '64 Valiant rag-top; slant-six 225, and four-speed. No speed mods.

Engine temp stays normal as long as I don't drive faster than 50-55 MPH. Beyond that, the faster I go, the hotter it runs. Also, if I'm driving at 50 MPH, and turn on the headlights, the engine temp rises noticeably (due to increased engine load from the alternator). Same goes for turning on the heater fan.
If I back out of the throttle, the temp comes right down.


I've replaced the water pump, tried three different stats (including a 160 deg), flushed the rad several times, etc.

Finally, I took it down to my radiator shop, and the guy looked inside the filler and said: "You're radiator's all choked-up !" and pointed to "fluffy" whitish crud restricting the tops of the tubes... I asked about rodding, and he said he doesn't do it any more; that my money would be better spent on a recore...

So, I've ordered a new radiator for an Aspen/Volare, for about 1/2 the cost of the recore, and will try that next.

Will report on my results...new rad is supposed to arrive this week.

De Soto Frank

Wow!, carful now.

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1980 Aspen 225 super six

I have had that exact problem on my 75 Cordoba, my brother's 4 cyl 92 Wrangler, and my buddy had it with his 78 Volare wagon. In all cases, a new radiator solved it. Also, a note on new radiators; warning: I have a buddy that has been a parts counterman at a Chrysler dealership for at least 15 years. One night I went over to his house, to find him taking the top end of his mom's early 90's Caravan, 3.0V6, because he figured that its overheat problem *had* to be either a bad head gasket or cracked head. He had replaced the water pump, several thermostats, flushed everything til he was blue in the face, AND put in a new radiator. He had bought a cheap discount parts store radiator. After finding no breaks in the gaskets and having the machine shop check the heads and tell him that they were fine, the problem was still there. He replaced the radiator AGAIN, this time with a Modine (GOOD BRAND, by the way), and the problem was finally gone. So as they say, you get what you pay for!
Don't skimp on a cheapie.

slantsixram, can you do us a favor and post which site you found that porting info on mild to wild? thanks, ron.