"Different" kind of overheating

[johnnyzoom]

Been gradually pushing my Comet as a daily driver. After travelling about 10 miles at 70 mph, got stuck in traffic jam today, after about 20 minutes overheated, eventually stalling (heat soak?). Outside temp only about 60 F.

Let cool off and traffic get moving, temp down to about 190 and fine rest of the way home. I've driven it this fast before for about the same length of time, without the immediate stop, and been fine. Handled Florida summer, including stop and go traffic, flawlessly (although not after having been pushed like this). New 3 row rad, hoses, thermostat, water pump.

Is this just too much punishment for a 42 year old car? Would an electric fan have made a difference? Is this a situation kind of like the old Groucho Marx joke "Hey Doc, my arm hurts when I go like this. Doctor: 'Then don't go like that' ".

Probably falls under auto 101 type question, thanks for your help.

 

[wallaka]

Could be heat soak, have you thought about making a heat shield? I have some scrap aluminum laying around and have put some thought into it, but have been too lazy to really worry at it.

 

[JackFish]

I'll toss out an idea or 2 - clogged heater core? Stuck thermostat? Air pocket?
Drag on the engine from some other source, like brakes or bearings?
Is it an automatic?
Did it boil over? Perhaps it's related to the how the guage works? How hot did it get?
My guage regularly reads running temp of 240*, and I have to believe that the gauge might be too sensitive, or not contacting the coolant properly and giving a reading that's more of a cylinder head temp reading than coolant.

 

[johnnyzoom]

I bypassed the heater core and the carb plate way back (Florida car). Yeah it's automatic, no it didn't boil over, car stalled first. I can't vouch 100% for the guage, but there've been no idiosyncrasies (sp?) so far, and I was beginning to get a whiff of that smell when a car's overheating. It also just had that 'feel' of an overheated car, things just not quite right. Gotta plead ignorance on exact temp, but it was about 80% to end of the guage.

Just checked timing last week, 12 BTDC as it's been. I guess if a vehicle is relying on movement to stay cool, that'd be a sign of thermostat or fan not kicking on (fan not applicable here).

Last Feb I had a mechanic replace my exhaust manifold after a month of trying to remove some broken bolts myself. He pulled the head to do it, and replaced the gasket. I wonder if he tightened it correctly, he no longer works at the shop and no one knows where he went! It weeps around 3 and 4, which I've read is not uncommon.

Anybody else push their 200's up around 70mph on a regular basis?

Thanks for the replies

 

[JackFish]

I wonder if he might have put the gasket in flipped wrong?
Yeah, I regularly drive mine on trips at that speed.

 

[addo]

A reversed gasket leaks coolant soon as you fill it - pretty obvious. It's not subtle like some of the bent motors are.

 

[johnnyzoom]

I had a mechanic do it (head gasket) when I was new on here, didn't feel confident enough to do it myself. Now I'd like to, whole point of this car was for me to learn on my own.

Addo or anyone else, can you elaborate or speculate on what I'd likely see if that gasket wasn't tightened correctly? Is the 3 step torque method for the i6 common practice for installing any head gasket (I wonder if he just torqued it once)? Assume the head would warp before the motor would?

Thanks for the replies, I'll leave it alone here now and get to work on it this weekend.

-- Johnny

 

[Anonymous]

i would say a water pump that isnt working 100%

 

[mustang6]

With all the new components you list, I'd say it just wasn't moving enough air at idle to keep up with the heat soak that occured when you were going fast and then had to do the stop and go. I'm assuming none of your new components have failed, but you should still check for belt slippage and proper fan clutch operation (if you have one).

An electric helper fan that only turns on when the temp exceeds a certain threshold (or manually engaged by a switch you flip) would fix this. It's also possible that a good old fan shroud would take care of it as well.

 

[johnnyzoom]

With all the new components you list, I'd say it just wasn't moving enough air at idle to keep up with the heat soak that occured when you were going fast and then had to do the stop and go. I'm assuming none of your new components have failed, but you should still check for belt slippage and proper fan clutch operation (if you have one).

An electric helper fan that only turns on when the temp exceeds a certain threshold (or manually engaged by a switch you flip) would fix this. It's also possible that a good old fan shroud would take care of it as well.

Maybe this is the answer I "wanted" to hear. When the car heats up during normal use, the needle gradually moves right, when it's at about 40% it'll pop back down to about 25%, assuming this is 180F thermostat opening up. Pretty sure I bled coolant correctly when last changed.

Drove same route today at 65 mph and no problems. Seems like the threshold is 70mph. Again, outside temps here are cool, 60-68 degrees.

i would say a water pump that isnt working 100%

Have to plead ignorance on good way to check water pump is working. Start cold with radiator cap off and watch/listen?

 

[addo]

You can also get "stagnation" in airflow, where a portion of the air around a body doesn't move, much or at all. The airflow past your vehicle as you make 70, may in fact beget such a stagnant zone in front of the grille.

 

[falcon60]

You can also get "stagnation" in airflow, where a portion of the air around a body doesn't move, much or at all. The airflow past your vehicle as you make 70, may in fact beget such a stagnant zone in front of the grille.

Addo makes a valid point. I have a Malibu that reacts to just such an airflow situation if the car is driven in a strong cross-wind at highway speeds. Apparently the flow through the rad is reduced under that condition with my car.
I have a hunch that a good shroud (like mustang6 says) may help the problem you're having. It sure sounds like an airflow (or lack of) problem.

Terry

 

[80broncoman]

As to the others saying the pump may not be 100% the car being 42 yrs old, and the pumps being as cheap as they are I stick a new one on it.

You don't by chance have like 10 coats of black paint on your radiator do you. this would in effect insulate and slow air folw down through the rad.

 

[johnnyzoom]

Heat and humidity are a constant battle with cars here in Fla., I made the cooling system a priority when I started on this Comet, everything is new. I wouldn't say there's too much paint on the rad.

Watched that guage like a hawk today on same (last for a while) trip, starts to slowly creep up at 68 mph, to about 50%, never going past that. If there's time to reduce speed, giving it some regular airflow, cools back down immediately. By the way, where have I been going 70 mph at? An 8 mile bridge from Tampa to St. Pete, that is WINDY.

You guys are the best auto-detectives on the internet.

I will triple check everything but concentrate on airflow. I've wanted to put a shroud on there anyway.

Thanks guys

 

[addo]

If you could fabricate a belly pan reaching from the radiator support, to 6" before the firewall, it might assist in creating a vacuum at the rear of your engine bay, below the toeboards.

This would aid in drawing air through the radiator. It's a common practice in newer cars with their streamlined snouts.

 

[johnnyzoom]

Will do that Addo. Also found this old post with some ideas

http://fordsix.com/forum/viewtopic.php? ... ht=airflow

 

[Anonymous]

I was warned about the stamped vs cast h2o pump impeller... as the cheaper stamped impeller doesn't move as much water. I corrected this with a thin piece of stainless riveted to the impeller, effectively making it operate like a cast impeller... simply cut a small disc the diameter of the impeller turbines, and rivet on to the impeller... a simple improvement....

 

[66 Fastback]

Before you go and add electric fans or pans to help direct air flow, go back to the basics.

Have you verified that the harmonic balancer has not slipped by checking TDC of the #1 cyl with the mark on the balancer? You could have a slipped balancer and your indicated timing of 12 degrees may not be what you actually have.

What distributor are you running?
Is it the Load-a-matic?
Does the vacuum cannister hold vacuum?
When vacuum is applied, is it advancing the timing as it should?

If it is a later model distributor with vacuum and centrifugal advance, after you verify that the vacuum cannister is working, you might tie it into manifold vacuum to help the engine cool.

Retarded timing will make an engine run hot. At idle, the vacuum is high and the distributor should have full vacuum advance, which will raise engine rpm's and fan speed to help cool the engine, (assuming the timing is correct).
Doug

 

[66 Fastback]

I forgot to mention that a cause of your engine stalling could be a bad condenser on your points system. I've had those things warm up and die and then have to wait a while before it would cool down and start again.
Doug

 

[Anonymous]

I have had the same problem with my mustang six in southern Cal when I lived there. The car is an automatic and that may have contributed to the overheating problem, trying to cool both with such a small radiator. The radiator will be going into the shop next to have it rebuilt, to take it out of the equation. I am a firm believer in shrouds and am going to try and find one to fabricate for the car. There was talk about electric fans, is this a good way to go? I have heard that it free's up some horse power.