This is my last shot before I pull this engine and start from scratch. The cooling system has been a problem for a while. So far I have replaced the following; rediator, water pump, thermostat, hoses, and radiator cap. I've also flushed the block, bled all of the air out, and did a pressure test to it. The car still runs hot after any length of time at highway speed(65+) Under that speed I can run all day long with no problem. When I say hot, I mean 220 plus. If I get off the highway and go back to intown driving the temp comes back down to about 190. The thermostat is a 195 degree unit. Other than an expensive aluminum racing radiator I don't know what else to do. The engine starts pinging at the higher temps so I'm assuming that it doesn't like running that hot. Please, I'm begging for help!

Don't know what size radiator you have, but my /6 Ford had same problem til I put in a radiator with 1 more core. That might be what you need.

Richard

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Part of Tyrde-Browne Racing

Make sure you aren't missing any air dams or baffles in front of or below the radiator. If the factory installed them, they're required in order to provide adequate airfolow through the radiator. Many newer cars have an air dam at exactly the right height to be ripped off by a parking lot wheel stop or curb, and overheating at speed will result. '73-'93 D and W series trucks have a rubber flap along the bottom of the radiator.

Also make sure there's nothing blocking radiator airflow, such as a license plate or aftermarket lights.

Ken

Check your timing and advance curve.

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

Just got done checking the timing. Its right where the emissions sticker says it should be. It seems that all the airdams and seals that were factory installed are still there. I thought there might be an airdam underneath but there is no evidence of anything like that ever being there. I don't know if I wrote this earlier but its a 79 Aspen wagon. Does anyone know if there is supposed to be an airdam? Again I don't see any evidence of anything missing underneath. The radiator was my next thought. I was trying to exhaust all other options because I just bought this one, and am trying not to start throwing money at it. But if thats all thats left I guess thats the next step. Keep the suggestions coming. I really appreciate any and all ideas.

What kind of fan does it have?

It has a clutch fan. Thats also been checked out and is functioning properly.

Hi nottrndy, do you have radiator hoses with steel spiral inserts? If not, a soft hose may collapse under the suction from the pump at high revs. BTW, no air dams for the Aspen, mine doesn't even have a fan shroud.

Olaf (77 Aspen Wagon)

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Aspenized

Put the thermostat in some boiling water and see when it opens, and how far it opens.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Its impossible to collapse a lower radiator hose if the cooling system is pressurized. Its been many (20+?) years since a new lower hose included a reinforcing spring.

Ken

Did you verify that the timing mark is actually at TDC when it indicates TDC? Its possible for the sheave to slip on the balancer hub, resulting in an erroneous indication. Manually turn the crankshaft to #1 TDC and verify the timing mark.

The emissions sticker setting will have the timing retarded somewhat to reduce emissions. Try advancing it a few degrees.

Have you checked the vacuum advance actuator? Hook up a MityVac or similar hand vacuum pump and verify that it holds vacuum and moves the breaker plate. If it does not, it has a perforated diaphragm and requires replacement. Then connect a vacuum gauge with a tee into the distributor hose to verify the application of vacuum while you are driving.

Also verify that the thermostatic vacuum switches are working and are correctly connected. iirc the distributor doesn't see full vacuum until the engine is warm.

Ken

His problem is at highway speed. Over ~20 mph there is more airflow due to the motion of the vehicle than a fan could provide. The thermostatic clutch limits the fan speed (to ~1500 rpm iirc) in order to reduce its load on the engine.

Ken

do you have an infared thermometer like a raytech? check the radiator temp up down side to side to see if it has a cold spot because of blockages. i had seen one that was brand new reman that was blocked up. same scenario as yours.

When you flushed the block did you remove the plug on the passenger side of the motor towards the back, above and behind the oil filter? If not, flush the block again and remove that plug. If you remove that plug and coolant doesn't come out, then you need to stick a pick or a screwdriver up in that hole and dig the rust crud out until you get a good flow of coolant. This is supposed to be a regular maintenance procedure on the slant six, but not many do it (well, I have never done it )

I would focus on the cooling system first, but you may have another problem. Have you checked for a vacuum leak? It sounds like you may be running very lean. Have you looked at your plug color after a highway run? What carburetor and ignition system do you have? What vehicle is this in?

I was thinking along the same lines as Reed. As soon as I read that it pings when the temp climbs, I started thinking overly lean fuel. A super lean mixture will cause higher exhaust temps as well as pinging. I would imagine a lean mixture (and thus, higher temps) would also be exacerbated by higher engine RPMs.

Also, I noticed someone mention incorrect timing marks on the vibration dampener. Just curious, but does the dampener (generally) only slip the opposite direction of the engine and does that make the timing appear more advanced or retarded (more slippage, more retarded or more slippage, more advanced)?

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'66 Dodge Dart